From patchwork Mon Nov 23 15:42:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Earnshaw X-Patchwork-Id: 41151 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 496753870849; Mon, 23 Nov 2020 15:42:59 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 496753870849 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1606146179; bh=iyAxtJpIrnA/IQl50qDp5A0xmaQ+vbCqmYAjIOHxe6U=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=v6sH87Zp7N5sY6JzOIgnGIWXE3Bgxedbz+wKRazbfi6ff/c+CmcFFOvA0VnMtHKoC qjhRUMI3YQPRfTdcD2zgZswyzWDBmv2osUNWA84AVzhDhZlwl97Q5wv++BEKgKM1Tn R7xpWdU5TaXj3haahd2vOQBSnc/PE/49LHEu9YJU= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id 15D7F386F818 for ; Mon, 23 Nov 2020 15:42:54 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 15D7F386F818 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C823D143D; Mon, 23 Nov 2020 07:42:53 -0800 (PST) Received: from eagle.buzzard.freeserve.co.uk (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1D4113F718; Mon, 23 Nov 2020 07:42:53 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v3 1/8] config: Allow memory tagging to be enabled when configuring glibc Date: Mon, 23 Nov 2020 15:42:29 +0000 Message-Id: <20201123154236.25809-2-rearnsha@arm.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123154236.25809-1-rearnsha@arm.com> References: <20201123154236.25809-1-rearnsha@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-13.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Earnshaw via Libc-alpha From: Richard Earnshaw Reply-To: Richard Earnshaw Cc: Richard Earnshaw Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" This patch adds the configuration machinery to allow memory tagging to be enabled from the command line via the configure option --enable-memory-tagging. The current default is off, though in time we may change that once the API is more stable. --- INSTALL | 14 ++++++++++++++ config.h.in | 3 +++ config.make.in | 2 ++ configure | 17 +++++++++++++++++ configure.ac | 10 ++++++++++ manual/install.texi | 13 +++++++++++++ 6 files changed, 59 insertions(+) diff --git a/INSTALL b/INSTALL index 2b00f80df5..f2476df6c0 100644 --- a/INSTALL +++ b/INSTALL @@ -142,6 +142,20 @@ if 'CFLAGS' is specified it must enable optimization. For example: non-CET processors. '--enable-cet' has been tested for i686, x86_64 and x32 on CET processors. +'--enable-memory-tagging' + Enable memory tagging support on architectures that support it. + When the GNU C Library is built with this option then the resulting + library will be able to control the use of tagged memory when + hardware support is present by use of the tunable + 'glibc.memtag.enable'. This includes the generation of tagged + memory when using the 'malloc' APIs. + + At present only AArch64 platforms with MTE provide this + functionality, although the library will still operate (without + memory tagging) on older versions of the architecture. + + The default is to disable support for memory tagging. + '--disable-profile' Don't build libraries with profiling information. You may want to use this option if you don't plan to do profiling. diff --git a/config.h.in b/config.h.in index b823c8e080..2f4c626c19 100644 --- a/config.h.in +++ b/config.h.in @@ -160,6 +160,9 @@ /* Define if __stack_chk_guard canary should be randomized at program startup. */ #undef ENABLE_STACKGUARD_RANDOMIZE +/* Define if memory tagging support should be enabled. */ +#undef _LIBC_MTAG + /* Package description. */ #undef PKGVERSION diff --git a/config.make.in b/config.make.in index 1ac9417245..7ae27564fd 100644 --- a/config.make.in +++ b/config.make.in @@ -84,6 +84,8 @@ mach-interface-list = @mach_interface_list@ experimental-malloc = @experimental_malloc@ +memory-tagging = @memory_tagging@ + nss-crypt = @libc_cv_nss_crypt@ static-nss-crypt = @libc_cv_static_nss_crypt@ diff --git a/configure b/configure index 4795e721e5..d22654739f 100755 --- a/configure +++ b/configure @@ -676,6 +676,7 @@ build_nscd libc_cv_static_nss_crypt libc_cv_nss_crypt build_crypt +memory_tagging experimental_malloc enable_werror all_warnings @@ -781,6 +782,7 @@ enable_all_warnings enable_werror enable_multi_arch enable_experimental_malloc +enable_memory_tagging enable_crypt enable_nss_crypt enable_systemtap @@ -1450,6 +1452,8 @@ Optional Features: architectures --disable-experimental-malloc disable experimental malloc features + --enable-memory-tagging enable memory tagging if supported by the + architecture [default=no] --disable-crypt do not build nor install the passphrase hashing library, libcrypt --enable-nss-crypt enable libcrypt to use nss @@ -3519,6 +3523,19 @@ fi +# Check whether --enable-memory-tagging was given. +if test "${enable_memory_tagging+set}" = set; then : + enableval=$enable_memory_tagging; memory_tagging=$enableval +else + memory_tagging=no +fi + +if test "$memory_tagging" = yes; then + $as_echo "#define _LIBC_MTAG 1" >>confdefs.h + +fi + + # Check whether --enable-crypt was given. if test "${enable_crypt+set}" = set; then : enableval=$enable_crypt; build_crypt=$enableval diff --git a/configure.ac b/configure.ac index 93e68fb696..78af01d05b 100644 --- a/configure.ac +++ b/configure.ac @@ -311,6 +311,16 @@ AC_ARG_ENABLE([experimental-malloc], [experimental_malloc=yes]) AC_SUBST(experimental_malloc) +AC_ARG_ENABLE([memory-tagging], + AC_HELP_STRING([--enable-memory-tagging], + [enable memory tagging if supported by the architecture @<:@default=no@:>@]), + [memory_tagging=$enableval], + [memory_tagging=no]) +if test "$memory_tagging" = yes; then + AC_DEFINE(_LIBC_MTAG) +fi +AC_SUBST(memory_tagging) + AC_ARG_ENABLE([crypt], AC_HELP_STRING([--disable-crypt], [do not build nor install the passphrase hashing library, libcrypt]), diff --git a/manual/install.texi b/manual/install.texi index 2e164476d5..30fb6aaa46 100644 --- a/manual/install.texi +++ b/manual/install.texi @@ -171,6 +171,19 @@ NOTE: @option{--enable-cet} has been tested for i686, x86_64 and x32 on non-CET processors. @option{--enable-cet} has been tested for i686, x86_64 and x32 on CET processors. +@item --enable-memory-tagging +Enable memory tagging support on architectures that support it. When +@theglibc{} is built with this option then the resulting library will +be able to control the use of tagged memory when hardware support is +present by use of the tunable @samp{glibc.memtag.enable}. This includes +the generation of tagged memory when using the @code{malloc} APIs. + +At present only AArch64 platforms with MTE provide this functionality, +although the library will still operate (without memory tagging) on +older versions of the architecture. + +The default is to disable support for memory tagging. + @item --disable-profile Don't build libraries with profiling information. You may want to use this option if you don't plan to do profiling. From patchwork Mon Nov 23 15:42:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Earnshaw X-Patchwork-Id: 41150 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id B81B9386F822; Mon, 23 Nov 2020 15:42:58 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org B81B9386F822 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1606146178; bh=33xB7d/YwiO1DdVZZZJE2ohK2Wfe38XoUkzukfPmjRE=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=N/YmM/4o/5N472x5axPNhFG1FBKMq5JTMm5NRYQsjuJYk7ZxyzSDHettcJ9WSX4Qf g/Y4B+LydGSbnCBYwPLf2537kwMVYFIGhUBjbKvHFv8PdUYrLtpACQUyRVw6QjtJ6D YOEwSm8yyhNJoHVyJr6DMLImPvrjlGKbEdPykOGw= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id 20A9C386F81C for ; Mon, 23 Nov 2020 15:42:55 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 20A9C386F81C Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B59DE1478; Mon, 23 Nov 2020 07:42:54 -0800 (PST) Received: from eagle.buzzard.freeserve.co.uk (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0A42C3F718; Mon, 23 Nov 2020 07:42:53 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v3 2/8] elf: Add a tunable to control use of tagged memory Date: Mon, 23 Nov 2020 15:42:30 +0000 Message-Id: <20201123154236.25809-3-rearnsha@arm.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123154236.25809-1-rearnsha@arm.com> References: <20201123154236.25809-1-rearnsha@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-13.8 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Earnshaw via Libc-alpha From: Richard Earnshaw Reply-To: Richard Earnshaw Cc: Richard Earnshaw Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Add a new glibc tunable: mtag.enable, bound to the environment variable _MTAG_ENABLE. This is a decimal constant in the range 0-255 but used as a bit-field. Bit 0 enables use of tagged memory in the malloc family of functions. Bit 1 enables precise faulting of tag failure on platforms where this can be controlled. Other bits are currently unused, but if set will cause memory tag checking for the current process to be enabled in the kernel. Reviewed-by: Siddhesh Poyarekar --- elf/dl-tunables.list | 9 +++++++++ manual/tunables.texi | 31 +++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+) diff --git a/elf/dl-tunables.list b/elf/dl-tunables.list index e1d8225128..652cadc334 100644 --- a/elf/dl-tunables.list +++ b/elf/dl-tunables.list @@ -141,4 +141,13 @@ glibc { default: 512 } } + +memtag { + enable { + type: INT_32 + minval: 0 + maxval: 255 + env_alias: _MTAG_ENABLE + } + } } diff --git a/manual/tunables.texi b/manual/tunables.texi index d72d7a5ec0..6ab432a73f 100644 --- a/manual/tunables.texi +++ b/manual/tunables.texi @@ -36,6 +36,8 @@ their own namespace. * POSIX Thread Tunables:: Tunables in the POSIX thread subsystem * Hardware Capability Tunables:: Tunables that modify the hardware capabilities seen by @theglibc{} +* Memory Tagging Tunables:: Tunables that control the use of hardware + memory tagging @end menu @node Tunable names @@ -484,3 +486,32 @@ instead. This tunable is specific to i386 and x86-64. @end deftp + +@node Memory Tagging Tunables +@section Memory Tagging Tunables +@cindex memory tagging tunables + +@deftp {Tunable namespace} glibc.memtag +If the hardware supports memory tagging, these tunables can be used to +control the way @theglibc{} uses this feature. Currently, only AArch64 +supports this feature. +@end deftp + +@deftp Tunable glibc.memtag.enable +This tunable takes a value between 0 and 255 and acts as a bitmask +that enables various capabilities. + +Bit 0 (the least significant bit) causes the malloc subsystem to allocate +tagged memory, with each allocation being assigned a random tag. + +Bit 1 enables precise faulting mode for tag violations on systems that +support deferred tag violation reporting. This may cause programs +to run more slowly. + +Other bits are currently reserved. + +@Theglibc{} startup code will automatically enable memory tagging +support in the kernel if this tunable has any non-zero value. + +The default value is @samp{0}, which disables all memory tagging. +@end deftp From patchwork Mon Nov 23 15:42:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Earnshaw X-Patchwork-Id: 41154 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 779EE3870892; Mon, 23 Nov 2020 15:43:01 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 779EE3870892 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1606146181; bh=79ONgYQwYSta4Z96BFGh+fK4eFQtAfGFF7rit9cSMhY=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=sbv3/NJTlRu79Y/1sKdvpTfFv/j2cN4ZZeRmpWorvthL/xhgkaCoLo1sH+eSPEjXn epojLxihZhqdvFgrvrrE52sFfjvUBKNtHqtGWNvcw7xqbRI8E2fL9ouAP26BWCGf2e X7hYf98Gjxj9U5EcetsmGIqyBT5wxaPPMMCFmSvc= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id 49478386F81F for ; Mon, 23 Nov 2020 15:42:56 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 49478386F81F Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DCEBE1480; Mon, 23 Nov 2020 07:42:55 -0800 (PST) Received: from eagle.buzzard.freeserve.co.uk (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EDD7F3F718; Mon, 23 Nov 2020 07:42:54 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v3 3/8] malloc: Basic support for memory tagging in the malloc() family Date: Mon, 23 Nov 2020 15:42:31 +0000 Message-Id: <20201123154236.25809-4-rearnsha@arm.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123154236.25809-1-rearnsha@arm.com> References: <20201123154236.25809-1-rearnsha@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-14.0 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, KAM_SHORT, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Earnshaw via Libc-alpha From: Richard Earnshaw Reply-To: Richard Earnshaw Cc: Richard Earnshaw Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" This patch adds the basic support for memory tagging. Various flavours are supported, particularly being able to turn on tagged memory at run-time: this allows the same code to be used on systems where memory tagging support is not present without neededing a separate build of glibc. Also, depending on whether the kernel supports it, the code will use mmap for the default arena if morecore does not, or cannot support tagged memory (on AArch64 it is not available). All the hooks use function pointers to allow this to work without needing ifuncs. malloc: allow memory tagging to be controlled from a tunable --- malloc/arena.c | 43 ++++++++- malloc/hooks.c | 6 ++ malloc/malloc.c | 186 ++++++++++++++++++++++++++++-------- malloc/malloc.h | 7 ++ sysdeps/generic/libc-mtag.h | 52 ++++++++++ 5 files changed, 252 insertions(+), 42 deletions(-) create mode 100644 sysdeps/generic/libc-mtag.h diff --git a/malloc/arena.c b/malloc/arena.c index 202daf15b0..835fcc0fb3 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -274,17 +274,36 @@ next_env_entry (char ***position) #endif -#ifdef SHARED +#if defined(SHARED) || defined(_LIBC_MTAG) static void * __failing_morecore (ptrdiff_t d) { return (void *) MORECORE_FAILURE; } +#endif +#ifdef SHARED extern struct dl_open_hook *_dl_open_hook; libc_hidden_proto (_dl_open_hook); #endif +#ifdef _LIBC_MTAG +static void * +__mtag_tag_new_usable (void *ptr) +{ + if (ptr) + ptr = __libc_mtag_tag_region (__libc_mtag_new_tag (ptr), + __malloc_usable_size (ptr)); + return ptr; +} + +static void * +__mtag_tag_new_memset (void *ptr, int val, size_t size) +{ + return __libc_mtag_memset_with_tag (__libc_mtag_new_tag (ptr), val, size); +} +#endif + static void ptmalloc_init (void) { @@ -293,6 +312,24 @@ ptmalloc_init (void) __malloc_initialized = 0; +#ifdef _LIBC_MTAG + if ((TUNABLE_GET_FULL (glibc, memtag, enable, int32_t, NULL) & 1) != 0) + { + /* If the environment says that we should be using tagged memory + and that morecore does not support tagged regions, then + disable it. */ + if (__MTAG_SBRK_UNTAGGED) + __morecore = __failing_morecore; + + __mtag_mmap_flags = __MTAG_MMAP_FLAGS; + __tag_new_memset = __mtag_tag_new_memset; + __tag_region = __libc_mtag_tag_region; + __tag_new_usable = __mtag_tag_new_usable; + __tag_at = __libc_mtag_address_get_tag; + __mtag_granule_mask = ~(size_t)(__MTAG_GRANULE_SIZE - 1); + } +#endif + #ifdef SHARED /* In case this libc copy is in a non-default namespace, never use brk. Likewise if dlopened from statically linked program. */ @@ -512,7 +549,7 @@ new_heap (size_t size, size_t top_pad) } } } - if (__mprotect (p2, size, PROT_READ | PROT_WRITE) != 0) + if (__mprotect (p2, size, MTAG_MMAP_FLAGS | PROT_READ | PROT_WRITE) != 0) { __munmap (p2, HEAP_MAX_SIZE); return 0; @@ -542,7 +579,7 @@ grow_heap (heap_info *h, long diff) { if (__mprotect ((char *) h + h->mprotect_size, (unsigned long) new_size - h->mprotect_size, - PROT_READ | PROT_WRITE) != 0) + MTAG_MMAP_FLAGS | PROT_READ | PROT_WRITE) != 0) return -2; h->mprotect_size = new_size; diff --git a/malloc/hooks.c b/malloc/hooks.c index a2b93e5446..52bb3863cd 100644 --- a/malloc/hooks.c +++ b/malloc/hooks.c @@ -56,6 +56,12 @@ static int using_malloc_checking; void __malloc_check_init (void) { +#if HAVE_TUNABLES && defined (_LIBC_MTAG) + /* If memory tagging is enabled, there is no need for the boundary + checking cookie as well. */ + if ((TUNABLE_GET_FULL (glibc, memtag, enable, int32_t, NULL) & 1) != 0) + return; +#endif using_malloc_checking = 1; __malloc_hook = malloc_check; __free_hook = free_check; diff --git a/malloc/malloc.c b/malloc/malloc.c index 5b87bdb081..b866e87bc3 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -242,6 +242,9 @@ /* For DIAG_PUSH/POP_NEEDS_COMMENT et al. */ #include +/* For memory tagging. */ +#include + #include /* For SINGLE_THREAD_P. */ @@ -378,6 +381,52 @@ __malloc_assert (const char *assertion, const char *file, unsigned int line, void * __default_morecore (ptrdiff_t); void *(*__morecore)(ptrdiff_t) = __default_morecore; +#ifdef _LIBC_MTAG +static void * +__default_tag_region (void *ptr, size_t size) +{ + return ptr; +} + +static void * +__default_tag_nop (void *ptr) +{ + return ptr; +} + +static int __mtag_mmap_flags = 0; +static size_t __mtag_granule_mask = ~(size_t)0; + +static void *(*__tag_new_memset)(void *, int, size_t) = memset; +static void *(*__tag_region)(void *, size_t) = __default_tag_region; +static void *(*__tag_new_usable)(void *) = __default_tag_nop; +static void *(*__tag_at)(void *) = __default_tag_nop; + +# define TAG_NEW_MEMSET(ptr, val, size) __tag_new_memset (ptr, val, size) +# define TAG_REGION(ptr, size) __tag_region (ptr, size) +# define TAG_NEW_USABLE(ptr) __tag_new_usable (ptr) +# define TAG_AT(ptr) __tag_at (ptr) +#else +# define TAG_NEW_MEMSET(ptr, val, size) memset (ptr, val, size) +# define TAG_REGION(ptr, size) (ptr) +# define TAG_NEW_USABLE(ptr) (ptr) +# define TAG_AT(ptr) (ptr) +#endif + +/* When using tagged memory, we cannot share the end of the user block + with the header for the next chunk, so ensure that we allocate + blocks that are rounded up to the granule size. Take care not to + overflow from close to MAX_SIZE_T to a small number. */ +static inline size_t +ROUND_UP_ALLOCATION_SIZE(size_t bytes) +{ +#ifdef _LIBC_MTAG + return (bytes + ~__mtag_granule_mask) & __mtag_granule_mask; +#else + return bytes; +#endif +} + #include @@ -1187,8 +1236,9 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ /* conversion from malloc headers to user pointers, and back */ -#define chunk2mem(p) ((void*)((char*)(p) + 2*SIZE_SZ)) -#define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ)) +#define chunk2mem(p) ((void*)TAG_AT (((char*)(p) + 2*SIZE_SZ))) +#define chunk2rawmem(p) ((void*)((char*)(p) + 2*SIZE_SZ)) +#define mem2chunk(mem) ((mchunkptr)TAG_AT (((char*)(mem) - 2*SIZE_SZ))) /* The smallest possible chunk */ #define MIN_CHUNK_SIZE (offsetof(struct malloc_chunk, fd_nextsize)) @@ -1222,6 +1272,7 @@ checked_request2size (size_t req, size_t *sz) __nonnull (1) { if (__glibc_unlikely (req > PTRDIFF_MAX)) return false; + req = ROUND_UP_ALLOCATION_SIZE (req); *sz = request2size (req); return true; } @@ -1967,7 +2018,7 @@ do_check_chunk (mstate av, mchunkptr p) /* chunk is page-aligned */ assert (((prev_size (p) + sz) & (GLRO (dl_pagesize) - 1)) == 0); /* mem is aligned */ - assert (aligned_OK (chunk2mem (p))); + assert (aligned_OK (chunk2rawmem (p))); } } @@ -1991,7 +2042,7 @@ do_check_free_chunk (mstate av, mchunkptr p) if ((unsigned long) (sz) >= MINSIZE) { assert ((sz & MALLOC_ALIGN_MASK) == 0); - assert (aligned_OK (chunk2mem (p))); + assert (aligned_OK (chunk2rawmem (p))); /* ... matching footer field */ assert (prev_size (next_chunk (p)) == sz); /* ... and is fully consolidated */ @@ -2070,7 +2121,7 @@ do_check_remalloced_chunk (mstate av, mchunkptr p, INTERNAL_SIZE_T s) assert ((sz & MALLOC_ALIGN_MASK) == 0); assert ((unsigned long) (sz) >= MINSIZE); /* ... and alignment */ - assert (aligned_OK (chunk2mem (p))); + assert (aligned_OK (chunk2rawmem (p))); /* chunk is less than MINSIZE more than request */ assert ((long) (sz) - (long) (s) >= 0); assert ((long) (sz) - (long) (s + MINSIZE) < 0); @@ -2325,7 +2376,8 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) /* Don't try if size wraps around 0 */ if ((unsigned long) (size) > (unsigned long) (nb)) { - mm = (char *) (MMAP (0, size, PROT_READ | PROT_WRITE, 0)); + mm = (char *) (MMAP (0, size, + MTAG_MMAP_FLAGS | PROT_READ | PROT_WRITE, 0)); if (mm != MAP_FAILED) { @@ -2339,14 +2391,14 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) if (MALLOC_ALIGNMENT == 2 * SIZE_SZ) { - /* For glibc, chunk2mem increases the address by 2*SIZE_SZ and + /* For glibc, chunk2rawmem increases the address by 2*SIZE_SZ and MALLOC_ALIGN_MASK is 2*SIZE_SZ-1. Each mmap'ed area is page aligned and therefore definitely MALLOC_ALIGN_MASK-aligned. */ - assert (((INTERNAL_SIZE_T) chunk2mem (mm) & MALLOC_ALIGN_MASK) == 0); + assert (((INTERNAL_SIZE_T) chunk2rawmem (mm) & MALLOC_ALIGN_MASK) == 0); front_misalign = 0; } else - front_misalign = (INTERNAL_SIZE_T) chunk2mem (mm) & MALLOC_ALIGN_MASK; + front_misalign = (INTERNAL_SIZE_T) chunk2rawmem (mm) & MALLOC_ALIGN_MASK; if (front_misalign > 0) { correction = MALLOC_ALIGNMENT - front_misalign; @@ -2518,7 +2570,9 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) /* Don't try if size wraps around 0 */ if ((unsigned long) (size) > (unsigned long) (nb)) { - char *mbrk = (char *) (MMAP (0, size, PROT_READ | PROT_WRITE, 0)); + char *mbrk = (char *) (MMAP (0, size, + MTAG_MMAP_FLAGS | PROT_READ | PROT_WRITE, + 0)); if (mbrk != MAP_FAILED) { @@ -2589,7 +2643,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) /* Guarantee alignment of first new chunk made from this space */ - front_misalign = (INTERNAL_SIZE_T) chunk2mem (brk) & MALLOC_ALIGN_MASK; + front_misalign = (INTERNAL_SIZE_T) chunk2rawmem (brk) & MALLOC_ALIGN_MASK; if (front_misalign > 0) { /* @@ -2647,10 +2701,10 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) { if (MALLOC_ALIGNMENT == 2 * SIZE_SZ) /* MORECORE/mmap must correctly align */ - assert (((unsigned long) chunk2mem (brk) & MALLOC_ALIGN_MASK) == 0); + assert (((unsigned long) chunk2rawmem (brk) & MALLOC_ALIGN_MASK) == 0); else { - front_misalign = (INTERNAL_SIZE_T) chunk2mem (brk) & MALLOC_ALIGN_MASK; + front_misalign = (INTERNAL_SIZE_T) chunk2rawmem (brk) & MALLOC_ALIGN_MASK; if (front_misalign > 0) { /* @@ -2835,7 +2889,7 @@ munmap_chunk (mchunkptr p) if (DUMPED_MAIN_ARENA_CHUNK (p)) return; - uintptr_t mem = (uintptr_t) chunk2mem (p); + uintptr_t mem = (uintptr_t) chunk2rawmem (p); uintptr_t block = (uintptr_t) p - prev_size (p); size_t total_size = prev_size (p) + size; /* Unfortunately we have to do the compilers job by hand here. Normally @@ -2890,7 +2944,7 @@ mremap_chunk (mchunkptr p, size_t new_size) p = (mchunkptr) (cp + offset); - assert (aligned_OK (chunk2mem (p))); + assert (aligned_OK (chunk2rawmem (p))); assert (prev_size (p) == offset); set_head (p, (new_size - offset) | IS_MMAPPED); @@ -3071,14 +3125,15 @@ __libc_malloc (size_t bytes) && tcache && tcache->counts[tc_idx] > 0) { - return tcache_get (tc_idx); + victim = tcache_get (tc_idx); + return TAG_NEW_USABLE (victim); } DIAG_POP_NEEDS_COMMENT; #endif if (SINGLE_THREAD_P) { - victim = _int_malloc (&main_arena, bytes); + victim = TAG_NEW_USABLE (_int_malloc (&main_arena, bytes)); assert (!victim || chunk_is_mmapped (mem2chunk (victim)) || &main_arena == arena_for_chunk (mem2chunk (victim))); return victim; @@ -3099,6 +3154,8 @@ __libc_malloc (size_t bytes) if (ar_ptr != NULL) __libc_lock_unlock (ar_ptr->mutex); + victim = TAG_NEW_USABLE (victim); + assert (!victim || chunk_is_mmapped (mem2chunk (victim)) || ar_ptr == arena_for_chunk (mem2chunk (victim))); return victim; @@ -3122,8 +3179,17 @@ __libc_free (void *mem) if (mem == 0) /* free(0) has no effect */ return; +#ifdef _LIBC_MTAG + /* Quickly check that the freed pointer matches the tag for the memory. + This gives a useful double-free detection. */ + *(volatile char *)mem; +#endif + p = mem2chunk (mem); + /* Mark the chunk as belonging to the library again. */ + (void)TAG_REGION (chunk2rawmem (p), __malloc_usable_size (mem)); + if (chunk_is_mmapped (p)) /* release mmapped memory. */ { /* See if the dynamic brk/mmap threshold needs adjusting. @@ -3173,6 +3239,12 @@ __libc_realloc (void *oldmem, size_t bytes) if (oldmem == 0) return __libc_malloc (bytes); +#ifdef _LIBC_MTAG + /* Perform a quick check to ensure that the pointer's tag matches the + memory's tag. */ + *(volatile char*) oldmem; +#endif + /* chunk corresponding to oldmem */ const mchunkptr oldp = mem2chunk (oldmem); /* its size */ @@ -3228,7 +3300,15 @@ __libc_realloc (void *oldmem, size_t bytes) #if HAVE_MREMAP newp = mremap_chunk (oldp, nb); if (newp) - return chunk2mem (newp); + { + void *newmem = chunk2rawmem (newp); + /* Give the new block a different tag. This helps to ensure + that stale handles to the previous mapping are not + reused. There's a performance hit for both us and the + caller for doing this, so we might want to + reconsider. */ + return TAG_NEW_USABLE (newmem); + } #endif /* Note the extra SIZE_SZ overhead. */ if (oldsize - SIZE_SZ >= nb) @@ -3311,7 +3391,6 @@ _mid_memalign (size_t alignment, size_t bytes, void *address) return 0; } - /* Make sure alignment is power of 2. */ if (!powerof2 (alignment)) { @@ -3326,8 +3405,7 @@ _mid_memalign (size_t alignment, size_t bytes, void *address) p = _int_memalign (&main_arena, alignment, bytes); assert (!p || chunk_is_mmapped (mem2chunk (p)) || &main_arena == arena_for_chunk (mem2chunk (p))); - - return p; + return TAG_NEW_USABLE (p); } arena_get (ar_ptr, bytes + alignment + MINSIZE); @@ -3345,7 +3423,7 @@ _mid_memalign (size_t alignment, size_t bytes, void *address) assert (!p || chunk_is_mmapped (mem2chunk (p)) || ar_ptr == arena_for_chunk (mem2chunk (p))); - return p; + return TAG_NEW_USABLE (p); } /* For ISO C11. */ weak_alias (__libc_memalign, aligned_alloc) @@ -3354,17 +3432,22 @@ libc_hidden_def (__libc_memalign) void * __libc_valloc (size_t bytes) { + void *p; + if (__malloc_initialized < 0) ptmalloc_init (); void *address = RETURN_ADDRESS (0); size_t pagesize = GLRO (dl_pagesize); - return _mid_memalign (pagesize, bytes, address); + p = _mid_memalign (pagesize, bytes, address); + return TAG_NEW_USABLE (p); } void * __libc_pvalloc (size_t bytes) { + void *p; + if (__malloc_initialized < 0) ptmalloc_init (); @@ -3381,19 +3464,22 @@ __libc_pvalloc (size_t bytes) } rounded_bytes = rounded_bytes & -(pagesize - 1); - return _mid_memalign (pagesize, rounded_bytes, address); + p = _mid_memalign (pagesize, rounded_bytes, address); + return TAG_NEW_USABLE (p); } void * __libc_calloc (size_t n, size_t elem_size) { mstate av; - mchunkptr oldtop, p; - INTERNAL_SIZE_T sz, csz, oldtopsize; + mchunkptr oldtop; + INTERNAL_SIZE_T sz, oldtopsize; void *mem; +#ifndef _LIBC_MTAG unsigned long clearsize; unsigned long nclears; INTERNAL_SIZE_T *d; +#endif ptrdiff_t bytes; if (__glibc_unlikely (__builtin_mul_overflow (n, elem_size, &bytes))) @@ -3401,6 +3487,7 @@ __libc_calloc (size_t n, size_t elem_size) __set_errno (ENOMEM); return NULL; } + sz = bytes; void *(*hook) (size_t, const void *) = @@ -3470,7 +3557,14 @@ __libc_calloc (size_t n, size_t elem_size) if (mem == 0) return 0; - p = mem2chunk (mem); + /* If we are using memory tagging, then we need to set the tags + regardless of MORECORE_CLEARS, so we zero the whole block while + doing so. */ +#ifdef _LIBC_MTAG + return TAG_NEW_MEMSET (mem, 0, __malloc_usable_size (mem)); +#else + mchunkptr p = mem2chunk (mem); + INTERNAL_SIZE_T csz = chunksize (p); /* Two optional cases in which clearing not necessary */ if (chunk_is_mmapped (p)) @@ -3481,8 +3575,6 @@ __libc_calloc (size_t n, size_t elem_size) return mem; } - csz = chunksize (p); - #if MORECORE_CLEARS if (perturb_byte == 0 && (p == oldtop && csz > oldtopsize)) { @@ -3525,6 +3617,7 @@ __libc_calloc (size_t n, size_t elem_size) } return mem; +#endif } /* @@ -4621,7 +4714,7 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, av->top = chunk_at_offset (oldp, nb); set_head (av->top, (newsize - nb) | PREV_INUSE); check_inuse_chunk (av, oldp); - return chunk2mem (oldp); + return TAG_NEW_USABLE (chunk2rawmem (oldp)); } /* Try to expand forward into next chunk; split off remainder below */ @@ -4654,7 +4747,10 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, } else { - memcpy (newmem, chunk2mem (oldp), oldsize - SIZE_SZ); + void *oldmem = chunk2mem (oldp); + newmem = TAG_NEW_USABLE (newmem); + memcpy (newmem, oldmem, __malloc_usable_size (oldmem)); + (void) TAG_REGION (chunk2rawmem (oldp), oldsize); _int_free (av, oldp, 1); check_inuse_chunk (av, newp); return chunk2mem (newp); @@ -4676,6 +4772,8 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, else /* split remainder */ { remainder = chunk_at_offset (newp, nb); + /* Clear any user-space tags before writing the header. */ + remainder = TAG_REGION (remainder, remainder_size); set_head_size (newp, nb | (av != &main_arena ? NON_MAIN_ARENA : 0)); set_head (remainder, remainder_size | PREV_INUSE | (av != &main_arena ? NON_MAIN_ARENA : 0)); @@ -4685,8 +4783,8 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, } check_inuse_chunk (av, newp); - return chunk2mem (newp); -} + return TAG_NEW_USABLE (chunk2rawmem (newp)); + } /* ------------------------------ memalign ------------------------------ @@ -4763,7 +4861,7 @@ _int_memalign (mstate av, size_t alignment, size_t bytes) p = newp; assert (newsize >= nb && - (((unsigned long) (chunk2mem (p))) % alignment) == 0); + (((unsigned long) (chunk2rawmem (p))) % alignment) == 0); } /* Also give back spare room at the end */ @@ -4817,7 +4915,7 @@ mtrim (mstate av, size_t pad) + sizeof (struct malloc_chunk) + psm1) & ~psm1); - assert ((char *) chunk2mem (p) + 4 * SIZE_SZ <= paligned_mem); + assert ((char *) chunk2rawmem (p) + 4 * SIZE_SZ <= paligned_mem); assert ((char *) p + size > paligned_mem); /* This is the size we could potentially free. */ @@ -4880,20 +4978,30 @@ musable (void *mem) mchunkptr p; if (mem != 0) { + size_t result = 0; + p = mem2chunk (mem); if (__builtin_expect (using_malloc_checking == 1, 0)) - return malloc_check_get_size (p); + return malloc_check_get_size (p); if (chunk_is_mmapped (p)) { if (DUMPED_MAIN_ARENA_CHUNK (p)) - return chunksize (p) - SIZE_SZ; + result = chunksize (p) - SIZE_SZ; else - return chunksize (p) - 2 * SIZE_SZ; + result = chunksize (p) - 2 * SIZE_SZ; } else if (inuse (p)) - return chunksize (p) - SIZE_SZ; + result = chunksize (p) - SIZE_SZ; + +#ifdef _LIBC_MTAG + /* The usable space may be reduced if memory tagging is needed, + since we cannot share the user-space data with malloc's internal + data structure. */ + result &= __mtag_granule_mask; +#endif + return result; } return 0; } diff --git a/malloc/malloc.h b/malloc/malloc.h index b2371f7704..cf8827e520 100644 --- a/malloc/malloc.h +++ b/malloc/malloc.h @@ -77,6 +77,13 @@ extern void *pvalloc (size_t __size) __THROW __attribute_malloc__ __wur; contiguous pieces of memory. */ extern void *(*__morecore) (ptrdiff_t __size) __MALLOC_DEPRECATED; +#ifdef _LIBC_MTAG +extern int __mtag_mmap_flags; +#define MTAG_MMAP_FLAGS __mtag_mmap_flags +#else +#define MTAG_MMAP_FLAGS 0 +#endif + /* Default value of `__morecore'. */ extern void *__default_morecore (ptrdiff_t __size) __THROW __attribute_malloc__ __MALLOC_DEPRECATED; diff --git a/sysdeps/generic/libc-mtag.h b/sysdeps/generic/libc-mtag.h new file mode 100644 index 0000000000..3e9885451c --- /dev/null +++ b/sysdeps/generic/libc-mtag.h @@ -0,0 +1,52 @@ +/* libc-internal interface for tagged (colored) memory support. + Copyright (C) 2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#ifndef _GENERIC_LIBC_MTAG_H +#define _GENERIC_LIBC_MTAG_H 1 + +/* Generic bindings for systems that do not support memory tagging. */ + +/* Used to ensure additional alignment when objects need to have distinct + tags. */ +#define __MTAG_GRANULE_SIZE 1 + +/* Non-zero if memory obtained via morecore (sbrk) is not tagged. */ +#define __MTAG_SBRK_UNTAGGED 0 + +/* Extra flags to pass to mmap() to request a tagged region of memory. */ +#define __MTAG_MMAP_FLAGS 0 + +/* Set the tags for a region of memory, which must have size and alignment + that are multiples of __MTAG_GRANULE_SIZE. Size cannot be zero. + void *__libc_mtag_tag_region (const void *, size_t) */ +#define __libc_mtag_tag_region(p, s) (p) + +/* Optimized equivalent to __libc_mtag_tag_region followed by memset. */ +#define __libc_mtag_memset_with_tag memset + +/* Convert address P to a pointer that is tagged correctly for that + location. + void *__libc_mtag_address_get_tag (void*) */ +#define __libc_mtag_address_get_tag(p) (p) + +/* Assign a new (random) tag to a pointer P (does not adjust the tag on + the memory addressed). + void *__libc_mtag_new_tag (void*) */ +#define __libc_mtag_new_tag(p) (p) + +#endif /* _GENERIC_LIBC_MTAG_H */ From patchwork Mon Nov 23 15:42:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Earnshaw X-Patchwork-Id: 41153 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id E58AF386F825; Mon, 23 Nov 2020 15:43:00 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org E58AF386F825 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1606146181; bh=dk1oOCp024lGIJEoomSIIBQm6VbjKpShF4O/stQ4sKA=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=X5JwXfMqBkpE5JZfiqS1U60CMjgdixGfawz1L9ysnOtSmBpvgy7a6mgF2eeHnfJvE rIcUkl5Rz6RMYgb6iTP8efD3sZdLAjZl26/Doyh9pF2AwmKPESvJMILfC62e9g0fod eaBTL4/aVdmbhE9ho/XfBodlFUDCw4AfcOyp0xD0= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id 19CF3386F81C for ; Mon, 23 Nov 2020 15:42:57 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 19CF3386F81C Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CC43914BF; Mon, 23 Nov 2020 07:42:56 -0800 (PST) Received: from eagle.buzzard.freeserve.co.uk (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1F4073F718; Mon, 23 Nov 2020 07:42:56 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v3 4/8] malloc: Clean up commentary Date: Mon, 23 Nov 2020 15:42:32 +0000 Message-Id: <20201123154236.25809-5-rearnsha@arm.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123154236.25809-1-rearnsha@arm.com> References: <20201123154236.25809-1-rearnsha@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-13.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Earnshaw via Libc-alpha From: Richard Earnshaw Reply-To: Richard Earnshaw Cc: Richard Earnshaw Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" This patch will be merged with its predecessor before being committed, it is kept separate for now to ease reviewing. --- malloc/arena.c | 8 +++ malloc/malloc.c | 112 +++++++++++++++++++++++++++++------- sysdeps/generic/libc-mtag.h | 2 +- 3 files changed, 101 insertions(+), 21 deletions(-) diff --git a/malloc/arena.c b/malloc/arena.c index 835fcc0fb3..e348b10978 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -288,6 +288,10 @@ libc_hidden_proto (_dl_open_hook); #endif #ifdef _LIBC_MTAG + +/* Generate a new (random) tag value for PTR and tag the memory it + points to upto __malloc_usable_size (PTR). Return the newly tagged + pointer. */ static void * __mtag_tag_new_usable (void *ptr) { @@ -297,6 +301,10 @@ __mtag_tag_new_usable (void *ptr) return ptr; } +/* Generate a new (random) tag value for PTR, set the tags for the + memory to the new tag and initialize the memory contents to VAL. + In practice this function will only be called with VAL=0, but we + keep this parameter to maintain the same prototype as memset. */ static void * __mtag_tag_new_memset (void *ptr, int val, size_t size) { diff --git a/malloc/malloc.c b/malloc/malloc.c index b866e87bc3..deabeb010b 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -381,7 +381,65 @@ __malloc_assert (const char *assertion, const char *file, unsigned int line, void * __default_morecore (ptrdiff_t); void *(*__morecore)(ptrdiff_t) = __default_morecore; +/* Memory tagging. */ + +/* Some systems support the concept of tagging (sometimes known as + coloring) memory locations on a fine grained basis. Each memory + location is given a color (normally allocated randomly) and + pointers are also colored. When the pointer is dereferenced, the + pointer's color is checked against the memory's color and if they + differ the access is faulted (sometimes lazily). + + We use this in glibc by maintaining a single color for the malloc + data structures that are interleaved with the user data and then + assigning separate colors for each block allocation handed out. In + this way simple buffer overruns will be rapidly detected. When + memory is freed, the memory is recolored back to the glibc default + so that simple use-after-free errors can also be detected. + + If memory is reallocated the buffer is recolored even if the + address remains the same. This has a performance impact, but + guarantees that the old pointer cannot mistakenly be reused (code + that compares old against new will see a mismatch and will then + need to behave as though realloc moved the data to a new location). + + Internal API for memory tagging support. + + The aim is to keep the code for memory tagging support as close to + the normal APIs in glibc as possible, so that if tagging is not + enabled in the library, or is disabled at runtime then standard + operations can continue to be used. Support macros are used to do + this: + + void *TAG_NEW_MEMSET (void *ptr, int, val, size_t size) + + Has the same interface as memset(), but additionally allocates a + new tag, colors the memory with that tag and returns a pointer that + is correctly colored for that location. The non-tagging version + will simply call memset. + + void *TAG_REGION (void *ptr, size_t size) + + Color the region of memory pointed to by PTR and size SIZE with + the color of PTR. Returns the original pointer. + + void *TAG_NEW_USABLE (void *ptr) + + Allocate a new random color and use it to color the region of + memory starting at PTR and of size __malloc_usable_size() with that + color. Returns PTR suitably recolored for accessing the memory there. + + void *TAG_AT (void *ptr) + + Read the current color of the memory at the address pointed to by + PTR (ignoring it's current color) and return PTR recolored to that + color. PTR must be valid address in all other respects. When + tagging is not enabled, it simply returns the original pointer. +*/ + #ifdef _LIBC_MTAG + +/* Default implementaions when memory tagging is supported, but disabled. */ static void * __default_tag_region (void *ptr, size_t size) { @@ -413,21 +471,6 @@ static void *(*__tag_at)(void *) = __default_tag_nop; # define TAG_AT(ptr) (ptr) #endif -/* When using tagged memory, we cannot share the end of the user block - with the header for the next chunk, so ensure that we allocate - blocks that are rounded up to the granule size. Take care not to - overflow from close to MAX_SIZE_T to a small number. */ -static inline size_t -ROUND_UP_ALLOCATION_SIZE(size_t bytes) -{ -#ifdef _LIBC_MTAG - return (bytes + ~__mtag_granule_mask) & __mtag_granule_mask; -#else - return bytes; -#endif -} - - #include /* @@ -1234,10 +1277,26 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ---------- Size and alignment checks and conversions ---------- */ -/* conversion from malloc headers to user pointers, and back */ +/* Conversion from malloc headers to user pointers, and back. When + using memory tagging the user data and the malloc data structure + headers have distinct tags. Converting fully from one to the other + involves extracting the tag at the other address and creating a + suitable pointer using it. That can be quite expensive. There are + many occasions, though when the pointer will not be dereferenced + (for example, because we only want to assert that the pointer is + correctly aligned). In these cases it is more efficient not + to extract the tag, since the answer will be the same either way. + chunk2rawmem() can be used in these cases. + */ -#define chunk2mem(p) ((void*)TAG_AT (((char*)(p) + 2*SIZE_SZ))) +/* Convert a user mem pointer to a chunk address without correcting + the tag. */ #define chunk2rawmem(p) ((void*)((char*)(p) + 2*SIZE_SZ)) + +/* Convert between user mem pointers and chunk pointers, updating any + memory tags on the pointer to respect the tag value at that + location. */ +#define chunk2mem(p) ((void*)TAG_AT (((char*)(p) + 2*SIZE_SZ))) #define mem2chunk(mem) ((mchunkptr)TAG_AT (((char*)(mem) - 2*SIZE_SZ))) /* The smallest possible chunk */ @@ -1257,7 +1316,8 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ & MALLOC_ALIGN_MASK) /* pad request bytes into a usable size -- internal version */ - +/* Note: This must be a macro that evaluates to a compile time constant + if passed a literal constant. */ #define request2size(req) \ (((req) + SIZE_SZ + MALLOC_ALIGN_MASK < MINSIZE) ? \ MINSIZE : \ @@ -1272,7 +1332,18 @@ checked_request2size (size_t req, size_t *sz) __nonnull (1) { if (__glibc_unlikely (req > PTRDIFF_MAX)) return false; - req = ROUND_UP_ALLOCATION_SIZE (req); + +#ifdef _LIBC_MTAG + /* When using tagged memory, we cannot share the end of the user + block with the header for the next chunk, so ensure that we + allocate blocks that are rounded up to the granule size. Take + care not to overflow from close to MAX_SIZE_T to a small + number. Ideally, this would be part of request2size(), but that + must be a macro that produces a compile time constant if passed + a constant literal. */ + req = (req + ~__mtag_granule_mask) & __mtag_granule_mask; +#endif + *sz = request2size (req); return true; } @@ -3391,6 +3462,7 @@ _mid_memalign (size_t alignment, size_t bytes, void *address) return 0; } + /* Make sure alignment is power of 2. */ if (!powerof2 (alignment)) { @@ -4784,7 +4856,7 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, check_inuse_chunk (av, newp); return TAG_NEW_USABLE (chunk2rawmem (newp)); - } +} /* ------------------------------ memalign ------------------------------ diff --git a/sysdeps/generic/libc-mtag.h b/sysdeps/generic/libc-mtag.h index 3e9885451c..07f0203253 100644 --- a/sysdeps/generic/libc-mtag.h +++ b/sysdeps/generic/libc-mtag.h @@ -1,5 +1,5 @@ /* libc-internal interface for tagged (colored) memory support. - Copyright (C) 2019 Free Software Foundation, Inc. + Copyright (C) 2020 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or From patchwork Mon Nov 23 15:42:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Earnshaw X-Patchwork-Id: 41156 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 1385F38708A8; Mon, 23 Nov 2020 15:43:03 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 1385F38708A8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1606146183; bh=rpo3QQFndB3GxGgI39Habk/9JaxuKB5CjaSKLbiYyFg=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=B5aPI/aYUWnwX0LF5kdU2iYBPVtcIFT5fjY9s7Oq7Zqu+dqbxXbkH0T9Pp+y9gqUS xt0Pq7jSPVck1M1Z9rfwBs6amZ/2YJc/iWpLuTIN3UlMI/+fWjQ9dDwg3SwtWasX1e MnulDYmioFyPBgFkDt0+kcBbhsewoy/1ffjqwlX4= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id 1AC56386F825 for ; Mon, 23 Nov 2020 15:42:58 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 1AC56386F825 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D81271534; Mon, 23 Nov 2020 07:42:57 -0800 (PST) Received: from eagle.buzzard.freeserve.co.uk (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0F2373F718; Mon, 23 Nov 2020 07:42:56 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v3 5/8] malloc: support MALLOC_CHECK_ in conjunction with _MTAG_ENABLE. Date: Mon, 23 Nov 2020 15:42:33 +0000 Message-Id: <20201123154236.25809-6-rearnsha@arm.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123154236.25809-1-rearnsha@arm.com> References: <20201123154236.25809-1-rearnsha@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-14.0 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Earnshaw via Libc-alpha From: Richard Earnshaw Reply-To: Richard Earnshaw Cc: Richard Earnshaw Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Note, I propose that this patch will be merged into the main malloc changes before committing, it is kept separate here to simplify reviewing. --- malloc/arena.c | 16 ++++++-- malloc/hooks.c | 85 ++++++++++++++++++++++++--------------- malloc/malloc.c | 104 +++++++++++++++++++++++++++++------------------- 3 files changed, 127 insertions(+), 78 deletions(-) diff --git a/malloc/arena.c b/malloc/arena.c index e348b10978..da4bdc9d51 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -290,14 +290,22 @@ libc_hidden_proto (_dl_open_hook); #ifdef _LIBC_MTAG /* Generate a new (random) tag value for PTR and tag the memory it - points to upto __malloc_usable_size (PTR). Return the newly tagged - pointer. */ + points to upto the end of the usable size for the chunk containing + it. Return the newly tagged pointer. */ static void * __mtag_tag_new_usable (void *ptr) { if (ptr) - ptr = __libc_mtag_tag_region (__libc_mtag_new_tag (ptr), - __malloc_usable_size (ptr)); + { + mchunkptr cp = mem2chunk(ptr); + /* This likely will never happen, but we can't handle retagging + chunks from the dumped main arena. So just return the + existing pointer. */ + if (DUMPED_MAIN_ARENA_CHUNK (cp)) + return ptr; + ptr = __libc_mtag_tag_region (__libc_mtag_new_tag (ptr), + CHUNK_AVAILABLE_SIZE (cp) - CHUNK_HDR_SZ); + } return ptr; } diff --git a/malloc/hooks.c b/malloc/hooks.c index 52bb3863cd..c6d7ed774f 100644 --- a/malloc/hooks.c +++ b/malloc/hooks.c @@ -56,12 +56,6 @@ static int using_malloc_checking; void __malloc_check_init (void) { -#if HAVE_TUNABLES && defined (_LIBC_MTAG) - /* If memory tagging is enabled, there is no need for the boundary - checking cookie as well. */ - if ((TUNABLE_GET_FULL (glibc, memtag, enable, int32_t, NULL) & 1) != 0) - return; -#endif using_malloc_checking = 1; __malloc_hook = malloc_check; __free_hook = free_check; @@ -69,6 +63,13 @@ __malloc_check_init (void) __memalign_hook = memalign_check; } +/* When memory is tagged, the checking data is stored in the user part + of the chunk. We can't rely on the user not having modified the + tags, so fetch the tag at each location before dereferencing + it. */ +#define SAFE_CHAR_OFFSET(p,offset) \ + ((unsigned char *) TAG_AT (((unsigned char *) p) + offset)) + /* A simple, standard set of debugging hooks. Overhead is `only' one byte per chunk; still this will catch most cases of double frees or overruns. The goal here is to avoid obscure crashes due to invalid @@ -86,7 +87,6 @@ magicbyte (const void *p) return magic; } - /* Visualize the chunk as being partitioned into blocks of 255 bytes from the highest address of the chunk, downwards. The end of each block tells us the size of that block, up to the actual size of the requested @@ -102,16 +102,16 @@ malloc_check_get_size (mchunkptr p) assert (using_malloc_checking == 1); - for (size = chunksize (p) - 1 + (chunk_is_mmapped (p) ? 0 : SIZE_SZ); - (c = ((unsigned char *) p)[size]) != magic; + for (size = CHUNK_AVAILABLE_SIZE (p) - 1; + (c = *SAFE_CHAR_OFFSET (p, size)) != magic; size -= c) { - if (c <= 0 || size < (c + 2 * SIZE_SZ)) + if (c <= 0 || size < (c + CHUNK_HDR_SZ)) malloc_printerr ("malloc_check_get_size: memory corruption"); } /* chunk2mem size. */ - return size - 2 * SIZE_SZ; + return size - CHUNK_HDR_SZ; } /* Instrument a chunk with overrun detector byte(s) and convert it @@ -130,9 +130,8 @@ mem2mem_check (void *ptr, size_t req_sz) p = mem2chunk (ptr); magic = magicbyte (p); - max_sz = chunksize (p) - 2 * SIZE_SZ; - if (!chunk_is_mmapped (p)) - max_sz += SIZE_SZ; + max_sz = CHUNK_AVAILABLE_SIZE (p) - CHUNK_HDR_SZ; + for (i = max_sz - 1; i > req_sz; i -= block_sz) { block_sz = MIN (i - req_sz, 0xff); @@ -141,9 +140,9 @@ mem2mem_check (void *ptr, size_t req_sz) if (block_sz == magic) --block_sz; - m_ptr[i] = block_sz; + *SAFE_CHAR_OFFSET (m_ptr, i) = block_sz; } - m_ptr[req_sz] = magic; + *SAFE_CHAR_OFFSET (m_ptr, req_sz) = magic; return (void *) m_ptr; } @@ -176,9 +175,11 @@ mem2chunk_check (void *mem, unsigned char **magic_p) next_chunk (prev_chunk (p)) != p))) return NULL; - for (sz += SIZE_SZ - 1; (c = ((unsigned char *) p)[sz]) != magic; sz -= c) + for (sz = CHUNK_AVAILABLE_SIZE (p) - 1; + (c = *SAFE_CHAR_OFFSET (p, sz)) != magic; + sz -= c) { - if (c == 0 || sz < (c + 2 * SIZE_SZ)) + if (c == 0 || sz < (c + CHUNK_HDR_SZ)) return NULL; } } @@ -199,15 +200,19 @@ mem2chunk_check (void *mem, unsigned char **magic_p) ((prev_size (p) + sz) & page_mask) != 0) return NULL; - for (sz -= 1; (c = ((unsigned char *) p)[sz]) != magic; sz -= c) + for (sz = CHUNK_AVAILABLE_SIZE (p) - 1; + (c = *SAFE_CHAR_OFFSET (p, sz)) != magic; + sz -= c) { - if (c == 0 || sz < (c + 2 * SIZE_SZ)) + if (c == 0 || sz < (c + CHUNK_HDR_SZ)) return NULL; } } - ((unsigned char *) p)[sz] ^= 0xFF; + + unsigned char* safe_p = SAFE_CHAR_OFFSET (p, sz); + *safe_p ^= 0xFF; if (magic_p) - *magic_p = (unsigned char *) p + sz; + *magic_p = safe_p; return p; } @@ -244,7 +249,7 @@ malloc_check (size_t sz, const void *caller) top_check (); victim = _int_malloc (&main_arena, nb); __libc_lock_unlock (main_arena.mutex); - return mem2mem_check (victim, sz); + return mem2mem_check (TAG_NEW_USABLE (victim), sz); } static void @@ -255,6 +260,12 @@ free_check (void *mem, const void *caller) if (!mem) return; +#ifdef _LIBC_MTAG + /* Quickly check that the freed pointer matches the tag for the memory. + This gives a useful double-free detection. */ + *(volatile char *)mem; +#endif + __libc_lock_lock (main_arena.mutex); p = mem2chunk_check (mem, NULL); if (!p) @@ -265,6 +276,8 @@ free_check (void *mem, const void *caller) munmap_chunk (p); return; } + /* Mark the chunk as belonging to the library again. */ + (void)TAG_REGION (chunk2rawmem (p), CHUNK_AVAILABLE_SIZE (p) - CHUNK_HDR_SZ); _int_free (&main_arena, p, 1); __libc_lock_unlock (main_arena.mutex); } @@ -272,7 +285,7 @@ free_check (void *mem, const void *caller) static void * realloc_check (void *oldmem, size_t bytes, const void *caller) { - INTERNAL_SIZE_T nb; + INTERNAL_SIZE_T chnb; void *newmem = 0; unsigned char *magic_p; size_t rb; @@ -290,14 +303,21 @@ realloc_check (void *oldmem, size_t bytes, const void *caller) free_check (oldmem, NULL); return NULL; } + +#ifdef _LIBC_MTAG + /* Quickly check that the freed pointer matches the tag for the memory. + This gives a useful double-free detection. */ + *(volatile char *)oldmem; +#endif + __libc_lock_lock (main_arena.mutex); const mchunkptr oldp = mem2chunk_check (oldmem, &magic_p); __libc_lock_unlock (main_arena.mutex); if (!oldp) malloc_printerr ("realloc(): invalid pointer"); - const INTERNAL_SIZE_T oldsize = chunksize (oldp); + const INTERNAL_SIZE_T oldchsize = CHUNK_AVAILABLE_SIZE (oldp); - if (!checked_request2size (rb, &nb)) + if (!checked_request2size (rb, &chnb)) goto invert; __libc_lock_lock (main_arena.mutex); @@ -305,14 +325,13 @@ realloc_check (void *oldmem, size_t bytes, const void *caller) if (chunk_is_mmapped (oldp)) { #if HAVE_MREMAP - mchunkptr newp = mremap_chunk (oldp, nb); + mchunkptr newp = mremap_chunk (oldp, chnb); if (newp) newmem = chunk2mem (newp); else #endif { - /* Note the extra SIZE_SZ overhead. */ - if (oldsize - SIZE_SZ >= nb) + if (oldchsize >= chnb) newmem = oldmem; /* do nothing */ else { @@ -321,7 +340,7 @@ realloc_check (void *oldmem, size_t bytes, const void *caller) newmem = _int_malloc (&main_arena, rb); if (newmem) { - memcpy (newmem, oldmem, oldsize - 2 * SIZE_SZ); + memcpy (newmem, oldmem, oldchsize - CHUNK_HDR_SZ); munmap_chunk (oldp); } } @@ -330,7 +349,7 @@ realloc_check (void *oldmem, size_t bytes, const void *caller) else { top_check (); - newmem = _int_realloc (&main_arena, oldp, oldsize, nb); + newmem = _int_realloc (&main_arena, oldp, oldchsize, chnb); } DIAG_PUSH_NEEDS_COMMENT; @@ -349,7 +368,7 @@ invert: __libc_lock_unlock (main_arena.mutex); - return mem2mem_check (newmem, bytes); + return mem2mem_check (TAG_NEW_USABLE (newmem), bytes); } static void * @@ -391,7 +410,7 @@ memalign_check (size_t alignment, size_t bytes, const void *caller) top_check (); mem = _int_memalign (&main_arena, alignment, bytes + 1); __libc_lock_unlock (main_arena.mutex); - return mem2mem_check (mem, bytes); + return mem2mem_check (TAG_NEW_USABLE (mem), bytes); } #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_25) diff --git a/malloc/malloc.c b/malloc/malloc.c index deabeb010b..bd78d4bbc6 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -425,9 +425,10 @@ void *(*__morecore)(ptrdiff_t) = __default_morecore; void *TAG_NEW_USABLE (void *ptr) - Allocate a new random color and use it to color the region of - memory starting at PTR and of size __malloc_usable_size() with that - color. Returns PTR suitably recolored for accessing the memory there. + Allocate a new random color and use it to color the user region of + a chunk; this may include data from the subsequent chunk's header + if tagging is sufficiently fine grained. Returns PTR suitably + recolored for accessing the memory there. void *TAG_AT (void *ptr) @@ -1289,15 +1290,19 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ chunk2rawmem() can be used in these cases. */ +/* The chunk header is two SIZE_SZ elements, but this is used widely, so + we define it here for clarity later. */ +#define CHUNK_HDR_SZ (2 * SIZE_SZ) + /* Convert a user mem pointer to a chunk address without correcting the tag. */ -#define chunk2rawmem(p) ((void*)((char*)(p) + 2*SIZE_SZ)) +#define chunk2rawmem(p) ((void*)((char*)(p) + CHUNK_HDR_SZ)) /* Convert between user mem pointers and chunk pointers, updating any memory tags on the pointer to respect the tag value at that location. */ -#define chunk2mem(p) ((void*)TAG_AT (((char*)(p) + 2*SIZE_SZ))) -#define mem2chunk(mem) ((mchunkptr)TAG_AT (((char*)(mem) - 2*SIZE_SZ))) +#define chunk2mem(p) ((void*)TAG_AT (((char*)(p) + CHUNK_HDR_SZ))) +#define mem2chunk(mem) ((mchunkptr)TAG_AT (((char*)(mem) - CHUNK_HDR_SZ))) /* The smallest possible chunk */ #define MIN_CHUNK_SIZE (offsetof(struct malloc_chunk, fd_nextsize)) @@ -1312,7 +1317,7 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ #define aligned_OK(m) (((unsigned long)(m) & MALLOC_ALIGN_MASK) == 0) #define misaligned_chunk(p) \ - ((uintptr_t)(MALLOC_ALIGNMENT == 2 * SIZE_SZ ? (p) : chunk2mem (p)) \ + ((uintptr_t)(MALLOC_ALIGNMENT == CHUNK_HDR_SZ ? (p) : chunk2mem (p)) \ & MALLOC_ALIGN_MASK) /* pad request bytes into a usable size -- internal version */ @@ -1323,6 +1328,17 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MINSIZE : \ ((req) + SIZE_SZ + MALLOC_ALIGN_MASK) & ~MALLOC_ALIGN_MASK) +/* Available size of chunk. This is the size of the real usable data + in the chunk, plus the chunk header. */ +#ifdef _LIBC_MTAG +#define CHUNK_AVAILABLE_SIZE(p) \ + ((chunksize (p) + (chunk_is_mmapped (p) ? 0 : SIZE_SZ)) \ + & __mtag_granule_mask) +#else +#define CHUNK_AVAILABLE_SIZE(p) \ + (chunksize (p) + (chunk_is_mmapped (p) ? 0 : SIZE_SZ)) +#endif + /* Check if REQ overflows when padded and aligned and if the resulting value is less than PTRDIFF_T. Returns TRUE and the requested size or MINSIZE in case the value is less than MINSIZE on SZ or false if any of the previous @@ -1442,7 +1458,6 @@ checked_request2size (size_t req, size_t *sz) __nonnull (1) /* Set size at footer (only when chunk is not in use) */ #define set_foot(p, s) (((mchunkptr) ((char *) (p) + (s)))->mchunk_prev_size = (s)) - #pragma GCC poison mchunk_size #pragma GCC poison mchunk_prev_size @@ -1538,7 +1553,7 @@ typedef struct malloc_chunk *mbinptr; #define NBINS 128 #define NSMALLBINS 64 #define SMALLBIN_WIDTH MALLOC_ALIGNMENT -#define SMALLBIN_CORRECTION (MALLOC_ALIGNMENT > 2 * SIZE_SZ) +#define SMALLBIN_CORRECTION (MALLOC_ALIGNMENT > CHUNK_HDR_SZ) #define MIN_LARGE_SIZE ((NSMALLBINS - SMALLBIN_CORRECTION) * SMALLBIN_WIDTH) #define in_smallbin_range(sz) \ @@ -2438,7 +2453,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) See the front_misalign handling below, for glibc there is no need for further alignments unless we have have high alignment. */ - if (MALLOC_ALIGNMENT == 2 * SIZE_SZ) + if (MALLOC_ALIGNMENT == CHUNK_HDR_SZ) size = ALIGN_UP (nb + SIZE_SZ, pagesize); else size = ALIGN_UP (nb + SIZE_SZ + MALLOC_ALIGN_MASK, pagesize); @@ -2460,11 +2475,13 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) address argument for later munmap in free() and realloc(). */ - if (MALLOC_ALIGNMENT == 2 * SIZE_SZ) + if (MALLOC_ALIGNMENT == CHUNK_HDR_SZ) { - /* For glibc, chunk2rawmem increases the address by 2*SIZE_SZ and - MALLOC_ALIGN_MASK is 2*SIZE_SZ-1. Each mmap'ed area is page - aligned and therefore definitely MALLOC_ALIGN_MASK-aligned. */ + /* For glibc, chunk2rawmem increases the address by + CHUNK_HDR_SZ and MALLOC_ALIGN_MASK is + CHUNK_HDR_SZ-1. Each mmap'ed area is page + aligned and therefore definitely + MALLOC_ALIGN_MASK-aligned. */ assert (((INTERNAL_SIZE_T) chunk2rawmem (mm) & MALLOC_ALIGN_MASK) == 0); front_misalign = 0; } @@ -2557,18 +2574,20 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) become the top chunk again later. Note that a footer is set up, too, although the chunk is marked in use. */ old_size = (old_size - MINSIZE) & ~MALLOC_ALIGN_MASK; - set_head (chunk_at_offset (old_top, old_size + 2 * SIZE_SZ), 0 | PREV_INUSE); + set_head (chunk_at_offset (old_top, old_size + CHUNK_HDR_SZ), + 0 | PREV_INUSE); if (old_size >= MINSIZE) { - set_head (chunk_at_offset (old_top, old_size), (2 * SIZE_SZ) | PREV_INUSE); - set_foot (chunk_at_offset (old_top, old_size), (2 * SIZE_SZ)); + set_head (chunk_at_offset (old_top, old_size), + CHUNK_HDR_SZ | PREV_INUSE); + set_foot (chunk_at_offset (old_top, old_size), CHUNK_HDR_SZ); set_head (old_top, old_size | PREV_INUSE | NON_MAIN_ARENA); _int_free (av, old_top, 1); } else { - set_head (old_top, (old_size + 2 * SIZE_SZ) | PREV_INUSE); - set_foot (old_top, (old_size + 2 * SIZE_SZ)); + set_head (old_top, (old_size + CHUNK_HDR_SZ) | PREV_INUSE); + set_foot (old_top, (old_size + CHUNK_HDR_SZ)); } } else if (!tried_mmap) @@ -2770,7 +2789,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) /* handle non-contiguous cases */ else { - if (MALLOC_ALIGNMENT == 2 * SIZE_SZ) + if (MALLOC_ALIGNMENT == CHUNK_HDR_SZ) /* MORECORE/mmap must correctly align */ assert (((unsigned long) chunk2rawmem (brk) & MALLOC_ALIGN_MASK) == 0); else @@ -2820,7 +2839,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) multiple of MALLOC_ALIGNMENT. We know there is at least enough space in old_top to do this. */ - old_size = (old_size - 4 * SIZE_SZ) & ~MALLOC_ALIGN_MASK; + old_size = (old_size - 2 * CHUNK_HDR_SZ) & ~MALLOC_ALIGN_MASK; set_head (old_top, old_size | PREV_INUSE); /* @@ -2830,9 +2849,10 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av) lost. */ set_head (chunk_at_offset (old_top, old_size), - (2 * SIZE_SZ) | PREV_INUSE); - set_head (chunk_at_offset (old_top, old_size + 2 * SIZE_SZ), - (2 * SIZE_SZ) | PREV_INUSE); + CHUNK_HDR_SZ | PREV_INUSE); + set_head (chunk_at_offset (old_top, + old_size + CHUNK_HDR_SZ), + CHUNK_HDR_SZ | PREV_INUSE); /* If possible, release the rest. */ if (old_size >= MINSIZE) @@ -3259,7 +3279,7 @@ __libc_free (void *mem) p = mem2chunk (mem); /* Mark the chunk as belonging to the library again. */ - (void)TAG_REGION (chunk2rawmem (p), __malloc_usable_size (mem)); + (void)TAG_REGION (chunk2rawmem (p), CHUNK_AVAILABLE_SIZE (p) - CHUNK_HDR_SZ); if (chunk_is_mmapped (p)) /* release mmapped memory. */ { @@ -3358,7 +3378,7 @@ __libc_realloc (void *oldmem, size_t bytes) return NULL; /* Copy as many bytes as are available from the old chunk and fit into the new size. NB: The overhead for faked - mmapped chunks is only SIZE_SZ, not 2 * SIZE_SZ as for + mmapped chunks is only SIZE_SZ, not CHUNK_HDR_SZ as for regular mmapped chunks. */ if (bytes > oldsize - SIZE_SZ) bytes = oldsize - SIZE_SZ; @@ -3390,7 +3410,7 @@ __libc_realloc (void *oldmem, size_t bytes) if (newmem == 0) return 0; /* propagate failure */ - memcpy (newmem, oldmem, oldsize - 2 * SIZE_SZ); + memcpy (newmem, oldmem, oldsize - CHUNK_HDR_SZ); munmap_chunk (oldp); return newmem; } @@ -3629,13 +3649,13 @@ __libc_calloc (size_t n, size_t elem_size) if (mem == 0) return 0; + mchunkptr p = mem2chunk (mem); /* If we are using memory tagging, then we need to set the tags regardless of MORECORE_CLEARS, so we zero the whole block while doing so. */ #ifdef _LIBC_MTAG - return TAG_NEW_MEMSET (mem, 0, __malloc_usable_size (mem)); + return TAG_NEW_MEMSET (mem, 0, CHUNK_AVAILABLE_SIZE (p) - CHUNK_HDR_SZ); #else - mchunkptr p = mem2chunk (mem); INTERNAL_SIZE_T csz = chunksize (p); /* Two optional cases in which clearing not necessary */ @@ -3927,10 +3947,10 @@ _int_malloc (mstate av, size_t bytes) size = chunksize (victim); mchunkptr next = chunk_at_offset (victim, size); - if (__glibc_unlikely (size <= 2 * SIZE_SZ) + if (__glibc_unlikely (size <= CHUNK_HDR_SZ) || __glibc_unlikely (size > av->system_mem)) malloc_printerr ("malloc(): invalid size (unsorted)"); - if (__glibc_unlikely (chunksize_nomask (next) < 2 * SIZE_SZ) + if (__glibc_unlikely (chunksize_nomask (next) < CHUNK_HDR_SZ) || __glibc_unlikely (chunksize_nomask (next) > av->system_mem)) malloc_printerr ("malloc(): invalid next size (unsorted)"); if (__glibc_unlikely ((prev_size (next) & ~(SIZE_BITS)) != size)) @@ -4429,7 +4449,7 @@ _int_free (mstate av, mchunkptr p, int have_lock) ) { if (__builtin_expect (chunksize_nomask (chunk_at_offset (p, size)) - <= 2 * SIZE_SZ, 0) + <= CHUNK_HDR_SZ, 0) || __builtin_expect (chunksize (chunk_at_offset (p, size)) >= av->system_mem, 0)) { @@ -4440,7 +4460,7 @@ _int_free (mstate av, mchunkptr p, int have_lock) if (!have_lock) { __libc_lock_lock (av->mutex); - fail = (chunksize_nomask (chunk_at_offset (p, size)) <= 2 * SIZE_SZ + fail = (chunksize_nomask (chunk_at_offset (p, size)) <= CHUNK_HDR_SZ || chunksize (chunk_at_offset (p, size)) >= av->system_mem); __libc_lock_unlock (av->mutex); } @@ -4449,7 +4469,7 @@ _int_free (mstate av, mchunkptr p, int have_lock) malloc_printerr ("free(): invalid next size (fast)"); } - free_perturb (chunk2mem(p), size - 2 * SIZE_SZ); + free_perturb (chunk2mem(p), size - CHUNK_HDR_SZ); atomic_store_relaxed (&av->have_fastchunks, true); unsigned int idx = fastbin_index(size); @@ -4518,11 +4538,11 @@ _int_free (mstate av, mchunkptr p, int have_lock) malloc_printerr ("double free or corruption (!prev)"); nextsize = chunksize(nextchunk); - if (__builtin_expect (chunksize_nomask (nextchunk) <= 2 * SIZE_SZ, 0) + if (__builtin_expect (chunksize_nomask (nextchunk) <= CHUNK_HDR_SZ, 0) || __builtin_expect (nextsize >= av->system_mem, 0)) malloc_printerr ("free(): invalid next size (normal)"); - free_perturb (chunk2mem(p), size - 2 * SIZE_SZ); + free_perturb (chunk2mem(p), size - CHUNK_HDR_SZ); /* consolidate backward */ if (!prev_inuse(p)) { @@ -4753,7 +4773,7 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, unsigned long remainder_size; /* its size */ /* oldmem size */ - if (__builtin_expect (chunksize_nomask (oldp) <= 2 * SIZE_SZ, 0) + if (__builtin_expect (chunksize_nomask (oldp) <= CHUNK_HDR_SZ, 0) || __builtin_expect (oldsize >= av->system_mem, 0)) malloc_printerr ("realloc(): invalid old size"); @@ -4764,7 +4784,7 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, next = chunk_at_offset (oldp, oldsize); INTERNAL_SIZE_T nextsize = chunksize (next); - if (__builtin_expect (chunksize_nomask (next) <= 2 * SIZE_SZ, 0) + if (__builtin_expect (chunksize_nomask (next) <= CHUNK_HDR_SZ, 0) || __builtin_expect (nextsize >= av->system_mem, 0)) malloc_printerr ("realloc(): invalid next size"); @@ -4821,7 +4841,8 @@ _int_realloc(mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize, { void *oldmem = chunk2mem (oldp); newmem = TAG_NEW_USABLE (newmem); - memcpy (newmem, oldmem, __malloc_usable_size (oldmem)); + memcpy (newmem, oldmem, + CHUNK_AVAILABLE_SIZE (oldp) - CHUNK_HDR_SZ); (void) TAG_REGION (chunk2rawmem (oldp), oldsize); _int_free (av, oldp, 1); check_inuse_chunk (av, newp); @@ -4987,7 +5008,8 @@ mtrim (mstate av, size_t pad) + sizeof (struct malloc_chunk) + psm1) & ~psm1); - assert ((char *) chunk2rawmem (p) + 4 * SIZE_SZ <= paligned_mem); + assert ((char *) chunk2rawmem (p) + 2 * CHUNK_HDR_SZ + <= paligned_mem); assert ((char *) p + size > paligned_mem); /* This is the size we could potentially free. */ @@ -5062,7 +5084,7 @@ musable (void *mem) if (DUMPED_MAIN_ARENA_CHUNK (p)) result = chunksize (p) - SIZE_SZ; else - result = chunksize (p) - 2 * SIZE_SZ; + result = chunksize (p) - CHUNK_HDR_SZ; } else if (inuse (p)) result = chunksize (p) - SIZE_SZ; From patchwork Mon Nov 23 15:42:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Earnshaw X-Patchwork-Id: 41155 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 04DAB3870895; Mon, 23 Nov 2020 15:43:02 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 04DAB3870895 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1606146182; bh=hkQZxJIH/zI4Fodh+Jdrrguilj4vxFmM/5T2cE+L6co=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=dfByj8eqmrXlDStA23V0hamhgRunRWSnJKRsuynuIWgIt1vyDZl7HGr+MAanntj29 OkrhAPCDwjybpQ6dRhJUTS9nd+vvCgUI50v/1+xLGCWtaLp3N+ByDe+ItTZqqYOGhR 2cdHnUovLfa0sm5etG7voBCvqev1q6nojRLc921Y= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id E3DC9386F81C for ; Mon, 23 Nov 2020 15:42:58 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E3DC9386F81C Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C4EBB153B; Mon, 23 Nov 2020 07:42:58 -0800 (PST) Received: from eagle.buzzard.freeserve.co.uk (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1A27F3F718; Mon, 23 Nov 2020 07:42:57 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v3 6/8] linux: Add compatibility definitions to sys/prctl.h for MTE Date: Mon, 23 Nov 2020 15:42:34 +0000 Message-Id: <20201123154236.25809-7-rearnsha@arm.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123154236.25809-1-rearnsha@arm.com> References: <20201123154236.25809-1-rearnsha@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-14.0 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Earnshaw via Libc-alpha From: Richard Earnshaw Reply-To: Richard Earnshaw Cc: Richard Earnshaw Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Older versions of the Linux kernel headers obviously lack support for memory tagging, but we still want to be able to build in support when using those (obviously it can't be enabled on such systems). The linux kernel extensions are made to the platform-independent header (linux/prctl.h), so this patch takes a similar approach. --- sysdeps/unix/sysv/linux/sys/prctl.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/sysdeps/unix/sysv/linux/sys/prctl.h b/sysdeps/unix/sysv/linux/sys/prctl.h index 7f748ebeeb..4d01379c23 100644 --- a/sysdeps/unix/sysv/linux/sys/prctl.h +++ b/sysdeps/unix/sysv/linux/sys/prctl.h @@ -21,6 +21,24 @@ #include #include /* The magic values come from here */ +/* Recent extensions to linux which may post-date the kernel headers + we're picking up... */ + +/* Memory tagging control operations (for AArch64). */ +#ifndef PR_TAGGED_ADDR_ENABLE +# define PR_TAGGED_ADDR_ENABLE (1UL << 8) +#endif + +#ifndef PR_MTE_TCF_SHIFT +# define PR_MTE_TCF_SHIFT 1 +# define PR_MTE_TCF_NONE (0UL << PR_MTE_TCF_SHIFT) +# define PR_MTE_TCF_SYNC (1UL << PR_MTE_TCF_SHIFT) +# define PR_MTE_TCF_ASYNC (2UL << PR_MTE_TCF_SHIFT) +# define PR_MTE_TCF_MASK (3UL << PR_MTE_TCF_SHIFT) +# define PR_MTE_TAG_SHIFT 3 +# define PR_MTE_TAG_MASK (0xffffUL << PR_MTE_TAG_SHIFT) +#endif + __BEGIN_DECLS /* Control process execution. */ From patchwork Mon Nov 23 15:42:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Earnshaw X-Patchwork-Id: 41157 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 9711238708AA; Mon, 23 Nov 2020 15:43:03 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9711238708AA DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1606146183; bh=pcJ8EC3+UH/pP78bBIZjYUzpmv7gQYSu1mg0Dxw4ZnQ=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=DemcCoRnMsxtiZC2MvqWf+Jbq4odX2I1aKiIxVIXAY15vAmkoDDqiaxckWICJb1nK W0zB1pQPOodxeMy6YjxeODyzz10d+USgAKMj5njehiqDrxt41mr62KC4ZHenhBJHXS ZSfuvV2+NbSqIg2jf+JCqqlQpgDPWHH+2B7GICjQ= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id 1E20D3870874 for ; Mon, 23 Nov 2020 15:43:00 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 1E20D3870874 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B1E7D15AD; Mon, 23 Nov 2020 07:42:59 -0800 (PST) Received: from eagle.buzzard.freeserve.co.uk (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 06D8E3F718; Mon, 23 Nov 2020 07:42:58 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v3 7/8] aarch64: Add sysv specific enabling code for memory tagging Date: Mon, 23 Nov 2020 15:42:35 +0000 Message-Id: <20201123154236.25809-8-rearnsha@arm.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123154236.25809-1-rearnsha@arm.com> References: <20201123154236.25809-1-rearnsha@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-14.1 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Earnshaw via Libc-alpha From: Richard Earnshaw Reply-To: Richard Earnshaw Cc: Richard Earnshaw Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Add various defines and stubs for enabling MTE on AArch64 sysv-like systems such as Linux. The HWCAP feature bit is copied over in the same way as other feature bits. Similarly we add a new wrapper header for mman.h to define the PROT_MTE flag that can be used with mmap and related functions. We add a new field to struct cpu_features that can be used, for example, to check whether or not certain ifunc'd routines should be bound to MTE-safe versions. Finally, if we detect that MTE should be enabled (ie via the glibc tunable); we enable MTE during startup as required. --- sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h | 1 + sysdeps/unix/sysv/linux/aarch64/bits/mman.h | 7 +++++ .../unix/sysv/linux/aarch64/cpu-features.c | 28 +++++++++++++++++++ .../unix/sysv/linux/aarch64/cpu-features.h | 1 + 4 files changed, 37 insertions(+) diff --git a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h index af90d8a626..389852f1d9 100644 --- a/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h +++ b/sysdeps/unix/sysv/linux/aarch64/bits/hwcap.h @@ -73,3 +73,4 @@ #define HWCAP2_DGH (1 << 15) #define HWCAP2_RNG (1 << 16) #define HWCAP2_BTI (1 << 17) +#define HWCAP2_MTE (1 << 18) diff --git a/sysdeps/unix/sysv/linux/aarch64/bits/mman.h b/sysdeps/unix/sysv/linux/aarch64/bits/mman.h index ecae046344..3658b958b5 100644 --- a/sysdeps/unix/sysv/linux/aarch64/bits/mman.h +++ b/sysdeps/unix/sysv/linux/aarch64/bits/mman.h @@ -1,4 +1,5 @@ /* Definitions for POSIX memory map interface. Linux/AArch64 version. + Copyright (C) 2020 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -25,6 +26,12 @@ #define PROT_BTI 0x10 +/* The following definitions basically come from the kernel headers. + But the kernel header is not namespace clean. */ + +/* Other flags. */ +#define PROT_MTE 0x20 /* Normal Tagged mapping. */ + #include /* Include generic Linux declarations. */ diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c index b9ab827aca..aa4a82c6e8 100644 --- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c +++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c @@ -19,6 +19,7 @@ #include #include #include +#include #define DCZID_DZP_MASK (1 << 4) #define DCZID_BS_MASK (0xf) @@ -86,4 +87,31 @@ init_cpu_features (struct cpu_features *cpu_features) /* Check if BTI is supported. */ cpu_features->bti = GLRO (dl_hwcap2) & HWCAP2_BTI; + + /* Setup memory tagging support if the HW and kernel support it, and if + the user has requested it. */ + cpu_features->mte_state = 0; + +#ifdef _LIBC_MTAG +# if HAVE_TUNABLES + int mte_state = TUNABLE_GET (glibc, memtag, enable, unsigned, 0); + cpu_features->mte_state = (GLRO (dl_hwcap2) & HWCAP2_MTE) ? mte_state : 0; + /* If we lack the MTE feature, disable the tunable, since it will + otherwise cause instructions that won't run on this CPU to be used. */ + TUNABLE_SET (glibc, memtag, enable, unsigned, cpu_features->mte_state); +# endif + + /* For now, disallow tag 0, so that we can clearly see when tagged + addresses are being allocated. */ + if (cpu_features->mte_state & 2) + __prctl (PR_SET_TAGGED_ADDR_CTRL, + (PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_SYNC + | (0xfffe << PR_MTE_TAG_SHIFT)), + 0, 0, 0); + else if (cpu_features->mte_state) + __prctl (PR_SET_TAGGED_ADDR_CTRL, + (PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_ASYNC + | (0xfffe << PR_MTE_TAG_SHIFT)), + 0, 0, 0); +#endif } diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.h b/sysdeps/unix/sysv/linux/aarch64/cpu-features.h index 00a4d0c8e7..838d5c9aba 100644 --- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.h +++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.h @@ -70,6 +70,7 @@ struct cpu_features uint64_t midr_el1; unsigned zva_size; bool bti; + unsigned mte_state; }; #endif /* _CPU_FEATURES_AARCH64_H */ From patchwork Mon Nov 23 15:42:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Earnshaw X-Patchwork-Id: 41158 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 9710038708B1; Mon, 23 Nov 2020 15:43:05 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9710038708B1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1606146185; bh=7dbwOtOgUW/2h7VzXhRVjAPOOHHA3MSr2ScD8muqD4U=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=KQXUdPVF5IPr7CfU80rTJCS//wdn/SbbG1hlPjgXhPLq/MlpGhBh2r4+97//Ob5WC 0wHeow1g3c5pT27GI6w/TEflMBQMZarUiy2g2hZYhbC3BFqVIYnBX9GaUmIpDDX3t5 45tSl28083H/o/Aa/BdickMKnfRnJZ9KC6Tpzq0w= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id C6F6A3870885 for ; Mon, 23 Nov 2020 15:43:00 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org C6F6A3870885 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A868E15DB; Mon, 23 Nov 2020 07:43:00 -0800 (PST) Received: from eagle.buzzard.freeserve.co.uk (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E80483F718; Mon, 23 Nov 2020 07:42:59 -0800 (PST) To: libc-alpha@sourceware.org Subject: [PATCH v3 8/8] aarch64: Add aarch64-specific files for memory tagging support Date: Mon, 23 Nov 2020 15:42:36 +0000 Message-Id: <20201123154236.25809-9-rearnsha@arm.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201123154236.25809-1-rearnsha@arm.com> References: <20201123154236.25809-1-rearnsha@arm.com> MIME-Version: 1.0 X-Spam-Status: No, score=-14.1 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, KAM_SHORT, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Earnshaw via Libc-alpha From: Richard Earnshaw Reply-To: Richard Earnshaw Cc: Richard Earnshaw Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" This final patch provides the architecture-specific implementation of the memory-tagging support hooks for aarch64. --- sysdeps/aarch64/Makefile | 5 +++ sysdeps/aarch64/__mtag_address_get_tag.S | 31 +++++++++++++ sysdeps/aarch64/__mtag_memset_tag.S | 46 +++++++++++++++++++ sysdeps/aarch64/__mtag_new_tag.S | 38 ++++++++++++++++ sysdeps/aarch64/__mtag_tag_region.S | 44 ++++++++++++++++++ sysdeps/aarch64/libc-mtag.h | 57 ++++++++++++++++++++++++ 6 files changed, 221 insertions(+) create mode 100644 sysdeps/aarch64/__mtag_address_get_tag.S create mode 100644 sysdeps/aarch64/__mtag_memset_tag.S create mode 100644 sysdeps/aarch64/__mtag_new_tag.S create mode 100644 sysdeps/aarch64/__mtag_tag_region.S create mode 100644 sysdeps/aarch64/libc-mtag.h diff --git a/sysdeps/aarch64/Makefile b/sysdeps/aarch64/Makefile index d8e06d27b2..2e88fc84a4 100644 --- a/sysdeps/aarch64/Makefile +++ b/sysdeps/aarch64/Makefile @@ -40,4 +40,9 @@ endif ifeq ($(subdir),misc) sysdep_headers += sys/ifunc.h +sysdep_routines += __mtag_tag_region __mtag_new_tag __mtag_address_get_tag +endif + +ifeq ($(subdir),string) +sysdep_routines += __mtag_memset_tag endif diff --git a/sysdeps/aarch64/__mtag_address_get_tag.S b/sysdeps/aarch64/__mtag_address_get_tag.S new file mode 100644 index 0000000000..654c9d660c --- /dev/null +++ b/sysdeps/aarch64/__mtag_address_get_tag.S @@ -0,0 +1,31 @@ +/* Copyright (C) 2020 Free Software Foundation, Inc. + + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library. If not, see + . */ + +#include + +#define ptr x0 + + .arch armv8.5-a + .arch_extension memtag + +ENTRY (__libc_mtag_address_get_tag) + + ldg ptr, [ptr] + ret +END (__libc_mtag_address_get_tag) +libc_hidden_builtin_def (__libc_mtag_address_get_tag) diff --git a/sysdeps/aarch64/__mtag_memset_tag.S b/sysdeps/aarch64/__mtag_memset_tag.S new file mode 100644 index 0000000000..bc98dc49d2 --- /dev/null +++ b/sysdeps/aarch64/__mtag_memset_tag.S @@ -0,0 +1,46 @@ +/* Copyright (C) 2020 Free Software Foundation, Inc. + + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library. If not, see + . */ + +#include +/* Use the same register names and assignments as memset. */ +#include "memset-reg.h" + + .arch armv8.5-a + .arch_extension memtag + +/* NB, only supported on variants with 64-bit pointers. */ + +/* FIXME: This is a minimal implementation. We could do much better than + this for large values of COUNT. */ + +ENTRY_ALIGN(__libc_mtag_memset_with_tag, 6) + + and valw, valw, 255 + orr valw, valw, valw, lsl 8 + orr valw, valw, valw, lsl 16 + orr val, val, val, lsl 32 + mov dst, dstin + +L(loop): + stgp val, val, [dst], #16 + subs count, count, 16 + bne L(loop) + ldg dstin, [dstin] // Recover the tag created (might be untagged). + ret +END (__libc_mtag_memset_with_tag) +libc_hidden_builtin_def (__libc_mtag_memset_with_tag) diff --git a/sysdeps/aarch64/__mtag_new_tag.S b/sysdeps/aarch64/__mtag_new_tag.S new file mode 100644 index 0000000000..3a22995e9f --- /dev/null +++ b/sysdeps/aarch64/__mtag_new_tag.S @@ -0,0 +1,38 @@ +/* Copyright (C) 2020 Free Software Foundation, Inc. + + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library. If not, see + . */ + +#include + + .arch armv8.5-a + .arch_extension memtag + +/* NB, only supported on variants with 64-bit pointers. */ + +/* FIXME: This is a minimal implementation. We could do better than + this for larger values of COUNT. */ + +#define ptr x0 +#define xset x1 + +ENTRY(__libc_mtag_new_tag) + // Guarantee that the new tag is not the same as now. + gmi xset, ptr, xzr + irg ptr, ptr, xset + ret +END (__libc_mtag_new_tag) +libc_hidden_builtin_def (__libc_mtag_new_tag) diff --git a/sysdeps/aarch64/__mtag_tag_region.S b/sysdeps/aarch64/__mtag_tag_region.S new file mode 100644 index 0000000000..41019781d0 --- /dev/null +++ b/sysdeps/aarch64/__mtag_tag_region.S @@ -0,0 +1,44 @@ +/* Copyright (C) 2020 Free Software Foundation, Inc. + + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library. If not, see + . */ + +#include +/* Use the same register names and assignments as memset. */ + + .arch armv8.5-a + .arch_extension memtag + +/* NB, only supported on variants with 64-bit pointers. */ + +/* FIXME: This is a minimal implementation. We could do better than + this for larger values of COUNT. */ + +#define dstin x0 +#define count x1 +#define dst x2 + +ENTRY_ALIGN(__libc_mtag_tag_region, 6) + + mov dst, dstin +L(loop): + stg dst, [dst], #16 + subs count, count, 16 + bne L(loop) + ldg dstin, [dstin] // Recover the tag created (might be untagged). + ret +END (__libc_mtag_tag_region) +libc_hidden_builtin_def (__libc_mtag_tag_region) diff --git a/sysdeps/aarch64/libc-mtag.h b/sysdeps/aarch64/libc-mtag.h new file mode 100644 index 0000000000..9c7d00c541 --- /dev/null +++ b/sysdeps/aarch64/libc-mtag.h @@ -0,0 +1,57 @@ +/* libc-internal interface for tagged (colored) memory support. + Copyright (C) 2020 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#ifndef _AARCH64_LIBC_MTAG_H +#define _AARCH64_LIBC_MTAG_H 1 + +#ifndef _LIBC_MTAG +/* Generic bindings for systems that do not support memory tagging. */ +#include_next "libc-mtag.h" +#else + +/* Used to ensure additional alignment when objects need to have distinct + tags. */ +#define __MTAG_GRANULE_SIZE 16 + +/* Non-zero if memory obtained via morecore (sbrk) is not tagged. */ +#define __MTAG_SBRK_UNTAGGED 1 + +/* Extra flags to pass to mmap to get tagged pages. */ +#define __MTAG_MMAP_FLAGS PROT_MTE + +/* Set the tags for a region of memory, which must have size and alignment + that are multiples of __MTAG_GRANULE_SIZE. Size cannot be zero. + void *__libc_mtag_tag_region (const void *, size_t) */ +void *__libc_mtag_tag_region (void *, size_t); + +/* Optimized equivalent to __libc_mtag_tag_region followed by memset. */ +void *__libc_mtag_memset_with_tag(void *, int, size_t); + +/* Convert address P to a pointer that is tagged correctly for that + location. + void *__libc_mtag_address_get_tag (void*) */ +void *__libc_mtag_address_get_tag(void *); + +/* Assign a new (random) tag to a pointer P (does not adjust the tag on + the memory addressed). + void *__libc_mtag_new_tag (void*) */ +void *__libc_mtag_new_tag(void *); + +#endif /* _LIBC_MTAG */ + +#endif /* _AARCH64_LIBC_MTAG_H */