[1/8] x86-64 memchr/wmemchr: Properly handle the length parameter [BZ# 24097]
Commit Message
On x32, the size_t parameter may be passed in the lower 32 bits of a
64-bit register with the non-zero upper 32 bits. The string/memory
functions written in assembly can only use the lower 32 bits of a
64-bit register as length or must clear the upper 32 bits before using
the full 64-bit register for length.
This pach fixes memchr/wmemchr for x32. Tested on x86-64 and x32. On
x86-64, libc.so is the same with and withou the fix.
[BZ# 24097]
* sysdeps/x86_64/memchr.S: Use RDX_LP for length. Clear the
upper 32 bits of RDX register.
* sysdeps/x86_64/multiarch/memchr-avx2.S: Likewise.
* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memchr and
tst-size_t-wmemchr.
* sysdeps/x86_64/x32/test-size_t.h: New file.
* sysdeps/x86_64/x32/tst-size_t-memchr.c: Likewise.
* sysdeps/x86_64/x32/tst-size_t-wmemchr.c: Likewise.
---
sysdeps/x86_64/memchr.S | 10 +-
sysdeps/x86_64/multiarch/memchr-avx2.S | 8 +-
sysdeps/x86_64/x32/Makefile | 8 ++
sysdeps/x86_64/x32/test-size_t.h | 170 ++++++++++++++++++++++++
sysdeps/x86_64/x32/tst-size_t-memchr.c | 72 ++++++++++
sysdeps/x86_64/x32/tst-size_t-wmemchr.c | 20 +++
6 files changed, 283 insertions(+), 5 deletions(-)
create mode 100644 sysdeps/x86_64/x32/test-size_t.h
create mode 100644 sysdeps/x86_64/x32/tst-size_t-memchr.c
create mode 100644 sysdeps/x86_64/x32/tst-size_t-wmemchr.c
Comments
On Thu, Jan 17, 2019 at 8:54 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On x32, the size_t parameter may be passed in the lower 32 bits of a
> 64-bit register with the non-zero upper 32 bits. The string/memory
> functions written in assembly can only use the lower 32 bits of a
> 64-bit register as length or must clear the upper 32 bits before using
> the full 64-bit register for length.
>
> This pach fixes memchr/wmemchr for x32. Tested on x86-64 and x32. On
> x86-64, libc.so is the same with and withou the fix.
>
> [BZ# 24097]
> * sysdeps/x86_64/memchr.S: Use RDX_LP for length. Clear the
> upper 32 bits of RDX register.
> * sysdeps/x86_64/multiarch/memchr-avx2.S: Likewise.
> * sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memchr and
> tst-size_t-wmemchr.
> * sysdeps/x86_64/x32/test-size_t.h: New file.
> * sysdeps/x86_64/x32/tst-size_t-memchr.c: Likewise.
> * sysdeps/x86_64/x32/tst-size_t-wmemchr.c: Likewise.
> diff --git a/sysdeps/x86_64/x32/test-size_t.h b/sysdeps/x86_64/x32/test-size_t.h
> new file mode 100644
> index 0000000000..fbef565bda
> --- /dev/null
> +++ b/sysdeps/x86_64/x32/test-size_t.h
> @@ -0,0 +1,170 @@
> +/* Test string/memory functions with size_t in the lower 32 bits of
> + 64-bit register.
> + 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
> + <http://www.gnu.org/licenses/>. */
> +
> +#include <stdint.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/mman.h>
> +#include <sys/param.h>
> +#include <unistd.h>
> +#include <fcntl.h>
> +#include <error.h>
> +#include <errno.h>
> +#include <time.h>
> +#include <ifunc-impl-list.h>
> +
> +/* On x32, parameter_t may be passed in a 64-bit register with the LEN
> + field in the lower 32 bits. When the LEN field of 64-bit register
> + is passed to string/memory function as the size_t parameter, only
> + the lower 32 bits can be used. */
> +typedef struct
> +{
> + union
> + {
> + size_t len;
> + void (*fn) (void);
> + };
> + void *p;
> +} parameter_t;
> +
> +typedef struct
> +{
> + const char *name;
> + void (*fn) (void);
> + long test;
> +} impl_t;
> +extern impl_t __start_impls[], __stop_impls[];
> +
> +#define IMPL(name, test) \
> + impl_t tst_ ## name \
> + __attribute__ ((section ("impls"), aligned (sizeof (void *)))) \
> + = { __STRING (name), (void (*) (void))name, test };
> +
> +#ifndef _GNU_SOURCE
> +#define _GNU_SOURCE
> +#endif
> +
> +#undef __USE_STRING_INLINES
> +
> +/* We are compiled under _ISOMAC, so libc-symbols.h does not do this
> + for us. */
> +#include "config.h"
> +#ifdef HAVE_CC_INHIBIT_LOOP_TO_LIBCALL
> +# define inhibit_loop_to_libcall \
> + __attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns")))
> +#else
> +# define inhibit_loop_to_libcall
> +#endif
> +
> +#define GL(x) _##x
> +#define GLRO(x) _##x
> +
> +unsigned char *buf1, *buf2;
> +size_t page_size;
> +
> +#define CALL(parm, ...) \
> + (* (proto_t) (parm).fn) (__VA_ARGS__)
> +
> +#ifdef TEST_NAME
> +/* Increase size of FUNC_LIST if assert is triggered at run-time. */
> +static struct libc_ifunc_impl func_list[32];
> +static int func_count;
> +static int impl_count = -1;
> +static impl_t *impl_array;
> +
> +# define FOR_EACH_IMPL(impl, notall) \
> + impl_t *impl; \
> + int count; \
> + if (impl_count == -1) \
> + { \
> + impl_count = 0; \
> + if (func_count != 0) \
> + { \
> + int f; \
> + impl_t *skip = NULL, *a; \
> + for (impl = __start_impls; impl < __stop_impls; ++impl) \
> + if (strcmp (impl->name, TEST_NAME) == 0) \
> + skip = impl; \
> + else \
> + impl_count++; \
> + a = impl_array = malloc ((impl_count + func_count) * \
> + sizeof (impl_t)); \
> + for (impl = __start_impls; impl < __stop_impls; ++impl) \
> + if (impl != skip) \
> + *a++ = *impl; \
> + for (f = 0; f < func_count; f++) \
> + if (func_list[f].usable) \
> + { \
> + a->name = func_list[f].name; \
> + a->fn = func_list[f].fn; \
> + a->test = 1; \
> + a++; \
> + } \
> + impl_count = a - impl_array; \
> + } \
> + else \
> + { \
> + impl_count = __stop_impls - __start_impls; \
> + impl_array = __start_impls; \
> + } \
> + } \
> + impl = impl_array; \
> + for (count = 0; count < impl_count; ++count, ++impl) \
> + if (!notall || impl->test)
> +#else
> +# define FOR_EACH_IMPL(impl, notall) \
> + for (impl_t *impl = __start_impls; impl < __stop_impls; ++impl) \
> + if (!notall || impl->test)
> +#endif
> +
> +#ifndef BUF1PAGES
> +# define BUF1PAGES 1
> +#endif
> +
> +static void
> +test_init (void)
> +{
> +#ifdef TEST_NAME
> + func_count = __libc_ifunc_impl_list (TEST_NAME, func_list,
> + (sizeof func_list
> + / sizeof func_list[0]));
> +#endif
> +
> + page_size = 2 * getpagesize ();
> +#ifdef MIN_PAGE_SIZE
> + if (page_size < MIN_PAGE_SIZE)
> + page_size = MIN_PAGE_SIZE;
> +#endif
> + buf1 = mmap (0, (BUF1PAGES + 1) * page_size, PROT_READ | PROT_WRITE,
> + MAP_PRIVATE | MAP_ANON, -1, 0);
> + if (buf1 == MAP_FAILED)
> + error (EXIT_FAILURE, errno, "mmap failed");
> + if (mprotect (buf1 + BUF1PAGES * page_size, page_size, PROT_NONE))
> + error (EXIT_FAILURE, errno, "mprotect failed");
> + buf2 = mmap (0, 2 * page_size, PROT_READ | PROT_WRITE,
> + MAP_PRIVATE | MAP_ANON, -1, 0);
> + if (buf2 == MAP_FAILED)
> + error (EXIT_FAILURE, errno, "mmap failed");
> + if (mprotect (buf2 + page_size, page_size, PROT_NONE))
> + error (EXIT_FAILURE, errno, "mprotect failed");
> +
> + memset (buf1, 0xa5, BUF1PAGES * page_size);
> + memset (buf2, 0x5a, page_size);
> +}
We can reuse <string/test-string.h>:
#define TEST_MAIN
#include <string/test-string.h>
/* On x32, parameter_t may be passed in a 64-bit register with the LEN
field in the lower 32 bits. When the LEN field of 64-bit register
is passed to string/memory function as the size_t parameter, only
the lower 32 bits can be used. */
typedef struct
{
union
{
size_t len;
void (*fn) (void);
};
void *p;
} parameter_t;
@@ -34,12 +34,16 @@ ENTRY(MEMCHR)
mov %edi, %ecx
#ifdef USE_AS_WMEMCHR
- test %rdx, %rdx
+ test %RDX_LP, %RDX_LP
jz L(return_null)
- shl $2, %rdx
+ shl $2, %RDX_LP
#else
+# ifdef __ILP32__
+ /* Clear the upper 32 bits. */
+ movl %edx, %edx
+# endif
punpcklbw %xmm1, %xmm1
- test %rdx, %rdx
+ test %RDX_LP, %RDX_LP
jz L(return_null)
punpcklbw %xmm1, %xmm1
#endif
@@ -40,16 +40,20 @@
ENTRY (MEMCHR)
# ifndef USE_AS_RAWMEMCHR
/* Check for zero length. */
- testq %rdx, %rdx
+ test %RDX_LP, %RDX_LP
jz L(null)
# endif
movl %edi, %ecx
/* Broadcast CHAR to YMM0. */
vmovd %esi, %xmm0
# ifdef USE_AS_WMEMCHR
- shl $2, %rdx
+ shl $2, %RDX_LP
vpbroadcastd %xmm0, %ymm0
# else
+# ifdef __ILP32__
+ /* Clear the upper 32 bits. */
+ movl %edx, %edx
+# endif
vpbroadcastb %xmm0, %ymm0
# endif
/* Check if we may cross page boundary with one vector load. */
@@ -4,3 +4,11 @@ ifeq ($(subdir),math)
# 64-bit llround. Add -fno-builtin-lround to silence the compiler.
CFLAGS-s_llround.c += -fno-builtin-lround
endif
+
+ifeq ($(subdir),string)
+tests += tst-size_t-memchr
+endif
+
+ifeq ($(subdir),wcsmbs)
+tests += tst-size_t-wmemchr
+endif
new file mode 100644
@@ -0,0 +1,170 @@
+/* Test string/memory functions with size_t in the lower 32 bits of
+ 64-bit register.
+ 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/param.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <error.h>
+#include <errno.h>
+#include <time.h>
+#include <ifunc-impl-list.h>
+
+/* On x32, parameter_t may be passed in a 64-bit register with the LEN
+ field in the lower 32 bits. When the LEN field of 64-bit register
+ is passed to string/memory function as the size_t parameter, only
+ the lower 32 bits can be used. */
+typedef struct
+{
+ union
+ {
+ size_t len;
+ void (*fn) (void);
+ };
+ void *p;
+} parameter_t;
+
+typedef struct
+{
+ const char *name;
+ void (*fn) (void);
+ long test;
+} impl_t;
+extern impl_t __start_impls[], __stop_impls[];
+
+#define IMPL(name, test) \
+ impl_t tst_ ## name \
+ __attribute__ ((section ("impls"), aligned (sizeof (void *)))) \
+ = { __STRING (name), (void (*) (void))name, test };
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#undef __USE_STRING_INLINES
+
+/* We are compiled under _ISOMAC, so libc-symbols.h does not do this
+ for us. */
+#include "config.h"
+#ifdef HAVE_CC_INHIBIT_LOOP_TO_LIBCALL
+# define inhibit_loop_to_libcall \
+ __attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns")))
+#else
+# define inhibit_loop_to_libcall
+#endif
+
+#define GL(x) _##x
+#define GLRO(x) _##x
+
+unsigned char *buf1, *buf2;
+size_t page_size;
+
+#define CALL(parm, ...) \
+ (* (proto_t) (parm).fn) (__VA_ARGS__)
+
+#ifdef TEST_NAME
+/* Increase size of FUNC_LIST if assert is triggered at run-time. */
+static struct libc_ifunc_impl func_list[32];
+static int func_count;
+static int impl_count = -1;
+static impl_t *impl_array;
+
+# define FOR_EACH_IMPL(impl, notall) \
+ impl_t *impl; \
+ int count; \
+ if (impl_count == -1) \
+ { \
+ impl_count = 0; \
+ if (func_count != 0) \
+ { \
+ int f; \
+ impl_t *skip = NULL, *a; \
+ for (impl = __start_impls; impl < __stop_impls; ++impl) \
+ if (strcmp (impl->name, TEST_NAME) == 0) \
+ skip = impl; \
+ else \
+ impl_count++; \
+ a = impl_array = malloc ((impl_count + func_count) * \
+ sizeof (impl_t)); \
+ for (impl = __start_impls; impl < __stop_impls; ++impl) \
+ if (impl != skip) \
+ *a++ = *impl; \
+ for (f = 0; f < func_count; f++) \
+ if (func_list[f].usable) \
+ { \
+ a->name = func_list[f].name; \
+ a->fn = func_list[f].fn; \
+ a->test = 1; \
+ a++; \
+ } \
+ impl_count = a - impl_array; \
+ } \
+ else \
+ { \
+ impl_count = __stop_impls - __start_impls; \
+ impl_array = __start_impls; \
+ } \
+ } \
+ impl = impl_array; \
+ for (count = 0; count < impl_count; ++count, ++impl) \
+ if (!notall || impl->test)
+#else
+# define FOR_EACH_IMPL(impl, notall) \
+ for (impl_t *impl = __start_impls; impl < __stop_impls; ++impl) \
+ if (!notall || impl->test)
+#endif
+
+#ifndef BUF1PAGES
+# define BUF1PAGES 1
+#endif
+
+static void
+test_init (void)
+{
+#ifdef TEST_NAME
+ func_count = __libc_ifunc_impl_list (TEST_NAME, func_list,
+ (sizeof func_list
+ / sizeof func_list[0]));
+#endif
+
+ page_size = 2 * getpagesize ();
+#ifdef MIN_PAGE_SIZE
+ if (page_size < MIN_PAGE_SIZE)
+ page_size = MIN_PAGE_SIZE;
+#endif
+ buf1 = mmap (0, (BUF1PAGES + 1) * page_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANON, -1, 0);
+ if (buf1 == MAP_FAILED)
+ error (EXIT_FAILURE, errno, "mmap failed");
+ if (mprotect (buf1 + BUF1PAGES * page_size, page_size, PROT_NONE))
+ error (EXIT_FAILURE, errno, "mprotect failed");
+ buf2 = mmap (0, 2 * page_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANON, -1, 0);
+ if (buf2 == MAP_FAILED)
+ error (EXIT_FAILURE, errno, "mmap failed");
+ if (mprotect (buf2 + page_size, page_size, PROT_NONE))
+ error (EXIT_FAILURE, errno, "mprotect failed");
+
+ memset (buf1, 0xa5, BUF1PAGES * page_size);
+ memset (buf2, 0x5a, page_size);
+}
new file mode 100644
@@ -0,0 +1,72 @@
+/* Test memchr with size_t in the lower 32 bits of 64-bit register.
+ 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
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef WIDE
+# define TEST_NAME "memchr"
+#else
+# define TEST_NAME "wmemchr"
+#endif /* WIDE */
+#include "test-size_t.h"
+
+#ifndef WIDE
+# define MEMCHR memchr
+# define CHAR char
+# define UCHAR unsigned char
+#else
+# include <wchar.h>
+# define MEMCHR wmemchr
+# define CHAR wchar_t
+# define UCHAR wchar_t
+#endif /* WIDE */
+
+IMPL (MEMCHR, 1)
+
+typedef CHAR * (*proto_t) (const CHAR*, int, size_t);
+
+static CHAR *
+__attribute__ ((noinline, noclone))
+do_memchr (parameter_t a, parameter_t b)
+{
+ return CALL (b, a.p, (uintptr_t) b.p, a.len);
+}
+
+static int
+do_test (void)
+{
+ test_init ();
+
+ parameter_t src = { { page_size / sizeof (CHAR) }, buf2 };
+ parameter_t c = { { 0 }, (void *) (uintptr_t) 0x12 };
+
+ int ret = 0;
+ FOR_EACH_IMPL (impl, 0)
+ {
+ c.fn = impl->fn;
+ CHAR *res = do_memchr (src, c);
+ if (res)
+ {
+ error (0, 0, "Wrong result in function %s: %p != NULL",
+ impl->name, res);
+ ret = 1;
+ }
+ }
+
+ return ret ? EXIT_FAILURE : EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>
new file mode 100644
@@ -0,0 +1,20 @@
+/* Test wmemchr with size_t in the lower 32 bits of 64-bit register.
+ 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
+ <http://www.gnu.org/licenses/>. */
+
+#define WIDE 1
+#include "tst-size_t-memchr.c"