V2: [PATCH 01/24] x86: Rename __glibc_reserved1 to feature_1 in tcbhead_t [BZ #22563]
Commit Message
On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
> This will be used by CET run-time control.
>
> [BZ #22563]
> * nptl/pthread_create.c (__pthread_create_2_1): Use
> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
> Likewise.
> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
> to feature_1.
> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
Here is the updated patch to add feature_1 to tcbhead_t and
introduce macros for CET enabling. OK for master?
H.J.
----
feature_1 has X86_FEATURE_1_IBT and X86_FEATURE_1_SHSTK bits for CET
run-time control.
CET_ENABLED, IBT_ENABLED and SHSTK_ENABLED are defined to 1 or 0 to
indicate that if CET, IBT and SHSTK are enabled.
[BZ #22563]
* nptl/pthread_create.c (__pthread_create_2_1): Use
THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
* sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
* sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
Likewise.
* sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
to feature_1.
* sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
* sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
* sysdeps/x86/sysdep.h (X86_FEATURE_1_IBT): New.
(X86_FEATURE_1_SHSTK): Likewise.
(CET_ENABLED): Likewise.
(IBT_ENABLED): Likewise.
(SHSTK_ENABLED): Likewise.
---
nptl/pthread_create.c | 5 +++++
sysdeps/i386/nptl/tcb-offsets.sym | 1 +
sysdeps/i386/nptl/tls.h | 5 ++++-
sysdeps/unix/sysv/linux/x86/pthreaddef.h | 24 +++++++++++++++++++++
sysdeps/x86/sysdep.h | 27 ++++++++++++++++++++++++
sysdeps/x86_64/nptl/tcb-offsets.sym | 1 +
sysdeps/x86_64/nptl/tls.h | 5 ++++-
7 files changed, 66 insertions(+), 2 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/x86/pthreaddef.h
Comments
On 07/13/2018 09:19 AM, H.J. Lu wrote:
> On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
>> This will be used by CET run-time control.
>>
>> [BZ #22563]
>> * nptl/pthread_create.c (__pthread_create_2_1): Use
>> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
>> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
>> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
>> Likewise.
>> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
>> to feature_1.
>> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
>> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
>
> Here is the updated patch to add feature_1 to tcbhead_t and
> introduce macros for CET enabling. OK for master?
Fix the typo-prone macro API and post a v3 please.
Thank you.
>
> H.J.
> ----
> feature_1 has X86_FEATURE_1_IBT and X86_FEATURE_1_SHSTK bits for CET
> run-time control.
>
> CET_ENABLED, IBT_ENABLED and SHSTK_ENABLED are defined to 1 or 0 to
> indicate that if CET, IBT and SHSTK are enabled.
OK.
>
> [BZ #22563]
> * nptl/pthread_create.c (__pthread_create_2_1): Use
> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
> Likewise.
> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
> to feature_1.
> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
> * sysdeps/x86/sysdep.h (X86_FEATURE_1_IBT): New.
> (X86_FEATURE_1_SHSTK): Likewise.
> (CET_ENABLED): Likewise.
> (IBT_ENABLED): Likewise.
> (SHSTK_ENABLED): Likewise.
> ---
> nptl/pthread_create.c | 5 +++++
> sysdeps/i386/nptl/tcb-offsets.sym | 1 +
> sysdeps/i386/nptl/tls.h | 5 ++++-
> sysdeps/unix/sysv/linux/x86/pthreaddef.h | 24 +++++++++++++++++++++
> sysdeps/x86/sysdep.h | 27 ++++++++++++++++++++++++
> sysdeps/x86_64/nptl/tcb-offsets.sym | 1 +
> sysdeps/x86_64/nptl/tls.h | 5 ++++-
> 7 files changed, 66 insertions(+), 2 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/x86/pthreaddef.h
>
> diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
> index 92c945b12b..16998f4bbd 100644
> --- a/nptl/pthread_create.c
> +++ b/nptl/pthread_create.c
> @@ -712,6 +712,11 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
> THREAD_COPY_POINTER_GUARD (pd);
> #endif
>
> + /* Copy additonal info. */
> +#ifdef THREAD_COPY_ADDITONAL_INFO
> + THREAD_COPY_ADDITONAL_INFO (pd);
> +#endif
This is a typo-prone macro API.
Please find a way to define this unconditionally.
> +
> /* Verify the sysinfo bits were copied in allocate_stack if needed. */
> #ifdef NEED_DL_SYSINFO
> CHECK_THREAD_SYSINFO (pd);
> diff --git a/sysdeps/i386/nptl/tcb-offsets.sym b/sysdeps/i386/nptl/tcb-offsets.sym
> index 7d7fe5e71c..fbac241c45 100644
> --- a/sysdeps/i386/nptl/tcb-offsets.sym
> +++ b/sysdeps/i386/nptl/tcb-offsets.sym
> @@ -12,3 +12,4 @@ CLEANUP offsetof (struct pthread, cleanup)
> CLEANUP_PREV offsetof (struct _pthread_cleanup_buffer, __prev)
> MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
> POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
> +FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
> diff --git a/sysdeps/i386/nptl/tls.h b/sysdeps/i386/nptl/tls.h
> index afb71ce431..21e23cd809 100644
> --- a/sysdeps/i386/nptl/tls.h
> +++ b/sysdeps/i386/nptl/tls.h
> @@ -41,7 +41,10 @@ typedef struct
> uintptr_t stack_guard;
> uintptr_t pointer_guard;
> int gscope_flag;
> - int __glibc_reserved1;
> + /* Bit 0: X86_FEATURE_1_IBT.
> + Bit 1: X86_FEATURE_1_SHSTK.
> + */
> + unsigned int feature_1;
OK.
> /* Reservation of some values for the TM ABI. */
> void *__private_tm[3];
> /* GCC split stack support. */
> diff --git a/sysdeps/unix/sysv/linux/x86/pthreaddef.h b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
> new file mode 100644
> index 0000000000..539f6540d0
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/x86/pthreaddef.h
> @@ -0,0 +1,24 @@
> +/* Pthread macros. Linux/x86 version.
> + Copyright (C) 2018 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_next <pthreaddef.h>
> +
> +/* Wee need to copy feature_1 in pthread_create. */
> +#define THREAD_COPY_ADDITONAL_INFO(descr) \
> + ((descr)->header.feature_1 \
> + = THREAD_GETMEM (THREAD_SELF, header.feature_1))
OK.
> diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h
> index afcb7cfd76..976566aa37 100644
> --- a/sysdeps/x86/sysdep.h
> +++ b/sysdeps/x86/sysdep.h
> @@ -21,6 +21,33 @@
>
> #include <sysdeps/generic/sysdep.h>
>
> +/* __CET__ is defined by GCC with Control-Flow Protection values:
> +
> +enum cf_protection_level
> +{
> + CF_NONE = 0,
> + CF_BRANCH = 1 << 0,
> + CF_RETURN = 1 << 1,
> + CF_FULL = CF_BRANCH | CF_RETURN,
> + CF_SET = 1 << 2
> +};
> +*/
> +
> +/* Set if CF_BRANCH (IBT) is enabled. */
> +#define X86_FEATURE_1_IBT (1U << 0)
OK. Thanks for defining this, it makes the assembly easier to read.
> +/* Set if CF_RETURN (SHSTK) is enabled. */
> +#define X86_FEATURE_1_SHSTK (1U << 1)
OK.
> +
> +#ifdef __CET__
> +# define CET_ENABLED 1
> +# define IBT_ENABLED (__CET__ & X86_FEATURE_1_IBT)
> +# define SHSTK_ENABLED (__CET__ & X86_FEATURE_1_SHSTK)
> +#else
> +# define CET_ENABLED 0
> +# define IBT_ENABLED 0
> +# define SHSTK_ENABLED 0
> +#endif
> +
> #ifdef __ASSEMBLER__
>
> /* Syntactic details of assembler. */
> diff --git a/sysdeps/x86_64/nptl/tcb-offsets.sym b/sysdeps/x86_64/nptl/tcb-offsets.sym
> index be63404a16..387621e88c 100644
> --- a/sysdeps/x86_64/nptl/tcb-offsets.sym
> +++ b/sysdeps/x86_64/nptl/tcb-offsets.sym
> @@ -12,6 +12,7 @@ MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
> MULTIPLE_THREADS_OFFSET offsetof (tcbhead_t, multiple_threads)
> POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
> VGETCPU_CACHE_OFFSET offsetof (tcbhead_t, vgetcpu_cache)
> +FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
OK.
>
> -- Not strictly offsets, but these values are also used in the TCB.
> TCB_CANCELSTATE_BITMASK CANCELSTATE_BITMASK
> diff --git a/sysdeps/x86_64/nptl/tls.h b/sysdeps/x86_64/nptl/tls.h
> index 65c0051dcf..f042a0250a 100644
> --- a/sysdeps/x86_64/nptl/tls.h
> +++ b/sysdeps/x86_64/nptl/tls.h
> @@ -51,7 +51,10 @@ typedef struct
> uintptr_t stack_guard;
> uintptr_t pointer_guard;
> unsigned long int vgetcpu_cache[2];
> - int __glibc_reserved1;
> + /* Bit 0: X86_FEATURE_1_IBT.
> + Bit 1: X86_FEATURE_1_SHSTK.
> + */
> + unsigned int feature_1;
OK.
> int __glibc_unused1;
> /* Reservation of some values for the TM ABI. */
> void *__private_tm[4];
>
Cheers,
Carlos.
On 07/13/2018 12:51 PM, Carlos O'Donell wrote:
> On 07/13/2018 09:19 AM, H.J. Lu wrote:
>> On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
>>> This will be used by CET run-time control.
>>>
>>> [BZ #22563]
>>> * nptl/pthread_create.c (__pthread_create_2_1): Use
>>> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
>>> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
>>> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
>>> Likewise.
>>> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
>>> to feature_1.
>>> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
>>> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
>>
>> Here is the updated patch to add feature_1 to tcbhead_t and
>> introduce macros for CET enabling. OK for master?
>
> Fix the typo-prone macro API and post a v3 please.
>
> Thank you.
Umm, has this been tested with the sanitizers? I thought they used that
field.
jeff
On 07/13/2018 02:55 PM, Jeff Law wrote:
> On 07/13/2018 12:51 PM, Carlos O'Donell wrote:
>> On 07/13/2018 09:19 AM, H.J. Lu wrote:
>>> On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
>>>> This will be used by CET run-time control.
>>>>
>>>> [BZ #22563]
>>>> * nptl/pthread_create.c (__pthread_create_2_1): Use
>>>> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
>>>> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
>>>> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
>>>> Likewise.
>>>> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
>>>> to feature_1.
>>>> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
>>>> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
>>>
>>> Here is the updated patch to add feature_1 to tcbhead_t and
>>> introduce macros for CET enabling. OK for master?
>>
>> Fix the typo-prone macro API and post a v3 please.
>>
>> Thank you.
> Umm, has this been tested with the sanitizers? I thought they used that
> field.
The size of tcbhead_t has not changed, which is something that might impact
the santiziers.
But now that you mention it, why do I vaguely remember a conversation about
the santizers using the reserved bytes as storage for themselves?
Is that what you are talking about?
HJ, could you look into this please?
I think the sanitizers are not within their rights to use any bytes in the
tcbhead_t structure, particularly reserved bytes. We should coordinate with
them, but that should not stop the acceptance of this patch in 2.28.
Cheers,
Carlos.
On 07/13/2018 01:05 PM, Carlos O'Donell wrote:
> On 07/13/2018 02:55 PM, Jeff Law wrote:
>> On 07/13/2018 12:51 PM, Carlos O'Donell wrote:
>>> On 07/13/2018 09:19 AM, H.J. Lu wrote:
>>>> On Wed, Jun 13, 2018 at 08:31:44AM -0700, H.J. Lu wrote:
>>>>> This will be used by CET run-time control.
>>>>>
>>>>> [BZ #22563]
>>>>> * nptl/pthread_create.c (__pthread_create_2_1): Use
>>>>> THREAD_COPY_ADDITONAL_INFO to copy additonal info if defined.
>>>>> * sysdeps/i386/nptl/tcb-offsets.sym (FEATURE_1_OFFSET): New.
>>>>> * sysdeps/x86_64/nptl/tcb-offsets.sym (FEATURE_1_OFFSET):
>>>>> Likewise.
>>>>> * sysdeps/i386/nptl/tls.h (tcbhead_t): Rename __glibc_reserved1
>>>>> to feature_1.
>>>>> * sysdeps/x86_64/nptl/tls.h (tcbhead_t): Likewise.
>>>>> * sysdeps/unix/sysv/linux/x86/pthreaddef.h: New file.
>>>>
>>>> Here is the updated patch to add feature_1 to tcbhead_t and
>>>> introduce macros for CET enabling. OK for master?
>>>
>>> Fix the typo-prone macro API and post a v3 please.
>>>
>>> Thank you.
>> Umm, has this been tested with the sanitizers? I thought they used that
>> field.
>
> The size of tcbhead_t has not changed, which is something that might impact
> the santiziers.
>
> But now that you mention it, why do I vaguely remember a conversation about
> the santizers using the reserved bytes as storage for themselves?
>
> Is that what you are talking about?
>
> HJ, could you look into this please?
>
> I think the sanitizers are not within their rights to use any bytes in the
> tcbhead_t structure, particularly reserved bytes. We should coordinate with
> them, but that should not stop the acceptance of this patch in 2.28.
sanitizer_common/sanitizer_linux.cc:
static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
static const u32 kEsrMagic = 0x45535201;
u8 *aux = ucontext->uc_mcontext.__reserved;
while (true) {
_aarch64_ctx *ctx = (_aarch64_ctx *)aux;
if (ctx->size == 0) break;
if (ctx->magic == kEsrMagic) {
*esr = ((__sanitizer_esr_context *)ctx)->esr;
return true;
}
aux += ctx->size;
}
return false;
}
It's seriously lame that they're abusing the reserved field like that...
I see that HJ is just changing x86, so we may be OK here since the
sanitizer code in question is aarch64 specific.
Jeff
* Jeff Law:
> On 07/13/2018 01:05 PM, Carlos O'Donell wrote:
>> I think the sanitizers are not within their rights to use any bytes in the
>> tcbhead_t structure, particularly reserved bytes. We should coordinate with
>> them, but that should not stop the acceptance of this patch in 2.28.
> sanitizer_common/sanitizer_linux.cc:
>
> static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
> static const u32 kEsrMagic = 0x45535201;
> u8 *aux = ucontext->uc_mcontext.__reserved;
> while (true) {
> _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
> if (ctx->size == 0) break;
> if (ctx->magic == kEsrMagic) {
> *esr = ((__sanitizer_esr_context *)ctx)->esr;
> return true;
> }
> aux += ctx->size;
> }
> return false;
> }
>
> It's seriously lame that they're abusing the reserved field like that...
In this case, __reserved doesn't mean “reserved for future use”, but
“reserved as an allocation area for the kernel for dynamically sized
data structures”. This is part of the kernel/userspace API.
On 07/13/2018 03:16 PM, Florian Weimer wrote:
> * Jeff Law:
>
>> On 07/13/2018 01:05 PM, Carlos O'Donell wrote:
>>> I think the sanitizers are not within their rights to use any bytes in the
>>> tcbhead_t structure, particularly reserved bytes. We should coordinate with
>>> them, but that should not stop the acceptance of this patch in 2.28.
>> sanitizer_common/sanitizer_linux.cc:
>>
>> static bool Aarch64GetESR(ucontext_t *ucontext, u64 *esr) {
>> static const u32 kEsrMagic = 0x45535201;
>> u8 *aux = ucontext->uc_mcontext.__reserved;
>> while (true) {
>> _aarch64_ctx *ctx = (_aarch64_ctx *)aux;
>> if (ctx->size == 0) break;
>> if (ctx->magic == kEsrMagic) {
>> *esr = ((__sanitizer_esr_context *)ctx)->esr;
>> return true;
>> }
>> aux += ctx->size;
>> }
>> return false;
>> }
>>
>> It's seriously lame that they're abusing the reserved field like that...
>
> In this case, __reserved doesn't mean “reserved for future use”, but
> “reserved as an allocation area for the kernel for dynamically sized
> data structures”. This is part of the kernel/userspace API.
Right, and this isn't in the tcbhead_t structure either, this is the
on-stack uc_mcontext.
Cheers,
Carlos.
@@ -712,6 +712,11 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr,
THREAD_COPY_POINTER_GUARD (pd);
#endif
+ /* Copy additonal info. */
+#ifdef THREAD_COPY_ADDITONAL_INFO
+ THREAD_COPY_ADDITONAL_INFO (pd);
+#endif
+
/* Verify the sysinfo bits were copied in allocate_stack if needed. */
#ifdef NEED_DL_SYSINFO
CHECK_THREAD_SYSINFO (pd);
@@ -12,3 +12,4 @@ CLEANUP offsetof (struct pthread, cleanup)
CLEANUP_PREV offsetof (struct _pthread_cleanup_buffer, __prev)
MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
+FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
@@ -41,7 +41,10 @@ typedef struct
uintptr_t stack_guard;
uintptr_t pointer_guard;
int gscope_flag;
- int __glibc_reserved1;
+ /* Bit 0: X86_FEATURE_1_IBT.
+ Bit 1: X86_FEATURE_1_SHSTK.
+ */
+ unsigned int feature_1;
/* Reservation of some values for the TM ABI. */
void *__private_tm[3];
/* GCC split stack support. */
new file mode 100644
@@ -0,0 +1,24 @@
+/* Pthread macros. Linux/x86 version.
+ Copyright (C) 2018 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_next <pthreaddef.h>
+
+/* Wee need to copy feature_1 in pthread_create. */
+#define THREAD_COPY_ADDITONAL_INFO(descr) \
+ ((descr)->header.feature_1 \
+ = THREAD_GETMEM (THREAD_SELF, header.feature_1))
@@ -21,6 +21,33 @@
#include <sysdeps/generic/sysdep.h>
+/* __CET__ is defined by GCC with Control-Flow Protection values:
+
+enum cf_protection_level
+{
+ CF_NONE = 0,
+ CF_BRANCH = 1 << 0,
+ CF_RETURN = 1 << 1,
+ CF_FULL = CF_BRANCH | CF_RETURN,
+ CF_SET = 1 << 2
+};
+*/
+
+/* Set if CF_BRANCH (IBT) is enabled. */
+#define X86_FEATURE_1_IBT (1U << 0)
+/* Set if CF_RETURN (SHSTK) is enabled. */
+#define X86_FEATURE_1_SHSTK (1U << 1)
+
+#ifdef __CET__
+# define CET_ENABLED 1
+# define IBT_ENABLED (__CET__ & X86_FEATURE_1_IBT)
+# define SHSTK_ENABLED (__CET__ & X86_FEATURE_1_SHSTK)
+#else
+# define CET_ENABLED 0
+# define IBT_ENABLED 0
+# define SHSTK_ENABLED 0
+#endif
+
#ifdef __ASSEMBLER__
/* Syntactic details of assembler. */
@@ -12,6 +12,7 @@ MUTEX_FUTEX offsetof (pthread_mutex_t, __data.__lock)
MULTIPLE_THREADS_OFFSET offsetof (tcbhead_t, multiple_threads)
POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
VGETCPU_CACHE_OFFSET offsetof (tcbhead_t, vgetcpu_cache)
+FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
-- Not strictly offsets, but these values are also used in the TCB.
TCB_CANCELSTATE_BITMASK CANCELSTATE_BITMASK
@@ -51,7 +51,10 @@ typedef struct
uintptr_t stack_guard;
uintptr_t pointer_guard;
unsigned long int vgetcpu_cache[2];
- int __glibc_reserved1;
+ /* Bit 0: X86_FEATURE_1_IBT.
+ Bit 1: X86_FEATURE_1_SHSTK.
+ */
+ unsigned int feature_1;
int __glibc_unused1;
/* Reservation of some values for the TM ABI. */
void *__private_tm[4];