[PATCH] libitm/x86: Correct offsets of __private_tm and pointer_guard

[H.J. Lu]

On Tue, Jun 12, 2018 at 1:23 AM, Torvald Riegel <triegel@redhat.com> wrote:
> On Wed, 2018-05-30 at 07:54 -0700, H.J. Lu wrote:
>> In glibc, sysdeps/i386/nptl/tls.h has
>>
>> typedef struct
>> {
>>   void *tcb;            /* Pointer to the TCB.  Not necessarily the
>>                            thread descriptor used by libpthread.  */
>>   dtv_t *dtv;
>>   void *self;           /* Pointer to the thread descriptor.  */
>>   int multiple_threads;
>>   uintptr_t sysinfo;
>>   uintptr_t stack_guard;
>>   uintptr_t pointer_guard;
>>   int gscope_flag;
>>   int __glibc_reserved1;
>>   /* Reservation of some values for the TM ABI.  */
>>   void *__private_tm[4];
>>   /* GCC split stack support.  */
>>   void *__private_ss;
>> } tcbhead_t;
>>
>> and sysdeps/x86_64/nptl/tls.h has
>>
>> typedef struct
>> {
>>   void *tcb;            /* Pointer to the TCB.  Not necessarily the
>>                            thread descriptor used by libpthread.  */
>>   dtv_t *dtv;
>>   void *self;           /* Pointer to the thread descriptor.  */
>>   int multiple_threads;
>>   int gscope_flag;
>>   uintptr_t sysinfo;
>>   uintptr_t stack_guard;
>>   uintptr_t pointer_guard;
>>   unsigned long int vgetcpu_cache[2];
>>   int __glibc_reserved1;
>>   int __glibc_unused1;
>>   /* Reservation of some values for the TM ABI.  */
>>   void *__private_tm[4];
>>   /* GCC split stack support.  */
>>   void *__private_ss;
>>   long int __glibc_reserved2;
>>   /* Must be kept even if it is no longer used by glibc since programs,
>>      like AddressSanitizer, depend on the size of tcbhead_t.  */
>>   __128bits __glibc_unused2[8][4] __attribute__ ((aligned (32)));
>>
>>   void *__padding[8];
>> } tcbhead_t;
>>
>> The offsets of __private_tm are
>>
>> i386:   36 bytes
>> x32:    48 bytes
>> x86_64: 80 bytes
>>
>> and the offsets of pointer_guard are:
>>
>> i386:   24 bytes
>> x32:    28 bytes
>> x86_64: 48 bytes
>>
>> Update SEG_READ and SEG_WRITE to use the offset of __private_tm as base
>> and correct the offset of pointer_guard for x32.
>>
>> Tested on i686, x86-64 and x32.  OK for trunk and release branches?
>
> The patch itself looks okay to me, but the commit message is pretty
> cryptic.  I can't ack for release branches.
>

I checked in the patch with the updated commit message:

https://gcc.gnu.org/ml/gcc-cvs/2018-06/msg00446.html

Jakub, is this OK for release branches.

Thanks.

-- 
H.J.