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.
