@@ -134,6 +134,6 @@ along with GCC; see the file COPYING3. If not see
/* i386 glibc provides __stack_chk_guard in %gs:0x14. */
#define TARGET_THREAD_SSP_OFFSET 0x14
-/* We steal the last transactional memory word. */
-#define TARGET_THREAD_SPLIT_STACK_OFFSET 0x30
+/* i386 glibc provides __private_ss in %gs:0x34. */
+#define TARGET_THREAD_SPLIT_STACK_OFFSET 0x34
#endif
@@ -86,9 +86,11 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#define TARGET_THREAD_SSP_OFFSET \
(TARGET_64BIT ? (TARGET_X32 ? 0x18 : 0x28) : 0x14)
-/* We steal the last transactional memory word. */
+/* i386 glibc provides __private_ss in %gs:0x34,
+ x32 glibc provides it in %fs:0x40.
+ x86_64 glibc provides it in %fs:0x70. */
#define TARGET_THREAD_SPLIT_STACK_OFFSET \
- (TARGET_64BIT ? (TARGET_X32 ? 0x40 : 0x70) : 0x30)
+ (TARGET_64BIT ? (TARGET_X32 ? 0x40 : 0x70) : 0x34)
#endif
#undef WCHAR_TYPE
TARGET_THREAD_SPLIT_STACK_OFFSET has been wrong for Linux/i386 from the start. Should we change glibc for GCC's mistake or fix GCC? H.J. --- 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; Update i386 TARGET_THREAD_SPLIT_STACK_OFFSET to 0x34 to match the offset of __private_ss. PR target/85990 * config/i386/gnu-user.h (TARGET_THREAD_SPLIT_STACK_OFFSET): Set to 0x34. * config/i386/gnu-user64.h (TARGET_THREAD_SPLIT_STACK_OFFSET): Set to 0x34 for -m32. --- gcc/config/i386/gnu-user.h | 4 ++-- gcc/config/i386/gnu-user64.h | 6 ++++-- 2 files changed, 6 insertions(+), 4 deletions(-)