From 0221ce2a90be2d40fc90f0b5dcec77a1ec013f53 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 12 Jun 2018 06:23:28 -0700 Subject: i386: Change offset of __private_ss to 0x30 [BZ #23250] 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; The offset of __private_ss is 0x34. But GCC defines /* We steal the last transactional memory word. */ #define TARGET_THREAD_SPLIT_STACK_OFFSET 0x30 and libgcc/config/i386/morestack.S has cmpl %gs:0x30,%eax # See if we have enough space. movl %eax,%gs:0x30 # Save the new stack boundary. movl %eax,%gs:0x30 # Save the new stack boundary. movl %ecx,%gs:0x30 # Save new stack boundary. movl %eax,%gs:0x30 movl %gs:0x30,%eax movl %eax,%gs:0x30 Since update TARGET_THREAD_SPLIT_STACK_OFFSET changes split stack ABI, this patch updates tcbhead_t to match GCC. [BZ #23250] [BZ #10686] * sysdeps/i386/nptl/tls.h (tcbhead_t): Change __private_tm[4] to _private_tm[3] and add __glibc_reserved2. Add _Static_assert of offset of __private_ss == 0x30. * sysdeps/x86_64/nptl/tls.h: Add _Static_assert of offset of __private_ss == 0x40 for ILP32 and == 0x70 for LP64. --- sysdeps/x86_64/nptl/tls.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'sysdeps/x86_64/nptl') diff --git a/sysdeps/x86_64/nptl/tls.h b/sysdeps/x86_64/nptl/tls.h index 6da1c04a98..65c0051dcf 100644 --- a/sysdeps/x86_64/nptl/tls.h +++ b/sysdeps/x86_64/nptl/tls.h @@ -65,6 +65,16 @@ typedef struct void *__padding[8]; } tcbhead_t; +# ifdef __ILP32__ +/* morestack.S in libgcc uses offset 0x40 to access __private_ss, */ +_Static_assert (offsetof (tcbhead_t, __private_ss) == 0x40, + "offset of __private_ss != 0x40"); +# else +/* morestack.S in libgcc uses offset 0x70 to access __private_ss, */ +_Static_assert (offsetof (tcbhead_t, __private_ss) == 0x70, + "offset of __private_ss != 0x70"); +# endif + #else /* __ASSEMBLER__ */ # include #endif -- cgit v1.2.3