From a25eadc86739fe3f4f0a35dfe6e5047978e2d2e5 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 12 Jun 2018 15:35:22 +0000 Subject: [PATCH] Linux/x86: Update TARGET_THREAD_SPLIT_STACK_OFFSET comments Glibc 2.18 was changed by commit ecbf434213c0333d81706074e4d107ac45011635 Author: Andreas Jaeger Date: Wed May 15 20:20:54 2013 +0200 Reserve new TLS field for x86 and x86_64 [BZ #10686] * sysdeps/x86_64/tls.h (struct tcbhead_t): Add __private_ss field. * sysdeps/i386/tls.h (struct tcbhead_t): Likewise. to reduce the size of __private_tm to make room for __private_ss, which was supposed to be used for TARGET_THREAD_SPLIT_STACK_OFFSET: 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; But the offset of __private_ss for i386 was mistakenly set to 0x30, instead of 0x34 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, glibc 2.28 has been changed by commit 0221ce2a90be2d40fc90f0b5dcec77a1ec013f53 Author: H.J. Lu Date: Tue Jun 12 06:23:28 2018 -0700 i386: Change offset of __private_ss to 0x30 [BZ #23250] to match GCC: 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[3]; /* GCC split stack support. */ void *__private_ss; void *__glibc_reserved2; } tcbhead_t; PR target/85990 * config/i386/gnu-user.h (TARGET_THREAD_SPLIT_STACK_OFFSET): Update comments. * config/i386/gnu-user64.h (TARGET_THREAD_SPLIT_STACK_OFFSET): Likewise. From-SVN: r261501 --- gcc/ChangeLog | 8 ++++++++ gcc/config/i386/gnu-user.h | 2 +- gcc/config/i386/gnu-user64.h | 4 +++- 3 files changed, 12 insertions(+), 2 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 610abcd8c0a..0170e1e8416 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2018-06-12 H.J. Lu + + PR target/85990 + * config/i386/gnu-user.h (TARGET_THREAD_SPLIT_STACK_OFFSET): + Update comments. + * config/i386/gnu-user64.h (TARGET_THREAD_SPLIT_STACK_OFFSET): + Likewise. + 2018-06-12 Martin Liska * doc/options.texi: Document IntegerRange. diff --git a/gcc/config/i386/gnu-user.h b/gcc/config/i386/gnu-user.h index d1dad685e72..56449a5439e 100644 --- a/gcc/config/i386/gnu-user.h +++ b/gcc/config/i386/gnu-user.h @@ -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. */ +/* i386 glibc provides __private_ss in %gs:0x30. */ #define TARGET_THREAD_SPLIT_STACK_OFFSET 0x30 #endif diff --git a/gcc/config/i386/gnu-user64.h b/gcc/config/i386/gnu-user64.h index 491416fec0c..f7a68fdecf0 100644 --- a/gcc/config/i386/gnu-user64.h +++ b/gcc/config/i386/gnu-user64.h @@ -86,7 +86,9 @@ 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:0x30. + 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) #endif -- 2.30.2