diff options
| author | H.J. Lu <hjl.tools@gmail.com> | 2023-12-20 19:42:12 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2023-12-22 05:37:17 -0800 |
| commit | 81be2a61dafc168327c1639e97b6dae128c7ccf3 (patch) | |
| tree | 0f56678699b9deab602178f811dd9f0c45a22472 | |
| parent | 3502440397bbb840e2f7223734aa5cc2cc0e29b6 (diff) | |
| download | glibc-81be2a61dafc168327c1639e97b6dae128c7ccf3.tar.gz glibc-81be2a61dafc168327c1639e97b6dae128c7ccf3.tar.xz glibc-81be2a61dafc168327c1639e97b6dae128c7ccf3.zip | |
x86-64: Fix the tcb field load for x32 [BZ #31185]
_dl_tlsdesc_undefweak and _dl_tlsdesc_dynamic access the thread pointer
via the tcb field in TCB:
_dl_tlsdesc_undefweak:
_CET_ENDBR
movq 8(%rax), %rax
subq %fs:0, %rax
ret
_dl_tlsdesc_dynamic:
...
subq %fs:0, %rax
movq -8(%rsp), %rdi
ret
Since the tcb field in TCB is a pointer, %fs:0 is a 32-bit location,
not 64-bit. It should use "sub %fs:0, %RAX_LP" instead. Since
_dl_tlsdesc_undefweak returns ptrdiff_t and _dl_make_tlsdesc_dynamic
returns void *, RAX_LP is appropriate here for x32 and x86-64. This
fixes BZ #31185.
| -rw-r--r-- | sysdeps/x86_64/dl-tlsdesc.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sysdeps/x86_64/dl-tlsdesc.S b/sysdeps/x86_64/dl-tlsdesc.S index c4823547d7..4579424bf7 100644 --- a/sysdeps/x86_64/dl-tlsdesc.S +++ b/sysdeps/x86_64/dl-tlsdesc.S @@ -61,7 +61,7 @@ _dl_tlsdesc_return: _dl_tlsdesc_undefweak: _CET_ENDBR movq 8(%rax), %rax - subq %fs:0, %rax + sub %fs:0, %RAX_LP ret cfi_endproc .size _dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak @@ -116,7 +116,7 @@ _dl_tlsdesc_dynamic: addq TLSDESC_MODOFF(%rdi), %rax .Lret: movq -16(%rsp), %rsi - subq %fs:0, %rax + sub %fs:0, %RAX_LP movq -8(%rsp), %rdi ret .Lslow: |