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| author | H.J. Lu <hjl.tools@gmail.com> | 2024-02-26 06:37:03 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2024-02-28 09:02:56 -0800 |
| commit | 0aac205a814a8511e98d02b91a8dc908f1c53cde (patch) | |
| tree | e9ad8dfa06abd2f6d9b521bb95e9b7cfaa0d7de7 /sysdeps/x86/sysdep.h | |
| parent | e6350be7e9cae8f71c96c1f06eab61b9acb227c8 (diff) | |
| download | glibc-0aac205a814a8511e98d02b91a8dc908f1c53cde.tar.gz glibc-0aac205a814a8511e98d02b91a8dc908f1c53cde.tar.xz glibc-0aac205a814a8511e98d02b91a8dc908f1c53cde.zip | |
x86: Update _dl_tlsdesc_dynamic to preserve caller-saved registers
Compiler generates the following instruction sequence for GNU2 dynamic TLS access: leaq tls_var@TLSDESC(%rip), %rax call *tls_var@TLSCALL(%rax) or leal tls_var@TLSDESC(%ebx), %eax call *tls_var@TLSCALL(%eax) CALL instruction is transparent to compiler which assumes all registers, except for EFLAGS and RAX/EAX, are unchanged after CALL. When _dl_tlsdesc_dynamic is called, it calls __tls_get_addr on the slow path. __tls_get_addr is a normal function which doesn't preserve any caller-saved registers. _dl_tlsdesc_dynamic saved and restored integer caller-saved registers, but didn't preserve any other caller-saved registers. Add _dl_tlsdesc_dynamic IFUNC functions for FNSAVE, FXSAVE, XSAVE and XSAVEC to save and restore all caller-saved registers. This fixes BZ #31372. Add GLRO(dl_x86_64_runtime_resolve) with GLRO(dl_x86_tlsdesc_dynamic) to optimize elf_machine_runtime_setup. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
Diffstat (limited to 'sysdeps/x86/sysdep.h')
| -rw-r--r-- | sysdeps/x86/sysdep.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h index 837fd28734..485cad9c02 100644 --- a/sysdeps/x86/sysdep.h +++ b/sysdeps/x86/sysdep.h @@ -70,6 +70,12 @@ | (1 << X86_XSTATE_ZMM_H_ID)) #endif +/* States which should be saved for TLSDESC_CALL and TLS_DESC_CALL. + Compiler assumes that all registers, including x87 FPU stack registers, + are unchanged after CALL, except for EFLAGS and RAX/EAX. */ +#define TLSDESC_CALL_STATE_SAVE_MASK \ + (STATE_SAVE_MASK | (1 << X86_XSTATE_X87_ID)) + /* Constants for bits in __x86_string_control: */ /* Avoid short distance REP MOVSB. */ |