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a364304718
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>
(cherry picked from commit 0aac205a81)
21 lines
662 B
C
21 lines
662 B
C
#ifndef __x86_64__
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#include <sys/platform/x86.h>
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#define IS_SUPPORTED() CPU_FEATURE_ACTIVE (SSE2)
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#endif
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/* Clear XMM0...XMM7 */
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#define PREPARE_MALLOC() \
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{ \
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asm volatile ("xorps %%xmm0, %%xmm0" : : : "xmm0" ); \
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asm volatile ("xorps %%xmm1, %%xmm1" : : : "xmm1" ); \
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asm volatile ("xorps %%xmm2, %%xmm2" : : : "xmm2" ); \
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asm volatile ("xorps %%xmm3, %%xmm3" : : : "xmm3" ); \
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asm volatile ("xorps %%xmm4, %%xmm4" : : : "xmm4" ); \
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asm volatile ("xorps %%xmm5, %%xmm5" : : : "xmm5" ); \
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asm volatile ("xorps %%xmm6, %%xmm6" : : : "xmm6" ); \
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asm volatile ("xorps %%xmm7, %%xmm7" : : : "xmm7" ); \
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}
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#include <elf/tst-gnu2-tls2.c>
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