From 0aac205a814a8511e98d02b91a8dc908f1c53cde Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 26 Feb 2024 06:37:03 -0800 Subject: 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 --- sysdeps/x86/tst-gnu2-tls2.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) create mode 100644 sysdeps/x86/tst-gnu2-tls2.c (limited to 'sysdeps/x86/tst-gnu2-tls2.c') diff --git a/sysdeps/x86/tst-gnu2-tls2.c b/sysdeps/x86/tst-gnu2-tls2.c new file mode 100644 index 0000000000..de900a423b --- /dev/null +++ b/sysdeps/x86/tst-gnu2-tls2.c @@ -0,0 +1,20 @@ +#ifndef __x86_64__ +#include + +#define IS_SUPPORTED() CPU_FEATURE_ACTIVE (SSE2) +#endif + +/* Clear XMM0...XMM7 */ +#define PREPARE_MALLOC() \ +{ \ + asm volatile ("xorps %%xmm0, %%xmm0" : : : "xmm0" ); \ + asm volatile ("xorps %%xmm1, %%xmm1" : : : "xmm1" ); \ + asm volatile ("xorps %%xmm2, %%xmm2" : : : "xmm2" ); \ + asm volatile ("xorps %%xmm3, %%xmm3" : : : "xmm3" ); \ + asm volatile ("xorps %%xmm4, %%xmm4" : : : "xmm4" ); \ + asm volatile ("xorps %%xmm5, %%xmm5" : : : "xmm5" ); \ + asm volatile ("xorps %%xmm6, %%xmm6" : : : "xmm6" ); \ + asm volatile ("xorps %%xmm7, %%xmm7" : : : "xmm7" ); \ +} + +#include -- cgit v1.2.3-70-g09d2