From 717ebfa85c8240d32d0d19d86a484c31c55c9617 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 18 Mar 2024 06:40:16 -0700 Subject: x86-64: Allocate state buffer space for RDI, RSI and RBX _dl_tlsdesc_dynamic preserves RDI, RSI and RBX before realigning stack. After realigning stack, it saves RCX, RDX, R8, R9, R10 and R11. Define TLSDESC_CALL_REGISTER_SAVE_AREA to allocate space for RDI, RSI and RBX to avoid clobbering saved RDI, RSI and RBX values on stack by xsave to STATE_SAVE_OFFSET(%rsp). +==================+<- stack frame start aligned at 8 or 16 bytes | |<- RDI saved in the red zone | |<- RSI saved in the red zone | |<- RBX saved in the red zone | |<- paddings for stack realignment of 64 bytes |------------------|<- xsave buffer end aligned at 64 bytes | |<- | |<- | |<- |------------------|<- xsave buffer start at STATE_SAVE_OFFSET(%rsp) | |<- 8-byte padding for 64-byte alignment | |<- 8-byte padding for 64-byte alignment | |<- R11 | |<- R10 | |<- R9 | |<- R8 | |<- RDX | |<- RCX +==================+<- RSP aligned at 64 bytes Define TLSDESC_CALL_REGISTER_SAVE_AREA, the total register save area size for all integer registers by adding 24 to STATE_SAVE_OFFSET since RDI, RSI and RBX are saved onto stack without adjusting stack pointer first, using the red-zone. This fixes BZ #31501. Reviewed-by: Sunil K Pandey --- sysdeps/x86/cpu-features.c | 11 +++-- sysdeps/x86/sysdep.h | 60 +++++++++++++++++++++++--- sysdeps/x86_64/tst-gnu2-tls2mod1.S | 87 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 147 insertions(+), 11 deletions(-) create mode 100644 sysdeps/x86_64/tst-gnu2-tls2mod1.S diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 4ea373d..3d7c281 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -311,7 +311,7 @@ update_active (struct cpu_features *cpu_features) /* NB: On AMX capable processors, ebx always includes AMX states. */ unsigned int xsave_state_full_size - = ALIGN_UP (ebx + STATE_SAVE_OFFSET, 64); + = ALIGN_UP (ebx + TLSDESC_CALL_REGISTER_SAVE_AREA, 64); cpu_features->xsave_state_size = xsave_state_full_size; @@ -401,8 +401,10 @@ update_active (struct cpu_features *cpu_features) unsigned int amx_size = (xstate_amx_comp_offsets[31] + xstate_amx_comp_sizes[31]); - amx_size = ALIGN_UP (amx_size + STATE_SAVE_OFFSET, - 64); + amx_size + = ALIGN_UP ((amx_size + + TLSDESC_CALL_REGISTER_SAVE_AREA), + 64); /* Set xsave_state_full_size to the compact AMX state size for XSAVEC. NB: xsave_state_full_size is only used in _dl_tlsdesc_dynamic_xsave and @@ -410,7 +412,8 @@ update_active (struct cpu_features *cpu_features) cpu_features->xsave_state_full_size = amx_size; #endif cpu_features->xsave_state_size - = ALIGN_UP (size + STATE_SAVE_OFFSET, 64); + = ALIGN_UP (size + TLSDESC_CALL_REGISTER_SAVE_AREA, + 64); CPU_FEATURE_SET (cpu_features, XSAVEC); } } diff --git a/sysdeps/x86/sysdep.h b/sysdeps/x86/sysdep.h index db8e576..7359149 100644 --- a/sysdeps/x86/sysdep.h +++ b/sysdeps/x86/sysdep.h @@ -38,14 +38,59 @@ #ifdef __x86_64__ /* Offset for fxsave/xsave area used by _dl_runtime_resolve. Also need space to preserve RCX, RDX, RSI, RDI, R8, R9 and RAX. It must be - aligned to 16 bytes for fxsave and 64 bytes for xsave. - - NB: Is is non-zero because of the 128-byte red-zone. Some registers - are saved on stack without adjusting stack pointer first. When we - update stack pointer to allocate more space, we need to take the - red-zone into account. */ + aligned to 16 bytes for fxsave and 64 bytes for xsave. It is non-zero + because MOV, instead of PUSH, is used to save registers onto stack. + + +==================+<- stack frame start aligned at 8 or 16 bytes + | |<- paddings for stack realignment of 64 bytes + |------------------|<- xsave buffer end aligned at 64 bytes + | |<- + | |<- + | |<- + |------------------|<- xsave buffer start at STATE_SAVE_OFFSET(%rsp) + | |<- 8-byte padding for 64-byte alignment + | |<- R9 + | |<- R8 + | |<- RDI + | |<- RSI + | |<- RDX + | |<- RCX + | |<- RAX + +==================+<- RSP aligned at 64 bytes + + */ # define STATE_SAVE_OFFSET (8 * 7 + 8) +/* _dl_tlsdesc_dynamic preserves RDI, RSI and RBX before realigning + stack. After realigning stack, it saves RCX, RDX, R8, R9, R10 and + R11. Allocate space for RDI, RSI and RBX to avoid clobbering saved + RDI, RSI and RBX values on stack by xsave. + + +==================+<- stack frame start aligned at 8 or 16 bytes + | |<- RDI saved in the red zone + | |<- RSI saved in the red zone + | |<- RBX saved in the red zone + | |<- paddings for stack realignment of 64 bytes + |------------------|<- xsave buffer end aligned at 64 bytes + | |<- + | |<- + | |<- + |------------------|<- xsave buffer start at STATE_SAVE_OFFSET(%rsp) + | |<- 8-byte padding for 64-byte alignment + | |<- 8-byte padding for 64-byte alignment + | |<- R11 + | |<- R10 + | |<- R9 + | |<- R8 + | |<- RDX + | |<- RCX + +==================+<- RSP aligned at 64 bytes + + Define the total register save area size for all integer registers by + adding 24 to STATE_SAVE_OFFSET since RDI, RSI and RBX are saved onto + stack without adjusting stack pointer first, using the red-zone. */ +# define TLSDESC_CALL_REGISTER_SAVE_AREA (STATE_SAVE_OFFSET + 24) + /* Save SSE, AVX, AVX512, mask, bound and APX registers. Bound and APX registers are mutually exclusive. */ # define STATE_SAVE_MASK \ @@ -66,8 +111,9 @@ (STATE_SAVE_MASK | AMX_STATE_SAVE_MASK) #else /* Offset for fxsave/xsave area used by _dl_tlsdesc_dynamic. Since i386 - doesn't have red-zone, use 0 here. */ + uses PUSH to save registers onto stack, use 0 here. */ # define STATE_SAVE_OFFSET 0 +# define TLSDESC_CALL_REGISTER_SAVE_AREA 0 /* Save SSE, AVX, AXV512, mask and bound registers. */ # define STATE_SAVE_MASK \ diff --git a/sysdeps/x86_64/tst-gnu2-tls2mod1.S b/sysdeps/x86_64/tst-gnu2-tls2mod1.S new file mode 100644 index 0000000..1d63666 --- /dev/null +++ b/sysdeps/x86_64/tst-gnu2-tls2mod1.S @@ -0,0 +1,87 @@ +/* Check if TLSDESC relocation preserves %rdi, %rsi and %rbx. + Copyright (C) 2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include + +/* On AVX512 machines, OFFSET == 40 caused _dl_tlsdesc_dynamic_xsavec + to clobber %rdi, %rsi and %rbx. On Intel AVX CPUs, the state size + is 960 bytes and this test didn't fail. It may be due to the unused + last 128 bytes. On AMD AVX CPUs, the state size is 832 bytes and + this test might fail without the fix. */ +#ifndef OFFSET +# define OFFSET 40 +#endif + + .text + .p2align 4 + .globl apply_tls + .type apply_tls, @function +apply_tls: + cfi_startproc + _CET_ENDBR + pushq %rbp + cfi_def_cfa_offset (16) + cfi_offset (6, -16) + movdqu (%RDI_LP), %xmm0 + lea tls_var1@TLSDESC(%rip), %RAX_LP + mov %RSP_LP, %RBP_LP + cfi_def_cfa_register (6) + /* Align stack to 64 bytes. */ + and $-64, %RSP_LP + sub $OFFSET, %RSP_LP + pushq %rbx + /* Set %ebx to 0xbadbeef. */ + movl $0xbadbeef, %ebx + movl $0xbadbeef, %esi + movq %rdi, saved_rdi(%rip) + movq %rsi, saved_rsi(%rip) + call *tls_var1@TLSCALL(%RAX_LP) + /* Check if _dl_tlsdesc_dynamic preserves %rdi, %rsi and %rbx. */ + cmpq saved_rdi(%rip), %rdi + jne L(hlt) + cmpq saved_rsi(%rip), %rsi + jne L(hlt) + cmpl $0xbadbeef, %ebx + jne L(hlt) + add %fs:0, %RAX_LP + movups %xmm0, 32(%RAX_LP) + movdqu 16(%RDI_LP), %xmm1 + mov %RAX_LP, %RBX_LP + movups %xmm1, 48(%RAX_LP) + lea 32(%RBX_LP), %RAX_LP + pop %rbx + leave + cfi_def_cfa (7, 8) + ret +L(hlt): + hlt + cfi_endproc + .size apply_tls, .-apply_tls + .hidden tls_var1 + .globl tls_var1 + .section .tbss,"awT",@nobits + .align 16 + .type tls_var1, @object + .size tls_var1, 3200 +tls_var1: + .zero 3200 + .local saved_rdi + .comm saved_rdi,8,8 + .local saved_rsi + .comm saved_rsi,8,8 + .section .note.GNU-stack,"",@progbits -- cgit v1.1