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x86-64: Allocate state buffer space for RDI, RSI and RBX

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_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 <skpgkp2@gmail.com>
This commit is contained in:
H.J. Lu 2024-03-18 06:40:16 -07:00
parent f44f3aed31
commit 717ebfa85c
3 changed files with 146 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
sysdeps/x86/cpu-features.c
View File

@ -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);
}
}

58
sysdeps/x86/sysdep.h
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@ -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.
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.
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. */
+==================+<- 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 \

87
sysdeps/x86_64/tst-gnu2-tls2mod1.S Normal file
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@ -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
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
/* 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