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glibc/sysdeps/x86_64/dl-trampoline.h
Noah Goldstein 58bcf7b71a x86-64: Small improvements to dl-trampoline.S 
1.  Remove sse2 instructions when using the avx512 or avx version.

2.  Fixup some format nits in how the address offsets where aligned.

3.  Use more space efficient instructions in the conditional AVX
    restoral.
        - vpcmpeqq          -> vpcmpeqb
        - cmp imm32, r; jz  -> inc r; jz

4.  Use `rep movsb` instead of `rep movsq`. The former is guranteed to
    be fast with the ERMS flags, the latter is not. The latter also
    wastes an instruction in size setup.
2022-06-29 19:47:52 -07:00

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/* PLT trampolines. x86-64 version.
Copyright (C) 2009-2022 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
<https://www.gnu.org/licenses/>. */
#ifndef SECTION
# define SECTION(p) p
#endif
.section SECTION(.text),"ax",@progbits
#ifdef _dl_runtime_resolve
# undef REGISTER_SAVE_AREA
# undef LOCAL_STORAGE_AREA
# undef BASE
# if (STATE_SAVE_ALIGNMENT % 16) != 0
# error STATE_SAVE_ALIGNMENT must be multples of 16
# endif
# if (STATE_SAVE_OFFSET % STATE_SAVE_ALIGNMENT) != 0
# error STATE_SAVE_OFFSET must be multples of STATE_SAVE_ALIGNMENT
# endif
# if DL_RUNTIME_RESOLVE_REALIGN_STACK
/* Local stack area before jumping to function address: RBX. */
# define LOCAL_STORAGE_AREA 8
# define BASE rbx
# ifdef USE_FXSAVE
/* Use fxsave to save XMM registers. */
# define REGISTER_SAVE_AREA (512 + STATE_SAVE_OFFSET)
# if (REGISTER_SAVE_AREA % 16) != 0
# error REGISTER_SAVE_AREA must be multples of 16
# endif
# endif
# else
# ifndef USE_FXSAVE
# error USE_FXSAVE must be defined
# endif
/* Use fxsave to save XMM registers. */
# define REGISTER_SAVE_AREA (512 + STATE_SAVE_OFFSET + 8)
/* Local stack area before jumping to function address: All saved
registers. */
# define LOCAL_STORAGE_AREA REGISTER_SAVE_AREA
# define BASE rsp
# if (REGISTER_SAVE_AREA % 16) != 8
# error REGISTER_SAVE_AREA must be odd multples of 8
# endif
# endif
.globl _dl_runtime_resolve
.hidden _dl_runtime_resolve
.type _dl_runtime_resolve, @function
.align 16
cfi_startproc
_dl_runtime_resolve:
cfi_adjust_cfa_offset(16) # Incorporate PLT
_CET_ENDBR
# if DL_RUNTIME_RESOLVE_REALIGN_STACK
# if LOCAL_STORAGE_AREA != 8
# error LOCAL_STORAGE_AREA must be 8
# endif
pushq %rbx # push subtracts stack by 8.
cfi_adjust_cfa_offset(8)
cfi_rel_offset(%rbx, 0)
mov %RSP_LP, %RBX_LP
cfi_def_cfa_register(%rbx)
and $-STATE_SAVE_ALIGNMENT, %RSP_LP
# endif
# ifdef REGISTER_SAVE_AREA
sub $REGISTER_SAVE_AREA, %RSP_LP
# if !DL_RUNTIME_RESOLVE_REALIGN_STACK
cfi_adjust_cfa_offset(REGISTER_SAVE_AREA)
# endif
# else
# Allocate stack space of the required size to save the state.
# if IS_IN (rtld)
sub _rtld_local_ro+RTLD_GLOBAL_RO_DL_X86_CPU_FEATURES_OFFSET+XSAVE_STATE_SIZE_OFFSET(%rip), %RSP_LP
# else
sub _dl_x86_cpu_features+XSAVE_STATE_SIZE_OFFSET(%rip), %RSP_LP
# endif
# endif
# Preserve registers otherwise clobbered.
movq %rax, REGISTER_SAVE_RAX(%rsp)
movq %rcx, REGISTER_SAVE_RCX(%rsp)
movq %rdx, REGISTER_SAVE_RDX(%rsp)
movq %rsi, REGISTER_SAVE_RSI(%rsp)
movq %rdi, REGISTER_SAVE_RDI(%rsp)
movq %r8, REGISTER_SAVE_R8(%rsp)
movq %r9, REGISTER_SAVE_R9(%rsp)
# ifdef USE_FXSAVE
fxsave STATE_SAVE_OFFSET(%rsp)
# else
movl $STATE_SAVE_MASK, %eax
xorl %edx, %edx
# Clear the XSAVE Header.
# ifdef USE_XSAVE
movq %rdx, (STATE_SAVE_OFFSET + 512)(%rsp)
movq %rdx, (STATE_SAVE_OFFSET + 512 + 8)(%rsp)
# endif
movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 2)(%rsp)
movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 3)(%rsp)
movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 4)(%rsp)
movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 5)(%rsp)
movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 6)(%rsp)
movq %rdx, (STATE_SAVE_OFFSET + 512 + 8 * 7)(%rsp)
# ifdef USE_XSAVE
xsave STATE_SAVE_OFFSET(%rsp)
# else
xsavec STATE_SAVE_OFFSET(%rsp)
# endif
# endif
# Copy args pushed by PLT in register.
# %rdi: link_map, %rsi: reloc_index
mov (LOCAL_STORAGE_AREA + 8)(%BASE), %RSI_LP
mov LOCAL_STORAGE_AREA(%BASE), %RDI_LP
call _dl_fixup # Call resolver.
mov %RAX_LP, %R11_LP # Save return value
# Get register content back.
# ifdef USE_FXSAVE
fxrstor STATE_SAVE_OFFSET(%rsp)
# else
movl $STATE_SAVE_MASK, %eax
xorl %edx, %edx
xrstor STATE_SAVE_OFFSET(%rsp)
# endif
movq REGISTER_SAVE_R9(%rsp), %r9
movq REGISTER_SAVE_R8(%rsp), %r8
movq REGISTER_SAVE_RDI(%rsp), %rdi
movq REGISTER_SAVE_RSI(%rsp), %rsi
movq REGISTER_SAVE_RDX(%rsp), %rdx
movq REGISTER_SAVE_RCX(%rsp), %rcx
movq REGISTER_SAVE_RAX(%rsp), %rax
# if DL_RUNTIME_RESOLVE_REALIGN_STACK
mov %RBX_LP, %RSP_LP
cfi_def_cfa_register(%rsp)
movq (%rsp), %rbx
cfi_restore(%rbx)
# endif
# Adjust stack(PLT did 2 pushes)
add $(LOCAL_STORAGE_AREA + 16), %RSP_LP
cfi_adjust_cfa_offset(-(LOCAL_STORAGE_AREA + 16))
jmp *%r11 # Jump to function address.
cfi_endproc
.size _dl_runtime_resolve, .-_dl_runtime_resolve
#endif
#if !defined PROF && defined _dl_runtime_profile
# if (LR_VECTOR_OFFSET % VEC_SIZE) != 0
# error LR_VECTOR_OFFSET must be multples of VEC_SIZE
# endif
.globl _dl_runtime_profile
.hidden _dl_runtime_profile
.type _dl_runtime_profile, @function
.align 16
_dl_runtime_profile:
cfi_startproc
cfi_adjust_cfa_offset(16) # Incorporate PLT
_CET_ENDBR
/* The La_x86_64_regs data structure pointed to by the
fourth paramater must be VEC_SIZE-byte aligned. This must
be explicitly enforced. We have the set up a dynamically
sized stack frame. %rbx points to the top half which
has a fixed size and preserves the original stack pointer. */
sub $32, %RSP_LP # Allocate the local storage.
cfi_adjust_cfa_offset(32)
movq %rbx, (%rsp)
cfi_rel_offset(%rbx, 0)
/* On the stack:
56(%rbx) parameter #1
48(%rbx) return address
40(%rbx) reloc index
32(%rbx) link_map
24(%rbx) La_x86_64_regs pointer
16(%rbx) framesize
8(%rbx) rax
(%rbx) rbx
*/
movq %rax, 8(%rsp)
mov %RSP_LP, %RBX_LP
cfi_def_cfa_register(%rbx)
/* Actively align the La_x86_64_regs structure. */
and $-VEC_SIZE, %RSP_LP
/* sizeof(La_x86_64_regs). Need extra space for 8 SSE registers
to detect if any xmm0-xmm7 registers are changed by audit
module. */
sub $(LR_SIZE + XMM_SIZE*8), %RSP_LP
movq %rsp, 24(%rbx)
/* Fill the La_x86_64_regs structure. */
movq %rdx, LR_RDX_OFFSET(%rsp)
movq %r8, LR_R8_OFFSET(%rsp)
movq %r9, LR_R9_OFFSET(%rsp)
movq %rcx, LR_RCX_OFFSET(%rsp)
movq %rsi, LR_RSI_OFFSET(%rsp)
movq %rdi, LR_RDI_OFFSET(%rsp)
movq %rbp, LR_RBP_OFFSET(%rsp)
lea 48(%rbx), %RAX_LP
movq %rax, LR_RSP_OFFSET(%rsp)
/* We always store the XMM registers even if AVX is available.
This is to provide backward binary compatibility for existing
audit modules. */
VMOVA %xmm0, (LR_XMM_OFFSET + XMM_SIZE*0)(%rsp)
VMOVA %xmm1, (LR_XMM_OFFSET + XMM_SIZE*1)(%rsp)
VMOVA %xmm2, (LR_XMM_OFFSET + XMM_SIZE*2)(%rsp)
VMOVA %xmm3, (LR_XMM_OFFSET + XMM_SIZE*3)(%rsp)
VMOVA %xmm4, (LR_XMM_OFFSET + XMM_SIZE*4)(%rsp)
VMOVA %xmm5, (LR_XMM_OFFSET + XMM_SIZE*5)(%rsp)
VMOVA %xmm6, (LR_XMM_OFFSET + XMM_SIZE*6)(%rsp)
VMOVA %xmm7, (LR_XMM_OFFSET + XMM_SIZE*7)(%rsp)
# ifdef RESTORE_AVX
/* This is to support AVX audit modules. */
VMOVA %VEC(0), (LR_VECTOR_OFFSET + VECTOR_SIZE*0)(%rsp)
VMOVA %VEC(1), (LR_VECTOR_OFFSET + VECTOR_SIZE*1)(%rsp)
VMOVA %VEC(2), (LR_VECTOR_OFFSET + VECTOR_SIZE*2)(%rsp)
VMOVA %VEC(3), (LR_VECTOR_OFFSET + VECTOR_SIZE*3)(%rsp)
VMOVA %VEC(4), (LR_VECTOR_OFFSET + VECTOR_SIZE*4)(%rsp)
VMOVA %VEC(5), (LR_VECTOR_OFFSET + VECTOR_SIZE*5)(%rsp)
VMOVA %VEC(6), (LR_VECTOR_OFFSET + VECTOR_SIZE*6)(%rsp)
VMOVA %VEC(7), (LR_VECTOR_OFFSET + VECTOR_SIZE*7)(%rsp)
/* Save xmm0-xmm7 registers to detect if any of them are
changed by audit module. */
vmovdqa %xmm0, (LR_SIZE + XMM_SIZE*0)(%rsp)
vmovdqa %xmm1, (LR_SIZE + XMM_SIZE*1)(%rsp)
vmovdqa %xmm2, (LR_SIZE + XMM_SIZE*2)(%rsp)
vmovdqa %xmm3, (LR_SIZE + XMM_SIZE*3)(%rsp)
vmovdqa %xmm4, (LR_SIZE + XMM_SIZE*4)(%rsp)
vmovdqa %xmm5, (LR_SIZE + XMM_SIZE*5)(%rsp)
vmovdqa %xmm6, (LR_SIZE + XMM_SIZE*6)(%rsp)
vmovdqa %xmm7, (LR_SIZE + XMM_SIZE*7)(%rsp)
# endif
mov %RSP_LP, %RCX_LP # La_x86_64_regs pointer to %rcx.
mov 48(%rbx), %RDX_LP # Load return address if needed.
mov 40(%rbx), %RSI_LP # Copy args pushed by PLT in register.
mov 32(%rbx), %RDI_LP # %rdi: link_map, %rsi: reloc_index
lea 16(%rbx), %R8_LP # Address of framesize
call _dl_profile_fixup # Call resolver.
mov %RAX_LP, %R11_LP # Save return value.
movq 8(%rbx), %rax # Get back register content.
movq LR_RDX_OFFSET(%rsp), %rdx
movq LR_R8_OFFSET(%rsp), %r8
movq LR_R9_OFFSET(%rsp), %r9
VMOVA (LR_XMM_OFFSET + XMM_SIZE*0)(%rsp), %xmm0
VMOVA (LR_XMM_OFFSET + XMM_SIZE*1)(%rsp), %xmm1
VMOVA (LR_XMM_OFFSET + XMM_SIZE*2)(%rsp), %xmm2
VMOVA (LR_XMM_OFFSET + XMM_SIZE*3)(%rsp), %xmm3
VMOVA (LR_XMM_OFFSET + XMM_SIZE*4)(%rsp), %xmm4
VMOVA (LR_XMM_OFFSET + XMM_SIZE*5)(%rsp), %xmm5
VMOVA (LR_XMM_OFFSET + XMM_SIZE*6)(%rsp), %xmm6
VMOVA (LR_XMM_OFFSET + XMM_SIZE*7)(%rsp), %xmm7
# ifdef RESTORE_AVX
/* Check if any xmm0-xmm7 registers are changed by audit
module. */
vpcmpeqb (LR_SIZE)(%rsp), %xmm0, %xmm8
vpmovmskb %xmm8, %esi
incw %si
je 2f
vmovdqa %xmm0, (LR_VECTOR_OFFSET)(%rsp)
jmp 1f
2: VMOVA (LR_VECTOR_OFFSET)(%rsp), %VEC(0)
vmovdqa %xmm0, (LR_XMM_OFFSET)(%rsp)
1: vpcmpeqb (LR_SIZE + XMM_SIZE)(%rsp), %xmm1, %xmm8
vpmovmskb %xmm8, %esi
incw %si
je 2f
vmovdqa %xmm1, (LR_VECTOR_OFFSET + VECTOR_SIZE)(%rsp)
jmp 1f
2: VMOVA (LR_VECTOR_OFFSET + VECTOR_SIZE)(%rsp), %VEC(1)
vmovdqa %xmm1, (LR_XMM_OFFSET + XMM_SIZE)(%rsp)
1: vpcmpeqb (LR_SIZE + XMM_SIZE*2)(%rsp), %xmm2, %xmm8
vpmovmskb %xmm8, %esi
incw %si
je 2f
vmovdqa %xmm2, (LR_VECTOR_OFFSET + VECTOR_SIZE*2)(%rsp)
jmp 1f
2: VMOVA (LR_VECTOR_OFFSET + VECTOR_SIZE*2)(%rsp), %VEC(2)
vmovdqa %xmm2, (LR_XMM_OFFSET + XMM_SIZE*2)(%rsp)
1: vpcmpeqb (LR_SIZE + XMM_SIZE*3)(%rsp), %xmm3, %xmm8
vpmovmskb %xmm8, %esi
incw %si
je 2f
vmovdqa %xmm3, (LR_VECTOR_OFFSET + VECTOR_SIZE*3)(%rsp)
jmp 1f
2: VMOVA (LR_VECTOR_OFFSET + VECTOR_SIZE*3)(%rsp), %VEC(3)
vmovdqa %xmm3, (LR_XMM_OFFSET + XMM_SIZE*3)(%rsp)
1: vpcmpeqb (LR_SIZE + XMM_SIZE*4)(%rsp), %xmm4, %xmm8
vpmovmskb %xmm8, %esi
incw %si
je 2f
vmovdqa %xmm4, (LR_VECTOR_OFFSET + VECTOR_SIZE*4)(%rsp)
jmp 1f
2: VMOVA (LR_VECTOR_OFFSET + VECTOR_SIZE*4)(%rsp), %VEC(4)
vmovdqa %xmm4, (LR_XMM_OFFSET + XMM_SIZE*4)(%rsp)
1: vpcmpeqb (LR_SIZE + XMM_SIZE*5)(%rsp), %xmm5, %xmm8
vpmovmskb %xmm8, %esi
incw %si
je 2f
vmovdqa %xmm5, (LR_VECTOR_OFFSET + VECTOR_SIZE*5)(%rsp)
jmp 1f
2: VMOVA (LR_VECTOR_OFFSET + VECTOR_SIZE*5)(%rsp), %VEC(5)
vmovdqa %xmm5, (LR_XMM_OFFSET + XMM_SIZE*5)(%rsp)
1: vpcmpeqb (LR_SIZE + XMM_SIZE*6)(%rsp), %xmm6, %xmm8
vpmovmskb %xmm8, %esi
incw %si
je 2f
vmovdqa %xmm6, (LR_VECTOR_OFFSET + VECTOR_SIZE*6)(%rsp)
jmp 1f
2: VMOVA (LR_VECTOR_OFFSET + VECTOR_SIZE*6)(%rsp), %VEC(6)
vmovdqa %xmm6, (LR_XMM_OFFSET + XMM_SIZE*6)(%rsp)
1: vpcmpeqb (LR_SIZE + XMM_SIZE*7)(%rsp), %xmm7, %xmm8
vpmovmskb %xmm8, %esi
incw %si
je 2f
vmovdqa %xmm7, (LR_VECTOR_OFFSET + VECTOR_SIZE*7)(%rsp)
jmp 1f
2: VMOVA (LR_VECTOR_OFFSET + VECTOR_SIZE*7)(%rsp), %VEC(7)
vmovdqa %xmm7, (LR_XMM_OFFSET + XMM_SIZE*7)(%rsp)
1:
# endif
mov 16(%rbx), %RCX_LP # Anything in framesize?
test %RCX_LP, %RCX_LP
jns 3f
/* There's nothing in the frame size, so there
will be no call to the _dl_audit_pltexit. */
/* Get back registers content. */
movq LR_RCX_OFFSET(%rsp), %rcx
movq LR_RSI_OFFSET(%rsp), %rsi
movq LR_RDI_OFFSET(%rsp), %rdi
mov %RBX_LP, %RSP_LP
movq (%rsp), %rbx
cfi_restore(%rbx)
cfi_def_cfa_register(%rsp)
add $48, %RSP_LP # Adjust the stack to the return value
# (eats the reloc index and link_map)
cfi_adjust_cfa_offset(-48)
jmp *%r11 # Jump to function address.
3:
cfi_adjust_cfa_offset(48)
cfi_rel_offset(%rbx, 0)
cfi_def_cfa_register(%rbx)
/* At this point we need to prepare new stack for the function
which has to be called. We copy the original stack to a
temporary buffer of the size specified by the 'framesize'
returned from _dl_profile_fixup */
lea LR_RSP_OFFSET(%rbx), %RSI_LP # stack
add $8, %RCX_LP
and $-16, %RCX_LP
sub %RCX_LP, %RSP_LP
mov %RSP_LP, %RDI_LP
rep movsb
movq 24(%rdi), %rcx # Get back register content.
movq 32(%rdi), %rsi
movq 40(%rdi), %rdi
call *%r11
mov 24(%rbx), %RSP_LP # Drop the copied stack content
/* Now we have to prepare the La_x86_64_retval structure for the
_dl_audit_pltexit. The La_x86_64_regs is being pointed by rsp now,
so we just need to allocate the sizeof(La_x86_64_retval) space on
the stack, since the alignment has already been taken care of. */
# ifdef RESTORE_AVX
/* sizeof(La_x86_64_retval). Need extra space for 2 SSE
registers to detect if xmm0/xmm1 registers are changed
by audit module. Since rsp is aligned to VEC_SIZE, we
need to make sure that the address of La_x86_64_retval +
LRV_VECTOR0_OFFSET is aligned to VEC_SIZE. */
# define LRV_SPACE (LRV_SIZE + XMM_SIZE*2)
# define LRV_MISALIGNED ((LRV_SIZE + LRV_VECTOR0_OFFSET) & (VEC_SIZE - 1))
# if LRV_MISALIGNED == 0
sub $LRV_SPACE, %RSP_LP
# else
sub $(LRV_SPACE + VEC_SIZE - LRV_MISALIGNED), %RSP_LP
# endif
# else
sub $LRV_SIZE, %RSP_LP # sizeof(La_x86_64_retval)
# endif
mov %RSP_LP, %RCX_LP # La_x86_64_retval argument to %rcx.
/* Fill in the La_x86_64_retval structure. */
movq %rax, LRV_RAX_OFFSET(%rcx)
movq %rdx, LRV_RDX_OFFSET(%rcx)
VMOVA %xmm0, LRV_XMM0_OFFSET(%rcx)
VMOVA %xmm1, LRV_XMM1_OFFSET(%rcx)
# ifdef RESTORE_AVX
/* This is to support AVX audit modules. */
VMOVA %VEC(0), LRV_VECTOR0_OFFSET(%rcx)
VMOVA %VEC(1), LRV_VECTOR1_OFFSET(%rcx)
/* Save xmm0/xmm1 registers to detect if they are changed
by audit module. */
vmovdqa %xmm0, (LRV_SIZE + XMM_SIZE*0)(%rcx)
vmovdqa %xmm1, (LRV_SIZE + XMM_SIZE*1)(%rcx)
# endif
fstpt LRV_ST0_OFFSET(%rcx)
fstpt LRV_ST1_OFFSET(%rcx)
movq 24(%rbx), %rdx # La_x86_64_regs argument to %rdx.
movq 40(%rbx), %rsi # Copy args pushed by PLT in register.
movq 32(%rbx), %rdi # %rdi: link_map, %rsi: reloc_index
call _dl_audit_pltexit
/* Restore return registers. */
movq LRV_RAX_OFFSET(%rsp), %rax
movq LRV_RDX_OFFSET(%rsp), %rdx
VMOVA LRV_XMM0_OFFSET(%rsp), %xmm0
VMOVA LRV_XMM1_OFFSET(%rsp), %xmm1
# ifdef RESTORE_AVX
/* Check if xmm0/xmm1 registers are changed by audit module. */
vpcmpeqb (LRV_SIZE)(%rsp), %xmm0, %xmm2
vpmovmskb %xmm2, %esi
incw %si
jne 1f
VMOVA LRV_VECTOR0_OFFSET(%rsp), %VEC(0)
1: vpcmpeqb (LRV_SIZE + XMM_SIZE)(%rsp), %xmm1, %xmm2
vpmovmskb %xmm2, %esi
incw %si
jne 1f
VMOVA LRV_VECTOR1_OFFSET(%rsp), %VEC(1)
1:
# endif
fldt LRV_ST1_OFFSET(%rsp)
fldt LRV_ST0_OFFSET(%rsp)
mov %RBX_LP, %RSP_LP
movq (%rsp), %rbx
cfi_restore(%rbx)
cfi_def_cfa_register(%rsp)
add $48, %RSP_LP # Adjust the stack to the return value
# (eats the reloc index and link_map)
cfi_adjust_cfa_offset(-48)
retq
cfi_endproc
.size _dl_runtime_profile, .-_dl_runtime_profile
#endif
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