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LibELF: Store SSE registers in x86_64 PLT Trampoline

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Save and restore XMM registers so userspace programs don't
randomly lose values from calls. This fixes a crash in ScummVM.
This commit is contained in:
Peter 2021-10-30 23:26:52 +02:00 • committed by Andreas Kling
parent 80aa1b93d1
commit 24fdf99d8b
1 changed files with 21 additions and 3 deletions
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24
Userland/Libraries/LibELF/Arch/x86_64/plt_trampoline.S
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@ -10,6 +10,15 @@
.type _plt_trampoline,@function .type _plt_trampoline,@function
_plt_trampoline: # (object, relocation_index) _plt_trampoline: # (object, relocation_index)
# save flags/registers (https://stackoverflow.com/questions/18024672/what-registers-are-preserved-through-a-linux-x86-64-function-call) # save flags/registers (https://stackoverflow.com/questions/18024672/what-registers-are-preserved-through-a-linux-x86-64-function-call)
subq $128, %rsp
movdqu %xmm0, 0x0(%rsp)
movdqu %xmm1, 0x10(%rsp)
movdqu %xmm2, 0x20(%rsp)
movdqu %xmm3, 0x30(%rsp)
movdqu %xmm4, 0x40(%rsp)
movdqu %xmm5, 0x50(%rsp)
movdqu %xmm6, 0x60(%rsp)
movdqu %xmm7, 0x70(%rsp)
pushfq pushfq
pushq %rax pushq %rax
pushq %rcx pushq %rcx
@ -21,8 +30,8 @@ _plt_trampoline: # (object, relocation_index)
pushq %r10 pushq %r10
pushq %r11 pushq %r11
movq 80(%rsp), %rdi # object movq 208(%rsp), %rdi # object
movq 88(%rsp), %rsi # relocation_index movq 216(%rsp), %rsi # relocation_index
# offset = index * sizeof(Elf64_Rela) # offset = index * sizeof(Elf64_Rela)
shlq $3, %rsi shlq $3, %rsi
@ -35,7 +44,7 @@ _plt_trampoline: # (object, relocation_index)
movq %rbp, %rsp movq %rbp, %rsp
popq %rbp popq %rbp
movq %rax, 88(%rsp) # replace object argument with symbol address movq %rax, 216(%rsp) # replace object argument with symbol address
# restore flags/registers # restore flags/registers
popq %r11 popq %r11
@ -49,6 +58,15 @@ _plt_trampoline: # (object, relocation_index)
popq %rax popq %rax
popfq popfq
movdqu 0x0(%rsp), %xmm0
movdqu 0x10(%rsp), %xmm1
movdqu 0x20(%rsp), %xmm2
movdqu 0x30(%rsp), %xmm3
movdqu 0x40(%rsp), %xmm4
movdqu 0x50(%rsp), %xmm5
movdqu 0x60(%rsp), %xmm6
movdqu 0x70(%rsp), %xmm7
addq $128, %rsp
addq $8, %rsp # remove relocation_index argument addq $8, %rsp # remove relocation_index argument
retq retq