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Reduce size of getcpu vdso

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Summary: The `getcpu` VDSO was just returning 0 unconditionally. This was an old hack to determinize the getcpu syscall, but we don't need this anymore because we just intercept it and determinize it instead. Reducing the size of this vdso function will make it more compatible with various VDSO implementations.

Reviewed By: wkhughes

Differential Revision: D41506684

fbshipit-source-id: 3dacad93971ecc7969d725f8b7e984a189a0ebb4
This commit is contained in:
Jason White 2022-11-23 13:55:56 -08:00 committed by Facebook GitHub Bot
parent debce82715
commit c448d10586
1 changed files with 4 additions and 10 deletions
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14
reverie-ptrace/src/vdso.rs
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@ -28,7 +28,7 @@ mod vdso_syms {
#![allow(non_upper_case_globals)]
pub const time: &[u8; 8] = &[
0xb8, 0xc9, 0x0, 0x0, 0x0, // mov %SYS_time, %eax
0xb8, 0xc9, 0x00, 0x00, 0x00, // mov %SYS_time, %eax
0x0f, 0x05, // syscall
0xc3, // retq
];
@ -39,16 +39,10 @@ mod vdso_syms {
0xc3, // retq
];
pub const getcpu: &[u8; 32] = &[
0x48, 0x85, 0xff, // test %rdi, %rdi
0x74, 0x06, // je ..
0xc7, 0x07, 0x00, 0x00, 0x00, 0x00, // movl $0x0, (%rdi)
0x48, 0x85, 0xf6, // test %rsi, %rsi
0x74, 0x06, // je ..
0xc7, 0x06, 0x00, 0x00, 0x00, 0x00, // movl $0x0, (%rsi)
0x31, 0xc0, // xor %eax, %eax
pub const getcpu: &[u8; 8] = &[
0xb8, 0x35, 0x01, 0x00, 0x00, // mov SYS_getcpu, %eax
0x0f, 0x05, // syscall
0xc3, // retq
0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00, // nopl 0x0(%rax)
];
pub const gettimeofday: &[u8; 8] = &[