39 lines
1016 B
C
39 lines
1016 B
C
#ifndef COSMOPOLITAN_LIBC_SYSV_MACROS_H_
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#define COSMOPOLITAN_LIBC_SYSV_MACROS_H_
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#ifdef __ASSEMBLER__
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#include "libc/macros.internal.inc"
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/* clang-format off */
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/**
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* @fileoverview System Five jump slot generator.
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*
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* We need to pass a magic number to the SYSCALL instruction in %rax.
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* That's only possible to do in C using asm() macro wrappers, like in
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* Chromium's "System Call Support" library. This technique is simpler
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* to implement, gains us object-level ABI compatibility, hookability,
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* and the ability to support significantly more functions, without the
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* risk of slowing down builds too much with complicated headers.
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*/
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.macro .scall name:req num:req kw1 kw2
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.ifnb \kw2
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.align 16
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\name: movabs $\num,%rax
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jmp *__systemfive(%rip)
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.else
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\name: push %rbp
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mov %rsp,%rbp
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movabs $\num,%rax
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.hookable
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call *__systemfive(%rip)
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pop %rbp
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ret
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.endif
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.endfn \name,\kw1,\kw2
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.previous
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.endm
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/* clang-format on */
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#endif /* __ASSEMBLER__ */
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#endif /* COSMOPOLITAN_LIBC_SYSV_MACROS_H_ */
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