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[metal] Export struct offsets from C code (#625)

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Rather than computing them by hand.
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tkchia 2022-09-18 17:54:55 +08:00 • committed by GitHub
parent cdf9e8c8a3
commit c937fbb222
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3 changed files with 37 additions and 17 deletions
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19
libc/intrin/mman.greg.c
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@ -128,7 +128,26 @@ static noasan textreal void __invert_memory(struct mman *mm, uint64_t *pml4t) {
}
}
/**
* Exports information about the offset of a field within a structure type,
* so that assembly language routines can use it. This macro can be invoked
* from inside a function whose code is known to be emitted.
*/
#define export_offsetof(type, member) \
do { \
asm volatile(".globl \"" #type "::" #member "\"\n\t" \
".set \"" #type "::" #member "\",%c0" \
: /* no outputs */ \
: "i" (offsetof(type, member))); \
} while (0)
noasan textreal void __setup_mman(struct mman *mm, uint64_t *pml4t) {
export_offsetof(struct mman, pc_drive_base_table);
export_offsetof(struct mman, pc_drive_last_sector);
export_offsetof(struct mman, pc_drive_last_head);
export_offsetof(struct mman, e820);
export_offsetof(struct mman, e820_end);
export_offsetof(struct mman, bad_idt);
__normalize_e820(mm);
__invert_memory(mm, pml4t);
}