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

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Rather than computing them by hand.
This commit is contained in:
tkchia 2022-09-18 17:54:55 +08:00 committed by GitHub
parent cdf9e8c8a3
commit c937fbb222
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 37 additions and 17 deletions
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24
ape/ape.S
View file

@ -235,8 +235,9 @@ pc: cld
#endif
ljmp $0,$REAL(1f)
1: mov %cx,%ds
mov $IMAGE_BASE_REAL-0x0500,%cx # clears bss
mov $0x0500>>4,%ax # struct mman
.set mm,0x0500 # struct mman
mov $IMAGE_BASE_REAL-mm,%cx # clears bss
mov $mm>>4,%ax
mov %ax,%es
xor %ax,%ax
xor %di,%di
@ -328,7 +329,7 @@ dsknfo: push %bx
movpp %es,%ds
xor %si,%si
mov %si,%es
mov $0x1d10,%si # mman::pc_drive_base_table
mov $mm+"struct mman::pc_drive_base_table",%si
xchg %si,%di
movsw #→ headunloadtime, headloadtime
movsw #→ shutofftime, bytespersector
@ -381,11 +382,11 @@ pcread: push %ax
add $512>>4,%si
mov %si,%es
inc %al # ++sector
cmp 0x1d1c,%al # mman::pc_drive_last_sector
cmp mm+"struct mman::pc_drive_last_sector",%al
jbe 2f
mov $1,%al
inc %dh # ++head
cmp 0x1d20,%dh # mman::pc_drive_last_head
cmp mm+"struct mman::pc_drive_last_head",%dh
jbe 2f
xor %dh,%dh
inc %cx # ++cylinder
@ -1288,10 +1289,9 @@ lcheck: pushf # check for i8086 / i8088 / i80186
.endfn lcheck
// Gets memory map from BIOS.
e820: mov $0x0510>>4,%di # mman::e820
mov %di,%es
xor %di,%di # es:di is destination buffer
xor %ebx,%ebx # ebx is an api state tracker
e820: xor %ebx,%ebx # %ebx is an api state tracker
mov %bx,%es
mov $mm+"struct mman::e820",%di # es:di is destination buffer
1: mov $0xE820,%eax # magic
mov $8+8+4+4,%ecx # sizeof(struct SmapEntry)
mov $0x534d4150,%edx # magic number
@ -1315,7 +1315,7 @@ e820: mov $0x0510>>4,%di # mman::e820
4: add $8+8+4+4,%di # keep entry
5: test %ebx,%ebx # last entry?
jz 8f
cmp $(256-1)*(8+8+4+4),%di
cmp $mm+"struct mman::e820_end"-(8+8+4+4),%di
jb 1b
8: xor %ax,%ax # add a blank sentinel entry
mov $(8+8)/2,%cx
@ -1425,7 +1425,7 @@ pinit: push %ds
//
// @see Intel Manual V3A §4.1.2
golong: cli
lidt 0x1d22 # mman::bad_idt
lidt mm+"struct mman::bad_idt"
mov %cr4,%eax
or $CR4_PAE|CR4_PGE|CR4_OSFXSR,%eax
mov %eax,%cr4
@ -1458,7 +1458,7 @@ long: xor %eax,%eax
xor %ebx,%ebx
xor %ebp,%ebp
push %rbp
mov $0x0500,%rdi # mman
mov $mm,%rdi
mov %cr3,%rsi
mov $IMAGE_BASE_REAL,%edx
call __map_phdrs

19
libc/intrin/mman.greg.c
View file

@ -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);
}

11
libc/runtime/mman.internal.h
View file

@ -9,14 +9,15 @@ struct mman {
int32_t pdpi; /* 0x0508 */
int32_t e820n; /* 0x050c */
struct SmapEntry e820[256]; /* 0x0510 */
struct SmapEntry e820_end[0]; /* 0x1d10 */
char pc_drive_base_table[11]; /* 0x1d10 */
unsigned char pc_drive_type; /* 0x1d1b */
unsigned char pc_drive_last_sector; /* 0x1d1c */
unsigned short pc_drive_last_cylinder; /* 0x1d1d */
unsigned char pc_drives_attached; /* 0x1d1f */
unsigned char pc_drive_last_head; /* 0x1d20 */
unsigned char pc_drive; /* 0x1d21 */
char bad_idt[6]; /* 0x1d22 */
unsigned short pc_drive_last_cylinder; /* 0x1d1e */
unsigned char pc_drives_attached; /* 0x1d20 */
unsigned char pc_drive_last_head; /* 0x1d21 */
unsigned char pc_drive; /* 0x1d22 */
char bad_idt[6]; /* 0x1d23 */
};
COSMOPOLITAN_C_END_