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Get binaries closer to running without an o/s

Browse source 
blinkenlights now does a pretty good job emulating what happens when
binaries boot from BIOS into long mode. So it's been much easier to
debug the bare metal process and wrinkle out many issues.
This commit is contained in:
Justine Tunney 2020-10-29 04:53:20 -07:00
parent feed0d2b0e
commit 2d80bbc802
50 changed files with 974 additions and 1062 deletions
Download patch file Download diff file Expand all files Collapse all files

341
ape/ape.S
View file

@ -45,8 +45,11 @@
#include "libc/nexgen32e/vidya.h"
#include "libc/nt/pedef.h"
#include "libc/nexgen32e/vidya.h"
#include "libc/dce.h"
#include "libc/sysv/consts/prot.h"
#define USE_SYMBOL_HACK 0
.source "NOTICE"
.source "ape/ape.S"
.source "ape/ape.lds"
@ -179,6 +182,10 @@ stub: mov $0x40,%dl # *literally* dos
/ @noreturn
.code16
pc: cld
#if USE_SYMBOL_HACK
.byte 0x0f,0x1f,0207 # nop rdi binbase
.short (0x7c00-IMAGE_BASE_VIRTUAL)/512
#endif
mov $REAL_STACK_FRAME>>4,%di # we need a stack
xor %cx,%cx
rlstack %di,%cx
@ -197,6 +204,10 @@ pc: cld
xor %di,%di
rep
movsb %ds:(%si),%es:(%di)
#if USE_SYMBOL_HACK
.byte 0x0f,0x1f,0207 # nop rdi binbase
.short (IMAGE_BASE_REAL-0x7c00)/512
#endif
ljmp $0,$REAL(1f) # longjmp()
1: mov $-512,%cx # memcpy() [relocate this frame]
rep
@ -932,9 +943,6 @@ ape.str:
.Lstr.long:
.asciz "nolong"
.endobj .Lstr.long
.Lstr.hello:
.asciz "hello\n"
.endobj .Lstr.hello
.endobj ape.str
/ Serial Line Configuration (8250 UART 16550)
@ -964,7 +972,7 @@ sconf: .short 1843200/*hz*/ / 16/*wut*/ / 9600/*baud*/
.align 8
gdt: .short 2f-1f # table byte length
.long REAL(1f),0 # table address
.align 8
.zero 2
1:
/ ┌G:granularity (1 → limit *= 0x1000)
/ │┌D/B:default operation size (0 = 16|64bit, 1 = 32-bit)
@ -1047,13 +1055,8 @@ ape.grub.entry:
nop
nop
realmodeloader:
push %bp
mov %sp,%bp
call rlinit
call sinit4
call vinit
mov %es,XLM(VIDEO_POSITION_FAR_POINTER)
mov %ax,XLM(VIDEO_POSITION_FAR_POINTER)+2
mov $REAL(.Lstr.ape),%di
call rvputs
.optfn _start16
@ -1062,38 +1065,29 @@ realmodeloader:
.endfn realmodeloader,globl,hidden
.section .sort.text.real.init.1,"ax",@progbits
.type rrinit,@function
rlinit: push %bp
mov %sp,%bp
.previous/*
.type rlinit,@function
rlinit: .previous/*
...
decentralized function
...
*/.section .sort.text.real.init.3,"ax",@progbits
pop %bp
ret
.previous
/ Initializes present PC serial lines.
sinit4: push %bp
mov %sp,%bp
movw $4,%cx
movw $kBiosDataAreaXlm+COM1,%si
0: lodsb
mov %al,%dl
lodsb
mov %al,%dh
test %dx,%dx
sinit4: mov $4,%cx
mov $kBiosDataAreaXlm+COM1,%si
0: lodsw
test %ax,%ax
jz 1f
push %cx
push %si
mov %dx,%di
movw $REAL(sconf),%si
xchg %ax,%di
mov $REAL(sconf),%si
call sinit
pop %si
pop %cx
1: loop 0b
pop %bp
ret
.endfn sinit4,global,hidden
@ -1103,9 +1097,7 @@ sinit4: push %bp
/ @param char (*{es:,e,r}si)[4] register initial values
/ @mode long,legacy,real
/ @see www.lammertbies.nl/comm/info/serial-uart.html
sinit: push %bp
mov %sp,%bp
mov %di,%dx
sinit: mov %di,%dx
test %dx,%dx
jz 2f
push %dx
@ -1123,8 +1115,7 @@ sinit: push %bp
add $1,%dx
sub $1,%cx
jns 1b
2: pop %bp
ret
2: ret
.endfn sinit,global,hidden
/ Abnormally exits program.
@ -1132,9 +1123,7 @@ sinit: push %bp
/ @param di message
/ @mode real
/ @noreturn
rldie: push %bp
mov %sp,%bp
call rlpute
rldie: call rlpute
call rloff
.endfn rldie,globl,hidden
@ -1142,9 +1131,7 @@ rldie: push %bp
/
/ @mode real
/ @noreturn
rloff: push %bp
mov %sp,%bp
mov $kBiosDataAreaXlm+COM1,%di
rloff: mov $kBiosDataAreaXlm+COM1,%di
mov $4,%si
call sflush
call apmoff
@ -1154,9 +1141,7 @@ rloff: push %bp
/
/ @param di message
/ @mode real
rlpute: push %bp
mov %sp,%bp
mov kBiosDataAreaXlm+METAL_STDERR(%bx),%si
rlpute: mov kBiosDataAreaXlm+METAL_STDERR(%bx),%si
test %si,%si
jnz 1f
mov kBiosDataAreaXlm+METAL_STDOUT,%si
@ -1176,8 +1161,7 @@ rlpute: push %bp
pop %si
call rlput2
jmp 1b
2: pop %bp
ret
2: ret
.endfn rlpute,globl,hidden
/ Prints string to both video and serial.
@ -1185,9 +1169,7 @@ rlpute: push %bp
/ @param di NUL-terminated string
/ @param si serial port
/ @mode real
rlput2: push %bp
mov %sp,%bp
push %di
rlput2: push %di
push %si
call rvputs
pop %si
@ -1195,33 +1177,42 @@ rlput2: push %bp
test %si,%si
jz 1f
call sputs
1: pop %bp
ret
1: ret
.endfn rlput2,globl,hidden
/ Video put string.
/
/ @param di is the string
/ @mode real
rvputs: push %bp
mov %sp,%bp
mov %di,%si
les XLM(VIDEO_POSITION_FAR_POINTER),%di
call vputs
mov %es,XLM(VIDEO_POSITION_FAR_POINTER)
mov %ax,XLM(VIDEO_POSITION_FAR_POINTER)+2
pop %bp
ret
rvputs: mov %di,%si
0: lodsb
test %al,%al
je 1f
call rvputc
jmp 0b
1: ret
.endfn rvputs,globl,hidden
/ Video put char.
/
/ @param al is the char
/ @mode real
rvputc: push %bx # don't clobber bp,bx,di,si,cx
push %bp # original ibm pc scroll up bug
mov $7,%bx # normal mda/cga style page zero
mov $0x0e,%ah # teletype output al cp437
int $0x10 # vidya service
pop %bp # preserves al
pop %bx
ret
.endfn rvputc
/ Writes string to serial line.
/
/ @param di NUL-terminated string
/ @param si serial port
/ @mode long,legacy,real
sputs: push %bp
mov %sp,%bp
push %bx
sputs: push %bx
mov %di,%bx
1: xchg %bx,%si
lodsb
@ -1234,7 +1225,6 @@ sputs: push %bp
pop %si
jmp 1b
2: pop %bx
pop %bp
ret
.endfn sputs,globl
@ -1290,137 +1280,11 @@ sputc: push %ax
ret
.endfn sputc,globl
/ Asks BIOS to initialize Monochrome Display Adapter.
/
/ @return es:ax start of video page
/ @mode real
vinit: push $7
pop %ax
int $VIDYA_SERVICE
bbmov VIDYA_ADDR_MDA>>4,%ax,%ah,%al
mov %ax,%es
xor %ax,%ax
ret
.endfn vinit,globl
/ Prints byte to display w/ teletype emulation.
/
/ @param es:di screen position
/ @param sil byte
/ @return es:ax new screen position
/ @mode long,legacy,real
vputc: push %bp
mov %sp,%bp
sub $16,%sp # goal is to turn sil into a buffer
xchg %si,%ax # modrm sooo different in real mode
mov %di,%cx
mov %sp,%si
mov %sp,%di
stosb
mov %cx,%di
pushpop 1,%dx
jmp 23f
/ Prints string to display w/ teletype emulation.
/
/ @param es:di screen position
/ @param si NUL-terminated string
/ @return es:ax new screen position
/ @mode long,legacy,real
vputs: push %si # inlined strlen
1: lodsb
test %al,%al
jnz 1b
mov %si,%dx
pop %si
sub %si,%dx
/ fallthrough
/ Prints data to display w/ teletype emulation.
/
/ @param es:di screen position
/ @param si data address
/ @param dx data size in bytes
/ @return es:ax new screen position
/ @mode long,legacy,real
vtput: push %bp
mov %sp,%bp
23: push %bx
mov %dx,%cx
mov %di,%dx
bband VIDYA_REWIND,%dh,%dl
bbadd VIDYA_SIZE,%dh,%dl
bbmov VIDYA_COLUMNS*2-2,%bx,%bh,%bl
0: cmp %dx,%di
je 6f
ja 3f
lodsb # todo: utf8 → cp437
cmp $'\n,%al
je 4f
cmp $'\r,%al
je 5f
1: stosb
mov $VIDYA_ATTR_NORMAL,%al # todo: ansi color
stosb
2: loop 0b
3: mov %di,%ax
pop %bx
pop %bp
ret
4: add %bx,%di # line feed
jmp 2b
5: mov %di,%ax # carriage return
push %dx
xor %dx,%dx
idiv %bx # todo: division is deprecated
sub %dx,%di
pop %dx
jmp 2b
6: push %ax
push %cx
push %dx
push %si
mov %bx,%si
rlcall vscroll
mov %ax,%di
pop %si
pop %dx
pop %cx
pop %ax
jmp 2b
.endfn vtput,globl
.endfn vputs,globl
.endfn vputc,globl
/ Scrolls up content in display page.
/
/ @param es:di cursor address (bytes after aren't moved)
/ @param si byte difference, e.g. VIDYA_COLUMNS*2
/ @return es:ax new cursor address (which is es:di-si)
/ @mode long,legacy,real
vscroll:not %dx
mov %di,%cx
bband VIDYA_REWIND,%ch,%cl
xchg %cx,%di # di is now page addr, i.e. top-left
sub %si,%cx # cx is now future cursor address
push %cx
sub %di,%cx # cx is now memcpy size
mov %di,%si
add %cx,%si
mov $0,%ax
movpp %ds,%es
rep movsb
pop %ax
ret
.endfn vscroll,globl
/ Shuts down personal computer.
/
/ @mode real
/ @noreturn
apmoff: push %bp
mov %sp,%bp
mov $0x5300,%ax # apm installation check
apmoff: mov $0x5300,%ax # apm installation check
xor %bx,%bx # for the apm bios itself
int $APM_SERVICE
jc 1f
@ -1485,8 +1349,6 @@ apmoff: push %bp
long mode is long */
longmodeloader:
push %bp
mov %sp,%bp
call lcheck
call a20
mov $XLM(E820),%di
@ -1495,15 +1357,13 @@ longmodeloader:
jc 9f
call unreal
call hiload
call golong
jmp golong
9: mov $REAL(.Lstr.e820),%ax
call rldie
.endfn longmodeloader,globl,hidden
/ Long Mode Hardware Check
lcheck: push %bp
mov %sp,%bp
pushf # check for i8086 / i8088 / i80186
lcheck: pushf # check for i8086 / i8088 / i80186
pop %ax
test $0x80,%ah # see intel manual volume 1 20.1.2
jnz 9f # we now assume 32bit is supported
@ -1534,8 +1394,7 @@ lcheck: push %bp
cmp %edi,%edx
jne 10f
xor %ax,%ax
1: pop %bp
ret
1: ret
9: mov $REAL(.Lstr.oldskool),%ax
jmp 20f
10: mov $REAL(.Lstr.long),%ax
@ -1587,9 +1446,7 @@ e820: push %bp
/ Unreal Mode.
/ Makes 4gb of real memory accessible via %fs segment.
unreal: push %bp
mov %sp,%bp
cli
unreal: cli
lgdt REAL(gdt)
mov %cr0,%eax
or $CR0_PE,%al
@ -1599,16 +1456,13 @@ unreal: push %bp
mov %cx,%fs
and $~CR0_PE,%al
mov %eax,%cr0
ljmpl $0,$REAL(1f)
ljmp $0,$REAL(1f)
1: sti
pop %bp
ret
.endfn unreal
/ Loads remainder of executable off disk.
hiload: push %bp
mov %sp,%bp
push %bx
hiload: push %bx
mov $IMAGE_BASE_REAL,%esi # relocate, again
mov $IMAGE_BASE_PHYSICAL,%ebx
mov $v_ape_realsectors,%ecx
@ -1647,7 +1501,6 @@ hiload: push %bp
pop %cx
jmp 0b
9: pop %bx
pop %bp
ret
.endfn hiload
@ -1724,18 +1577,16 @@ a20: cli
/ stack segment base. This function only defines enough tables
/ to get us started.
#define TIP REAL_STACK_FRAME
pinit: push %bp
mov %sp,%bp
push %ds
pinit: push %ds
mov $(TIP-0x4000)>>4,%ax
mov %ax,%ds
movl $TIP-0x2000+PAGE_V+PAGE_RW,%ds:0x3000 # PML4T→PDPT
movl $TIP-0x3000+PAGE_V+PAGE_RW,%ds:0x2000 # PDPT→PDT
movl $TIP-0x4000+PAGE_V+PAGE_RW,%ds:0x1000 # PDT→PD
movl $TIP-0x2000+PAGE_V+PAGE_RW,0x3000 # PML4T→PDPT
movl $TIP-0x3000+PAGE_V+PAGE_RW,0x2000 # PDPT→PDT
movl $TIP-0x4000+PAGE_V+PAGE_RW,0x1000 # PDT→PD
mov $0x100000/0x1000,%cx # PD→512kb
mov $PAGE_V+PAGE_RW,%eax
xor %si,%si
0: mov %eax,%ds:(%si)
0: mov %eax,(%si)
add $0x1000,%eax
add $8,%si
loop 0b
@ -1743,7 +1594,6 @@ pinit: push %bp
movl $TIP-0x4000,XLM(PAGE_TABLE_STACK_POINTER) # STACK→XLM
mov $TIP-0x1000,%eax # PML4T→CR3
mov %eax,%cr3
pop %bp
ret
.endfn pinit,globl,hidden
@ -1765,44 +1615,47 @@ golong: cli
or $CR0_PE|CR0_PG|CR0_MP,%eax
and $~CR0_EM,%eax
mov %eax,%cr0
ljmp $GDT_LONG_CODE,$REAL(1f)
.code64
1: mov $GDT_LONG_DATA,%eax
mov %ax,%ds
mov %ax,%fs
mov %ax,%gs
xor %edx,%edx
jmp long
ljmp $GDT_LONG_CODE,$REAL(long)
.endfn golong
/ Long mode is long.
/
/ @noreturn
long: .frame0
xor %edi,%edi
call pageunmap
mov $e820map_xlm,%edi
call smapsort
mov $e820map_xlm,%edi
mov $g_pml4t,%esi
mov $g_ptsp_xlm,%edx
call flattenhighmemory
mov $REAL(.Lstr.hello),%edi
mov kBiosDataAreaXlm+METAL_STDOUT,%esi
call sputs
mov $kBiosDataAreaXlm+METAL_STDOUT,%edi
mov $4,%esi
call sflush
jmp triplf
lea triplf(%rip),%rdx
call _start
jmp triplf
.code64
long: push $GDT_LONG_DATA
pop %rax
mov %eax,%ds
mov %eax,%ss
mov %eax,%es
mov %eax,%fs
mov %eax,%gs
xor %ebp,%ebp
mov $REAL_STACK_FRAME+FRAMESIZE,%esp
call __map_image
mov $_metal,%eax
jmp *%rax
.endfn long
/ Long mode in virtual address space.
/ @noreturn
_metal:
#if USE_SYMBOL_HACK
.byte 0x0f,0x1f,0207 # nop rdi binbase
.long (IMAGE_BASE_VIRTUAL-IMAGE_BASE_REAL)/512
#endif
xor %eax,%eax # clear bss
mov $.Lape.bss.vaddr,%edi
mov $.Lape.bss.memsz,%ecx
rep stosb
movb $METAL,hostos(%rip)
push $0 # auxv
push $0
push $0 # envp
push $0 # auxv
push $0 # argc
xor %edi,%edi
jmp _start
.endfn _metal
/ Avoid linker script variables appearing as code in objdump.
.macro .ldsvar name:req
.type \name,@object

2
ape/config.h
View file

@ -32,7 +32,7 @@
#define METAL_STDOUT COM1
#endif
#ifndef METAL_STDERR
#define METAL_STDERR COM2 /* will fallback to stdout if COM2 not present */
#define METAL_STDERR COM1
#endif
/**

12
ape/lib/getpagetableentry.c
View file

@ -24,14 +24,16 @@ textreal static uint64_t pushpagetable(uint64_t *ptsp) {
return (*ptsp -= PAGESIZE) | PAGE_V | PAGE_RW;
}
textreal uint64_t *getpagetableentry(uint64_t vaddr, unsigned depth,
textreal uint64_t *getpagetableentry(int64_t vaddr, unsigned depth,
struct PageTable *pml4t, uint64_t *ptsp) {
uint64_t *entry;
unsigned char shift;
assert(depth <= 3);
assert(*ptsp % PAGESIZE == 0);
assert((intptr_t)pml4t % PAGESIZE == 0);
unsigned char shift = 39;
assert(!(*ptsp & 0xfff));
assert(!((uintptr_t)pml4t & 0xfff));
shift = 39;
for (;;) {
uint64_t *entry = &pml4t->p[(vaddr >> shift) & 511];
entry = &pml4t->p[(vaddr >> shift) & 511];
if (!depth--) return entry;
shift -= 9;
if (!*entry) *entry = pushpagetable(ptsp);

2
ape/lib/kbiosdataarea.S
View file

@ -37,7 +37,7 @@
.size kBiosDataAreaXlm,XLM_BIOS_DATA_AREA_SIZE
kBiosDataAreaXlm = XLM(BIOS_DATA_AREA)
.section .sort.real.init.2.kBiosDataArea,"ax",@progbits
.section .sort.text.real.init.2.kBiosDataArea,"ax",@progbits
movpp %ds,%es # copy bios data to valid page
mov $PC_BIOS_DATA_AREA,%si
mov $XLM(BIOS_DATA_AREA),%di

38
ape/lib/mapimage.c Normal file
View file

@ -0,0 +1,38 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "ape/lib/pc.h"
#include "ape/relocations.h"
#include "libc/runtime/runtime.h"
textreal static void __map_segment(uint64_t k, uint64_t a, uint64_t b) {
uint64_t *e;
for (; a < b; a += 0x1000) {
e = getpagetableentry(IMAGE_BASE_VIRTUAL + a, 3, &g_pml4t, &g_ptsp_xlm);
*e = (IMAGE_BASE_PHYSICAL + a) | k;
}
}
textreal void __map_image(void) {
pageunmap(0);
__map_segment(PAGE_V | PAGE_U, 0, (uintptr_t)_etext - IMAGE_BASE_VIRTUAL);
__map_segment(PAGE_V | PAGE_U | PAGE_RW | PAGE_XD,
(uintptr_t)_etext - IMAGE_BASE_VIRTUAL,
(uintptr_t)_end - IMAGE_BASE_VIRTUAL);
}

5
ape/lib/pageunmap.c
View file

@ -20,8 +20,9 @@
#include "ape/lib/pc.h"
#include "libc/bits/bits.h"
textreal void pageunmap(uint64_t vaddr) {
uint64_t *entry = getpagetableentry(vaddr, 3, &g_pml4t, &g_ptsp_xlm);
textreal void pageunmap(int64_t vaddr) {
uint64_t *entry;
entry = getpagetableentry(vaddr, 3, &g_pml4t, &g_ptsp_xlm);
*entry &= ~PAGE_V;
invlpg(vaddr);
}

5
ape/lib/pc.h
View file

@ -157,6 +157,7 @@
#define PAGE_1GB /* */ 0b110000000
#define PAGE_TA 0b11111111111111111111111111111111111111000000000000
#define PAGE_PA2 0b11111111111111111111111111111000000000000000000000
#define PAGE_XD 0x8000000000000000
#if !(__ASSEMBLER__ + __LINKER__ + 0)
#include "ape/config.h"
@ -213,9 +214,9 @@ extern uint64_t g_ptsp_xlm;
void bootdr(char drive) noreturn;
void smapsort(struct SmapEntry *);
uint64_t *getpagetableentry(uint64_t, unsigned, struct PageTable *, uint64_t *);
uint64_t *getpagetableentry(int64_t, unsigned, struct PageTable *, uint64_t *);
void flattenhighmemory(struct SmapEntry *, struct PageTable *, uint64_t *);
void pageunmap(uint64_t);
void pageunmap(int64_t);
forceinline unsigned long eflags(void) {
unsigned long res;