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提交 0ca1c040 创建 作者: Frans Kaashoek's avatar Frans Kaashoek
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Merge branch 'master' of git+ssh://amsterdam.csail.mit.edu/home/am0/6.828/xv6

上级 9b972c06 1e6f0146
全部展开 隐藏空白字符变更
内嵌 并排
正在显示 包含 94 行增加 和 84 行删除
LucidaSans-Typewriter83 deleted 100644 → 0
浏览文件 @ 9b972c06
差异被折叠。
bootasm.S
浏览文件 @ 0ca1c040
......@@ -12,8 +12,8 @@
start:
cli # BIOS enabled interrupts; disable
# Set up the important data segment registers (DS, ES, SS).
xorw %ax,%ax # Segment number zero
# Zero data segment registers DS, ES, and SS.
xorw %ax,%ax # Set %ax to zero
movw %ax,%ds # -> Data Segment
movw %ax,%es # -> Extra Segment
movw %ax,%ss # -> Stack Segment
......@@ -37,7 +37,7 @@ seta20.2:
outb %al,$0x60
# Switch from real to protected mode. Use a bootstrap GDT that makes
# virtual addresses map dierctly to physical addresses so that the
# virtual addresses map directly to physical addresses so that the
# effective memory map doesn't change during the transition.
lgdt gdtdesc
movl %cr0, %eax
......
console.c
浏览文件 @ 0ca1c040
......@@ -53,7 +53,7 @@ printint(int xx, int base, int sign)
void
cprintf(char *fmt, ...)
{
int i, c, state, locking;
int i, c, locking;
uint *argp;
char *s;
......@@ -65,7 +65,6 @@ cprintf(char *fmt, ...)
panic("null fmt");
argp = (uint*)(void*)(&fmt + 1);
state = 0;
for(i = 0; (c = fmt[i] & 0xff) != 0; i++){
if(c != '%'){
consputc(c);
......
defs.h
浏览文件 @ 0ca1c040
......@@ -62,11 +62,10 @@ extern uchar ioapicid;
void ioapicinit(void);
// kalloc.c
char* enter_alloc(void);
char* kalloc(void);
void kfree(char*);
void kinit(void);
uint detect_memory(void);
void kinit1(void*, void*);
void kinit2(void*, void*);
// kbd.c
void kbdintr(void);
......@@ -165,7 +164,7 @@ void uartputc(int);
void seginit(void);
void kvmalloc(void);
void vmenable(void);
pde_t* setupkvm(char* (*alloc)());
pde_t* setupkvm();
char* uva2ka(pde_t*, char*);
int allocuvm(pde_t*, uint, uint);
int deallocuvm(pde_t*, uint, uint);
......
entry.S
浏览文件 @ 0ca1c040
......@@ -36,7 +36,7 @@ multiboot_header:
.globl _start
_start = V2P_WO(entry)
# Entering xv6 on boot processor. Machine is mostly set up.
# Entering xv6 on boot processor, with paging off.
.globl entry
entry:
# Turn on page size extension for 4Mbyte pages
......
kalloc.c
浏览文件 @ 0ca1c040
......@@ -9,42 +9,45 @@
#include "mmu.h"
#include "spinlock.h"
void freerange(void *vstart, void *vend);
extern char end[]; // first address after kernel loaded from ELF file
struct run {
struct run *next;
};
struct {
struct spinlock lock;
int use_lock;
struct run *freelist;
} kmem;
extern char end[]; // first address after kernel loaded from ELF file
static char *newend;
// A simple page allocator to get off the ground during entry
char *
enter_alloc(void)
// Initialization happens in two phases.
// 1. main() calls kinit1() while still using entrypgdir to place just
// the pages mapped by entrypgdir on free list.
// 2. main() calls kinit2() with the rest of the physical pages
// after installing a full page table that maps them on all cores.
void
kinit1(void *vstart, void *vend)
{
if (newend == 0)
newend = end;
initlock(&kmem.lock, "kmem");
kmem.use_lock = 0;
freerange(vstart, vend);
}
if ((uint) newend >= KERNBASE + 0x400000)
panic("only first 4Mbyte are mapped during entry");
void *p = (void*)PGROUNDUP((uint)newend);
memset(p, 0, PGSIZE);
newend = newend + PGSIZE;
return p;
void
kinit2(void *vstart, void *vend)
{
freerange(vstart, vend);
kmem.use_lock = 1;
}
// Initialize free list of physical pages.
void
kinit(void)
freerange(void *vstart, void *vend)
{
char *p;
initlock(&kmem.lock, "kmem");
p = (char*)PGROUNDUP((uint)newend);
for(; p + PGSIZE <= (char*)p2v(PHYSTOP); p += PGSIZE)
p = (char*)PGROUNDUP((uint)vstart);
for(; p + PGSIZE <= (char*)vend; p += PGSIZE)
kfree(p);
}
......@@ -64,11 +67,13 @@ kfree(char *v)
// Fill with junk to catch dangling refs.
memset(v, 1, PGSIZE);
acquire(&kmem.lock);
if(kmem.use_lock)
acquire(&kmem.lock);
r = (struct run*)v;
r->next = kmem.freelist;
kmem.freelist = r;
release(&kmem.lock);
if(kmem.use_lock)
release(&kmem.lock);
}
// Allocate one 4096-byte page of physical memory.
......@@ -79,11 +84,13 @@ kalloc(void)
{
struct run *r;
acquire(&kmem.lock);
if(kmem.use_lock)
acquire(&kmem.lock);
r = kmem.freelist;
if(r)
kmem.freelist = r->next;
release(&kmem.lock);
if(kmem.use_lock)
release(&kmem.lock);
return (char*)r;
}
main.c
浏览文件 @ 0ca1c040
......@@ -9,6 +9,7 @@
static void startothers(void);
static void mpmain(void) __attribute__((noreturn));
extern pde_t *kpgdir;
extern char end[]; // first address after kernel loaded from ELF file
// Bootstrap processor starts running C code here.
// Allocate a real stack and switch to it, first
......@@ -16,6 +17,7 @@ extern pde_t *kpgdir;
int
main(void)
{
kinit1(end, P2V(4*1024*1024)); // phys page allocator
kvmalloc(); // kernel page table
mpinit(); // collect info about this machine
lapicinit(mpbcpu());
......@@ -33,9 +35,9 @@ main(void)
ideinit(); // disk
if(!ismp)
timerinit(); // uniprocessor timer
startothers(); // start other processors (must come before kinit)
kinit(); // initialize memory allocator
userinit(); // first user process (must come after kinit)
startothers(); // start other processors
kinit2(P2V(4*1024*1024), P2V(PHYSTOP)); // must come after startothers()
userinit(); // first user process
// Finish setting up this processor in mpmain.
mpmain();
}
......@@ -84,12 +86,7 @@ startothers(void)
// Tell entryother.S what stack to use, where to enter, and what
// pgdir to use. We cannot use kpgdir yet, because the AP processor
// is running in low memory, so we use entrypgdir for the APs too.
// kalloc can return addresses above 4Mbyte (the machine may have
// much more physical memory than 4Mbyte), which aren't mapped by
// entrypgdir, so we must allocate a stack using enter_alloc();
// this introduces the constraint that xv6 cannot use kalloc until
// after these last enter_alloc invocations.
stack = enter_alloc();
stack = kalloc();
*(void**)(code-4) = stack + KSTACKSIZE;
*(void**)(code-8) = mpenter;
*(int**)(code-12) = (void *) v2p(entrypgdir);
......@@ -109,9 +106,9 @@ startothers(void)
__attribute__((__aligned__(PGSIZE)))
pde_t entrypgdir[NPDENTRIES] = {
// Map VA's [0, 4MB) to PA's [0, 4MB)
[0] = (0) + PTE_P + PTE_W + PTE_PS,
[0] = (0) | PTE_P | PTE_W | PTE_PS,
// Map VA's [KERNBASE, KERNBASE+4MB) to PA's [0, 4MB)
[KERNBASE>>PDXSHIFT] = (0) + PTE_P + PTE_W + PTE_PS,
[KERNBASE>>PDXSHIFT] = (0) | PTE_P | PTE_W | PTE_PS,
};
//PAGEBREAK!
......
memlayout.h
浏览文件 @ 0ca1c040
......@@ -10,13 +10,13 @@
#ifndef __ASSEMBLER__
static inline uint v2p(void *a) { return (uint) a - KERNBASE; }
static inline void *p2v(uint a) { return (void *) a + KERNBASE; }
static inline uint v2p(void *a) { return ((uint) (a)) - KERNBASE; }
static inline void *p2v(uint a) { return (void *) ((a) + KERNBASE); }
#endif
#define V2P(a) ((uint) a - KERNBASE)
#define P2V(a) ((void *) a + KERNBASE)
#define V2P(a) (((uint) (a)) - KERNBASE)
#define P2V(a) (((void *) (a)) + KERNBASE)
#define V2P_WO(x) ((x) - KERNBASE) // same as V2P, but without casts
#define P2V_WO(x) ((x) + KERNBASE) // same as V2P, but without casts
runoff
浏览文件 @ 0ca1c040
......@@ -223,11 +223,17 @@ awk '
grep Pages: all.ps
# if we have the nice font, use it
nicefont=../LucidaSans-Typewriter83
if [ -f $nicefont ]
nicefont=LucidaSans-Typewriter83
if [ ! -f ../$nicefont ]
then
if git cat-file blob font:$nicefont > ../$nicefont~; then
mv ../$nicefont~ ../$nicefont
fi
fi
if [ -f ../$nicefont ]
then
echo nicefont
(sed 1q all.ps; cat $nicefont; sed '1d; s/Courier/LucidaSans-Typewriter83/' all.ps) >allf.ps
(sed 1q all.ps; cat ../$nicefont; sed "1d; s/Courier/$nicefont/" all.ps) >allf.ps
else
echo ugly font!
cp all.ps allf.ps
......
vm.c
浏览文件 @ 0ca1c040
......@@ -43,7 +43,7 @@ seginit(void)
// that corresponds to virtual address va. If alloc!=0,
// create any required page table pages.
static pte_t *
walkpgdir(pde_t *pgdir, const void *va, char* (*alloc)(void))
walkpgdir(pde_t *pgdir, const void *va, int alloc)
{
pde_t *pde;
pte_t *pgtab;
......@@ -52,7 +52,7 @@ walkpgdir(pde_t *pgdir, const void *va, char* (*alloc)(void))
if(*pde & PTE_P){
pgtab = (pte_t*)p2v(PTE_ADDR(*pde));
} else {
if(!alloc || (pgtab = (pte_t*)alloc()) == 0)
if(!alloc || (pgtab = (pte_t*)kalloc()) == 0)
return 0;
// Make sure all those PTE_P bits are zero.
memset(pgtab, 0, PGSIZE);
......@@ -68,8 +68,7 @@ walkpgdir(pde_t *pgdir, const void *va, char* (*alloc)(void))
// physical addresses starting at pa. va and size might not
// be page-aligned.
static int
mappages(pde_t *pgdir, void *va, uint size, uint pa,
int perm, char* (*alloc)(void))
mappages(pde_t *pgdir, void *va, uint size, uint pa, int perm)
{
char *a, *last;
pte_t *pte;
......@@ -77,7 +76,7 @@ mappages(pde_t *pgdir, void *va, uint size, uint pa,
a = (char*)PGROUNDDOWN((uint)va);
last = (char*)PGROUNDDOWN(((uint)va) + size - 1);
for(;;){
if((pte = walkpgdir(pgdir, a, alloc)) == 0)
if((pte = walkpgdir(pgdir, a, 1)) == 0)
return -1;
if(*pte & PTE_P)
panic("remap");
......@@ -90,53 +89,56 @@ mappages(pde_t *pgdir, void *va, uint size, uint pa,
return 0;
}
// The mappings from logical to virtual are one to one (i.e.,
// segmentation doesn't do anything). There is one page table per
// process, plus one that's used when a CPU is not running any process
// (kpgdir). A user process uses the same page table as the kernel; the
// page protection bits prevent it from accessing kernel memory.
// There is one page table per process, plus one that's used when
// a CPU is not running any process (kpgdir). The kernel uses the
// current process's page table during system calls and interrupts;
// page protection bits prevent user code from using the kernel's
// mappings.
//
// setupkvm() and exec() set up every page table like this:
// 0..KERNBASE: user memory (text+data+stack+heap), mapped to some free
// phys memory
//
// 0..KERNBASE: user memory (text+data+stack+heap), mapped to
// phys memory allocated by the kernel
// KERNBASE..KERNBASE+EXTMEM: mapped to 0..EXTMEM (for I/O space)
// KERNBASE+EXTMEM..KERNBASE+end: mapped to EXTMEM..end kernel,
// w. no write permission
// KERNBASE+end..KERBASE+PHYSTOP: mapped to end..PHYSTOP,
// rw data + free memory
// KERNBASE+EXTMEM..data: mapped to EXTMEM..V2P(data)
// for the kernel's instructions and r/o data
// data..KERNBASE+PHYSTOP: mapped to V2P(data)..PHYSTOP,
// rw data + free physical memory
// 0xfe000000..0: mapped direct (devices such as ioapic)
//
// The kernel allocates memory for its heap and for user memory
// between KERNBASE+end and the end of physical memory (PHYSTOP).
// The user program sits in the bottom of the address space, and the
// kernel at the top at KERNBASE.
// The kernel allocates physical memory for its heap and for user memory
// between V2P(end) and the end of physical memory (PHYSTOP)
// (directly addressable from end..P2V(PHYSTOP)).
// This table defines the kernel's mappings, which are present in
// every process's page table.
static struct kmap {
void *virt;
uint phys_start;
uint phys_end;
int perm;
} kmap[] = {
{ P2V(0), 0, 1024*1024, PTE_W}, // I/O space
{ (void*)KERNLINK, V2P(KERNLINK), V2P(data), 0}, // kernel text+rodata
{ data, V2P(data), PHYSTOP, PTE_W}, // kernel data, memory
{ (void*)DEVSPACE, DEVSPACE, 0, PTE_W}, // more devices
{ (void*) KERNBASE, 0, EXTMEM, PTE_W}, // I/O space
{ (void*) KERNLINK, V2P(KERNLINK), V2P(data), 0}, // kernel text+rodata
{ (void*) data, V2P(data), PHYSTOP, PTE_W}, // kernel data, memory
{ (void*) DEVSPACE, DEVSPACE, 0, PTE_W}, // more devices
};
// Set up kernel part of a page table.
pde_t*
setupkvm(char* (*alloc)(void))
setupkvm()
{
pde_t *pgdir;
struct kmap *k;
if((pgdir = (pde_t*)alloc()) == 0)
if((pgdir = (pde_t*)kalloc()) == 0)
return 0;
memset(pgdir, 0, PGSIZE);
if (p2v(PHYSTOP) > (void*)DEVSPACE)
panic("PHYSTOP too high");
for(k = kmap; k < &kmap[NELEM(kmap)]; k++)
if(mappages(pgdir, k->virt, k->phys_end - k->phys_start,
(uint)k->phys_start, k->perm, alloc) < 0)
(uint)k->phys_start, k->perm) < 0)
return 0;
return pgdir;
}
......@@ -146,7 +148,7 @@ setupkvm(char* (*alloc)(void))
void
kvmalloc(void)
{
kpgdir = setupkvm(enter_alloc);
kpgdir = setupkvm();
switchkvm();
}
......@@ -185,7 +187,7 @@ inituvm(pde_t *pgdir, char *init, uint sz)
panic("inituvm: more than a page");
mem = kalloc();
memset(mem, 0, PGSIZE);
mappages(pgdir, 0, PGSIZE, v2p(mem), PTE_W|PTE_U, kalloc);
mappages(pgdir, 0, PGSIZE, v2p(mem), PTE_W|PTE_U);
memmove(mem, init, sz);
}
......@@ -235,7 +237,7 @@ allocuvm(pde_t *pgdir, uint oldsz, uint newsz)
return 0;
}
memset(mem, 0, PGSIZE);
mappages(pgdir, (char*)a, PGSIZE, v2p(mem), PTE_W|PTE_U, kalloc);
mappages(pgdir, (char*)a, PGSIZE, v2p(mem), PTE_W|PTE_U);
}
return newsz;
}
......@@ -312,7 +314,7 @@ copyuvm(pde_t *pgdir, uint sz)
uint pa, i;
char *mem;
if((d = setupkvm(kalloc)) == 0)
if((d = setupkvm()) == 0)
return 0;
for(i = 0; i < sz; i += PGSIZE){
if((pte = walkpgdir(pgdir, (void *) i, 0)) == 0)
......@@ -323,7 +325,7 @@ copyuvm(pde_t *pgdir, uint sz)
if((mem = kalloc()) == 0)
goto bad;
memmove(mem, (char*)p2v(pa), PGSIZE);
if(mappages(d, (void*)i, PGSIZE, v2p(mem), PTE_W|PTE_U, kalloc) < 0)
if(mappages(d, (void*)i, PGSIZE, v2p(mem), PTE_W|PTE_U) < 0)
goto bad;
}
return d;
......
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