Rearrange vm.c so it's in logical order and prints nicely. Shorten a few functions in uninteresting ways to make them fit.
This commit is contained in:
Austin Clements
parent
f53e6110be
commit
f25a3f9a41
10
runoff.spec
10
runoff.spec
|
|
@ -42,8 +42,14 @@ odd: proc.h
|
|||
left: proc.c # VERY important
|
||||
odd: proc.c # VERY important
|
||||
|
||||
# setjmp.S either
|
||||
# vm.c either
|
||||
# A few more action packed spreads
|
||||
# page table creation and process loading
|
||||
# walkpgdir mappages setupkvm vmenable switch[ku]vm inituvm loaduvm
|
||||
# process memory management
|
||||
# allocuvm deallocuvm freevm
|
||||
right: vm.c
|
||||
odd: vm.c
|
||||
|
||||
# kalloc.c either
|
||||
|
||||
# syscall.h either
|
||||
|
|
|
|||
320
vm.c
320
vm.c
|
|
@ -6,86 +6,10 @@
|
|||
#include "proc.h"
|
||||
#include "elf.h"
|
||||
|
||||
// The mappings from logical to linear 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 using anything other
|
||||
// than its memory.
|
||||
//
|
||||
// setupkvm() and exec() set up every page table like this:
|
||||
// 0..640K : user memory (text, data, stack, heap)
|
||||
// 640K..1M : mapped direct (for IO space)
|
||||
// 1M..end : mapped direct (for the kernel's text and data)
|
||||
// end..PHYSTOP : mapped direct (kernel heap and user pages)
|
||||
// 0xfe000000..0 : mapped direct (devices such as ioapic)
|
||||
//
|
||||
// The kernel allocates memory for its heap and for user memory
|
||||
// between kernend and the end of physical memory (PHYSTOP).
|
||||
// The virtual address space of each user program includes the kernel
|
||||
// (which is inaccessible in user mode). The user program addresses
|
||||
// range from 0 till 640KB (USERTOP), which where the I/O hole starts
|
||||
// (both in physical memory and in the kernel's virtual address
|
||||
// space).
|
||||
|
||||
#define USERTOP 0xA0000
|
||||
|
||||
static pde_t *kpgdir; // for use in scheduler()
|
||||
|
||||
// return the address of the PTE in page table pgdir
|
||||
// that corresponds to linear address va. if create!=0,
|
||||
// create any required page table pages.
|
||||
static pte_t *
|
||||
walkpgdir(pde_t *pgdir, const void *va, int create)
|
||||
{
|
||||
uint r;
|
||||
pde_t *pde;
|
||||
pte_t *pgtab;
|
||||
|
||||
pde = &pgdir[PDX(va)];
|
||||
if(*pde & PTE_P){
|
||||
pgtab = (pte_t*) PTE_ADDR(*pde);
|
||||
} else if(!create || !(r = (uint) kalloc()))
|
||||
return 0;
|
||||
else {
|
||||
pgtab = (pte_t*) r;
|
||||
|
||||
// Make sure all those PTE_P bits are zero.
|
||||
memset(pgtab, 0, PGSIZE);
|
||||
|
||||
// The permissions here are overly generous, but they can
|
||||
// be further restricted by the permissions in the page table
|
||||
// entries, if necessary.
|
||||
*pde = PADDR(r) | PTE_P | PTE_W | PTE_U;
|
||||
}
|
||||
return &pgtab[PTX(va)];
|
||||
}
|
||||
|
||||
// create PTEs for linear addresses starting at la that refer to
|
||||
// physical addresses starting at pa. la and size might not
|
||||
// be page-aligned.
|
||||
static int
|
||||
mappages(pde_t *pgdir, void *la, uint size, uint pa, int perm)
|
||||
{
|
||||
char *first = PGROUNDDOWN(la);
|
||||
char *last = PGROUNDDOWN(la + size - 1);
|
||||
char *a = first;
|
||||
while(1){
|
||||
pte_t *pte = walkpgdir(pgdir, a, 1);
|
||||
if(pte == 0)
|
||||
return 0;
|
||||
if(*pte & PTE_P)
|
||||
panic("remap");
|
||||
*pte = pa | perm | PTE_P;
|
||||
if(a == last)
|
||||
break;
|
||||
a += PGSIZE;
|
||||
pa += PGSIZE;
|
||||
}
|
||||
return 1;
|
||||
}
|
||||
|
||||
// Set up CPU's kernel segment descriptors.
|
||||
// Run once at boot time on each CPU.
|
||||
void
|
||||
|
|
@ -114,6 +38,128 @@ ksegment(void)
|
|||
proc = 0;
|
||||
}
|
||||
|
||||
// return the address of the PTE in page table pgdir
|
||||
// that corresponds to linear address va. if create!=0,
|
||||
// create any required page table pages.
|
||||
static pte_t *
|
||||
walkpgdir(pde_t *pgdir, const void *va, int create)
|
||||
{
|
||||
uint r;
|
||||
pde_t *pde;
|
||||
pte_t *pgtab;
|
||||
|
||||
pde = &pgdir[PDX(va)];
|
||||
if(*pde & PTE_P){
|
||||
pgtab = (pte_t*) PTE_ADDR(*pde);
|
||||
} else if(!create || !(r = (uint) kalloc()))
|
||||
return 0;
|
||||
else {
|
||||
pgtab = (pte_t*) r;
|
||||
// Make sure all those PTE_P bits are zero.
|
||||
memset(pgtab, 0, PGSIZE);
|
||||
// The permissions here are overly generous, but they can
|
||||
// be further restricted by the permissions in the page table
|
||||
// entries, if necessary.
|
||||
*pde = PADDR(r) | PTE_P | PTE_W | PTE_U;
|
||||
}
|
||||
return &pgtab[PTX(va)];
|
||||
}
|
||||
|
||||
// create PTEs for linear addresses starting at la that refer to
|
||||
// physical addresses starting at pa. la and size might not
|
||||
// be page-aligned.
|
||||
static int
|
||||
mappages(pde_t *pgdir, void *la, uint size, uint pa, int perm)
|
||||
{
|
||||
char *a = PGROUNDDOWN(la);
|
||||
char *last = PGROUNDDOWN(la + size - 1);
|
||||
|
||||
while(1){
|
||||
pte_t *pte = walkpgdir(pgdir, a, 1);
|
||||
if(pte == 0)
|
||||
return 0;
|
||||
if(*pte & PTE_P)
|
||||
panic("remap");
|
||||
*pte = pa | perm | PTE_P;
|
||||
if(a == last)
|
||||
break;
|
||||
a += PGSIZE;
|
||||
pa += PGSIZE;
|
||||
}
|
||||
return 1;
|
||||
}
|
||||
|
||||
// The mappings from logical to linear 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 using anything other
|
||||
// than its memory.
|
||||
//
|
||||
// setupkvm() and exec() set up every page table like this:
|
||||
// 0..640K : user memory (text, data, stack, heap)
|
||||
// 640K..1M : mapped direct (for IO space)
|
||||
// 1M..end : mapped direct (for the kernel's text and data)
|
||||
// end..PHYSTOP : mapped direct (kernel heap and user pages)
|
||||
// 0xfe000000..0 : mapped direct (devices such as ioapic)
|
||||
//
|
||||
// The kernel allocates memory for its heap and for user memory
|
||||
// between kernend and the end of physical memory (PHYSTOP).
|
||||
// The virtual address space of each user program includes the kernel
|
||||
// (which is inaccessible in user mode). The user program addresses
|
||||
// range from 0 till 640KB (USERTOP), which where the I/O hole starts
|
||||
// (both in physical memory and in the kernel's virtual address
|
||||
// space).
|
||||
|
||||
// Allocate one page table for the machine for the kernel address
|
||||
// space for scheduler processes.
|
||||
void
|
||||
kvmalloc(void)
|
||||
{
|
||||
kpgdir = setupkvm();
|
||||
}
|
||||
|
||||
// Set up kernel part of a page table.
|
||||
pde_t*
|
||||
setupkvm(void)
|
||||
{
|
||||
pde_t *pgdir;
|
||||
|
||||
// Allocate page directory
|
||||
if(!(pgdir = (pde_t *) kalloc()))
|
||||
return 0;
|
||||
memset(pgdir, 0, PGSIZE);
|
||||
if(// Map IO space from 640K to 1Mbyte
|
||||
!mappages(pgdir, (void *)USERTOP, 0x60000, USERTOP, PTE_W) ||
|
||||
// Map kernel and free memory pool
|
||||
!mappages(pgdir, (void *)0x100000, PHYSTOP-0x100000, 0x100000, PTE_W) ||
|
||||
// Map devices such as ioapic, lapic, ...
|
||||
!mappages(pgdir, (void *)0xFE000000, 0x2000000, 0xFE000000, PTE_W))
|
||||
return 0;
|
||||
return pgdir;
|
||||
}
|
||||
|
||||
// Turn on paging.
|
||||
void
|
||||
vmenable(void)
|
||||
{
|
||||
uint cr0;
|
||||
|
||||
switchkvm(); // load kpgdir into cr3
|
||||
cr0 = rcr0();
|
||||
cr0 |= CR0_PG;
|
||||
lcr0(cr0);
|
||||
}
|
||||
|
||||
// Switch h/w page table register to the kernel-only page table, for when
|
||||
// no process is running.
|
||||
void
|
||||
switchkvm()
|
||||
{
|
||||
lcr3(PADDR(kpgdir)); // Switch to the kernel page table
|
||||
}
|
||||
|
||||
// Switch h/w page table and TSS registers to point to process p.
|
||||
void
|
||||
switchuvm(struct proc *p)
|
||||
|
|
@ -134,36 +180,6 @@ switchuvm(struct proc *p)
|
|||
popcli();
|
||||
}
|
||||
|
||||
// Switch h/w page table register to the kernel-only page table, for when
|
||||
// no process is running.
|
||||
void
|
||||
switchkvm()
|
||||
{
|
||||
lcr3(PADDR(kpgdir)); // Switch to the kernel page table
|
||||
}
|
||||
|
||||
// Set up kernel part of a page table.
|
||||
pde_t*
|
||||
setupkvm(void)
|
||||
{
|
||||
pde_t *pgdir;
|
||||
|
||||
// Allocate page directory
|
||||
if(!(pgdir = (pde_t *) kalloc()))
|
||||
return 0;
|
||||
memset(pgdir, 0, PGSIZE);
|
||||
// Map IO space from 640K to 1Mbyte
|
||||
if(!mappages(pgdir, (void *)USERTOP, 0x60000, USERTOP, PTE_W))
|
||||
return 0;
|
||||
// Map kernel and free memory pool
|
||||
if(!mappages(pgdir, (void *)0x100000, PHYSTOP-0x100000, 0x100000, PTE_W))
|
||||
return 0;
|
||||
// Map devices such as ioapic, lapic, ...
|
||||
if(!mappages(pgdir, (void *)0xFE000000, 0x2000000, 0xFE000000, PTE_W))
|
||||
return 0;
|
||||
return pgdir;
|
||||
}
|
||||
|
||||
// return the physical address that a given user address
|
||||
// maps to. the result is also a kernel logical address,
|
||||
// since the kernel maps the physical memory allocated to user
|
||||
|
|
@ -177,6 +193,37 @@ uva2ka(pde_t *pgdir, char *uva)
|
|||
return (char *)pa;
|
||||
}
|
||||
|
||||
void
|
||||
inituvm(pde_t *pgdir, char *init, uint sz)
|
||||
{
|
||||
char *mem = kalloc();
|
||||
if (sz >= PGSIZE)
|
||||
panic("inituvm: more than a page");
|
||||
memset(mem, 0, PGSIZE);
|
||||
mappages(pgdir, 0, PGSIZE, PADDR(mem), PTE_W|PTE_U);
|
||||
memmove(mem, init, sz);
|
||||
}
|
||||
|
||||
int
|
||||
loaduvm(pde_t *pgdir, char *addr, struct inode *ip, uint offset, uint sz)
|
||||
{
|
||||
uint i, pa, n;
|
||||
pte_t *pte;
|
||||
|
||||
if((uint)addr % PGSIZE != 0)
|
||||
panic("loaduvm: addr must be page aligned\n");
|
||||
for(i = 0; i < sz; i += PGSIZE){
|
||||
if(!(pte = walkpgdir(pgdir, addr+i, 0)))
|
||||
panic("loaduvm: address should exist\n");
|
||||
pa = PTE_ADDR(*pte);
|
||||
if(sz - i < PGSIZE) n = sz - i;
|
||||
else n = PGSIZE;
|
||||
if(readi(ip, (char *)pa, offset+i, n) != n)
|
||||
return 0;
|
||||
}
|
||||
return 1;
|
||||
}
|
||||
|
||||
// allocate sz bytes more memory for a process starting at the
|
||||
// given user address; allocates physical memory and page
|
||||
// table entries. addr and sz need not be page-aligned.
|
||||
|
|
@ -187,10 +234,9 @@ allocuvm(pde_t *pgdir, char *addr, uint sz)
|
|||
{
|
||||
if(addr + sz > (char*)USERTOP)
|
||||
return 0;
|
||||
char *first = PGROUNDDOWN(addr);
|
||||
char *a = PGROUNDDOWN(addr);
|
||||
char *last = PGROUNDDOWN(addr + sz - 1);
|
||||
char *a;
|
||||
for(a = first; a <= last; a += PGSIZE){
|
||||
for(; a <= last; a += PGSIZE){
|
||||
pte_t *pte = walkpgdir(pgdir, a, 0);
|
||||
if(pte == 0 || (*pte & PTE_P) == 0){
|
||||
char *mem = kalloc();
|
||||
|
|
@ -213,10 +259,9 @@ deallocuvm(pde_t *pgdir, char *addr, uint sz)
|
|||
{
|
||||
if(addr + sz > (char*)USERTOP)
|
||||
return 0;
|
||||
char *first = (char*) PGROUNDUP((uint)addr);
|
||||
char *a = (char *)PGROUNDUP((uint)addr);
|
||||
char *last = PGROUNDDOWN(addr + sz - 1);
|
||||
char *a;
|
||||
for(a = first; a <= last; a += PGSIZE){
|
||||
for(; a <= last; a += PGSIZE){
|
||||
pte_t *pte = walkpgdir(pgdir, a, 0);
|
||||
if(pte && (*pte & PTE_P) != 0){
|
||||
uint pa = PTE_ADDR(*pte);
|
||||
|
|
@ -246,37 +291,6 @@ freevm(pde_t *pgdir)
|
|||
kfree((void *) pgdir);
|
||||
}
|
||||
|
||||
int
|
||||
loaduvm(pde_t *pgdir, char *addr, struct inode *ip, uint offset, uint sz)
|
||||
{
|
||||
uint i, pa, n;
|
||||
pte_t *pte;
|
||||
|
||||
if((uint)addr % PGSIZE != 0)
|
||||
panic("loaduvm: addr must be page aligned\n");
|
||||
for(i = 0; i < sz; i += PGSIZE){
|
||||
if(!(pte = walkpgdir(pgdir, addr+i, 0)))
|
||||
panic("loaduvm: address should exist\n");
|
||||
pa = PTE_ADDR(*pte);
|
||||
if(sz - i < PGSIZE) n = sz - i;
|
||||
else n = PGSIZE;
|
||||
if(readi(ip, (char *)pa, offset+i, n) != n)
|
||||
return 0;
|
||||
}
|
||||
return 1;
|
||||
}
|
||||
|
||||
void
|
||||
inituvm(pde_t *pgdir, char *init, uint sz)
|
||||
{
|
||||
char *mem = kalloc();
|
||||
if (sz >= PGSIZE)
|
||||
panic("inituvm: more than a page");
|
||||
memset(mem, 0, PGSIZE);
|
||||
mappages(pgdir, 0, PGSIZE, PADDR(mem), PTE_W|PTE_U);
|
||||
memmove(mem, init, sz);
|
||||
}
|
||||
|
||||
// given a parent process's page table, create a copy
|
||||
// of it for a child.
|
||||
pde_t*
|
||||
|
|
@ -307,23 +321,3 @@ bad:
|
|||
return 0;
|
||||
}
|
||||
|
||||
// Allocate one page table for the machine for the kernel address
|
||||
// space for scheduler processes.
|
||||
void
|
||||
kvmalloc(void)
|
||||
{
|
||||
kpgdir = setupkvm();
|
||||
}
|
||||
|
||||
// Turn on paging.
|
||||
void
|
||||
vmenable(void)
|
||||
{
|
||||
uint cr0;
|
||||
|
||||
switchkvm(); // load kpgdir into cr3
|
||||
cr0 = rcr0();
|
||||
cr0 |= CR0_PG;
|
||||
lcr0(cr0);
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue