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
2 changed files with 165 additions and 165 deletions
10
runoff.spec
10
runoff.spec
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@ -42,8 +42,14 @@ odd: proc.h
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left: proc.c # VERY important
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odd: proc.c # VERY important
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# setjmp.S either
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# vm.c either
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# A few more action packed spreads
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# page table creation and process loading
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# walkpgdir mappages setupkvm vmenable switch[ku]vm inituvm loaduvm
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# process memory management
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# allocuvm deallocuvm freevm
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right: vm.c
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odd: vm.c
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# kalloc.c either
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# syscall.h either
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320
vm.c
320
vm.c
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@ -6,86 +6,10 @@
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#include "proc.h"
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#include "elf.h"
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// The mappings from logical to linear are one to one (i.e.,
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// segmentation doesn't do anything).
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// There is one page table per process, plus one that's used
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// when a CPU is not running any process (kpgdir).
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// A user process uses the same page table as the kernel; the
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// page protection bits prevent it from using anything other
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// than its memory.
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//
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// setupkvm() and exec() set up every page table like this:
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// 0..640K : user memory (text, data, stack, heap)
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// 640K..1M : mapped direct (for IO space)
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// 1M..end : mapped direct (for the kernel's text and data)
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// end..PHYSTOP : mapped direct (kernel heap and user pages)
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// 0xfe000000..0 : mapped direct (devices such as ioapic)
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//
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// The kernel allocates memory for its heap and for user memory
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// between kernend and the end of physical memory (PHYSTOP).
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// The virtual address space of each user program includes the kernel
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// (which is inaccessible in user mode). The user program addresses
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// range from 0 till 640KB (USERTOP), which where the I/O hole starts
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// (both in physical memory and in the kernel's virtual address
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// space).
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#define USERTOP 0xA0000
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static pde_t *kpgdir; // for use in scheduler()
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// return the address of the PTE in page table pgdir
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// that corresponds to linear address va. if create!=0,
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// create any required page table pages.
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static pte_t *
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walkpgdir(pde_t *pgdir, const void *va, int create)
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{
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uint r;
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pde_t *pde;
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pte_t *pgtab;
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pde = &pgdir[PDX(va)];
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if(*pde & PTE_P){
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pgtab = (pte_t*) PTE_ADDR(*pde);
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} else if(!create || !(r = (uint) kalloc()))
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return 0;
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else {
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pgtab = (pte_t*) r;
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// Make sure all those PTE_P bits are zero.
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memset(pgtab, 0, PGSIZE);
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// The permissions here are overly generous, but they can
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// be further restricted by the permissions in the page table
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// entries, if necessary.
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*pde = PADDR(r) | PTE_P | PTE_W | PTE_U;
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}
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return &pgtab[PTX(va)];
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}
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// create PTEs for linear addresses starting at la that refer to
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// physical addresses starting at pa. la and size might not
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// be page-aligned.
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static int
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mappages(pde_t *pgdir, void *la, uint size, uint pa, int perm)
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{
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char *first = PGROUNDDOWN(la);
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char *last = PGROUNDDOWN(la + size - 1);
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char *a = first;
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while(1){
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pte_t *pte = walkpgdir(pgdir, a, 1);
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if(pte == 0)
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return 0;
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if(*pte & PTE_P)
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panic("remap");
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*pte = pa | perm | PTE_P;
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if(a == last)
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break;
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a += PGSIZE;
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pa += PGSIZE;
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}
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return 1;
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}
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// Set up CPU's kernel segment descriptors.
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// Run once at boot time on each CPU.
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void
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@ -114,6 +38,128 @@ ksegment(void)
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proc = 0;
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}
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// return the address of the PTE in page table pgdir
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// that corresponds to linear address va. if create!=0,
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// create any required page table pages.
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static pte_t *
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walkpgdir(pde_t *pgdir, const void *va, int create)
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{
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uint r;
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pde_t *pde;
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pte_t *pgtab;
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pde = &pgdir[PDX(va)];
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if(*pde & PTE_P){
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pgtab = (pte_t*) PTE_ADDR(*pde);
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} else if(!create || !(r = (uint) kalloc()))
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return 0;
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else {
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pgtab = (pte_t*) r;
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// Make sure all those PTE_P bits are zero.
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memset(pgtab, 0, PGSIZE);
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// The permissions here are overly generous, but they can
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// be further restricted by the permissions in the page table
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// entries, if necessary.
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*pde = PADDR(r) | PTE_P | PTE_W | PTE_U;
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}
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return &pgtab[PTX(va)];
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}
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// create PTEs for linear addresses starting at la that refer to
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// physical addresses starting at pa. la and size might not
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// be page-aligned.
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static int
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mappages(pde_t *pgdir, void *la, uint size, uint pa, int perm)
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{
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char *a = PGROUNDDOWN(la);
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char *last = PGROUNDDOWN(la + size - 1);
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while(1){
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pte_t *pte = walkpgdir(pgdir, a, 1);
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if(pte == 0)
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return 0;
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if(*pte & PTE_P)
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panic("remap");
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*pte = pa | perm | PTE_P;
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if(a == last)
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break;
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a += PGSIZE;
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pa += PGSIZE;
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}
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return 1;
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}
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// The mappings from logical to linear are one to one (i.e.,
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// segmentation doesn't do anything).
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// There is one page table per process, plus one that's used
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// when a CPU is not running any process (kpgdir).
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// A user process uses the same page table as the kernel; the
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// page protection bits prevent it from using anything other
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// than its memory.
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//
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// setupkvm() and exec() set up every page table like this:
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// 0..640K : user memory (text, data, stack, heap)
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// 640K..1M : mapped direct (for IO space)
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// 1M..end : mapped direct (for the kernel's text and data)
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// end..PHYSTOP : mapped direct (kernel heap and user pages)
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// 0xfe000000..0 : mapped direct (devices such as ioapic)
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//
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// The kernel allocates memory for its heap and for user memory
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// between kernend and the end of physical memory (PHYSTOP).
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// The virtual address space of each user program includes the kernel
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// (which is inaccessible in user mode). The user program addresses
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// range from 0 till 640KB (USERTOP), which where the I/O hole starts
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// (both in physical memory and in the kernel's virtual address
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// space).
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// Allocate one page table for the machine for the kernel address
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// space for scheduler processes.
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void
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kvmalloc(void)
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{
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kpgdir = setupkvm();
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}
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// Set up kernel part of a page table.
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pde_t*
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setupkvm(void)
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{
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pde_t *pgdir;
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// Allocate page directory
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if(!(pgdir = (pde_t *) kalloc()))
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return 0;
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memset(pgdir, 0, PGSIZE);
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if(// Map IO space from 640K to 1Mbyte
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!mappages(pgdir, (void *)USERTOP, 0x60000, USERTOP, PTE_W) ||
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// Map kernel and free memory pool
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!mappages(pgdir, (void *)0x100000, PHYSTOP-0x100000, 0x100000, PTE_W) ||
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// Map devices such as ioapic, lapic, ...
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!mappages(pgdir, (void *)0xFE000000, 0x2000000, 0xFE000000, PTE_W))
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return 0;
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return pgdir;
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}
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// Turn on paging.
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void
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vmenable(void)
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{
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uint cr0;
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switchkvm(); // load kpgdir into cr3
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cr0 = rcr0();
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cr0 |= CR0_PG;
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lcr0(cr0);
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}
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// Switch h/w page table register to the kernel-only page table, for when
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// no process is running.
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void
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switchkvm()
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{
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lcr3(PADDR(kpgdir)); // Switch to the kernel page table
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}
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// Switch h/w page table and TSS registers to point to process p.
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void
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switchuvm(struct proc *p)
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@ -134,36 +180,6 @@ switchuvm(struct proc *p)
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popcli();
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}
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// Switch h/w page table register to the kernel-only page table, for when
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// no process is running.
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void
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switchkvm()
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{
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lcr3(PADDR(kpgdir)); // Switch to the kernel page table
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}
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// Set up kernel part of a page table.
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pde_t*
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setupkvm(void)
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{
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pde_t *pgdir;
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// Allocate page directory
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if(!(pgdir = (pde_t *) kalloc()))
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return 0;
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memset(pgdir, 0, PGSIZE);
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// Map IO space from 640K to 1Mbyte
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if(!mappages(pgdir, (void *)USERTOP, 0x60000, USERTOP, PTE_W))
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return 0;
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// Map kernel and free memory pool
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if(!mappages(pgdir, (void *)0x100000, PHYSTOP-0x100000, 0x100000, PTE_W))
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return 0;
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// Map devices such as ioapic, lapic, ...
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if(!mappages(pgdir, (void *)0xFE000000, 0x2000000, 0xFE000000, PTE_W))
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return 0;
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return pgdir;
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}
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// return the physical address that a given user address
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// maps to. the result is also a kernel logical address,
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// since the kernel maps the physical memory allocated to user
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@ -177,6 +193,37 @@ uva2ka(pde_t *pgdir, char *uva)
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return (char *)pa;
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}
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void
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inituvm(pde_t *pgdir, char *init, uint sz)
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{
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char *mem = kalloc();
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if (sz >= PGSIZE)
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panic("inituvm: more than a page");
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memset(mem, 0, PGSIZE);
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mappages(pgdir, 0, PGSIZE, PADDR(mem), PTE_W|PTE_U);
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memmove(mem, init, sz);
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}
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int
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loaduvm(pde_t *pgdir, char *addr, struct inode *ip, uint offset, uint sz)
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{
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uint i, pa, n;
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pte_t *pte;
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if((uint)addr % PGSIZE != 0)
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panic("loaduvm: addr must be page aligned\n");
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for(i = 0; i < sz; i += PGSIZE){
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if(!(pte = walkpgdir(pgdir, addr+i, 0)))
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panic("loaduvm: address should exist\n");
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pa = PTE_ADDR(*pte);
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if(sz - i < PGSIZE) n = sz - i;
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else n = PGSIZE;
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if(readi(ip, (char *)pa, offset+i, n) != n)
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return 0;
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}
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return 1;
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}
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// allocate sz bytes more memory for a process starting at the
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// given user address; allocates physical memory and page
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// table entries. addr and sz need not be page-aligned.
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@ -187,10 +234,9 @@ allocuvm(pde_t *pgdir, char *addr, uint sz)
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{
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if(addr + sz > (char*)USERTOP)
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return 0;
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char *first = PGROUNDDOWN(addr);
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char *a = PGROUNDDOWN(addr);
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char *last = PGROUNDDOWN(addr + sz - 1);
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char *a;
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for(a = first; a <= last; a += PGSIZE){
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for(; a <= last; a += PGSIZE){
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pte_t *pte = walkpgdir(pgdir, a, 0);
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if(pte == 0 || (*pte & PTE_P) == 0){
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char *mem = kalloc();
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@ -213,10 +259,9 @@ deallocuvm(pde_t *pgdir, char *addr, uint sz)
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{
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if(addr + sz > (char*)USERTOP)
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return 0;
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char *first = (char*) PGROUNDUP((uint)addr);
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char *a = (char *)PGROUNDUP((uint)addr);
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char *last = PGROUNDDOWN(addr + sz - 1);
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char *a;
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for(a = first; a <= last; a += PGSIZE){
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for(; a <= last; a += PGSIZE){
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pte_t *pte = walkpgdir(pgdir, a, 0);
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if(pte && (*pte & PTE_P) != 0){
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uint pa = PTE_ADDR(*pte);
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@ -246,37 +291,6 @@ freevm(pde_t *pgdir)
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kfree((void *) pgdir);
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}
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int
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loaduvm(pde_t *pgdir, char *addr, struct inode *ip, uint offset, uint sz)
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{
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uint i, pa, n;
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pte_t *pte;
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if((uint)addr % PGSIZE != 0)
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panic("loaduvm: addr must be page aligned\n");
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for(i = 0; i < sz; i += PGSIZE){
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if(!(pte = walkpgdir(pgdir, addr+i, 0)))
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panic("loaduvm: address should exist\n");
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pa = PTE_ADDR(*pte);
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if(sz - i < PGSIZE) n = sz - i;
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else n = PGSIZE;
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if(readi(ip, (char *)pa, offset+i, n) != n)
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return 0;
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}
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return 1;
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}
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void
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inituvm(pde_t *pgdir, char *init, uint sz)
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{
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char *mem = kalloc();
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if (sz >= PGSIZE)
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panic("inituvm: more than a page");
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memset(mem, 0, PGSIZE);
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mappages(pgdir, 0, PGSIZE, PADDR(mem), PTE_W|PTE_U);
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memmove(mem, init, sz);
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}
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// given a parent process's page table, create a copy
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// of it for a child.
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pde_t*
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@ -307,23 +321,3 @@ bad:
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return 0;
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}
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// Allocate one page table for the machine for the kernel address
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// space for scheduler processes.
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void
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kvmalloc(void)
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{
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kpgdir = setupkvm();
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}
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// Turn on paging.
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void
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vmenable(void)
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{
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uint cr0;
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switchkvm(); // load kpgdir into cr3
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cr0 = rcr0();
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cr0 |= CR0_PG;
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lcr0(cr0);
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}
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