diff options
| -rw-r--r-- | defs.h | 7 | ||||
| -rw-r--r-- | kalloc.c | 55 | ||||
| -rw-r--r-- | main.c | 15 | ||||
| -rw-r--r-- | vm.c | 25 |
4 files changed, 52 insertions, 50 deletions
@@ -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); @@ -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; } @@ -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); @@ -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"); @@ -127,19 +126,19 @@ static struct kmap { // 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; } @@ -149,7 +148,7 @@ setupkvm(char* (*alloc)(void)) void kvmalloc(void) { - kpgdir = setupkvm(enter_alloc); + kpgdir = setupkvm(); switchkvm(); } @@ -188,7 +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); } @@ -238,7 +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; } @@ -315,7 +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) @@ -326,7 +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; |