diff options
| -rw-r--r-- | kalloc.c | 5 | ||||
| -rw-r--r-- | memlayout.h | 1 | ||||
| -rw-r--r-- | vm.c | 16 |
3 files changed, 8 insertions, 14 deletions
@@ -19,7 +19,6 @@ struct { } kmem; extern char end[]; // first address after kernel loaded from ELF file -extern uint maxpa; // Maximum physical address static char *newend; // simple page allocator to get off the ground during entry @@ -51,7 +50,7 @@ kinit(void) initlock(&kmem.lock, "kmem"); p = (char*)PGROUNDUP((uint)newend); - for(; p + PGSIZE <= (char*)p2v(maxpa); p += PGSIZE) + for(; p + PGSIZE <= (char*)p2v(PHYSTOP); p += PGSIZE) kfree(p); } @@ -65,7 +64,7 @@ kfree(char *v) { struct run *r; - if((uint)v % PGSIZE || v < end || v2p(v) >= maxpa) + if((uint)v % PGSIZE || v < end || v2p(v) >= PHYSTOP) panic("kfree"); // Fill with junk to catch dangling refs. diff --git a/memlayout.h b/memlayout.h index 79429a9..ad4fda2 100644 --- a/memlayout.h +++ b/memlayout.h @@ -1,6 +1,7 @@ // Memory layout #define EXTMEM 0x100000 // Start of extended memory +#define PHYSTOP 0xE000000 // Top physical memory (too hard to get from E820) #define DEVSPACE 0xFE000000 // Other devices are at high addresses // Key addresses for address space layout (see kmap in vm.c for the layout) @@ -8,7 +8,6 @@ #include "elf.h" extern char data[]; // defined in data.S -uint maxpa; // max physical address pde_t *kpgdir; // for use in scheduler() struct segdesc gdt[NSEGS]; @@ -103,11 +102,11 @@ mappages(pde_t *pgdir, void *va, uint size, uint pa, int perm, char* (*alloc)(vo // 0..USERTOP : user memory (text, data, stack, heap), mapped to some unused phys mem // KERNBASE..KERNBASE+EXTMEM: mapped to 0..EXTMEM (below extended memory) // KERNBASE+EXTMEM..KERNBASE+end : mapped to EXTMEM..end (mapped without write permission) -// KERNBASE+end..KERBASE+maxpa : mapped to end..maxpa (rw data + free memory) +// KERNBASE+end..KERBASE+PHYSTOP : mapped to end..PHYSTOP (rw data + free memory) // 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 (maxpa). +// 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 sits in // the bottom of the address space, and the kernel at the top at KERNBASE. @@ -119,7 +118,7 @@ static struct kmap { } kmap[] = { { P2V(0), 0, 1024*1024, PTE_W}, // First 1Mbyte contains BIOS and some IO devices { (void *)KERNLINK, V2P(KERNLINK), V2P(data), 0}, // kernel text, rodata - { data, V2P(data), 0, PTE_W}, // kernel data, memory + { data, V2P(data), PHYSTOP, PTE_W}, // kernel data, memory { (void*)DEVSPACE, DEVSPACE, 0, PTE_W}, // more devices }; @@ -130,17 +129,12 @@ setupkvm(char* (*alloc)(void)) pde_t *pgdir; struct kmap *k; - if (kmap[2].phys_end == 0) { - maxpa = detect_memory(); - kmap[2].phys_end = maxpa; - if (p2v(maxpa) > kmap[3].virt) - panic("detect_memory: too much memory"); - - } if((pgdir = (pde_t*)alloc()) == 0) return 0; memset(pgdir, 0, PGSIZE); k = kmap; + 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) |