diff options
| -rw-r--r-- | defs.h | 1 | ||||
| -rw-r--r-- | kalloc.c | 13 | ||||
| -rw-r--r-- | lapic.c | 3 | ||||
| -rw-r--r-- | memlayout.h | 13 | ||||
| -rw-r--r-- | mmu.h | 14 | ||||
| -rw-r--r-- | vm.c | 26 |
6 files changed, 42 insertions, 28 deletions
@@ -66,6 +66,7 @@ char* enter_alloc(void); char* kalloc(void); void kfree(char*); void kinit(void); +uint detect_memory(void); // kbd.c void kbdintr(void); @@ -19,7 +19,8 @@ struct { } kmem; extern char end[]; // first address after kernel loaded from ELF file -char *newend; +extern uint maxpa; // Maximum physical address +static char *newend; // simple page allocator to get off the ground during entry char * @@ -36,6 +37,12 @@ enter_alloc(void) return p; } +uint +detect_memory(void) +{ + return 0xE000000; +} + // Initialize free list of physical pages. void kinit(void) @@ -44,7 +51,7 @@ kinit(void) initlock(&kmem.lock, "kmem"); p = (char*)PGROUNDUP((uint)newend); - for(; p + PGSIZE <= (char*)p2v(PHYSTOP); p += PGSIZE) + for(; p + PGSIZE <= (char*)p2v(maxpa); p += PGSIZE) kfree(p); } @@ -58,7 +65,7 @@ kfree(char *v) { struct run *r; - if((uint)v % PGSIZE || v < end || v2p(v) >= PHYSTOP) + if((uint)v % PGSIZE || v < end || v2p(v) >= maxpa) panic("kfree"); // Fill with junk to catch dangling refs. @@ -135,7 +135,6 @@ microdelay(int us) // Start additional processor running entry code at addr. // See Appendix B of MultiProcessor Specification. void - lapicstartap(uchar apicid, uint addr) { int i; @@ -169,3 +168,5 @@ lapicstartap(uchar apicid, uint addr) microdelay(200); } } + + diff --git a/memlayout.h b/memlayout.h index 1496678..79429a9 100644 --- a/memlayout.h +++ b/memlayout.h @@ -1,17 +1,12 @@ // Memory layout -#define PGSIZE 4096 // bytes mapped by a page -#define PGSHIFT 12 // log2(PGSIZE) - -#define KSTKSIZE (8*PGSIZE) // size of a kernel stack - -#define DEVSPACE 0xFE000000 // other devices are in the top of the phys address space -#define PHYSTOP 0xE000000 // use phys mem up to here as free pool +#define EXTMEM 0x100000 // Start of extended memory +#define DEVSPACE 0xFE000000 // Other devices are at high addresses // Key addresses for address space layout (see kmap in vm.c for the layout) -#define KERNBASE 0xF0000000 // First kernel virtual address +#define KERNBASE 0xF0000000 // First kernel virtual address #define USERTOP (KERNBASE-PGSIZE) // Highest user virtual address -#define KERNLINK 0xF0100000 // Address where kernel is linked +#define KERNLINK (KERNBASE+EXTMEM) // Address where kernel is linked #ifndef __ASSEMBLER__ @@ -100,32 +100,34 @@ struct segdesc { #define STS_IG32 0xE // 32-bit Interrupt Gate #define STS_TG32 0xF // 32-bit Trap Gate -// A linear address 'la' has a three-part structure as follows: +// A virtual address 'la' has a three-part structure as follows: // // +--------10------+-------10-------+---------12----------+ // | Page Directory | Page Table | Offset within Page | // | Index | Index | | // +----------------+----------------+---------------------+ -// \--- PDX(la) --/ \--- PTX(la) --/ +// \--- PDX(va) --/ \--- PTX(va) --/ // page directory index -#define PDX(la) (((uint)(la) >> PDXSHIFT) & 0x3FF) +#define PDX(va) (((uint)(va) >> PDXSHIFT) & 0x3FF) // page table index -#define PTX(la) (((uint)(la) >> PTXSHIFT) & 0x3FF) +#define PTX(va) (((uint)(va) >> PTXSHIFT) & 0x3FF) -// construct linear address from indexes and offset +// construct virtual address from indexes and offset #define PGADDR(d, t, o) ((uint)((d) << PDXSHIFT | (t) << PTXSHIFT | (o))) // Page directory and page table constants. #define NPDENTRIES 1024 // page directory entries per page directory #define NPTENTRIES 1024 // page table entries per page table +#define PGSIZE 4096 // bytes mapped by a page +#define PGSHIFT 12 // log2(PGSIZE) #define PTXSHIFT 12 // offset of PTX in a linear address #define PDXSHIFT 22 // offset of PDX in a linear address #define PGROUNDUP(sz) (((sz)+PGSIZE-1) & ~(PGSIZE-1)) -#define PGROUNDDOWN(a) ((char*)((((unsigned int)(a)) & ~(PGSIZE-1)))) +#define PGROUNDDOWN(a) (((a)) & ~(PGSIZE-1)) // Page table/directory entry flags. #define PTE_P 0x001 // Present @@ -8,6 +8,7 @@ #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]; @@ -64,8 +65,8 @@ walkpgdir(pde_t *pgdir, const void *va, char* (*alloc)(void)) return &pgtab[PTX(va)]; } -// Create PTEs for virtual addresses starting at la that refer to -// physical addresses starting at pa. la and size might not +// Create PTEs for virtual addresses starting at va that refer to +// 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)) @@ -73,8 +74,8 @@ mappages(pde_t *pgdir, void *va, uint size, uint pa, int perm, char* (*alloc)(vo char *a, *last; pte_t *pte; - a = PGROUNDDOWN(va); - last = PGROUNDDOWN(va + size - 1); + a = (char *) PGROUNDDOWN((uint) va); + last = (char *) PGROUNDDOWN(((uint) va) + size - 1); for(;;){ pte = walkpgdir(pgdir, a, alloc); if(pte == 0) @@ -100,13 +101,13 @@ mappages(pde_t *pgdir, void *va, uint size, uint pa, int perm, char* (*alloc)(vo // // setupkvm() and exec() set up every page table like this: // 0..USERTOP : user memory (text, data, stack, heap), mapped to some unused phys mem -// KERNBASE..KERNBASE+1M: mapped to 0..1M -// KERNBASE+1M..KERNBASE+end : mapped to 1M..end (mapped without write permission) -// KERNBASE+end..KERBASE+PHYSTOP : mapped to end..PHYSTOP (rw data + free memory) +// 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) // 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). +// between kernend and the end of physical memory (maxpa). // 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. @@ -118,7 +119,7 @@ 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), PHYSTOP, PTE_W}, // kernel data, memory + { data, V2P(data), 0, PTE_W}, // kernel data, memory { (void*)DEVSPACE, DEVSPACE, 0, PTE_W}, // more devices }; @@ -129,6 +130,13 @@ 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); |