Imbus/xv6-riscv-kernel
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Clean up memlayout.h

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Get rid of last instances of linear address and "la"
Get ready for detecting physical memory dynamically
This commit is contained in:
Frans Kaashoek 2011-08-16 15:47:22 -04:00
parent 427958cb71
commit c3dcf47966
6 changed files with 42 additions and 28 deletions
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26
vm.c
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@ -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);