xinyangli
8e4feb4010
NJU-ProjectN/abstract-machine 3348db971fd860be5cb28e21c18f9d0e65d0c96a Merge pull request #8 from Jasonyanyusong/master
64 lines
1.3 KiB
C
64 lines
1.3 KiB
C
#include <am.h>
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#include <nemu.h>
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#include <klib.h>
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static AddrSpace kas = {};
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static void* (*pgalloc_usr)(int) = NULL;
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static void (*pgfree_usr)(void*) = NULL;
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static int vme_enable = 0;
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static Area segments[] = { // Kernel memory mappings
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NEMU_PADDR_SPACE
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};
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#define USER_SPACE RANGE(0x40000000, 0xc0000000)
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bool vme_init(void* (*pgalloc_f)(int), void (*pgfree_f)(void*)) {
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pgalloc_usr = pgalloc_f;
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pgfree_usr = pgfree_f;
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kas.ptr = pgalloc_f(PGSIZE);
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int i;
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for (i = 0; i < LENGTH(segments); i ++) {
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void *va = segments[i].start;
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for (; va < segments[i].end; va += PGSIZE) {
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map(&kas, va, va, 0);
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}
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}
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set_cr3(kas.ptr);
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set_cr0(get_cr0() | CR0_PG);
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vme_enable = 1;
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return true;
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}
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void protect(AddrSpace *as) {
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PTE *updir = (PTE*)(pgalloc_usr(PGSIZE));
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as->ptr = updir;
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as->area = USER_SPACE;
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as->pgsize = PGSIZE;
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// map kernel space
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memcpy(updir, kas.ptr, PGSIZE);
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}
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void unprotect(AddrSpace *as) {
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}
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void __am_get_cur_as(Context *c) {
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c->cr3 = (vme_enable ? (void *)get_cr3() : NULL);
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}
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void __am_switch(Context *c) {
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if (vme_enable && c->cr3 != NULL) {
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set_cr3(c->cr3);
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}
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}
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void map(AddrSpace *as, void *va, void *pa, int prot) {
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}
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Context* ucontext(AddrSpace *as, Area kstack, void *entry) {
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return NULL;
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}
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