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tlb.c
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tlb.c
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#include "emu/cpu.h"
#include "emu/tlb.h"
void tlb_refresh(struct tlb *tlb, struct mmu *mmu) {
if (tlb->mmu == mmu && tlb->mem_changes == mmu->changes)
return;
tlb->mmu = mmu;
tlb->dirty_page = TLB_PAGE_EMPTY;
tlb->mem_changes = mmu->changes;
tlb_flush(tlb);
}
void tlb_flush(struct tlb *tlb) {
tlb->mem_changes = tlb->mmu->changes;
for (unsigned i = 0; i < TLB_SIZE; i++)
tlb->entries[i] = (struct tlb_entry) {.page = 1, .page_if_writable = 1};
}
void tlb_free(struct tlb *tlb) {
free(tlb);
}
bool __tlb_read_cross_page(struct tlb *tlb, addr_t addr, char *value, unsigned size) {
char *ptr1 = __tlb_read_ptr(tlb, addr);
if (ptr1 == NULL)
return false;
char *ptr2 = __tlb_read_ptr(tlb, (PAGE(addr) + 1) << PAGE_BITS);
if (ptr2 == NULL)
return false;
size_t part1 = PAGE_SIZE - PGOFFSET(addr);
assert(part1 < size);
memcpy(value, ptr1, part1);
memcpy(value + part1, ptr2, size - part1);
return true;
}
bool __tlb_write_cross_page(struct tlb *tlb, addr_t addr, const char *value, unsigned size) {
char *ptr1 = __tlb_write_ptr(tlb, addr);
if (ptr1 == NULL)
return false;
char *ptr2 = __tlb_write_ptr(tlb, (PAGE(addr) + 1) << PAGE_BITS);
if (ptr2 == NULL)
return false;
size_t part1 = PAGE_SIZE - PGOFFSET(addr);
assert(part1 < size);
memcpy(ptr1, value, part1);
memcpy(ptr2, value + part1, size - part1);
return true;
}
__no_instrument void *tlb_handle_miss(struct tlb *tlb, addr_t addr, int type) {
char *ptr = mmu_translate(tlb->mmu, TLB_PAGE(addr), type);
if (tlb->mmu->changes != tlb->mem_changes)
tlb_flush(tlb);
if (ptr == NULL) {
tlb->segfault_addr = addr;
return NULL;
}
tlb->dirty_page = TLB_PAGE(addr);
struct tlb_entry *tlb_ent = &tlb->entries[TLB_INDEX(addr)];
tlb_ent->page = TLB_PAGE(addr);
if (type == MEM_WRITE)
tlb_ent->page_if_writable = tlb_ent->page;
else
// 1 is not a valid page so this won't look like a hit
tlb_ent->page_if_writable = TLB_PAGE_EMPTY;
tlb_ent->data_minus_addr = (uintptr_t) ptr - TLB_PAGE(addr);
return (void *) (tlb_ent->data_minus_addr + addr);
}