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VMM -- Use a simple uint64 for page table entries

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This commit is contained in:
Thomas Lovén 2018-03-20 15:41:08 +01:00
parent cb09833ebc
commit 4011b5f12f
1 changed files with 28 additions and 42 deletions
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70
src/kernel/memory/vmm.c
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@ -3,34 +3,20 @@
#define FLAGS_MASK (PAGE_SIZE-1) #define FLAGS_MASK (PAGE_SIZE-1)
#define MASK_FLAGS(addr) ((uint64_t)addr & ~FLAGS_MASK) #define MASK_FLAGS(addr) ((uint64_t)addr & ~FLAGS_MASK)
union PTE { #define PRESENT(p) (p & PAGE_PRESENT)
uint64_t value;
struct {
uint64_t present:1;
uint64_t write:1;
uint64_t user:1;
uint64_t write_through:1;
uint64_t nocache:1;
uint64_t accessed:1;
uint64_t dirty:1;
uint64_t huge:1;
uint64_t global:1;
uint64_t flags:3;
};
};
#define PT(ptr) ((union PTE *)P2V(MASK_FLAGS(ptr))) #define PT(ptr) ((uint64_t *)P2V(MASK_FLAGS(ptr)))
// Get the entry correspoding to address addr in page dir P4 // Get the entry correspoding to address addr in page dir P4
// for P4 table (P4E), P3 table (P3E) and so on. // for P4 table (P4E), P3 table (P3E) and so on.
// Note: Those macros requires variables to be named // Note: Those macros requires variables to be named
#define P4E (PT(P4)[P4_OFFSET(addr)]) #define P4E (PT(P4)[P4_OFFSET(addr)])
#define P3E PT(P4E.value)[P3_OFFSET(addr)] #define P3E PT(P4E)[P3_OFFSET(addr)]
#define P2E PT(P3E.value)[P2_OFFSET(addr)] #define P2E PT(P3E)[P2_OFFSET(addr)]
#define P1E PT(P2E.value)[P1_OFFSET(addr)] #define P1E PT(P2E)[P1_OFFSET(addr)]
static int page_exists(uint64_t P4, uint64_t addr) static int page_exists(uint64_t P4, uint64_t addr)
{ {
if(P4 && P4E.present && P3E.present && P2E.present) if(P4 && PRESENT(P4E) && PRESENT(P3E) && PRESENT(P2E))
return 1; return 1;
return 0; return 0;
} }
@ -39,7 +25,7 @@ uint64_t vmm_get_page(uint64_t P4, uint64_t addr)
{ {
if(page_exists(P4, addr)) if(page_exists(P4, addr))
{ {
return P1E.value; return P1E;
} }
return -1; return -1;
} }
@ -53,7 +39,7 @@ int vmm_set_page(uint64_t P4, uint64_t addr, uint64_t page, uint16_t flags, int
touch_page(P4, addr, flags); touch_page(P4, addr, flags);
} }
P1E.value = page | flags; P1E = page | flags;
return 0; return 0;
} }
@ -61,17 +47,17 @@ int touch_page(uint64_t P4, uint64_t addr, uint16_t flags)
{ {
if(!P4) return -1; if(!P4) return -1;
if((!P4E.present) && (!(P4E.value = pmm_calloc()))) if((!PRESENT(P4E)) && (!(P4E = pmm_calloc())))
return -1; return -1;
P4E.value |= flags | PAGE_PRESENT; P4E |= flags | PAGE_PRESENT;
if((!P3E.present) && (!(P3E.value = pmm_calloc()))) if((!PRESENT(P3E)) && (!(P3E = pmm_calloc())))
return -1; return -1;
P3E.value |= flags | PAGE_PRESENT; P3E |= flags | PAGE_PRESENT;
if((!P2E.present) && (!(P2E.value = pmm_calloc()))) if((!PRESENT(P2E)) && (!(P2E = pmm_calloc())))
return -1; return -1;
P2E.value |= flags | PAGE_PRESENT; P2E |= flags | PAGE_PRESENT;
return 0; return 0;
} }
@ -81,31 +67,31 @@ void free_page(uint64_t P4, uint64_t addr, int free)
if(!page_exists(P4, addr)) if(!page_exists(P4, addr))
return; return;
union PTE *pt; uint64_t *pt;
P1E.value = 0; P1E = 0;
if(!free) if(!free)
return; return;
pt = PT(P2E.value); pt = PT(P2E);
for(int i = 0; i < ENTRIES_PER_PT; i++) for(int i = 0; i < ENTRIES_PER_PT; i++)
if(pt[i].value) if(pt[i])
return; return;
pmm_free(MASK_FLAGS(P2E.value)); pmm_free(MASK_FLAGS(P2E));
P2E.value = 0; P2E = 0;
pt = PT(P3E.value); pt = PT(P3E);
for(int i = 0; i < ENTRIES_PER_PT; i++) for(int i = 0; i < ENTRIES_PER_PT; i++)
if(pt[i].value) if(pt[i])
return; return;
pmm_free(MASK_FLAGS(P3E.value)); pmm_free(MASK_FLAGS(P3E));
P3E.value = 0; P3E = 0;
pt = PT(P4E.value); pt = PT(P4E);
for(int i = 0; i < ENTRIES_PER_PT; i++) for(int i = 0; i < ENTRIES_PER_PT; i++)
if(pt[i].value) if(pt[i])
return; return;
pmm_free(MASK_FLAGS(P4E.value)); pmm_free(MASK_FLAGS(P4E));
P4E.value = 0; P4E = 0;
} }