1 files changed, 129 insertions, 105 deletions

diff --git a/arch/x86_64/paging.c b/arch/x86_64/paging.c
index 9e8a5ed..dc27ca2 100644
--- a/arch/x86_64/paging.c
+++ b/arch/x86_64/paging.c
@@ -1,9 +1,10 @@
 #include "paging.h"
 #include "interrupt.h"
-#include <stddef.h>
-#include "lib/jove.h"
 #include "io/log.h"
+#include "lib/jove.h"
 #include "lib/string.h"
+#include "lib/hashtable.h"
+#include "mem/memory.h"
 #include "boot/boot.h"
 
 extern void *_kernel_end;
@@ -12,9 +13,16 @@ PAGEALIGN static uint64_t s_kernel_initial_pml4[512];
 PAGEALIGN static uint64_t s_kernel_initial_pml3[2][512];
 PAGEALIGN static uint64_t s_kernel_initial_pml2[2][512];
 PAGEALIGN static uint64_t s_kernel_initial_pml1[2][512];
-static struct PageDirectory s_kernel_initial_pd;
+static intmax_t s_next_pdid = 0;
+static page_directory_t s_kernel_initial_pd;
+
+page_directory_t *current_page_directory;
 
-struct PageDirectory *mem_current_pd;
+struct PageStateCache {
+    page_directory_t *pd;
+    size_t pmli[4];
+    pmle_t *pml[4];
+} s_state_cache;
 
 physptr_t
 mem_linear_tophys_koffset(uintptr_t virt)
@@ -29,17 +37,20 @@ mem_phys_tolinear(physptr_t phys)
 }
 
 static size_t
-s_paging_pmle(size_t l, uintptr_t addr)
+s_paging_pmli(size_t l, uintptr_t addr)
 {
     size_t shift = (12 + (9 * l));
     return (addr & (0x1FFULL << shift)) >> shift;
 }
 
-static union PageEntry*
-s_paging_fetch_table(union PageEntry *pt, size_t l, uintptr_t virt)
+static pmle_t*
+s_paging_fetch_table(pmle_t *pml, size_t l, uintptr_t virt)
 {
-    size_t pmle = s_paging_pmle(l, virt);
-    union PageEntry entry = pt[pmle];
+    size_t pmli = s_paging_pmli(l, virt);
+    if(s_state_cache.pmli[l] == pmli && s_state_cache.pml[l] != NULL)
+        return s_state_cache.pml[l];
+
+    pmle_t entry = pml[pmli];
     bool entry_new = false;
     if(!entry.p) {
         entry_new = true;
@@ -47,122 +58,134 @@ s_paging_fetch_table(union PageEntry *pt, size_t l, uintptr_t virt)
         entry.p = 1;
         entry.rw = 1;
         entry.us = 1;
-        pt[pmle] = entry;
+        pml[pmli] = entry;
     }
-    union PageEntry *table = (union PageEntry*)(mem_phys_tolinear(entry.paddr << 12));
-    if(entry_new) memset(table, 0, PAGESIZE);
+    pmle_t *table = (pmle_t*)(mem_phys_tolinear(entry.paddr << 12));
+    if(entry_new) memset(table, 0, PAGE_SIZE);
+
+    s_state_cache.pmli[l] = pmli;
+    s_state_cache.pml[l] = table;
     return table;
 }
 
-static union PageEntry*
-s_paging_get_table(union PageEntry *pt, size_t l, uintptr_t virt)
+static void
+s_paging_cache_tables(page_directory_t *pd, uintptr_t virt)
 {
-    if(pt == NULL) return NULL;
-    size_t pmle = s_paging_pmle(l, virt);
-    union PageEntry entry = pt[pmle];
-    if(!entry.p) return NULL;
-    return (union PageEntry*)(mem_phys_tolinear(entry.paddr << 12));
+    pmle_t *pml4 = (pmle_t*)pd->virt;
+    if(s_state_cache.pd != pd) memset(&s_state_cache, 0, sizeof(s_state_cache));
+
+    pmle_t *pml3 = s_paging_fetch_table(pml4, 3, virt);
+    pmle_t *pml2 = s_paging_fetch_table(pml3, 2, virt);
+    pmle_t *pml1 = s_paging_fetch_table(pml2, 1, virt);
 }
 
-physptr_t
-mem_linear_tophys(uintptr_t virt)
+static pmle_t*
+s_paging_get_table(pmle_t *pt, size_t l, uintptr_t virt)
 {
-    struct PageDirectory *pd = mem_current_pd;
-    union PageEntry *pml3 = s_paging_get_table(pd->pml4_vaddr, 3, virt);
-    union PageEntry *pml2 = s_paging_get_table(pd->pml4_vaddr, 3, virt);
-    union PageEntry *pml1 = s_paging_get_table(pd->pml4_vaddr, 3, virt);
-    if(pml1 == NULL) return 0;
-
-    size_t pml1i = s_paging_pmle(0, virt);
+    if(pt == NULL) return NULL;
+    size_t pmli = s_paging_pmli(l, virt);
+    if(s_state_cache.pmli[l] == pmli && s_state_cache.pml[l] != NULL)
+        return s_state_cache.pml[l];
 
-    if(!pml1[pml1i].p) return 0;
-    return pml1[pml1i].paddr << 12;
+    pmle_t entry = pt[pmli];
+    if(!entry.p) return NULL;
+    return (pmle_t*)(mem_phys_tolinear(entry.paddr << 12));
 }
 
-bool
-mem_check_ptr(const void *ptr)
+page_mapping_t
+mem_get_mapping_as(page_directory_t *pd, uintptr_t addr)
 {
-    if(ptr == NULL) return false;
-    return mem_linear_tophys((uintptr_t)ptr) != 0;
-}
+    spinlock_acquire(pd->lock);
+    page_mapping_t mapping = { 0 };
+    
+    pmle_t *pml4 = (pmle_t*)pd->virt;
+    if(s_state_cache.pd != pd) memset(&s_state_cache, 0, sizeof(s_state_cache));
 
-void
-mem_paging_map4k(struct PageDirectory *pd, physptr_t phys, uintptr_t virt, uint8_t flg)
-{
-    union PageEntry *pml3 = s_paging_fetch_table(pd->pml4_vaddr, 3, virt);
-    union PageEntry *pml2 = s_paging_fetch_table(pml3, 2, virt);
-    union PageEntry *pml1 = s_paging_fetch_table(pml2, 1, virt);
-    size_t pml1e = s_paging_pmle(0, virt);
-
-    pml1[pml1e] = (union PageEntry) {
-        .p = (flg & 1) > 0,
-        .rw = (flg & 2) > 0,
-        .us = (flg & 4) > 0,
-        .paddr = phys >> 12
+    pmle_t *pml3 = s_paging_get_table(pml4, 3, addr);
+    pmle_t *pml2 = s_paging_get_table(pml3, 2, addr);
+    pmle_t *pml1 = s_paging_get_table(pml2, 1, addr);
+    if(pml1 == NULL) goto release_return;
+
+    size_t pml1i = s_paging_pmli(0, addr);
+    pmle_t pml1e = pml1[pml1i];
+
+    mapping = (page_mapping_t) {
+        .phys = (pml1e.paddr << 12) & ~PAGE_MASK,
+        .pf = {
+            .present = pml1e.p,
+            .writeable = pml1e.rw,
+            .useraccess = pml1e.us,
+            .executable = !pml1e.xd
+        }
     };
+release_return:
+    spinlock_release(pd->lock);
+    return mapping;
 }
 
-union PageEntry
-mem_paging_fetch4k(struct PageDirectory *pd, uintptr_t virt)
-{
-    union PageEntry *pml3 = s_paging_fetch_table(pd->pml4_vaddr, 3, virt);
-    union PageEntry *pml2 = s_paging_fetch_table(pml3, 2, virt);
-    union PageEntry *pml1 = s_paging_fetch_table(pml2, 1, virt);
-    return pml1[s_paging_pmle(0, virt)];
-}
+page_mapping_t mem_get_mapping(uintptr_t addr)
+{ return mem_get_mapping_as(current_page_directory, addr); }
 
-void
-mem_pd_ensure_4k(struct PageDirectory *pd, uintptr_t virt, uint8_t flg)
-{
-    union PageEntry pml1e = mem_paging_fetch4k(pd, virt);
-    if(!pml1e.p) {
-        uintptr_t phys = mem_phys_alloc(1);
-        mem_paging_map4k(pd, phys, virt, flg);
-    }
-}
 
-void
-mem_pd_ensure_range(struct PageDirectory *pd, uintptr_t from, uintptr_t to, uint8_t flg)
+bool
+mem_check_ptr(const void *ptr)
 {
-    from &= ~0xFFF;
-    for(; from < to; from += PAGESIZE)
-        mem_pd_ensure_4k(pd, from, flg);
+    return mem_get_mapping((uintptr_t)ptr).pf.present != 0;
 }
 
 void
-mem_ensure_range_for(void *pd, uintptr_t from, uintptr_t to, bool rw, bool user)
+mem_set_mapping_as(page_directory_t *pd, page_mapping_t mapping, uintptr_t virt)
 {
-    mem_pd_ensure_range((struct PageDirectory*)pd, from, to, 1 | (rw << 1) | (user << 2));
+    spinlock_acquire(pd->lock);
+    s_paging_cache_tables(pd, virt);
+    pmle_t *pml1 = s_state_cache.pml[0];
+    size_t pml1i = s_paging_pmli(0, virt);
+
+    pml1[pml1i] = (pmle_t) {
+        .p = mapping.pf.present,
+        .rw = mapping.pf.writeable,
+        .us = mapping.pf.useraccess,
+        .xd = !mapping.pf.executable,
+        .paddr = mapping.phys >> 12
+    };
+    spinlock_release(pd->lock);
 }
 
+void mem_set_mapping(page_mapping_t mapping, uintptr_t virt)
+{ mem_set_mapping_as(current_page_directory, mapping, virt); }
+
 void
-mem_ensure_range(uintptr_t from, uintptr_t to, bool rw, bool user)
+mem_ensure_range_as(page_directory_t *pd, uintptr_t from, uintptr_t to, page_flags_t flg)
 {
-    mem_ensure_range_for(mem_current_pd, from, to, rw, user);
-}
+    spinlock_acquire(pd->lock);
+    from &= ~(PAGE_SIZE - 1);
 
-void mem_pd_new(struct PageDirectory *pd)
-{
-    physptr_t pml4p = mem_phys_alloc(1);
-    union PageEntry *pml4 = (union PageEntry*)mem_phys_tolinear(pml4p);
-    memset(pml4, 0, PAGESIZE);
-    memcpy(&pml4[256], &pd->pml4_vaddr[256], PAGESIZE / 2);
-
-    *pd = (struct PageDirectory){
-        .pml4_vaddr = pml4,
-        .pml4_paddr = pml4p,
-        .references = 1
-    };
-}
+    if(to < from) to = from;
+    size_t pages = (to - from) >> 12;
+    if(pages == 0) pages = 1;
+    for(size_t i = 0; i < pages; i++) {
+        uintptr_t waddr = from + (i << 12);
+        s_paging_cache_tables(pd, waddr);
+        pmle_t *pml1 = s_state_cache.pml[1];
+        size_t pml1i = s_paging_pmli(0, waddr);
 
-void mem_pd_clone(struct PageDirectory *pd, struct PageDirectory *parent)
-{
-    mem_pd_new(pd);
-    for(size_t i = 0; i < 256; i++) {
-        //TODO: Impl pd cloning
+        if(!pml1[pml1i].p) {
+            physptr_t phys = mem_phys_alloc(1);
+            pml1[pml1i] = (pmle_t) {
+                .p = flg.present,
+                .rw = flg.writeable,
+                .us = flg.useraccess,
+                .xd = !flg.executable,
+                .paddr = phys >> 12
+            };
+        }
     }
+    spinlock_release(pd->lock);
 }
 
+void mem_ensure_range(uintptr_t from, uintptr_t to, page_flags_t flg)
+{ mem_ensure_range_as(current_page_directory, from, to, flg); }
+
 struct Registers*
 s_pagefault_handler(struct Registers *state)
 {
@@ -189,16 +212,17 @@ s_pagefault_handler(struct Registers *state)
 void
 mem_paging_setup(void)
 {
-    memset(s_kernel_initial_pml4, 0, PAGESIZE);
-    memset(s_kernel_initial_pml3, 0, 2 * PAGESIZE);
-    memset(s_kernel_initial_pml2, 0, 2 * PAGESIZE);
-    memset(s_kernel_initial_pml1, 0, PAGESIZE);
-    s_kernel_initial_pd = (struct PageDirectory){
-        .pml4_vaddr = (union PageEntry*)&s_kernel_initial_pml4,
-        .pml4_paddr = mem_linear_tophys_koffset((uintptr_t)&s_kernel_initial_pml4),
-        .references = 1
+    memset(s_kernel_initial_pml4, 0, PAGE_SIZE);
+    memset(s_kernel_initial_pml3, 0, 2 * PAGE_SIZE);
+    memset(s_kernel_initial_pml2, 0, 2 * PAGE_SIZE);
+    memset(s_kernel_initial_pml1, 0, PAGE_SIZE);
+    s_kernel_initial_pd = (page_directory_t){
+        .phys = mem_linear_tophys_koffset((uintptr_t)&s_kernel_initial_pml4),
+        .virt = (union PageEntry*)&s_kernel_initial_pml4,
+        .ref = 1,
+        .id = s_next_pdid++
     };
-    mem_current_pd = &s_kernel_initial_pd;
+    current_page_directory = &s_kernel_initial_pd;
 
     /* Map first few GiBs */
     s_kernel_initial_pml4[256] =
@@ -208,7 +232,7 @@ mem_paging_setup(void)
         mem_linear_tophys_koffset((uintptr_t)&s_kernel_initial_pml2[0])
         | 3;
     for(int i = 0; i < 512; i++) {
-        s_kernel_initial_pml2[0][i] = (i * (PAGESIZE * 512)) | 0x80 | 3;
+        s_kernel_initial_pml2[0][i] = (i * (PAGE_SIZE * 512)) | 0x80 | 3;
     }
 
     size_t kernel_pml4e = (boot_kernel_virtual_base >> (39));
@@ -225,9 +249,9 @@ mem_paging_setup(void)
     s_kernel_initial_pml2[1][kernel_pml2e] =
         mem_linear_tophys_koffset((uintptr_t)&s_kernel_initial_pml1[0]) | 3;
     for(int i = 0; i < kernel_npages; i++) {
-        s_kernel_initial_pml1[0][i] = (i * PAGESIZE) + boot_kernel_physical_address | 3;
+        s_kernel_initial_pml1[0][i] = (i * PAGE_SIZE) + boot_kernel_physical_address | 3;
     }
     
     int_set_handler(14, s_pagefault_handler);
-    __asm__ volatile("mov %0, %%cr3":: "r"(s_kernel_initial_pd.pml4_paddr));
+    __asm__ volatile("mov %0, %%cr3":: "r"(s_kernel_initial_pd.phys));
 }