1 files changed, 173 insertions, 0 deletions
diff --git a/arch/x86_64/page.c b/arch/x86_64/page.c
new file mode 100644
index 0000000..d816f66
--- /dev/null
+++ b/arch/x86_64/page.c
@@ -0,0 +1,173 @@
+#include "arch/x86_64/page.h"
+#include "klib/rbtree.h"
+#include "arch/processor.h"
+#include "string.h"
+#include "jove.h"
+#include "memory.h"
+#include "print.h"
+
+extern void *_kernel_end;
+
+struct PageDirectoryListEntry {
+    struct PageDirectoryListEntry *next;
+    page_directory_t pd;
+};
+
+struct PageStateCache {
+    page_directory_t *pd;
+    size_t pmli[4];
+    pmle_t *pml[4];
+} s_state_cache;
+
+const uintptr_t USERLAND_MEMORY_BASE = KiB;
+const uintptr_t USERLAND_MEMORY_LIMIT = 0x00007FFFFFFFFFFFULL;
+
+const uintptr_t PHYSMAP_MEMORY_BASE = 0xFFFF800000000000ULL;
+const uintptr_t PHYSMAP_MEMORY_LIMIT = PHYSMAP_MEMORY_BASE + (1 * GiB);
+
+const uintptr_t KERNEL_MEMORY_BASE = 0xFFFF800000000000ULL;
+const uintptr_t KERNEL_MEMORY_LIMIT = 0xFFFFFFFFFFFFFFFFULL;
+
+static size_t
+s_paging_pmli(size_t l, uintptr_t addr)
+{
+    size_t shift = (PAGE_SHIFT + (9 * l));
+    return (addr & (0x1FFULL << shift)) >> shift;
+}
+
+static pmle_t*
+s_paging_fetch_table(pmle_t *pml, size_t l, uintptr_t virt)
+{
+    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;
+        entry.value = pm_alloc(1);
+        entry.p = 1;
+        entry.rw = 1;
+        entry.us = 1;
+        pml[pmli] = entry;
+    }
+    pmle_t *table = (pmle_t*)(pm_tovirt(entry.paddr << PAGE_SHIFT));
+    if(entry_new) memset(table, 0, PAGE_SIZE);
+
+    s_state_cache.pmli[l] = pmli;
+    s_state_cache.pml[l] = table;
+    return table;
+}
+
+static void
+s_paging_cache_tables(page_directory_t *pd, uintptr_t virt)
+{
+    pmle_t *pml4 = pd->pml;
+    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);
+}
+
+static pmle_t*
+s_paging_get_table(pmle_t *pt, size_t l, uintptr_t 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];
+
+    pmle_t entry = pt[pmli];
+    if(!entry.p) return NULL;
+    return (pmle_t*)(pm_tovirt(entry.paddr << PAGE_SHIFT));
+}
+
+page_mapping_t
+vm_pd_mapping_get(page_directory_t *pd, uintptr_t addr)
+{
+    spinlock_acquire(pd->lock);
+    page_mapping_t mapping = { 0 };
+    
+    pmle_t *pml4 = pd->pml;
+    if(s_state_cache.pd != pd) memset(&s_state_cache, 0, sizeof(s_state_cache));
+
+    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 << PAGE_SHIFT) & ~PAGE_MASK,
+        .pf = {
+            .present = pml1e.p,
+            .writeable = pml1e.rw,
+            .useraccess = pml1e.us,
+            .executable = !pml1e.xd
+        }
+    };
+release_return:
+    spinlock_release(pd->lock);
+    return mapping;
+}
+
+page_mapping_t vm_mapping_get(uintptr_t addr)
+{ return vm_pd_mapping_get(pd_current(), addr); }
+
+void
+mem_set_mapping_as(page_directory_t *pd, page_mapping_t mapping, uintptr_t virt)
+{
+    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 >> PAGE_SHIFT
+    };
+    spinlock_release(pd->lock);
+}
+
+void mem_set_mapping(page_mapping_t mapping, uintptr_t virt)
+{ mem_set_mapping_as(pd_current(), mapping, virt); }
+
+void
+vm_pd_ensure(page_directory_t *pd, uintptr_t from, uintptr_t to, page_flags_t flg)
+{
+    spinlock_acquire(pd->lock);
+    from &= ~(PAGE_SIZE - 1);
+    to += (to % PAGE_SIZE > 0 ? (PAGE_SIZE - (to % PAGE_SIZE)) : 0);
+
+    if(to < from) to = from;
+    size_t pages = (to - from) >> PAGE_SHIFT;
+    if(pages == 0) pages = 1;
+    for(size_t i = 0; i < pages; i++) {
+        uintptr_t waddr = from + (i << PAGE_SHIFT);
+        s_paging_cache_tables(pd, waddr);
+        pmle_t *pml1 = s_state_cache.pml[1];
+        size_t pml1i = s_paging_pmli(0, waddr);
+
+        if(!pml1[pml1i].p) {
+            physptr_t phys = pm_alloc(1);
+            pml1[pml1i] = (pmle_t) {
+                .p = flg.present,
+                .rw = flg.writeable,
+                .us = flg.useraccess,
+                .xd = !flg.executable,
+                .paddr = phys >> PAGE_SHIFT
+            };
+        }
+    }
+    spinlock_release(pd->lock);
+}
+
+void vm_ensure(uintptr_t from, uintptr_t to, page_flags_t flg)
+{ vm_pd_ensure(pd_current(), from, to, flg); }