1 files changed, 114 insertions, 0 deletions
diff --git a/arch/x86_64/page_directory.c b/arch/x86_64/page_directory.c
new file mode 100644
index 0000000..0506703
--- /dev/null
+++ b/arch/x86_64/page_directory.c
@@ -0,0 +1,114 @@
+#include "arch/x86_64/page.h"
+#include "arch/x86_64/object.h"
+#include "device/processor.h"
+#include "print.h"
+#include "memory.h"
+#include "object.h"
+#include "string.h"
+#include "jove.h"
+
+physptr_t s_kpbase(void);
+
+#if defined(__limine__)
+
+#include "boot/limine/limine.h"
+static struct limine_kernel_address_request s_kaddr_req = {
+    .id = LIMINE_KERNEL_ADDRESS_REQUEST
+};
+
+physptr_t s_kpbase(void) { return s_kaddr_req.response->physical_base; }
+
+#endif
+
+physptr_t 
+vmem_tophys_koff(virtptr_t v)
+{
+    return v - (physptr_t)&_kernel_start + s_kpbase();
+}
+
+#define IDENTITY_BASE 0xFFFF800000000000
+void*
+vmem_phys_tovirt(physptr_t p)
+{
+    return (void*)(p + IDENTITY_BASE);
+}
+
+uintptr_t vmem_ident_tophys(void *vptr)
+{
+    return ((uintptr_t)vptr) - IDENTITY_BASE;
+}
+
+void*
+pmle_get_page(pmle_t entry)
+{
+    uintptr_t pptr = entry.paddr << 12;
+    return vmem_phys_tovirt(pptr);
+}
+
+__attribute__((aligned(0x1000))) pmle_t s_kernel_pml4[512]; // Page L4
+__attribute__((aligned(0x1000))) pmle_t s_kernel_pml3[512]; // Page L3
+__attribute__((aligned(0x1000))) pmle_t s_kernel_pml2[512]; // Page directory
+__attribute__((aligned(0x1000))) pmle_t s_kernel_pml1[512]; // Page table
+
+__attribute__((aligned(0x1000))) pmle_t s_idmap_pml3[512];
+__attribute__((aligned(0x1000))) pmle_t s_idmap_pml2[512];
+
+void
+vmem_setup(void)
+{
+    memset(s_kernel_pml4, 0, 0x1000);
+    memset(s_kernel_pml3, 0, 0x1000);
+    memset(s_kernel_pml2, 0, 0x1000);
+    memset(s_kernel_pml1, 0, 0x1000);
+
+    memset(s_idmap_pml3, 0, 0x1000);
+    memset(s_idmap_pml2, 0, 0x1000);
+
+    virtptr_t kernel_start = (virtptr_t)&_kernel_start;
+    virtptr_t kernel_end = (virtptr_t)&_kernel_end;
+
+    size_t kernel_size = kernel_end - kernel_start;
+    size_t kernel_size_pages = (kernel_size / 0x1000) + 1;
+
+    physptr_t kernel_pml4_base = vmem_tophys_koff((virtptr_t)&s_kernel_pml4);
+    physptr_t kernel_pml3_base = vmem_tophys_koff((virtptr_t)&s_kernel_pml3);
+    physptr_t kernel_pml2_base = vmem_tophys_koff((virtptr_t)&s_kernel_pml2);
+    physptr_t kernel_pml1_base = vmem_tophys_koff((virtptr_t)&s_kernel_pml1);
+
+    physptr_t idmap_pml3_base = vmem_tophys_koff((virtptr_t)&s_idmap_pml3);
+    physptr_t idmap_pml2_base = vmem_tophys_koff((virtptr_t)&s_idmap_pml2);
+
+    processor_t *processor = processor_current();
+    processor->pdir = kernel_pml4_base;
+
+    //Map memory identity pages.
+    s_kernel_pml4[256].value = idmap_pml3_base | 2 | 1;
+    s_idmap_pml3[0].value = idmap_pml2_base | 2 | 1;
+    for(int i = 0; i < 512; i++) {
+        s_idmap_pml2[i].value = (i * 0x1000 * 512) | 0x80 | 2 | 1;
+    }
+    
+    //Map the kernel to himem.
+
+    pmli_t kernel_pml3_i = PML_I_FOR_LAYER(kernel_start, 3);
+    pmli_t kernel_pml2_i = PML_I_FOR_LAYER(kernel_start, 2);
+    pmli_t kernel_pml1_ib = PML_I_FOR_LAYER(kernel_start, 1);
+    pmli_t kernel_pml1_ie = PML_I_FOR_LAYER(kernel_end, 1) + 1;
+
+    s_kernel_pml4[511].value = kernel_pml3_base | 2 | 1;
+    s_kernel_pml3[kernel_pml3_i].value = kernel_pml2_base | 2 | 1;
+    s_kernel_pml2[kernel_pml2_i].value = kernel_pml1_base | 2 | 1;
+    for(pmli_t i = kernel_pml1_ib; i < kernel_pml1_ie; i++) {
+        s_kernel_pml1[i].value = ((i * 0x1000) + s_kpbase()) | 3;
+    }
+
+    __asm__ volatile("mov %0, %%cr3":: "r"(kernel_pml4_base));
+
+    //Add page mapping object to init directory.
+    uint8_t pm_i = _initDirectory.self.data++;
+    _initDirectory.entries[pm_i] = (objdir_entry_t) {
+        .type = KO_MEMORY_MAPPING_PAGE,
+        .data = kernel_pml4_base
+    };
+    _initData.pm_object = pm_i;
+}