Add a more proper 64-bit vmm
diff --git a/src/lib/blib.c b/src/lib/blib.c
index 6cbd9ef9..e5fe0558 100644
--- a/src/lib/blib.c
+++ b/src/lib/blib.c
@@ -65,6 +65,10 @@ void *balloc_aligned(size_t count, size_t alignment) {
if (new_base >= BUMP_ALLOCATOR_LIMIT)
panic("Memory allocation failed");
bump_allocator_base = new_base;
+
+ // Zero out allocated space
+ memset(ret, 0, count);
+
return ret;
}
diff --git a/src/mm/vmm64.c b/src/mm/vmm64.c
new file mode 100644
index 00000000..78e0ad4b
--- /dev/null
+++ b/src/mm/vmm64.c
@@ -0,0 +1,44 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <mm/vmm64.h>
+#include <lib/blib.h>
+
+#define PT_SIZE ((uint64_t)0x1000)
+
+typedef uint64_t pt_entry_t;
+
+static pt_entry_t *get_next_level(pt_entry_t *current_level, size_t entry) {
+ pt_entry_t *ret;
+
+ if (current_level[entry] & 0x1) {
+ // Present flag set
+ ret = (pt_entry_t *)(current_level[entry] & ~((pt_entry_t)0xfff));
+ } else {
+ // Allocate a table for the next level
+ ret = balloc_aligned(PT_SIZE, PT_SIZE);
+ // Present + writable + user (0b111)
+ current_level[entry] = (pt_entry_t)ret | 0b111;
+ }
+
+ return ret;
+}
+
+pagemap_t new_pagemap(void) {
+ return (pagemap_t)(size_t)balloc_aligned(PT_SIZE, PT_SIZE);
+}
+
+void map_page(pagemap_t pagemap, uint64_t virt_addr, uint64_t phys_addr, uint64_t flags) {
+ // Calculate the indices in the various tables using the virtual address
+ size_t pml4_entry = (virt_addr & ((uint64_t)0x1ff << 39)) >> 39;
+ size_t pml3_entry = (virt_addr & ((uint64_t)0x1ff << 30)) >> 30;
+ size_t pml2_entry = (virt_addr & ((uint64_t)0x1ff << 21)) >> 21;
+
+ pt_entry_t *pml4 = (pt_entry_t *)(size_t)pagemap;
+ pt_entry_t *pml3 = get_next_level(pml4, pml4_entry);
+ pt_entry_t *pml2 = get_next_level(pml3, pml3_entry);
+
+ // Set the entry as present and point it to the passed physical address
+ // Also set the specified flags
+ // We only use 2MiB pages else we would not have enough space
+ pml2[pml2_entry] = (pt_entry_t)(phys_addr | flags | (1 << 7));
+}
diff --git a/src/mm/vmm64.h b/src/mm/vmm64.h
new file mode 100644
index 00000000..7e63f58e
--- /dev/null
+++ b/src/mm/vmm64.h
@@ -0,0 +1,13 @@
+#ifndef __MM__VMM64_H__
+#define __MM__VMM64_H__
+
+#include <stdint.h>
+
+#define PAGE_SIZE ((uint64_t)0x200000)
+
+typedef uint64_t pagemap_t;
+
+pagemap_t new_pagemap(void);
+void map_page(pagemap_t pagemap, uint64_t virt_addr, uint64_t phys_addr, uint64_t flags);
+
+#endif
diff --git a/src/protos/stivale.c b/src/protos/stivale.c
index 6bec7370..beb8461e 100644
--- a/src/protos/stivale.c
+++ b/src/protos/stivale.c
@@ -16,6 +16,7 @@
#include <drivers/pic.h>
#include <fs/file.h>
#include <lib/asm.h>
+#include <mm/vmm64.h>
struct stivale_header {
uint64_t stack;
@@ -304,35 +305,20 @@ __attribute__((noreturn)) void stivale_spinup(int bits, bool level5pg,
for (size_t i = 0; i < 512 * 4; i++)
(&pagemap->pml2_0gb[0])[i] = (i * 0x200000) | 0x03 | (1 << 7);
} else {
- struct pagemap {
- uint64_t pml4[512];
- uint64_t pml3_lo[512];
- uint64_t pml3_hi[512];
- uint64_t pml2_0gb[512];
- uint64_t pml2_1gb[512];
- uint64_t pml2_2gb[512];
- uint64_t pml2_3gb[512];
- };
- struct pagemap *pagemap = balloc_aligned(sizeof(struct pagemap), 0x1000);
- pagemap_ptr = (void *)pagemap;
+ pagemap_t pagemap = new_pagemap();
- // zero out the pagemap
- for (uint64_t *p = (uint64_t *)pagemap; p < &pagemap->pml3_hi[512]; p++)
- *p = 0;
+ // Map 0 to 2GiB at 0xffffffff80000000
+ for (uint64_t i = 0; i < 0x80000000; i += PAGE_SIZE) {
+ map_page(pagemap, i + 0xffffffff80000000, i, 0x03);
+ }
- pagemap->pml4[511] = (uint64_t)(size_t)pagemap->pml3_hi | 0x03;
- pagemap->pml4[256] = (uint64_t)(size_t)pagemap->pml3_lo | 0x03;
- pagemap->pml4[0] = (uint64_t)(size_t)pagemap->pml3_lo | 0x03;
- pagemap->pml3_hi[510] = (uint64_t)(size_t)pagemap->pml2_0gb | 0x03;
- pagemap->pml3_hi[511] = (uint64_t)(size_t)pagemap->pml2_1gb | 0x03;
- pagemap->pml3_lo[0] = (uint64_t)(size_t)pagemap->pml2_0gb | 0x03;
- pagemap->pml3_lo[1] = (uint64_t)(size_t)pagemap->pml2_1gb | 0x03;
- pagemap->pml3_lo[2] = (uint64_t)(size_t)pagemap->pml2_2gb | 0x03;
- pagemap->pml3_lo[3] = (uint64_t)(size_t)pagemap->pml2_3gb | 0x03;
+ // Map 0 to 4GiB at 0xffff800000000000 and 0
+ for (uint64_t i = 0; i < 0x100000000; i += PAGE_SIZE) {
+ map_page(pagemap, i, i, 0x03);
+ map_page(pagemap, i + 0xffff800000000000, i, 0x03);
+ }
- // populate the page directories
- for (size_t i = 0; i < 512 * 4; i++)
- (&pagemap->pml2_0gb[0])[i] = (i * 0x200000) | 0x03 | (1 << 7);
+ pagemap_ptr = (void *)pagemap;
}
ASM(
