arch: i386: paging: add a proper paging API

Add a proper page control API. These functions allow the kernel to
directly map and unmap pages in the logical address space.

Signed-off-by: Danny Holman <dholman@gymli.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/i386/include/kernel/paging.h b/arch/i386/include/kernel/paging.h
new file mode 100644
index 0000000..c65718f
--- /dev/null
+++ b/arch/i386/include/kernel/paging.h
@@ -0,0 +1,52 @@
+#ifndef I386_PAGING_H
+#define I386_PAGING_H
+
+#include <kernel/isr.h>
+#include <stdint.h>
+
+#define PD_PRES         0x0001
+#define PD_RW           0x0002
+#define PD_USR          0x0004
+#define PD_PWT          0x0008
+#define PD_PCD          0x0010
+#define PD_ACC          0x0020
+#define PD_DIRTY        0x0040
+#define PD_PS           0x0080
+#define PD_GLOB         0x0100
+#define PD_PAT          0x1000
+
+#define ERR_PRESENT     0x1
+#define ERR_RW          0x2
+#define ERR_USER        0x4
+#define ERR_RESERVED    0x8
+#define ERR_INST        0x10
+
+#define BLOCK_SIZE 4096
+#define BLOCKS_PER_BUCKET 8
+#define BLOCK_ALIGN(addr) (((addr) & 0xFFFFF000) + 0x1000)
+
+#define SETBIT(x,i)     x[i/BLOCKS_PER_BUCKET] = x[i/BLOCKS_PER_BUCKET] | (1 << (i % BLOCKS_PER_BUCKET))
+#define CLEARBIT(x,i)   x[i/BLOCKS_PER_BUCKET] = x[i/BLOCKS_PER_BUCKET] & (~(1 << (i % BLOCKS_PER_BUCKET)))
+#define ISSET(x,i)      ((x[i/BLOCKS_PER_BUCKET] >> (i % BLOCKS_PER_BUCKET)) & 0x1)
+#define GETBUCKET(x,i)  (*((uint32_t*)&x[i/32]))
+
+#define PAGE_SIZE 4096
+
+struct page_frame {
+        int used;
+        uint32_t addr;
+};
+
+void load_page_dir(uint32_t pd_addr);
+void enable_paging(void);
+
+void paging_init();
+void page_fault_handler(struct isr_frame *frame);
+
+uint32_t get_paddr(uint32_t vaddr);
+uint32_t get_vaddr(uint32_t paddr);
+
+void map_page(uint32_t paddr, uint32_t vaddr, uint32_t flags);
+void unmap_page(uint32_t vaddr);
+
+#endif