diff options
Diffstat (limited to 'kernel/src/mem')
| -rw-r--r-- | kernel/src/mem/paging.c | 35 | ||||
| -rw-r--r-- | kernel/src/mem/paging_asm.S | 12 |
2 files changed, 47 insertions, 0 deletions
diff --git a/kernel/src/mem/paging.c b/kernel/src/mem/paging.c new file mode 100644 index 0000000..aa7f91e --- /dev/null +++ b/kernel/src/mem/paging.c @@ -0,0 +1,35 @@ +#include <stdint.h> +#include <paging.h> + +void load_pt_lvl4(uint64_t*); + +__attribute__((aligned(4096))) uint64_t page_table_lvl4[512]; +__attribute__((aligned(4096))) uint64_t page_table_lvl3[512]; +__attribute__((aligned(4096))) uint64_t page_table_lvl2_kernel[512]; +__attribute__((aligned(4096))) uint64_t page_table_lvl2_fb[512]; + +#define PAGE_SIZE 0x00200000 +#define FLAG_PRESENT 0x1 +#define FLAG_WRITABLE 0x2 +#define FLAG_HUGE 0x80 + +void init_paging(void) +{ + page_table_lvl4[0] = (uint64_t)page_table_lvl3 + FLAG_PRESENT + FLAG_WRITABLE; + page_table_lvl3[0] = (uint64_t)page_table_lvl2_kernel + FLAG_PRESENT + FLAG_WRITABLE; + page_table_lvl3[3] = (uint64_t)page_table_lvl2_fb + FLAG_PRESENT + FLAG_WRITABLE; + + // 0x00000000 - 0x00400000 : 0x00000000 - 0x00400000 + for (uint64_t i = 0; i < 2; i++) { + page_table_lvl2_kernel[i] = i * PAGE_SIZE + FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE; + } + + // TODO: remove initial mapping for fb and instead page on demand + + // 0xe0000000 - 0xffffffff : 0xe0000000 - 0xffffffff + for (uint64_t i = 0; i < 512; i++) { + page_table_lvl2_fb[i] = i * PAGE_SIZE + 0xc0000000 + FLAG_PRESENT + FLAG_WRITABLE + FLAG_HUGE; + } + + load_pt_lvl4(page_table_lvl4); +} diff --git a/kernel/src/mem/paging_asm.S b/kernel/src/mem/paging_asm.S new file mode 100644 index 0000000..5a1dcf7 --- /dev/null +++ b/kernel/src/mem/paging_asm.S @@ -0,0 +1,12 @@ +.section .text + +.global load_pt_lvl4 +load_pt_lvl4: + push %rbp + mov %rsp, %rbp + + mov %rdi, %cr3 + + mov %rbp, %rsp + pop %rbp + ret |