diff options
| author | Jake Mannens <jake72360@gmail.com> | 2018-06-25 03:57:22 +1000 |
|---|---|---|
| committer | Jake Mannens <jake72360@gmail.com> | 2018-06-25 03:57:22 +1000 |
| commit | fbbcb04f9e3197976d6ab4a79c45aa0a84e39aba (patch) | |
| tree | f2512a391cf13d77e48a9ad6e02d2d251cb7088a /kernel/page.s | |
| parent | 97d3551106495fa18969e2690720b621ba5a9c0b (diff) | |
Added the header asm/interrupt.h which includes a prototype for the
assembly function register_isr making it usable within the C portions of
the source.
Added a new file panic.s with the function panic that will print a panic
message, disable interrupts and halt the system.
Created the skeleton framework for paging in the new file page.s. The
new function paging_init (called in kboot) will setup a simple page
directory with two tables covering all addresses 0-8MB. It will also
mark pages from 0-1MB as 'supervisor-only' to protect the kernel. NOTE:
The function paging_init must be called before initialising the IDT as
it does not disable interrupts!
Modified the page fault handler to print the offending linear address
along with the supplied error code. Following that, the handler will
initiate a kernel panic. This function (along with panic) assumes
console I/O to be operational.
Modified the userspace test code to deliberately intiate a page fault by
accessing an unmapped page.
Diffstat (limited to 'kernel/page.s')
| -rw-r--r-- | kernel/page.s | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/kernel/page.s b/kernel/page.s new file mode 100644 index 0000000..4e40822 --- /dev/null +++ b/kernel/page.s @@ -0,0 +1,55 @@ +global paging_init + +align 4096 +page_dir: + times 4096 db 0 + +align 4096 +page_tables: + ; two page tables + times 4096 db 0 + times 4096 db 0 +.end: + +; here, we initialize paging. since the IDT +; has yet to be populated, we must take extra +; care as we can't afford to trigger a page +; fault. +paging_init: + push ebp + mov ebp, esp + push ebx + ; populate the page directory + mov eax, page_tables + or eax, 0x007 + mov [page_dir], eax + mov eax, (page_tables+4096) + or eax, 0x007 + mov [page_dir+4], eax + ; populate the page tables + mov ebx, page_tables + mov ecx, ((page_tables.end-page_tables)/4) + mov edx, 0 +.loop: + mov eax, edx + or eax, 0x003 + cmp edx, 0x100000 + jb .skip + or eax, 0x004 +.skip: + mov [ebx], eax + dec ecx + jz .end + add ebx, 4 + add edx, 4096 + jmp .loop +.end: + ; load the page directory and enable paging + mov eax, page_dir + mov cr3, eax + mov eax, cr0 + or eax, 0x80000000 + mov cr0, eax + pop ebx + pop ebp + ret |