diff options
| author | Danny Holman <dholman@gymli.org> | 2024-06-21 21:40:00 -0500 |
|---|---|---|
| committer | Danny Holman <dholman@gymli.org> | 2024-06-21 21:40:00 -0500 |
| commit | f1a0f10f54e17803f7d7095a61117aec52fafbf0 (patch) | |
| tree | a1b5f7cdcc4d51f8d3b15ba5f4c97316bbe02697 | |
| parent | e068ccbec7d61101e5bd9156eb63f157cf6a9846 (diff) | |
arch: boot: allocate a few pages at startup
Allocate a few pages at startup just to get the paging and physical
memory manager up and running.
Signed-off-by: Danny Holman <dholman@gymli.org>
| -rw-r--r-- | arch/i386/boot/boot.s | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/arch/i386/boot/boot.s b/arch/i386/boot/boot.s index 6d6da7d..29a3575 100644 --- a/arch/i386/boot/boot.s +++ b/arch/i386/boot/boot.s @@ -19,14 +19,16 @@ stack_top: .align 4096 boot_page_directory: .skip 4096 -boot_page_tables: - .skip 20480 +boot_page_table0: + .skip 4096 +boot_page_table1: + .skip 4096 .section .multiboot.text, "a" .global _start .type _start, @function _start: - movl $(boot_page_tables - 0xC0000000), %edi + movl $(boot_page_table0 - 0xC0000000), %edi movl $0, %esi movl $1023, %ecx @@ -43,13 +45,22 @@ _start: addl $4, %edi loop 1b -3: movl $0xB8003, boot_page_tables - 0xC0000000 + 1023 * 4 - movl $boot_page_tables, %ecx +3: movl $boot_page_directory, %ecx + subl $0xC0000000, %ecx + orl $0x003, %ecx + movl %ecx, boot_page_directory - 0xC0000000 + 1023 * 4 + + movl $boot_page_table0, %ecx subl $0xC0000000, %ecx orl $0x003, %ecx movl %ecx, boot_page_directory - 0xC0000000 - movl %ecx, boot_page_directory - 0xC0000000 + 4 * 768 + movl %ecx, boot_page_directory - 0xC0000000 + 768 * 4 + + movl $boot_page_table1, %ecx + subl $0xC0000000, %ecx + orl $0x003, %ecx + movl %ecx, boot_page_directory - 0xC0000000 + 1022 * 4 movl $boot_page_directory, %ecx subl $0xC0000000, %ecx @@ -64,13 +75,9 @@ _start: .section .text -4: movl %cr3, %ecx - movl %ecx, %cr3 - - movl $stack_top, %esp +4: movl $stack_top, %esp and $-16, %esp - pushl $boot_page_directory pushl %ebx pushl %eax call i386_entry |