diff options
Diffstat (limited to 'sys/arch/amd64/stand/efi32/run_i386.S')
| -rw-r--r-- | sys/arch/amd64/stand/efi32/run_i386.S | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/sys/arch/amd64/stand/efi32/run_i386.S b/sys/arch/amd64/stand/efi32/run_i386.S new file mode 100644 index 00000000000..ccb423d0079 --- /dev/null +++ b/sys/arch/amd64/stand/efi32/run_i386.S @@ -0,0 +1,115 @@ +/* $OpenBSD: run_i386.S,v 1.1 2019/05/11 02:33:34 mlarkin Exp $ */ + +/* + * Copyright (c) 2015 YASUOKA Masahiko <yasuoka@yasuoka.net> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include <machine/asm.h> +#include <machine/specialreg.h> + +#define CODE_SEGMENT 0x10 +#define DATA_SEGMENT 0x18 + + .globl _C_LABEL(run_i386_size) +_C_LABEL(run_i386_size): + .long run_i386_end - _C_LABEL(run_i386_start) + + .align 4 + .text + .globl _C_LABEL(run_i386_start) +_C_LABEL(run_i386_start): +start: + /* + * run_i386(_start) is to call the loaded kernel's start() with + * 32bit segment mode from x64 mode. + * %rdi == loaded start address, %rsi == kernel start address + */ + + /* re-arrange the parameters for the x86 calling convension */ + mov %edx, (run_i386_end - start - 0x20)(%rdi) + mov %ecx, (run_i386_end - start - 0x1c)(%rdi) + mov %r8d, (run_i386_end - start - 0x18)(%rdi) + mov %r9d, (run_i386_end - start - 0x14)(%rdi) + mov 0x8(%rsp), %edx + mov %edx, (run_i386_end - start - 0x10)(%rdi) + mov 0x10(%rsp), %edx + mov %edx, (run_i386_end - start - 0xc)(%rdi) + mov 0x18(%rsp), %edx + mov %edx, (run_i386_end - start - 0x8)(%rdi) + mov 0x20(%rsp), %edx + mov %edx, (run_i386_end - start - 0x4)(%rdi) + + /* Prepare jump address */ + lea (start32a - start)(%rdi), %rax + movl %eax, (start32r - start)(%rdi) + + cli + + /* Setup GDT */ + lea (gdt - start)(%rdi), %rax + mov %rax, (gdtrr - start)(%rdi) + lgdt (gdtr - start)(%rdi) + + /* Jump to set %cs */ + ljmp *(start32r - start)(%rdi) + + .align 4 +start32a: + .code32 + movl $DATA_SEGMENT, %eax + movl %eax, %ds + movl %eax, %es + movl %eax, %fs + movl %eax, %gs + movl %eax, %ss + + lea (run_i386_end - start - 0x20)(%edi), %eax + mov %eax, %esp + + /* Disable Paging in CR0 */ + movl %cr0, %eax + andl $(~CR0_PG), %eax + movl %eax, %cr0 + + /* Disable PAE in CR4 */ + movl %cr4, %eax + andl $(~CR4_PAE), %eax + movl %eax, %cr4 + + jmp start32b +start32b: + .code32 + + call *%esi + + .align 4 +start32r: + .long 0 + .long CODE_SEGMENT + .align 4 +gdt: + .long 0, 0 + .long 0, 0 + .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9f, 0xcf, 0x00 + .byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x93, 0xcf, 0x00 +gdtr: + .word gdtr - gdt +gdtrr: + .quad +start32end: + /* Space for the stack */ + .align 4 + .space 8192 +run_i386_end: |