Use real_to_prot (etc) from stand/lib.
Add a patchable header for boot parameters (eg console type).
This commit is contained in:
dsl
parent
3d4b6a197d
commit
44ac426707
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@ -1,4 +1,4 @@
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/* $NetBSD: start_pxe.S,v 1.1 2003/10/09 09:42:25 dsl Exp $ */
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/* $NetBSD: start_pxe.S,v 1.2 2003/10/09 10:36:26 dsl Exp $ */
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/*
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* Copyright 2001 Wasabi Systems, Inc.
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@ -43,18 +43,24 @@
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*/
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#include <machine/asm.h>
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#include <sys/bootblock.h>
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.text
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ENTRY(start)
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.code16
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/* Boot parameter area in same format as boot and bootxx */
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jmp 1f
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.balign 4
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.long X86_BOOT_MAGIC_PXE
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bootparams:
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.long 1f - bootparams
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#include <boot_params.S>
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.space 4 * 4 /* some spare */
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1:
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# start is loaded at 0x0:0x7c00 but we want 0x7c0:0x0
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# ljmp to the next instruction to adjust %cs
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ljmp $0x7c0, $start1
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# Our stack XXX probably not!
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.space 1024
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start1:
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ljmp $0x7c0, $2f
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2:
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# set up %ds
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xorl %eax, %eax
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mov %cs, %ax
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@ -64,23 +70,7 @@ start1:
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mov %ax, %ss
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movl $0xfffc, %esp /* stack at top of 64k segment */
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movl %eax, _C_LABEL(ourseg)
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shll $4, %eax
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/* fix up GDT entries for bootstrap */
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#define FIXUP(gdt_index) \
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movw %ax, gdt+gdt_index+2; \
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movb %bl, gdt+gdt_index+4
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shldl $16, %eax, %ebx
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FIXUP(bootcodeseg)
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FIXUP(bootrealseg)
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FIXUP(bootdataseg)
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/* fix up GDT pointer */
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addl $gdt, %eax
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movl %eax, gdtarg+2
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call gdt_fixup
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/* change to protected mode */
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calll _C_LABEL(real_to_prot)
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@ -115,290 +105,10 @@ _C_LABEL(exit):
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/* call ROM BASIC */
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int $0x18
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#else
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10:
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cli
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hlt
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jmp 10b
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#endif
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efail: .asciz "Boot fail\r\n"
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ENTRY(ourseg)
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.long 0
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/**************************************************************************
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GLOBAL DESCRIPTOR TABLE
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**************************************************************************/
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#ifdef __ELF__
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.align 16
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#else
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.align 4
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#endif
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gdt:
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.word 0, 0
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.byte 0, 0x00, 0x00, 0
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#ifdef SUPPORT_LINUX /* additional dummy */
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.word 0, 0
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.byte 0, 0x00, 0x00, 0
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#endif
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/* kernel code segment */
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.globl flatcodeseg
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flatcodeseg = . - gdt
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.word 0xffff, 0
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.byte 0, 0x9f, 0xcf, 0
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/* kernel data segment */
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.globl flatdataseg
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flatdataseg = . - gdt
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.word 0xffff, 0
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.byte 0, 0x93, 0xcf, 0
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/* boot code segment, base will be patched */
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bootcodeseg = . - gdt
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.word 0xffff, 0
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.byte 0, 0x9e, 0x4f, 0
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/* boot data segment, base will be patched */
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bootdataseg = . - gdt
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.word 0xffff, 0
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.byte 0, 0x92, 0x4f, 0
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/* 16 bit real mode, base will be patched */
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bootrealseg = . - gdt
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.word 0xffff, 0
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.byte 0, 0x9e, 0x00, 0
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/* limits (etc) for data segment in real mode */
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bootrealdata = . - gdt
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.word 0xffff, 0
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.byte 0, 0x92, 0x00, 0
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gdtlen = . - gdt
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#ifdef __ELF__
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.align 16
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#else
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.align 4
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#endif
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gdtarg:
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.word gdtlen-1 /* limit */
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.long 0 /* addr, will be inserted */
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CR0_PE = 0x1
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/*
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* real_to_prot()
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* transfer from real mode to protected mode.
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*/
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ENTRY(real_to_prot)
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.code16
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# guarantee that interrupt is disabled when in prot mode
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cli
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pushl %eax
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push %cs /* ensure %ds is correct */
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pop %ds
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# load the gdtr
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lgdt gdtarg
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# set the PE bit of CR0
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movl %cr0, %eax
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orl $CR0_PE, %eax
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movl %eax, %cr0
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# make intrasegment jump to flush the processor pipeline and
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# reload CS register
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ljmp $bootcodeseg, $xprot
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xprot:
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.code32
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# we are in USE32 mode now
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# set up the protected mode segment registers : DS, SS, ES
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mov $bootdataseg, %ax
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mov %ax, %ds
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mov %ax, %ss
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mov %ax, %es
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popl %eax
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ret
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/*
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* prot_to_real()
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* transfer from protected mode to real mode
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*/
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ENTRY(prot_to_real)
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.code32
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pushl %eax
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# set up a dummy stack frame for the second seg change.
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# Adjust the intersegment jump instruction following
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# the clearing of protected mode bit.
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# This is self-modifying code, but we need a writable
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# code segment, and an intersegment return does not give us that.
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movl _C_LABEL(ourseg), %eax
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movw %ax, xreal-2
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/*
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* Load the segment registers while still in protected mode.
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* Otherwise the control bits don't get changed.
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* The correct values are loaded later.
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*/
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movw $bootrealdata, %ax
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movw %ax, %ds
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movw %ax, %es
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movw %ax, %ss
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# Change to use16 mode.
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ljmp $bootrealseg, $x16
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x16:
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.code16
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# clear the PE bit of CR0
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movl %cr0, %eax
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andl $~CR0_PE, %eax
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movl %eax, %cr0
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ljmp $0, $xreal /* segment overwritten above */
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xreal:
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.code16
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# we are in real mode now
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# set up the real mode segment registers : DS, SS, ES
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mov %cs, %ax
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mov %ax, %ds
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mov %ax, %ss
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mov %ax, %es
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sti
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popl %eax
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retl
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/*
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* pbzero(dst, cnt)
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* where dst is a physical address and cnt is the length
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*/
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ENTRY(pbzero)
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.code32
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pushl %ebp
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movl %esp, %ebp
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pushl %es
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pushl %edi
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cld
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# set %es to point at the flat segment
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movl $flatdataseg, %eax
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mov %ax, %es
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movl 8(%ebp), %edi # destination
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movl 12(%ebp), %ecx # count
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xorl %eax, %eax # value
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rep
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stosb
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popl %edi
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popl %es
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popl %ebp
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ret
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/*
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* vpbcopy(src, dst, cnt)
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* where src is a virtual address and dst is a physical address
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*/
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ENTRY(vpbcopy)
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.code32
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pushl %ebp
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movl %esp, %ebp
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pushl %es
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pushl %esi
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pushl %edi
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cld
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# set %es to point at the flat segment
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movl $flatdataseg, %eax
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mov %ax, %es
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movl 8(%ebp), %esi # source
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movl 12(%ebp), %edi # destination
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movl 16(%ebp), %ecx # count
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rep
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movsb
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popl %edi
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popl %esi
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popl %es
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popl %ebp
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ret
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/*
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* pvbcopy(src, dst, cnt)
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* where src is a physical address and dst is a virtual address
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*/
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ENTRY(pvbcopy)
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.code32
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pushl %ebp
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movl %esp, %ebp
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pushl %ds
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pushl %esi
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pushl %edi
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cld
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# set %ds to point at the flat segment
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movl $flatdataseg, %eax
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mov %ax, %ds
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movl 8(%ebp), %esi # source
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movl 12(%ebp), %edi # destination
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movl 16(%ebp), %ecx # count
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rep
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movsb
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popl %edi
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popl %esi
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popl %ds
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popl %ebp
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ret
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ENTRY(vtophys)
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movl _C_LABEL(ourseg), %eax
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shll $4, %eax
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addl 4(%esp), %eax
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ret
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/*
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* message: write the error message in %ds:%esi to the console
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*/
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message:
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.code16
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/*
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* BIOS call "INT 10H Function 0Eh" to write character to console
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* Call with %ah = 0x0e
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* %al = character
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* %bh = page
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* %bl = foreground color
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*/
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pushl %eax
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pushl %ebx
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pushl %edx
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nextb:
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cld
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lodsb # load a byte into %al
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testb %al, %al
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jz done
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movb $0x0e, %ah
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movw $0x0001, %bx
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int $0x10
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jmp nextb
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done:
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popl %edx
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popl %ebx
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popl %eax
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ret
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