From ca987d4641cdcd7f27e153db17c5bf064934faf5 Mon Sep 17 00:00:00 2001 From: Warner Losh Date: Tue, 14 Nov 2017 23:02:19 +0000 Subject: Move sys/boot to stand. Fix all references to new location Sponsored by: Netflix --- stand/i386/libi386/relocater_tramp.S | 358 +++++++++++++++++++++++++++++++++++ 1 file changed, 358 insertions(+) create mode 100644 stand/i386/libi386/relocater_tramp.S (limited to 'stand/i386/libi386/relocater_tramp.S') diff --git a/stand/i386/libi386/relocater_tramp.S b/stand/i386/libi386/relocater_tramp.S new file mode 100644 index 000000000000..6db4a7509b2c --- /dev/null +++ b/stand/i386/libi386/relocater_tramp.S @@ -0,0 +1,358 @@ +/*- + * Copyright 2015 Toomas Soome + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD$ + */ + + +/* + * relocate is needed to support loading code which has to be located + * below 1MB, as both BTX and loader are using low memory area. + * + * relocate and start loaded code. Since loaded code may need to be + * placed to already occupied memory area, this code is moved to safe + * memory area and then btx __exec will be called with physical pointer + * to this area. __exec will set pointer to %eax and use call *%eax, + * so on entry, we have new "base" address in %eax. + * + * Relocate will first set up and load new safe GDT to shut down BTX, + * then loaded code will be relocated to final memory location, + * then machine will be switched from 32bit protected mode to 16bit + * protected mode following by switch to real mode with A20 enabled or + * disabled. Finally the loaded code will be started and it will take + * over the whole system. + * + * For now, the known "safe" memory area for relocate is 0x600, + * the actual "free" memory is supposed to start from 0x500, leaving + * first 0x100 bytes in reserve. As relocate code+data is very small, + * it will leave enough space to set up boot blocks to 0:7c00 or load + * linux kernel below 1MB space. + */ +/* + * segment selectors + */ + .set SEL_SCODE,0x8 + .set SEL_SDATA,0x10 + .set SEL_RCODE,0x18 + .set SEL_RDATA,0x20 + + .p2align 4 + .globl relocater +relocater: + cli + /* + * set up GDT from new location + */ + movl %eax, %esi /* our base address */ + add $(relocater.1-relocater), %eax + jmp *%eax +relocater.1: + /* set up jump */ + lea (relocater.2-relocater)(%esi), %eax + movl %eax, (jump_vector-relocater) (%esi) + + /* set up gdt */ + lea (gdt-relocater) (%esi), %eax + movl %eax, (gdtaddr-relocater) (%esi) + + /* load gdt */ + lgdt (gdtdesc - relocater) (%esi) + lidt (idt-relocater) (%esi) + + /* update cs */ + ljmp *(jump_vector-relocater) (%esi) + + .code32 +relocater.2: + xorl %eax, %eax + movb $SEL_SDATA, %al + movw %ax, %ss + movw %ax, %ds + movw %ax, %es + movw %ax, %fs + movw %ax, %gs + movl %cr0, %eax /* disable paging */ + andl $~0x80000000,%eax + movl %eax, %cr0 + xorl %ecx, %ecx /* flush TLB */ + movl %ecx, %cr3 + cld +/* + * relocate data loop. load source, dest and size from + * relocater_data[i], 0 value will stop the loop. + * registers used for move: %esi, %edi, %ecx. + * %ebx to keep base + * %edx for relocater_data offset + */ + movl %esi, %ebx /* base address */ + xorl %edx, %edx +loop.1: + movl (relocater_data-relocater)(%ebx, %edx, 4), %eax + testl %eax, %eax + jz loop.2 + movl (relocater_data-relocater)(%ebx, %edx, 4), %esi + inc %edx + movl (relocater_data-relocater)(%ebx, %edx, 4), %edi + inc %edx + movl (relocater_data-relocater)(%ebx, %edx, 4), %ecx + inc %edx + rep + movsb + jmp loop.1 +loop.2: + movl %ebx, %esi /* restore esi */ + /* + * data is relocated, switch to 16bit mode + */ + lea (relocater.3-relocater)(%esi), %eax + movl %eax, (jump_vector-relocater) (%esi) + movl $SEL_RCODE, %eax + movl %eax, (jump_vector-relocater+4) (%esi) + + ljmp *(jump_vector-relocater) (%esi) +relocater.3: + .code16 + + movw $SEL_RDATA, %ax + movw %ax, %ds + movw %ax, %es + movw %ax, %fs + movw %ax, %gs + movw %ax, %ss + lidt (idt-relocater) (%esi) + lea (relocater.4-relocater)(%esi), %eax + movl %eax, (jump_vector-relocater) (%esi) + xorl %eax, %eax + movl %eax, (jump_vector-relocater+4) (%esi) + /* clear PE */ + movl %cr0, %eax + dec %al + movl %eax, %cr0 + ljmp *(jump_vector-relocater) (%esi) +relocater.4: + xorw %ax, %ax + movw %ax, %ds + movw %ax, %es + movw %ax, %fs + movw %ax, %gs + movw %ax, %ss + /* + * set real mode irq offsets + */ + movw $0x7008,%bx + in $0x21,%al # Save master + push %ax # IMR + in $0xa1,%al # Save slave + push %ax # IMR + movb $0x11,%al # ICW1 to + outb %al,$0x20 # master, + outb %al,$0xa0 # slave + movb %bl,%al # ICW2 to + outb %al,$0x21 # master + movb %bh,%al # ICW2 to + outb %al,$0xa1 # slave + movb $0x4,%al # ICW3 to + outb %al,$0x21 # master + movb $0x2,%al # ICW3 to + outb %al,$0xa1 # slave + movb $0x1,%al # ICW4 to + outb %al,$0x21 # master, + outb %al,$0xa1 # slave + pop %ax # Restore slave + outb %al,$0xa1 # IMR + pop %ax # Restore master + outb %al,$0x21 # IMR + # done + /* + * Should A20 be left enabled? + */ + /* movw imm16, %ax */ + .byte 0xb8 + .globl relocator_a20_enabled +relocator_a20_enabled: + .word 0 + test %ax, %ax + jnz a20_done + + movw $0xa00, %ax + movw %ax, %sp + movw %ax, %bp + + /* Disable A20 */ + movw $0x2400, %ax + int $0x15 +# jnc a20_done + + call a20_check_state + testb %al, %al + jz a20_done + + inb $0x92 + andb $(~0x03), %al + outb $0x92 + jmp a20_done + +a20_check_state: + movw $100, %cx +1: + xorw %ax, %ax + movw %ax, %ds + decw %ax + movw %ax, %es + xorw %ax, %ax + movw $0x8000, %ax + movw %ax, %si + addw $0x10, %ax + movw %ax, %di + movb %ds:(%si), %dl + movb %es:(%di), %al + movb %al, %dh + decb %dh + movb %dh, %ds:(%si) + outb %al, $0x80 + outb %al, $0x80 + movb %es:(%di), %dh + subb %dh, %al + xorb $1, %al + movb %dl, %ds:(%si) + testb %al, %al + jz a20_done + loop 1b + ret +a20_done: + /* + * set up registers + */ + /* movw imm16, %ax. */ + .byte 0xb8 + .globl relocator_ds +relocator_ds: .word 0 + movw %ax, %ds + + /* movw imm16, %ax. */ + .byte 0xb8 + .globl relocator_es +relocator_es: .word 0 + movw %ax, %es + + /* movw imm16, %ax. */ + .byte 0xb8 + .globl relocator_fs +relocator_fs: .word 0 + movw %ax, %fs + + /* movw imm16, %ax. */ + .byte 0xb8 + .globl relocator_gs +relocator_gs: .word 0 + movw %ax, %gs + + /* movw imm16, %ax. */ + .byte 0xb8 + .globl relocator_ss +relocator_ss: .word 0 + movw %ax, %ss + + /* movw imm16, %ax. */ + .byte 0xb8 + .globl relocator_sp +relocator_sp: .word 0 + movzwl %ax, %esp + + /* movw imm32, %eax. */ + .byte 0x66, 0xb8 + .globl relocator_esi +relocator_esi: .long 0 + movl %eax, %esi + + /* movw imm32, %edx. */ + .byte 0x66, 0xba + .globl relocator_edx +relocator_edx: .long 0 + + /* movw imm32, %ebx. */ + .byte 0x66, 0xbb + .globl relocator_ebx +relocator_ebx: .long 0 + + /* movw imm32, %eax. */ + .byte 0x66, 0xb8 + .globl relocator_eax +relocator_eax: .long 0 + + /* movw imm32, %ebp. */ + .byte 0x66, 0xbd + .globl relocator_ebp +relocator_ebp: .long 0 + + sti + .byte 0xea /* ljmp */ + .globl relocator_ip +relocator_ip: + .word 0 + .globl relocator_cs +relocator_cs: + .word 0 + +/* GDT to reset BTX */ + .code32 + .p2align 4 +jump_vector: .long 0 + .long SEL_SCODE + +gdt: .word 0x0, 0x0 /* null entry */ + .byte 0x0, 0x0, 0x0, 0x0 + .word 0xffff, 0x0 /* SEL_SCODE */ + .byte 0x0, 0x9a, 0xcf, 0x0 + .word 0xffff, 0x0 /* SEL_SDATA */ + .byte 0x0, 0x92, 0xcf, 0x0 + .word 0xffff, 0x0 /* SEL_RCODE */ + .byte 0x0, 0x9a, 0x0f, 0x0 + .word 0xffff, 0x0 /* SEL_RDATA */ + .byte 0x0, 0x92, 0x0f, 0x0 +gdt.1: + +gdtdesc: .word gdt.1 - gdt - 1 /* limit */ +gdtaddr: .long 0 /* base */ + +idt: .word 0x3ff + .long 0 + + .globl relocater_data +relocater_data: + .long 0 /* src */ + .long 0 /* dest */ + .long 0 /* size */ + .long 0 /* src */ + .long 0 /* dest */ + .long 0 /* size */ + .long 0 /* src */ + .long 0 /* dest */ + .long 0 /* size */ + .long 0 + + .globl relocater_size +relocater_size: + .long relocater_size-relocater -- cgit v1.2.3