895 lines
22 KiB
ArmAsm
895 lines
22 KiB
ArmAsm
/* sections */
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#include <minix/config.h>
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#include <minix/const.h>
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#include <machine/asm.h>
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#include <machine/interrupt.h>
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#include <i386/vm.h>
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#include "archconst.h"
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#include "kernel/const.h"
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#include "sconst.h"
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#include "multiboot.h"
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/*
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* This file contains a number of assembly code utility routines needed by the
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* kernel.
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*/
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/*
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* The routines only guarantee to preserve the registers the C compiler
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* expects to be preserved (ebx, esi, edi, ebp, esp, segment registers, and
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* direction bit in the flags).
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*/
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/*===========================================================================*/
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/* monitor */
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/*===========================================================================*/
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/* PUBLIC void monitor(); */
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/* exit Minix and return to the monitor */
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ENTRY(monitor)
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movl _C_LABEL(mon_sp), %esp /* restore monitor stack pointer */
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movw $SS_SELECTOR, %dx /* monitor data segment */
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mov %dx, %ds
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mov %dx, %es
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mov %dx, %fs
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mov %dx, %gs
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mov %dx, %ss
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pop %edi
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pop %esi
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pop %ebp
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lretw /* return to the monitor */
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/*===========================================================================*/
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/* int86 */
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/*===========================================================================*/
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/* PUBLIC void int86(); */
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/* let the monitor make an 8086 interrupt call */
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ENTRY(int86)
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cmpb $0, _C_LABEL(mon_return) /* is the monitor there? */
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jne 0f
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movb $0x01, %ah /* an int 13 error seems appropriate */
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movb %ah, _C_LABEL(reg86)+0 /* reg86.w.f = 1 (set carry flag) */
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movb %ah, _C_LABEL(reg86)+13 /* reg86.b.ah = 0x01 = "invalid command" */
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ret
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0:
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push %ebp /* save C registers */
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push %esi
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push %edi
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push %ebx
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pushf /* save flags */
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cli /* no interruptions */
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inb $INT2_CTLMASK
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movb %al, %ah
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inb $INT_CTLMASK
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push %eax /* save interrupt masks */
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movl _C_LABEL(irq_use), %eax /* map of in-use IRQ's */
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and $~(1<<CLOCK_IRQ), %eax /* keep the clock ticking */
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outb $INT_CTLMASK /* enable all unused IRQ's and vv. */
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movb %ah, %al
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outb $INT2_CTLMASK
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mov $SS_SELECTOR, %eax /* monitor data segment */
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mov %ax, %ss
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xchgl _C_LABEL(mon_sp), %esp /* switch stacks */
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push _C_LABEL(reg86)+36 /* parameters used in INT call */
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push _C_LABEL(reg86)+32
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push _C_LABEL(reg86)+28
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push _C_LABEL(reg86)+24
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push _C_LABEL(reg86)+20
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push _C_LABEL(reg86)+16
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push _C_LABEL(reg86)+12
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push _C_LABEL(reg86)+8
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push _C_LABEL(reg86)+4
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push _C_LABEL(reg86)+0
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mov %ax, %ds /* remaining data selectors */
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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push %cs
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push $return /* kernel return address and selector */
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ljmpw *20+2*4+10*4+2*4(%esp)
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return:
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pop _C_LABEL(reg86)+0
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pop _C_LABEL(reg86)+4
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pop _C_LABEL(reg86)+8
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pop _C_LABEL(reg86)+12
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pop _C_LABEL(reg86)+16
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pop _C_LABEL(reg86)+20
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pop _C_LABEL(reg86)+24
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pop _C_LABEL(reg86)+28
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pop _C_LABEL(reg86)+32
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pop _C_LABEL(reg86)+36
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lgdt _C_LABEL(gdt)+GDT_SELECTOR /* reload global descriptor table */
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ljmp $CS_SELECTOR, $csinit
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csinit:
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mov $DS_SELECTOR, %eax
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mov %ax, %ds
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mov %ax, %es
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mov %ax, %fs
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mov %ax, %gs
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mov %ax, %ss
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xchgl _C_LABEL(mon_sp), %esp /* unswitch stacks */
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lidt _C_LABEL(gdt)+IDT_SELECTOR /* reload interrupt descriptor table */
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#ifdef CONFIG_APIC
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cmpl $0x0, lapic_addr
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jne 3f
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mov $0, %ebx
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jmp 4f
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3:
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mov $FLAT_DS_SELECTOR, %ebx
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mov %bx, %fs
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movl lapic_addr, %eax
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add $0x20, %eax
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.byte 0x64; mov (%eax), %ebx
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and $0xFF000000, %ebx
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shr $24, %ebx
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movzb %bl, %ebx
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4:
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add $apicid2cpuid, %ebx
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movzb (%ebx), %eax
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shl $3, %eax
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mov %eax, %ebx
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add $TSS_SELECTOR, %eax
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addl _C_LABEL(gdt)+DESC_ACCESS, %eax
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and $~0x02, %eax
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ltr %bx /* set TSS register */
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mov $DS_SELECTOR, %eax
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mov %ax, %fs
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#endif /* CONFIG_APIC */
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pop %eax
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outb $INT_CTLMASK /* restore interrupt masks */
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movb %ah, %al
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outb $INT2_CTLMASK
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6:
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addl %ecx, _C_LABEL(lost_ticks) /* record lost clock ticks */
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popf /* restore flags */
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pop %ebx /* restore C registers */
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pop %edi
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pop %esi
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pop %ebp
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ret
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/*===========================================================================*/
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/* exit */
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/*===========================================================================*/
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/*
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* PUBLIC void exit();
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* Some library routines use exit, so provide a dummy version.
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* Actual calls to exit cannot occur in the kernel.
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* GNU CC likes to call ___main from main() for nonobvious reasons.
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*/
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#ifdef __ACK__
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ENTRY(exit)
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ENTRY(_exit)
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ENTRY(__exit)
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sti
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jmp _C_LABEL(__exit)
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#endif
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ENTRY(__main)
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ret
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/*===========================================================================*/
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/* phys_insw */
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/*===========================================================================*/
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/*
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* PUBLIC void phys_insw(Port_t port, phys_bytes buf, size_t count);
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* Input an array from an I/O port. Absolute address version of insw().
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*/
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/* transfer data from (disk controller) port to memory */
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ENTRY(phys_insw)
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push %ebp
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mov %esp, %ebp
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cld
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push %edi
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push %es
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mov $FLAT_DS_SELECTOR, %ecx
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mov %cx, %es
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mov 8(%ebp), %edx /* port to read from */
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mov 12(%ebp), %edi /* destination addr */
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mov 16(%ebp), %ecx /* byte count */
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shr $1, %ecx /* word count */
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rep insw /* input many words */
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pop %es
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pop %edi
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pop %ebp
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ret
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/*===========================================================================*/
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/* phys_insb */
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/*===========================================================================*/
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/*
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* PUBLIC void phys_insb(Port_t port, phys_bytes buf, size_t count);
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* Input an array from an I/O port. Absolute address version of insb().
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*/
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/* transfer data from (disk controller) port to memory byte by byte */
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ENTRY(phys_insb)
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push %ebp
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mov %esp, %ebp
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cld
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push %edi
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push %es
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mov $FLAT_DS_SELECTOR, %ecx
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mov %cx, %es
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mov 8(%ebp), %edx /* port to read from */
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mov 12(%ebp), %edi /* destination addr */
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mov 16(%ebp), %ecx /* byte count */
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rep insb /* input many bytes */
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pop %es
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pop %edi
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pop %ebp
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ret
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/*===========================================================================*/
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/* phys_outsw */
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/*===========================================================================*/
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/*
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* PUBLIC void phys_outsw(Port_t port, phys_bytes buf, size_t count);
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* Output an array to an I/O port. Absolute address version of outsw().
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*/
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/* transfer data from memory to (disk controller) port */
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ENTRY(phys_outsw)
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push %ebp
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mov %esp, %ebp
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cld
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push %esi
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push %ds
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mov $FLAT_DS_SELECTOR, %ecx
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mov %cx, %ds
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mov 8(%ebp), %edx /* port to write to */
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mov 12(%ebp), %esi /* source addr */
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mov 16(%ebp), %ecx /* byte count */
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shr $1, %ecx /* word count */
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rep outsw /* output many words */
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pop %ds
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pop %esi
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pop %ebp
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ret
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/*===========================================================================*/
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/* phys_outsb */
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/*===========================================================================*/
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/*
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* PUBLIC void phys_outsb(Port_t port, phys_bytes buf, size_t count);
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* Output an array to an I/O port. Absolute address version of outsb().
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*/
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/* transfer data from memory to (disk controller) port byte by byte */
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ENTRY(phys_outsb)
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push %ebp
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mov %esp, %ebp
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cld
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push %esi
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push %ds
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mov $FLAT_DS_SELECTOR, %ecx
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mov %cx, %ds
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mov 8(%ebp), %edx /* port to write to */
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mov 12(%ebp), %esi /* source addr */
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mov 16(%ebp), %ecx /* byte count */
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rep outsb /* output many bytes */
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pop %ds
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pop %esi
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pop %ebp
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ret
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/*===========================================================================*/
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/* phys_copy */
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/*===========================================================================*/
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/*
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* PUBLIC phys_bytes phys_copy(phys_bytes source, phys_bytes destination,
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* phys_bytes bytecount);
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* Copy a block of data from anywhere to anywhere in physical memory.
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*/
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PC_ARGS = 4+4+4+4 /* 4 + 4 + 4 */
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/* es edi esi eip src dst len */
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ENTRY(phys_copy)
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cld
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push %esi
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push %edi
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push %es
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mov $FLAT_DS_SELECTOR, %eax
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mov %ax, %es
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mov PC_ARGS(%esp), %esi
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mov PC_ARGS+4(%esp), %edi
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mov PC_ARGS+4+4(%esp), %eax
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cmp $10, %eax /* avoid align overhead for small counts */
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jb pc_small
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mov %esi, %ecx /* align source, hope target is too */
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neg %ecx
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and $3, %ecx /* count for alignment */
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sub %ecx, %eax
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rep movsb %es:(%esi), %es:(%edi)
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mov %eax, %ecx
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shr $2, %ecx /* count of dwords */
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rep movsl %es:(%esi), %es:(%edi)
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and $3, %eax
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pc_small:
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xchg %eax, %ecx /* remainder */
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rep movsb %es:(%esi), %es:(%edi)
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mov $0, %eax /* 0 means: no fault */
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LABEL(phys_copy_fault) /* kernel can send us here */
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pop %es
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pop %edi
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pop %esi
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ret
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LABEL(phys_copy_fault_in_kernel) /* kernel can send us here */
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pop %es
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pop %edi
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pop %esi
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mov %cr2, %eax
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ret
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/*===========================================================================*/
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/* copy_msg_from_user */
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/*===========================================================================*/
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/*
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* int copy_msg_from_user(struct proc * p, message * user_mbuf, message * dst);
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*
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* Copies a message of 36 bytes from user process space to a kernel buffer. This
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* function assumes that the process address space is installed (cr3 loaded) and
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* the local descriptor table of this process is loaded too.
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*
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* The %gs segment register is used to access the userspace memory. We load the
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* process' data segment in this register.
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*
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* This function from the callers point of view either succeeds or returns an
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* error which gives the caller a chance to respond accordingly. In fact it
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* either succeeds or if it generates a pagefault, general protection or other
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* exception, the trap handler has to redirect the execution to
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* __user_copy_msg_pointer_failure where the error is reported to the caller
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* without resolving the pagefault. It is not kernel's problem to deal with
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* wrong pointers from userspace and the caller should return an error to
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* userspace as if wrong values or request were passed to the kernel
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*/
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ENTRY(copy_msg_from_user)
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push %gs
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mov 8(%esp), %eax
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movw DSREG(%eax), %gs
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/* load the source pointer */
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mov 12(%esp), %ecx
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/* load the destination pointer */
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mov 16(%esp), %edx
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mov %gs:0*4(%ecx), %eax
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mov %eax, 0*4(%edx)
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mov %gs:1*4(%ecx), %eax
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mov %eax, 1*4(%edx)
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mov %gs:2*4(%ecx), %eax
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mov %eax, 2*4(%edx)
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mov %gs:3*4(%ecx), %eax
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mov %eax, 3*4(%edx)
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mov %gs:4*4(%ecx), %eax
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mov %eax, 4*4(%edx)
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mov %gs:5*4(%ecx), %eax
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mov %eax, 5*4(%edx)
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mov %gs:6*4(%ecx), %eax
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mov %eax, 6*4(%edx)
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mov %gs:7*4(%ecx), %eax
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mov %eax, 7*4(%edx)
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mov %gs:8*4(%ecx), %eax
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mov %eax, 8*4(%edx)
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LABEL(__copy_msg_from_user_end)
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pop %gs
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movl $0, %eax
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ret
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/*===========================================================================*/
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/* copy_msg_to_user */
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/*===========================================================================*/
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/*
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* void copy_msg_to_user(struct proc * p, message * src, message * user_mbuf);
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*
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* Copies a message of 36 bytes to user process space from a kernel buffer. This
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* function assumes that the process address space is installed (cr3 loaded) and
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* the local descriptor table of this process is loaded too.
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*
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* All the other copy_msg_from_user() comments apply here as well!
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*/
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ENTRY(copy_msg_to_user)
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push %gs
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mov 8(%esp), %eax
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movw DSREG(%eax), %gs
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/* load the source pointer */
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mov 12(%esp), %ecx
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/* load the destination pointer */
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mov 16(%esp), %edx
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mov 0*4(%ecx), %eax
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mov %eax, %gs:0*4(%edx)
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mov 1*4(%ecx), %eax
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mov %eax, %gs:1*4(%edx)
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mov 2*4(%ecx), %eax
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mov %eax, %gs:2*4(%edx)
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mov 3*4(%ecx), %eax
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mov %eax, %gs:3*4(%edx)
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mov 4*4(%ecx), %eax
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mov %eax, %gs:4*4(%edx)
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mov 5*4(%ecx), %eax
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mov %eax, %gs:5*4(%edx)
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mov 6*4(%ecx), %eax
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mov %eax, %gs:6*4(%edx)
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mov 7*4(%ecx), %eax
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mov %eax, %gs:7*4(%edx)
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mov 8*4(%ecx), %eax
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mov %eax, %gs:8*4(%edx)
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LABEL(__copy_msg_to_user_end)
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pop %gs
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movl $0, %eax
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ret
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/*
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* if a function from a selected set of copies from or to userspace fails, it is
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* because of a wrong pointer supplied by the userspace. We have to clean up and
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* and return -1 to indicated that something wrong has happend. The place it was
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* called from has to handle this situation. The exception handler redirect us
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* here to continue, clean up and report the error
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*/
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ENTRY(__user_copy_msg_pointer_failure)
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pop %gs
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movl $-1, %eax
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ret
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/*===========================================================================*/
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/* phys_memset */
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/*===========================================================================*/
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/*
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* PUBLIC void phys_memset(phys_bytes source, unsigned long pattern,
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* phys_bytes bytecount);
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* Fill a block of physical memory with pattern.
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*/
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ENTRY(phys_memset)
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push %ebp
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mov %esp, %ebp
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push %esi
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push %ebx
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push %ds
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mov 8(%ebp), %esi
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mov 16(%ebp), %eax
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mov $FLAT_DS_SELECTOR, %ebx
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mov %bx, %ds
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mov 12(%ebp), %ebx
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shr $2, %eax
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fill_start:
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mov %ebx, (%esi)
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add $4, %esi
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dec %eax
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jne fill_start
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/* Any remaining bytes? */
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mov 16(%ebp), %eax
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and $3, %eax
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remain_fill:
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cmp $0, %eax
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je fill_done
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movb 12(%ebp), %bl
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movb %bl, (%esi)
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add $1, %esi
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inc %ebp
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dec %eax
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jmp remain_fill
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fill_done:
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pop %ds
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pop %ebx
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pop %esi
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pop %ebp
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ret
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/*===========================================================================*/
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/* mem_rdw */
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/*===========================================================================*/
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/*
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* PUBLIC u16_t mem_rdw(U16_t segment, u16_t *offset);
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* Load and return word at far pointer segment:offset.
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*/
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ENTRY(mem_rdw)
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mov %ds, %cx
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mov 4(%esp), %ds
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mov 4+4(%esp), %eax /* offset */
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movzwl (%eax), %eax /* word to return */
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mov %cx, %ds
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ret
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/*===========================================================================*/
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/* reset */
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/*===========================================================================*/
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/*
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* PUBLIC void reset();
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* Reset the system by loading IDT with offset 0 and interrupting.
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*/
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ENTRY(reset)
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lidt idt_zero
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int $3 /* anything goes, the 386 will not like it */
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.data
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idt_zero:
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.long 0, 0
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.text
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|
|
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/*===========================================================================*/
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/* halt_cpu */
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|
/*===========================================================================*/
|
|
/*
|
|
* PUBLIC void halt_cpu(void);
|
|
* reanables interrupts and puts the cpu in the halts state. Once an interrupt
|
|
* is handled the execution resumes by disabling interrupts and continues
|
|
*/
|
|
ENTRY(halt_cpu)
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|
sti
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|
hlt /* interrupts enabled only after this instruction is executed! */
|
|
/*
|
|
* interrupt handlers make sure that the interrupts are disabled when we
|
|
* get here so we take only _one_ interrupt after halting the CPU
|
|
*/
|
|
ret
|
|
|
|
/*===========================================================================*/
|
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/* read_flags */
|
|
/*===========================================================================*/
|
|
/*
|
|
* PUBLIC unsigned long read_cpu_flags(void);
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|
* Read CPU status flags from C.
|
|
*/
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|
ENTRY(read_cpu_flags)
|
|
pushf
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|
mov (%esp), %eax
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|
add $4, %esp
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|
ret
|
|
|
|
ENTRY(read_ds)
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|
mov $0, %eax
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|
mov %ds, %ax
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|
ret
|
|
|
|
ENTRY(read_cs)
|
|
mov $0, %eax
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|
mov %cs, %ax
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|
ret
|
|
|
|
ENTRY(read_ss)
|
|
mov $0, %eax
|
|
mov %ss, %ax
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* fpu_routines */
|
|
/*===========================================================================*/
|
|
|
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/* non-waiting FPU initialization */
|
|
ENTRY(fninit)
|
|
fninit
|
|
ret
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|
|
|
ENTRY(clts)
|
|
clts
|
|
ret
|
|
|
|
/* store status word (non-waiting) */
|
|
ENTRY(fnstsw)
|
|
xor %eax, %eax
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|
|
|
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
|
|
fnstsw %ax
|
|
ret
|
|
|
|
/* store control word (non-waiting) */
|
|
ENTRY(fnstcw)
|
|
push %eax
|
|
mov 8(%esp), %eax
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|
|
|
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
|
|
fnstcw (%eax)
|
|
pop %eax
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* fxsave */
|
|
/*===========================================================================*/
|
|
ENTRY(fxsave)
|
|
mov 4(%esp), %eax
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|
fxsave (%eax) /* Do not change the operand! (gas2ack) */
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* fnsave */
|
|
/*===========================================================================*/
|
|
ENTRY(fnsave)
|
|
mov 4(%esp), %eax
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|
fnsave (%eax) /* Do not change the operand! (gas2ack) */
|
|
fwait /* required for compatibility with processors prior pentium */
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* fxrstor */
|
|
/*===========================================================================*/
|
|
ENTRY(fxrstor)
|
|
mov 4(%esp), %eax
|
|
fxrstor (%eax) /* Do not change the operand! (gas2ack) */
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* frstor */
|
|
/*===========================================================================*/
|
|
ENTRY(frstor)
|
|
mov 4(%esp), %eax
|
|
frstor (%eax) /* Do not change the operand! (gas2ack) */
|
|
ret
|
|
|
|
|
|
/*===========================================================================*/
|
|
/* read_cr0 */
|
|
/*===========================================================================*/
|
|
/* PUBLIC unsigned long read_cr0(void); */
|
|
ENTRY(read_cr0)
|
|
push %ebp
|
|
mov %esp, %ebp
|
|
mov %cr0, %eax
|
|
pop %ebp
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* write_cr0 */
|
|
/*===========================================================================*/
|
|
/* PUBLIC void write_cr0(unsigned long value); */
|
|
ENTRY(write_cr0)
|
|
push %ebp
|
|
mov %esp, %ebp
|
|
mov 8(%ebp), %eax
|
|
mov %eax, %cr0
|
|
jmp 0f /* A jump is required for some flags */
|
|
0:
|
|
pop %ebp
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* read_cr2 */
|
|
/*===========================================================================*/
|
|
/* PUBLIC reg_t read_cr2(void); */
|
|
ENTRY(read_cr2)
|
|
mov %cr2, %eax
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* read_cr3 */
|
|
/*===========================================================================*/
|
|
/* PUBLIC unsigned long read_cr3(void); */
|
|
ENTRY(read_cr3)
|
|
push %ebp
|
|
mov %esp, %ebp
|
|
|
|
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
|
|
mov %cr3, %eax
|
|
pop %ebp
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* read_cr4 */
|
|
/*===========================================================================*/
|
|
/* PUBLIC unsigned long read_cr4(void); */
|
|
ENTRY(read_cr4)
|
|
push %ebp
|
|
mov %esp, %ebp
|
|
|
|
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
|
|
mov %cr4, %eax
|
|
pop %ebp
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* write_cr4 */
|
|
/*===========================================================================*/
|
|
/* PUBLIC void write_cr4(unsigned long value); */
|
|
ENTRY(write_cr4)
|
|
push %ebp
|
|
mov %esp, %ebp
|
|
mov 8(%ebp), %eax
|
|
|
|
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
|
|
mov %eax, %cr4
|
|
jmp 0f
|
|
0:
|
|
pop %ebp
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* write_cr3 */
|
|
/*===========================================================================*/
|
|
/* PUBLIC void write_cr3(unsigned long value); */
|
|
ENTRY(write_cr3)
|
|
push %ebp
|
|
mov %esp, %ebp
|
|
mov 8(%ebp), %eax
|
|
|
|
/* DO NOT CHANGE THE OPERAND!!! gas2ack does not handle it yet */
|
|
mov %eax, %cr3
|
|
|
|
pop %ebp
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* getcr3val */
|
|
/*===========================================================================*/
|
|
/* PUBLIC unsigned long getcr3val(void); */
|
|
ENTRY(getcr3val)
|
|
mov %cr3, %eax
|
|
ret
|
|
|
|
/*
|
|
* Read the Model Specific Register (MSR) of IA32 architecture
|
|
*
|
|
* void ia32_msr_read(u32_t reg, u32_t * hi, u32_t * lo)
|
|
*/
|
|
ENTRY(ia32_msr_read)
|
|
push %ebp
|
|
mov %esp, %ebp
|
|
|
|
mov 8(%ebp), %ecx
|
|
rdmsr
|
|
mov 12(%ebp), %ecx
|
|
mov %edx, (%ecx)
|
|
mov 16(%ebp), %ecx
|
|
mov %eax, (%ecx)
|
|
|
|
pop %ebp
|
|
ret
|
|
|
|
/*
|
|
* Write the Model Specific Register (MSR) of IA32 architecture
|
|
*
|
|
* void ia32_msr_write(u32_t reg, u32_t hi, u32_t lo)
|
|
*/
|
|
ENTRY(ia32_msr_write)
|
|
push %ebp
|
|
mov %esp, %ebp
|
|
|
|
mov 12(%ebp), %edx
|
|
mov 16(%ebp), %eax
|
|
mov 8(%ebp), %ecx
|
|
wrmsr
|
|
|
|
pop %ebp
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* idt_reload */
|
|
/*===========================================================================*/
|
|
/* PUBLIC void idt_reload (void); */
|
|
/* reload idt when returning to monitor. */
|
|
ENTRY(idt_reload)
|
|
lidt _C_LABEL(gdt)+IDT_SELECTOR /* reload interrupt descriptor table */
|
|
ret
|
|
|
|
/*
|
|
* void reload_segment_regs(void)
|
|
*/
|
|
|
|
#define RELOAD_SEG_REG(reg) \
|
|
mov reg, %ax ;\
|
|
mov %ax, reg ;
|
|
|
|
ENTRY(reload_ds)
|
|
RELOAD_SEG_REG(%ds)
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* switch_address_space */
|
|
/*===========================================================================*/
|
|
/* PUBLIC void switch_address_space(struct proc *p)
|
|
*
|
|
* sets the %cr3 register to the supplied value if it is not already set to the
|
|
* same value in which case it would only result in an extra TLB flush which is
|
|
* not desirable
|
|
*/
|
|
ENTRY(switch_address_space)
|
|
/* read the process pointer */
|
|
mov 4(%esp), %edx
|
|
/* enable process' segment descriptors */
|
|
lldt P_LDT_SEL(%edx)
|
|
/* get the new cr3 value */
|
|
movl P_CR3(%edx), %eax
|
|
/* test if the new cr3 != NULL */
|
|
cmpl $0, %eax
|
|
je 0f
|
|
|
|
/*
|
|
* test if the cr3 is loaded with the current value to avoid unnecessary
|
|
* TLB flushes
|
|
*/
|
|
mov %cr3, %ecx
|
|
cmp %ecx, %eax
|
|
je 0f
|
|
mov %eax, %cr3
|
|
mov %edx, _C_LABEL(ptproc)
|
|
0:
|
|
ret
|
|
|
|
/*===========================================================================*/
|
|
/* poweroff */
|
|
/*===========================================================================*/
|
|
/* PUBLIC void poweroff(); */
|
|
/* Jump to 16-bit poweroff code */
|
|
ENTRY(poweroff_jmp)
|
|
cli
|
|
/* Make real mode descriptor */
|
|
mov $(_C_LABEL(gdt) + SS_SELECTOR), %edi
|
|
mov $0x100, %eax
|
|
movw %ax, 2(%edi)
|
|
shr $16, %eax
|
|
movb %al, 4(%edi)
|
|
and $0xff00, %ax
|
|
andw $0xff, 6(%edi)
|
|
or %ax, 6(%edi)
|
|
mov $0xffff, %eax
|
|
movw %ax, (%edi)
|
|
shr $16, %eax
|
|
and $0xf, %ax
|
|
andb $0xf0, 6(%edi)
|
|
or %ax, 6(%edi)
|
|
|
|
/* Flush TLB */
|
|
xor %eax, %eax
|
|
mov %eax, %cr3
|
|
|
|
xor %esp, %esp /* clear esp for real mode*/
|
|
|
|
/* Reset IDTR */
|
|
lidt idt_ptr
|
|
|
|
mov $SS_SELECTOR, %ax
|
|
mov %ax, %ds
|
|
mov %ax, %es
|
|
mov %ax, %fs
|
|
mov %ax, %gs
|
|
mov %ax, %ss
|
|
|
|
/* Save real mode cr0 in eax */
|
|
mov %cr0, %eax
|
|
andl $~I386_CR0_PE, %eax
|
|
|
|
/* Jump to 16-bit code that is copied to below 1MB */
|
|
ljmp $MON_CS_SELECTOR, $0
|
|
|
|
.data
|
|
idt_ptr:
|
|
.short 0x3ff
|
|
.long 0x0
|