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yaml
---
r: 309143
b: refs/heads/master
c: 5a8c9ae
h: refs/heads/master
i:
  309141: ee9bcbf
  309139: 7c8e18a
  309135: 217b681
v: v3
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Jarkko Sakkinen authored and H. Peter Anvin committed May 8, 2012
1 parent f0bbbcf commit d769503
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Showing 7 changed files with 53 additions and 66 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 084ee1c641a068bfd1194d545f7dc9ab2043eb35
refs/heads/master: 5a8c9aebe04a78b069828d364798d5f24c5a42bd
4 changes: 4 additions & 0 deletions trunk/arch/x86/include/asm/realmode.h
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,10 @@ struct real_mode_header {
u32 text_start;
u32 ro_end;
u32 end;
/* reboot */
#ifdef CONFIG_X86_32
u32 machine_real_restart_asm;
#endif
} __attribute__((__packed__));

extern struct real_mode_header real_mode_header;
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1 change: 0 additions & 1 deletion trunk/arch/x86/kernel/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,6 @@ obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += cpu/
obj-y += acpi/
obj-y += reboot.o
obj-$(CONFIG_X86_32) += reboot_32.o
obj-$(CONFIG_MCA) += mca_32.o
obj-$(CONFIG_X86_MSR) += msr.o
obj-$(CONFIG_X86_CPUID) += cpuid.o
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25 changes: 3 additions & 22 deletions trunk/arch/x86/kernel/reboot.c
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
#ifdef CONFIG_X86_32
# include <linux/ctype.h>
# include <linux/mc146818rtc.h>
# include <asm/realmode.h>
#else
# include <asm/x86_init.h>
#endif
Expand Down Expand Up @@ -332,15 +333,10 @@ static int __init reboot_init(void)
}
core_initcall(reboot_init);

extern const unsigned char machine_real_restart_asm[];
extern const u64 machine_real_restart_gdt[3];

void machine_real_restart(unsigned int type)
{
void *restart_va;
unsigned long restart_pa;
void (*restart_lowmem)(unsigned int);
u64 *lowmem_gdt;
void (*restart_lowmem)(unsigned int) = (void (*)(unsigned int))
real_mode_header.machine_real_restart_asm;

local_irq_disable();

Expand Down Expand Up @@ -369,21 +365,6 @@ void machine_real_restart(unsigned int type)
too. */
*((unsigned short *)0x472) = reboot_mode;

/* Patch the GDT in the low memory trampoline */
lowmem_gdt = TRAMPOLINE_SYM(machine_real_restart_gdt);

restart_va = TRAMPOLINE_SYM(machine_real_restart_asm);
restart_pa = virt_to_phys(restart_va);
restart_lowmem = (void (*)(unsigned int))restart_pa;

/* GDT[0]: GDT self-pointer */
lowmem_gdt[0] =
(u64)(sizeof(machine_real_restart_gdt) - 1) +
((u64)virt_to_phys(lowmem_gdt) << 16);
/* GDT[1]: 64K real mode code segment */
lowmem_gdt[1] =
GDT_ENTRY(0x009b, restart_pa, 0xffff);

/* Jump to the identity-mapped low memory code */
restart_lowmem(type);
}
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1 change: 1 addition & 0 deletions trunk/arch/x86/realmode/rm/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@ subdir- := wakeup
always := realmode.bin

realmode-y += header.o
realmode-$(CONFIG_X86_32) += reboot_32.o

targets += $(realmode-y)

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3 changes: 3 additions & 0 deletions trunk/arch/x86/realmode/rm/header.S
Original file line number Diff line number Diff line change
Expand Up @@ -13,4 +13,7 @@ ENTRY(real_mode_header)
.long pa_text_start
.long pa_ro_end
.long pa_end
#ifdef CONFIG_X86_32
.long pa_machine_real_restart_asm
#endif
END(real_mode_header)
Original file line number Diff line number Diff line change
Expand Up @@ -13,34 +13,21 @@
*
* This code is called with the restart type (0 = BIOS, 1 = APM) in %eax.
*/
.section ".x86_trampoline","a"
.balign 16
.section ".text32", "ax"
.code32
ENTRY(machine_real_restart_asm)
r_base = .
/* Get our own relocated address */
call 1f
1: popl %ebx
subl $(1b - r_base), %ebx

/* Compute the equivalent real-mode segment */
movl %ebx, %ecx
shrl $4, %ecx

/* Patch post-real-mode segment jump */
movw (dispatch_table - r_base)(%ebx,%eax,2),%ax
movw %ax, (101f - r_base)(%ebx)
movw %cx, (102f - r_base)(%ebx)
.globl machine_real_restart_asm

.balign 16
machine_real_restart_asm:
/* Set up the IDT for real mode. */
lidtl (machine_real_restart_idt - r_base)(%ebx)
lidtl pa_machine_real_restart_idt

/*
* Set up a GDT from which we can load segment descriptors for real
* mode. The GDT is not used in real mode; it is just needed here to
* prepare the descriptors.
*/
lgdtl (machine_real_restart_gdt - r_base)(%ebx)
lgdtl pa_machine_real_restart_gdt

/*
* Load the data segment registers with 16-bit compatible values
Expand All @@ -51,7 +38,7 @@ r_base = .
movl %ecx, %fs
movl %ecx, %gs
movl %ecx, %ss
ljmpl $8, $1f - r_base
ljmpw $8, $1f

/*
* This is 16-bit protected mode code to disable paging and the cache,
Expand All @@ -76,27 +63,32 @@ r_base = .
*
* Most of this work is probably excessive, but it is what is tested.
*/
.text
.code16

.balign 16
machine_real_restart_asm16:
1:
xorl %ecx, %ecx
movl %cr0, %eax
andl $0x00000011, %eax
orl $0x60000000, %eax
movl %eax, %cr0
movl %cr0, %edx
andl $0x00000011, %edx
orl $0x60000000, %edx
movl %edx, %cr0
movl %ecx, %cr3
movl %cr0, %edx
andl $0x60000000, %edx /* If no cache bits -> no wbinvd */
jz 2f
wbinvd
2:
andb $0x10, %al
movl %eax, %cr0
andb $0x10, %dl
movl %edx, %cr0
.byte 0xea /* ljmpw */
101: .word 0 /* Offset */
102: .word 0 /* Segment */
.word 3f /* Offset */
.word real_mode_seg /* Segment */

bios:
ljmpw $0xf000, $0xfff0
3:
testb $0, %al
jz bios

apm:
movw $0x1000, %ax
Expand All @@ -106,30 +98,37 @@ apm:
movw $0x0001, %bx
movw $0x0003, %cx
int $0x15
/* This should never return... */

END(machine_real_restart_asm)
bios:
ljmpw $0xf000, $0xfff0

.balign 16
/* These must match <asm/reboot.h */
dispatch_table:
.word bios - r_base
.word apm - r_base
END(dispatch_table)
.section ".rodata", "a"
.globl machine_real_restart_idt, machine_real_restart_gdt

.balign 16
machine_real_restart_idt:
.word 0xffff /* Length - real mode default value */
.long 0 /* Base - real mode default value */
END(machine_real_restart_idt)

.balign 16
ENTRY(machine_real_restart_gdt)
.quad 0 /* Self-pointer, filled in by PM code */
.quad 0 /* 16-bit code segment, filled in by PM code */
machine_real_restart_gdt:
/* Self-pointer */
.word 0xffff /* Length - real mode default value */
.long pa_machine_real_restart_gdt
.word 0

/*
* 16-bit code segment pointing to real_mode_seg
* Selector value 8
*/
.word 0xffff /* Limit */
.long 0x9b000000 + pa_real_mode_base
.word 0

/*
* 16-bit data segment with the selector value 16 = 0x10 and
* base value 0x100; since this is consistent with real mode
* semantics we don't have to reload the segments once CR0.PE = 0.
*/
.quad GDT_ENTRY(0x0093, 0x100, 0xffff)
END(machine_real_restart_gdt)

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