Commit 5033cba0 authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds

[PATCH] kexec: x86 kexec core

This is the i386 implementation of kexec.
Signed-off-by: default avatarEric Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent dd2a1305
......@@ -953,6 +953,23 @@ config PHYSICAL_START
Don't change this unless you know what you are doing.
config KEXEC
bool "kexec system call (EXPERIMENTAL)"
depends on EXPERIMENTAL
help
kexec is a system call that implements the ability to shutdown your
current kernel, and to start another kernel. It is like a reboot
but it is indepedent of the system firmware. And like a reboot
you can start any kernel with it, not just Linux.
The name comes from the similiarity to the exec system call.
It is an ongoing process to be certain the hardware in a machine
is properly shutdown, so do not be surprised if this code does not
initially work for you. It may help to enable device hotplugging
support. As of this writing the exact hardware interface is
strongly in flux, so no good recommendation can be made.
endmenu
......
......@@ -24,6 +24,7 @@ obj-$(CONFIG_X86_MPPARSE) += mpparse.o
obj-$(CONFIG_X86_LOCAL_APIC) += apic.o nmi.o
obj-$(CONFIG_X86_IO_APIC) += io_apic.o
obj-$(CONFIG_X86_REBOOTFIXUPS) += reboot_fixups.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o crash.o
obj-$(CONFIG_X86_NUMAQ) += numaq.o
obj-$(CONFIG_X86_SUMMIT_NUMA) += summit.o
obj-$(CONFIG_KPROBES) += kprobes.o
......
/*
* Architecture specific (i386) functions for kexec based crash dumps.
*
* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
*
* Copyright (C) IBM Corporation, 2004. All rights reserved.
*
*/
#include <linux/init.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/irq.h>
#include <linux/reboot.h>
#include <linux/kexec.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <asm/processor.h>
#include <asm/hardirq.h>
#include <asm/nmi.h>
#include <asm/hw_irq.h>
#define MAX_NOTE_BYTES 1024
typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
note_buf_t crash_notes[NR_CPUS];
void machine_crash_shutdown(void)
{
/* This function is only called after the system
* has paniced or is otherwise in a critical state.
* The minimum amount of code to allow a kexec'd kernel
* to run successfully needs to happen here.
*
* In practice this means shooting down the other cpus in
* an SMP system.
*/
}
/*
* machine_kexec.c - handle transition of Linux booting another kernel
* Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/mm.h>
#include <linux/kexec.h>
#include <linux/delay.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/io.h>
#include <asm/apic.h>
#include <asm/cpufeature.h>
static inline unsigned long read_cr3(void)
{
unsigned long cr3;
asm volatile("movl %%cr3,%0": "=r"(cr3));
return cr3;
}
#define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
#define L0_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
#define L1_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
#define L2_ATTR (_PAGE_PRESENT)
#define LEVEL0_SIZE (1UL << 12UL)
#ifndef CONFIG_X86_PAE
#define LEVEL1_SIZE (1UL << 22UL)
static u32 pgtable_level1[1024] PAGE_ALIGNED;
static void identity_map_page(unsigned long address)
{
unsigned long level1_index, level2_index;
u32 *pgtable_level2;
/* Find the current page table */
pgtable_level2 = __va(read_cr3());
/* Find the indexes of the physical address to identity map */
level1_index = (address % LEVEL1_SIZE)/LEVEL0_SIZE;
level2_index = address / LEVEL1_SIZE;
/* Identity map the page table entry */
pgtable_level1[level1_index] = address | L0_ATTR;
pgtable_level2[level2_index] = __pa(pgtable_level1) | L1_ATTR;
/* Flush the tlb so the new mapping takes effect.
* Global tlb entries are not flushed but that is not an issue.
*/
load_cr3(pgtable_level2);
}
#else
#define LEVEL1_SIZE (1UL << 21UL)
#define LEVEL2_SIZE (1UL << 30UL)
static u64 pgtable_level1[512] PAGE_ALIGNED;
static u64 pgtable_level2[512] PAGE_ALIGNED;
static void identity_map_page(unsigned long address)
{
unsigned long level1_index, level2_index, level3_index;
u64 *pgtable_level3;
/* Find the current page table */
pgtable_level3 = __va(read_cr3());
/* Find the indexes of the physical address to identity map */
level1_index = (address % LEVEL1_SIZE)/LEVEL0_SIZE;
level2_index = (address % LEVEL2_SIZE)/LEVEL1_SIZE;
level3_index = address / LEVEL2_SIZE;
/* Identity map the page table entry */
pgtable_level1[level1_index] = address | L0_ATTR;
pgtable_level2[level2_index] = __pa(pgtable_level1) | L1_ATTR;
set_64bit(&pgtable_level3[level3_index], __pa(pgtable_level2) | L2_ATTR);
/* Flush the tlb so the new mapping takes effect.
* Global tlb entries are not flushed but that is not an issue.
*/
load_cr3(pgtable_level3);
}
#endif
static void set_idt(void *newidt, __u16 limit)
{
unsigned char curidt[6];
/* ia32 supports unaliged loads & stores */
(*(__u16 *)(curidt)) = limit;
(*(__u32 *)(curidt +2)) = (unsigned long)(newidt);
__asm__ __volatile__ (
"lidt %0\n"
: "=m" (curidt)
);
};
static void set_gdt(void *newgdt, __u16 limit)
{
unsigned char curgdt[6];
/* ia32 supports unaligned loads & stores */
(*(__u16 *)(curgdt)) = limit;
(*(__u32 *)(curgdt +2)) = (unsigned long)(newgdt);
__asm__ __volatile__ (
"lgdt %0\n"
: "=m" (curgdt)
);
};
static void load_segments(void)
{
#define __STR(X) #X
#define STR(X) __STR(X)
__asm__ __volatile__ (
"\tljmp $"STR(__KERNEL_CS)",$1f\n"
"\t1:\n"
"\tmovl $"STR(__KERNEL_DS)",%eax\n"
"\tmovl %eax,%ds\n"
"\tmovl %eax,%es\n"
"\tmovl %eax,%fs\n"
"\tmovl %eax,%gs\n"
"\tmovl %eax,%ss\n"
);
#undef STR
#undef __STR
}
typedef asmlinkage NORET_TYPE void (*relocate_new_kernel_t)(
unsigned long indirection_page, unsigned long reboot_code_buffer,
unsigned long start_address, unsigned int has_pae) ATTRIB_NORET;
const extern unsigned char relocate_new_kernel[];
extern void relocate_new_kernel_end(void);
const extern unsigned int relocate_new_kernel_size;
/*
* A architecture hook called to validate the
* proposed image and prepare the control pages
* as needed. The pages for KEXEC_CONTROL_CODE_SIZE
* have been allocated, but the segments have yet
* been copied into the kernel.
*
* Do what every setup is needed on image and the
* reboot code buffer to allow us to avoid allocations
* later.
*
* Currently nothing.
*/
int machine_kexec_prepare(struct kimage *image)
{
return 0;
}
/*
* Undo anything leftover by machine_kexec_prepare
* when an image is freed.
*/
void machine_kexec_cleanup(struct kimage *image)
{
}
/*
* Do not allocate memory (or fail in any way) in machine_kexec().
* We are past the point of no return, committed to rebooting now.
*/
NORET_TYPE void machine_kexec(struct kimage *image)
{
unsigned long page_list;
unsigned long reboot_code_buffer;
relocate_new_kernel_t rnk;
/* Interrupts aren't acceptable while we reboot */
local_irq_disable();
/* Compute some offsets */
reboot_code_buffer = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
page_list = image->head;
/* Set up an identity mapping for the reboot_code_buffer */
identity_map_page(reboot_code_buffer);
/* copy it out */
memcpy((void *)reboot_code_buffer, relocate_new_kernel, relocate_new_kernel_size);
/* The segment registers are funny things, they are
* automatically loaded from a table, in memory wherever you
* set them to a specific selector, but this table is never
* accessed again you set the segment to a different selector.
*
* The more common model is are caches where the behide
* the scenes work is done, but is also dropped at arbitrary
* times.
*
* I take advantage of this here by force loading the
* segments, before I zap the gdt with an invalid value.
*/
load_segments();
/* The gdt & idt are now invalid.
* If you want to load them you must set up your own idt & gdt.
*/
set_gdt(phys_to_virt(0),0);
set_idt(phys_to_virt(0),0);
/* now call it */
rnk = (relocate_new_kernel_t) reboot_code_buffer;
(*rnk)(page_list, reboot_code_buffer, image->start, cpu_has_pae);
}
/*
* relocate_kernel.S - put the kernel image in place to boot
* Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/linkage.h>
/*
* Must be relocatable PIC code callable as a C function, that once
* it starts can not use the previous processes stack.
*/
.globl relocate_new_kernel
relocate_new_kernel:
/* read the arguments and say goodbye to the stack */
movl 4(%esp), %ebx /* page_list */
movl 8(%esp), %ebp /* reboot_code_buffer */
movl 12(%esp), %edx /* start address */
movl 16(%esp), %ecx /* cpu_has_pae */
/* zero out flags, and disable interrupts */
pushl $0
popfl
/* set a new stack at the bottom of our page... */
lea 4096(%ebp), %esp
/* store the parameters back on the stack */
pushl %edx /* store the start address */
/* Set cr0 to a known state:
* 31 0 == Paging disabled
* 18 0 == Alignment check disabled
* 16 0 == Write protect disabled
* 3 0 == No task switch
* 2 0 == Don't do FP software emulation.
* 0 1 == Proctected mode enabled
*/
movl %cr0, %eax
andl $~((1<<31)|(1<<18)|(1<<16)|(1<<3)|(1<<2)), %eax
orl $(1<<0), %eax
movl %eax, %cr0
/* clear cr4 if applicable */
testl %ecx, %ecx
jz 1f
/* Set cr4 to a known state:
* Setting everything to zero seems safe.
*/
movl %cr4, %eax
andl $0, %eax
movl %eax, %cr4
jmp 1f
1:
/* Flush the TLB (needed?) */
xorl %eax, %eax
movl %eax, %cr3
/* Do the copies */
movl %ebx, %ecx
jmp 1f
0: /* top, read another word from the indirection page */
movl (%ebx), %ecx
addl $4, %ebx
1:
testl $0x1, %ecx /* is it a destination page */
jz 2f
movl %ecx, %edi
andl $0xfffff000, %edi
jmp 0b
2:
testl $0x2, %ecx /* is it an indirection page */
jz 2f
movl %ecx, %ebx
andl $0xfffff000, %ebx
jmp 0b
2:
testl $0x4, %ecx /* is it the done indicator */
jz 2f
jmp 3f
2:
testl $0x8, %ecx /* is it the source indicator */
jz 0b /* Ignore it otherwise */
movl %ecx, %esi /* For every source page do a copy */
andl $0xfffff000, %esi
movl $1024, %ecx
rep ; movsl
jmp 0b
3:
/* To be certain of avoiding problems with self-modifying code
* I need to execute a serializing instruction here.
* So I flush the TLB, it's handy, and not processor dependent.
*/
xorl %eax, %eax
movl %eax, %cr3
/* set all of the registers to known values */
/* leave %esp alone */
xorl %eax, %eax
xorl %ebx, %ebx
xorl %ecx, %ecx
xorl %edx, %edx
xorl %esi, %esi
xorl %edi, %edi
xorl %ebp, %ebp
ret
relocate_new_kernel_end:
.globl relocate_new_kernel_size
relocate_new_kernel_size:
.long relocate_new_kernel_end - relocate_new_kernel
......@@ -283,7 +283,7 @@ ENTRY(sys_call_table)
.long sys_mq_timedreceive /* 280 */
.long sys_mq_notify
.long sys_mq_getsetattr
.long sys_ni_syscall /* reserved for kexec */
.long sys_kexec_load
.long sys_waitid
.long sys_ni_syscall /* 285 */ /* available */
.long sys_add_key
......
#ifndef _I386_KEXEC_H
#define _I386_KEXEC_H
#include <asm/fixmap.h>
/*
* KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return.
* I.e. Maximum page that is mapped directly into kernel memory,
* and kmap is not required.
*
* Someone correct me if FIXADDR_START - PAGEOFFSET is not the correct
* calculation for the amount of memory directly mappable into the
* kernel memory space.
*/
/* Maximum physical address we can use pages from */
#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
/* Maximum address we can reach in physical address mode */
#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
/* Maximum address we can use for the control code buffer */
#define KEXEC_CONTROL_MEMORY_LIMIT TASK_SIZE
#define KEXEC_CONTROL_CODE_SIZE 4096
/* The native architecture */
#define KEXEC_ARCH KEXEC_ARCH_386
#endif /* _I386_KEXEC_H */
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