[PATCH] kexec: x86 kexec core
This is the i386 implementation of kexec. Signed-off-by: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Eric W. Biederman
Linus Torvalds
parent
dd2a13054f
commit
5033cba087
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@ -953,6 +953,23 @@ config PHYSICAL_START
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Don't change this unless you know what you are doing.
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config KEXEC
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bool "kexec system call (EXPERIMENTAL)"
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depends on EXPERIMENTAL
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help
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kexec is a system call that implements the ability to shutdown your
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current kernel, and to start another kernel. It is like a reboot
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but it is indepedent of the system firmware. And like a reboot
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you can start any kernel with it, not just Linux.
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The name comes from the similiarity to the exec system call.
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It is an ongoing process to be certain the hardware in a machine
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is properly shutdown, so do not be surprised if this code does not
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initially work for you. It may help to enable device hotplugging
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support. As of this writing the exact hardware interface is
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strongly in flux, so no good recommendation can be made.
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endmenu
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@ -24,6 +24,7 @@ obj-$(CONFIG_X86_MPPARSE) += mpparse.o
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obj-$(CONFIG_X86_LOCAL_APIC) += apic.o nmi.o
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obj-$(CONFIG_X86_IO_APIC) += io_apic.o
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obj-$(CONFIG_X86_REBOOTFIXUPS) += reboot_fixups.o
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obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o crash.o
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obj-$(CONFIG_X86_NUMAQ) += numaq.o
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obj-$(CONFIG_X86_SUMMIT_NUMA) += summit.o
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obj-$(CONFIG_KPROBES) += kprobes.o
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@ -0,0 +1,42 @@
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/*
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* Architecture specific (i386) functions for kexec based crash dumps.
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*
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* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
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*
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* Copyright (C) IBM Corporation, 2004. All rights reserved.
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*
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*/
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/smp.h>
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#include <linux/irq.h>
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#include <linux/reboot.h>
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#include <linux/kexec.h>
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#include <linux/irq.h>
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#include <linux/delay.h>
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#include <linux/elf.h>
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#include <linux/elfcore.h>
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#include <asm/processor.h>
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#include <asm/hardirq.h>
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#include <asm/nmi.h>
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#include <asm/hw_irq.h>
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#define MAX_NOTE_BYTES 1024
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typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
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note_buf_t crash_notes[NR_CPUS];
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void machine_crash_shutdown(void)
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{
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/* This function is only called after the system
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* has paniced or is otherwise in a critical state.
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* The minimum amount of code to allow a kexec'd kernel
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* to run successfully needs to happen here.
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*
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* In practice this means shooting down the other cpus in
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* an SMP system.
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*/
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}
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@ -0,0 +1,220 @@
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/*
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* machine_kexec.c - handle transition of Linux booting another kernel
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* Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/mm.h>
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#include <linux/kexec.h>
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#include <linux/delay.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/tlbflush.h>
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#include <asm/mmu_context.h>
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#include <asm/io.h>
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#include <asm/apic.h>
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#include <asm/cpufeature.h>
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static inline unsigned long read_cr3(void)
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{
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unsigned long cr3;
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asm volatile("movl %%cr3,%0": "=r"(cr3));
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return cr3;
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}
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#define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
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#define L0_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
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#define L1_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
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#define L2_ATTR (_PAGE_PRESENT)
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#define LEVEL0_SIZE (1UL << 12UL)
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#ifndef CONFIG_X86_PAE
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#define LEVEL1_SIZE (1UL << 22UL)
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static u32 pgtable_level1[1024] PAGE_ALIGNED;
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static void identity_map_page(unsigned long address)
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{
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unsigned long level1_index, level2_index;
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u32 *pgtable_level2;
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/* Find the current page table */
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pgtable_level2 = __va(read_cr3());
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/* Find the indexes of the physical address to identity map */
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level1_index = (address % LEVEL1_SIZE)/LEVEL0_SIZE;
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level2_index = address / LEVEL1_SIZE;
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/* Identity map the page table entry */
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pgtable_level1[level1_index] = address | L0_ATTR;
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pgtable_level2[level2_index] = __pa(pgtable_level1) | L1_ATTR;
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/* Flush the tlb so the new mapping takes effect.
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* Global tlb entries are not flushed but that is not an issue.
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*/
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load_cr3(pgtable_level2);
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}
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#else
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#define LEVEL1_SIZE (1UL << 21UL)
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#define LEVEL2_SIZE (1UL << 30UL)
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static u64 pgtable_level1[512] PAGE_ALIGNED;
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static u64 pgtable_level2[512] PAGE_ALIGNED;
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static void identity_map_page(unsigned long address)
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{
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unsigned long level1_index, level2_index, level3_index;
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u64 *pgtable_level3;
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/* Find the current page table */
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pgtable_level3 = __va(read_cr3());
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/* Find the indexes of the physical address to identity map */
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level1_index = (address % LEVEL1_SIZE)/LEVEL0_SIZE;
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level2_index = (address % LEVEL2_SIZE)/LEVEL1_SIZE;
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level3_index = address / LEVEL2_SIZE;
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/* Identity map the page table entry */
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pgtable_level1[level1_index] = address | L0_ATTR;
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pgtable_level2[level2_index] = __pa(pgtable_level1) | L1_ATTR;
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set_64bit(&pgtable_level3[level3_index], __pa(pgtable_level2) | L2_ATTR);
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/* Flush the tlb so the new mapping takes effect.
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* Global tlb entries are not flushed but that is not an issue.
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*/
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load_cr3(pgtable_level3);
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}
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#endif
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static void set_idt(void *newidt, __u16 limit)
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{
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unsigned char curidt[6];
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/* ia32 supports unaliged loads & stores */
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(*(__u16 *)(curidt)) = limit;
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(*(__u32 *)(curidt +2)) = (unsigned long)(newidt);
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__asm__ __volatile__ (
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"lidt %0\n"
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: "=m" (curidt)
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);
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};
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static void set_gdt(void *newgdt, __u16 limit)
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{
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unsigned char curgdt[6];
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/* ia32 supports unaligned loads & stores */
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(*(__u16 *)(curgdt)) = limit;
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(*(__u32 *)(curgdt +2)) = (unsigned long)(newgdt);
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__asm__ __volatile__ (
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"lgdt %0\n"
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: "=m" (curgdt)
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);
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};
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static void load_segments(void)
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{
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#define __STR(X) #X
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#define STR(X) __STR(X)
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__asm__ __volatile__ (
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"\tljmp $"STR(__KERNEL_CS)",$1f\n"
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"\t1:\n"
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"\tmovl $"STR(__KERNEL_DS)",%eax\n"
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"\tmovl %eax,%ds\n"
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"\tmovl %eax,%es\n"
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"\tmovl %eax,%fs\n"
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"\tmovl %eax,%gs\n"
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"\tmovl %eax,%ss\n"
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);
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#undef STR
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#undef __STR
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}
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typedef asmlinkage NORET_TYPE void (*relocate_new_kernel_t)(
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unsigned long indirection_page, unsigned long reboot_code_buffer,
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unsigned long start_address, unsigned int has_pae) ATTRIB_NORET;
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const extern unsigned char relocate_new_kernel[];
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extern void relocate_new_kernel_end(void);
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const extern unsigned int relocate_new_kernel_size;
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/*
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* A architecture hook called to validate the
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* proposed image and prepare the control pages
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* as needed. The pages for KEXEC_CONTROL_CODE_SIZE
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* have been allocated, but the segments have yet
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* been copied into the kernel.
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*
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* Do what every setup is needed on image and the
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* reboot code buffer to allow us to avoid allocations
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* later.
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*
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* Currently nothing.
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*/
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int machine_kexec_prepare(struct kimage *image)
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{
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return 0;
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}
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/*
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* Undo anything leftover by machine_kexec_prepare
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* when an image is freed.
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*/
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void machine_kexec_cleanup(struct kimage *image)
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{
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}
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/*
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* Do not allocate memory (or fail in any way) in machine_kexec().
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* We are past the point of no return, committed to rebooting now.
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*/
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NORET_TYPE void machine_kexec(struct kimage *image)
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{
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unsigned long page_list;
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unsigned long reboot_code_buffer;
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relocate_new_kernel_t rnk;
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/* Interrupts aren't acceptable while we reboot */
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local_irq_disable();
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/* Compute some offsets */
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reboot_code_buffer = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
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page_list = image->head;
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/* Set up an identity mapping for the reboot_code_buffer */
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identity_map_page(reboot_code_buffer);
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/* copy it out */
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memcpy((void *)reboot_code_buffer, relocate_new_kernel, relocate_new_kernel_size);
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/* The segment registers are funny things, they are
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* automatically loaded from a table, in memory wherever you
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* set them to a specific selector, but this table is never
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* accessed again you set the segment to a different selector.
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*
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* The more common model is are caches where the behide
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* the scenes work is done, but is also dropped at arbitrary
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* times.
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*
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* I take advantage of this here by force loading the
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* segments, before I zap the gdt with an invalid value.
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*/
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load_segments();
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/* The gdt & idt are now invalid.
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* If you want to load them you must set up your own idt & gdt.
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*/
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set_gdt(phys_to_virt(0),0);
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set_idt(phys_to_virt(0),0);
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/* now call it */
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rnk = (relocate_new_kernel_t) reboot_code_buffer;
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(*rnk)(page_list, reboot_code_buffer, image->start, cpu_has_pae);
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}
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@ -0,0 +1,120 @@
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/*
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* relocate_kernel.S - put the kernel image in place to boot
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* Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/linkage.h>
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/*
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* Must be relocatable PIC code callable as a C function, that once
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* it starts can not use the previous processes stack.
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*/
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.globl relocate_new_kernel
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relocate_new_kernel:
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/* read the arguments and say goodbye to the stack */
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movl 4(%esp), %ebx /* page_list */
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movl 8(%esp), %ebp /* reboot_code_buffer */
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movl 12(%esp), %edx /* start address */
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movl 16(%esp), %ecx /* cpu_has_pae */
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/* zero out flags, and disable interrupts */
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pushl $0
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popfl
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/* set a new stack at the bottom of our page... */
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lea 4096(%ebp), %esp
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/* store the parameters back on the stack */
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pushl %edx /* store the start address */
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/* Set cr0 to a known state:
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* 31 0 == Paging disabled
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* 18 0 == Alignment check disabled
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* 16 0 == Write protect disabled
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* 3 0 == No task switch
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* 2 0 == Don't do FP software emulation.
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* 0 1 == Proctected mode enabled
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*/
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movl %cr0, %eax
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andl $~((1<<31)|(1<<18)|(1<<16)|(1<<3)|(1<<2)), %eax
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orl $(1<<0), %eax
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movl %eax, %cr0
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/* clear cr4 if applicable */
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testl %ecx, %ecx
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jz 1f
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/* Set cr4 to a known state:
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* Setting everything to zero seems safe.
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*/
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movl %cr4, %eax
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andl $0, %eax
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movl %eax, %cr4
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jmp 1f
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1:
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/* Flush the TLB (needed?) */
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xorl %eax, %eax
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movl %eax, %cr3
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/* Do the copies */
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movl %ebx, %ecx
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jmp 1f
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0: /* top, read another word from the indirection page */
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movl (%ebx), %ecx
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addl $4, %ebx
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1:
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testl $0x1, %ecx /* is it a destination page */
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jz 2f
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movl %ecx, %edi
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andl $0xfffff000, %edi
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jmp 0b
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2:
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testl $0x2, %ecx /* is it an indirection page */
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jz 2f
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movl %ecx, %ebx
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andl $0xfffff000, %ebx
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jmp 0b
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2:
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testl $0x4, %ecx /* is it the done indicator */
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jz 2f
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jmp 3f
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2:
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testl $0x8, %ecx /* is it the source indicator */
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jz 0b /* Ignore it otherwise */
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movl %ecx, %esi /* For every source page do a copy */
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andl $0xfffff000, %esi
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movl $1024, %ecx
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rep ; movsl
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jmp 0b
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3:
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/* To be certain of avoiding problems with self-modifying code
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* I need to execute a serializing instruction here.
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* So I flush the TLB, it's handy, and not processor dependent.
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*/
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xorl %eax, %eax
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movl %eax, %cr3
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/* set all of the registers to known values */
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/* leave %esp alone */
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xorl %eax, %eax
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xorl %ebx, %ebx
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xorl %ecx, %ecx
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xorl %edx, %edx
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xorl %esi, %esi
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xorl %edi, %edi
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xorl %ebp, %ebp
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ret
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relocate_new_kernel_end:
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.globl relocate_new_kernel_size
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relocate_new_kernel_size:
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.long relocate_new_kernel_end - relocate_new_kernel
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@ -283,7 +283,7 @@ ENTRY(sys_call_table)
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.long sys_mq_timedreceive /* 280 */
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.long sys_mq_notify
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.long sys_mq_getsetattr
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.long sys_ni_syscall /* reserved for kexec */
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.long sys_kexec_load
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.long sys_waitid
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.long sys_ni_syscall /* 285 */ /* available */
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.long sys_add_key
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@ -0,0 +1,28 @@
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#ifndef _I386_KEXEC_H
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#define _I386_KEXEC_H
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#include <asm/fixmap.h>
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/*
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* KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return.
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* I.e. Maximum page that is mapped directly into kernel memory,
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* and kmap is not required.
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*
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* Someone correct me if FIXADDR_START - PAGEOFFSET is not the correct
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* calculation for the amount of memory directly mappable into the
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* kernel memory space.
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*/
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/* Maximum physical address we can use pages from */
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#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
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/* Maximum address we can reach in physical address mode */
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#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
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/* Maximum address we can use for the control code buffer */
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#define KEXEC_CONTROL_MEMORY_LIMIT TASK_SIZE
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#define KEXEC_CONTROL_CODE_SIZE 4096
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/* The native architecture */
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#define KEXEC_ARCH KEXEC_ARCH_386
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#endif /* _I386_KEXEC_H */
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