[PATCH] kexec: x86_64 kexec implementation
This is the x86_64 implementation of machine kexec. 32bit compatibility
support has been implemented, and machine_kexec has been enhanced to not care
about the changing internal kernel paget table structures.
From: Alexander Nyberg <alexn@dsv.su.se>
build fix
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
d89559589a
commit
5234f5eb04
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@ -380,6 +380,23 @@ 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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config SECCOMP
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bool "Enable seccomp to safely compute untrusted bytecode"
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depends on PROC_FS
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@ -589,7 +589,7 @@ ia32_sys_call_table:
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.quad compat_sys_mq_timedreceive /* 280 */
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.quad compat_sys_mq_notify
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.quad compat_sys_mq_getsetattr
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.quad quiet_ni_syscall /* reserved for kexec */
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.quad compat_sys_kexec_load /* reserved for kexec */
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.quad compat_sys_waitid
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.quad quiet_ni_syscall /* sys_altroot */
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.quad sys_add_key
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@ -20,6 +20,7 @@ obj-$(CONFIG_SMP) += smp.o smpboot.o trampoline.o
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obj-$(CONFIG_X86_LOCAL_APIC) += apic.o nmi.o
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obj-$(CONFIG_X86_IO_APIC) += io_apic.o mpparse.o \
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genapic.o genapic_cluster.o genapic_flat.o
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obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o crash.o
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obj-$(CONFIG_PM) += suspend.o
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obj-$(CONFIG_SOFTWARE_SUSPEND) += suspend_asm.o
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obj-$(CONFIG_CPU_FREQ) += cpufreq/
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@ -0,0 +1,38 @@
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/*
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* Architecture specific (x86_64) 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 <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 +1,245 @@
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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 <linux/string.h>
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#include <linux/reboot.h>
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#include <asm/pda.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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#include <asm/hw_irq.h>
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#define LEVEL0_SIZE (1UL << 12UL)
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#define LEVEL1_SIZE (1UL << 21UL)
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#define LEVEL2_SIZE (1UL << 30UL)
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#define LEVEL3_SIZE (1UL << 39UL)
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#define LEVEL4_SIZE (1UL << 48UL)
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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 | _PAGE_PSE)
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#define L2_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
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#define L3_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
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static void init_level2_page(
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u64 *level2p, unsigned long addr)
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{
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unsigned long end_addr;
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addr &= PAGE_MASK;
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end_addr = addr + LEVEL2_SIZE;
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while(addr < end_addr) {
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*(level2p++) = addr | L1_ATTR;
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addr += LEVEL1_SIZE;
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}
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}
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static int init_level3_page(struct kimage *image,
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u64 *level3p, unsigned long addr, unsigned long last_addr)
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{
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unsigned long end_addr;
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int result;
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result = 0;
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addr &= PAGE_MASK;
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end_addr = addr + LEVEL3_SIZE;
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while((addr < last_addr) && (addr < end_addr)) {
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struct page *page;
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u64 *level2p;
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page = kimage_alloc_control_pages(image, 0);
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if (!page) {
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result = -ENOMEM;
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goto out;
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}
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level2p = (u64 *)page_address(page);
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init_level2_page(level2p, addr);
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*(level3p++) = __pa(level2p) | L2_ATTR;
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addr += LEVEL2_SIZE;
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}
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/* clear the unused entries */
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while(addr < end_addr) {
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*(level3p++) = 0;
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addr += LEVEL2_SIZE;
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}
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out:
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return result;
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}
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static int init_level4_page(struct kimage *image,
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u64 *level4p, unsigned long addr, unsigned long last_addr)
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{
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unsigned long end_addr;
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int result;
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result = 0;
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addr &= PAGE_MASK;
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end_addr = addr + LEVEL4_SIZE;
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while((addr < last_addr) && (addr < end_addr)) {
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struct page *page;
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u64 *level3p;
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page = kimage_alloc_control_pages(image, 0);
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if (!page) {
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result = -ENOMEM;
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goto out;
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}
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level3p = (u64 *)page_address(page);
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result = init_level3_page(image, level3p, addr, last_addr);
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if (result) {
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goto out;
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}
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*(level4p++) = __pa(level3p) | L3_ATTR;
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addr += LEVEL3_SIZE;
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}
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/* clear the unused entries */
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while(addr < end_addr) {
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*(level4p++) = 0;
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addr += LEVEL3_SIZE;
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}
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out:
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return result;
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}
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static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
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{
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u64 *level4p;
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level4p = (u64 *)__va(start_pgtable);
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return init_level4_page(image, level4p, 0, end_pfn << PAGE_SHIFT);
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}
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static void set_idt(void *newidt, u16 limit)
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{
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unsigned char curidt[10];
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/* x86-64 supports unaliged loads & stores */
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(*(u16 *)(curidt)) = limit;
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(*(u64 *)(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[10];
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/* x86-64 supports unaligned loads & stores */
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(*(u16 *)(curgdt)) = limit;
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(*(u64 *)(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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__asm__ __volatile__ (
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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,%ss\n"
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"\tmovl %eax,%fs\n"
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"\tmovl %eax,%gs\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 NORET_TYPE void (*relocate_new_kernel_t)(
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unsigned long indirection_page, unsigned long control_code_buffer,
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unsigned long start_address, unsigned long pgtable) ATTRIB_NORET;
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const extern unsigned char relocate_new_kernel[];
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const extern unsigned long relocate_new_kernel_size;
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int machine_kexec_prepare(struct kimage *image)
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{
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unsigned long start_pgtable, control_code_buffer;
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int result;
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/* Calculate the offsets */
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start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
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control_code_buffer = start_pgtable + 4096UL;
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/* Setup the identity mapped 64bit page table */
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result = init_pgtable(image, start_pgtable);
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if (result) {
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return result;
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}
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/* Place the code in the reboot code buffer */
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memcpy(__va(control_code_buffer), relocate_new_kernel, relocate_new_kernel_size);
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return 0;
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}
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void machine_kexec_cleanup(struct kimage *image)
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{
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return;
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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 control_code_buffer;
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unsigned long start_pgtable;
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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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/* Calculate the offsets */
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page_list = image->head;
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start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
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control_code_buffer = start_pgtable + 4096UL;
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/* Set the low half of the page table to my identity mapped
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* page table for kexec. Leave the high half pointing at the
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* kernel pages. Don't bother to flush the global pages
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* as that will happen when I fully switch to my identity mapped
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* page table anyway.
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*/
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memcpy(__va(read_cr3()), __va(start_pgtable), PAGE_SIZE/2);
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__flush_tlb();
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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 unless you set the segment to a different selector.
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*
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* The more common model 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) control_code_buffer;
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(*rnk)(page_list, control_code_buffer, image->start, start_pgtable);
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}
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@ -0,0 +1,143 @@
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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) 2002-2005 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/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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.code64
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relocate_new_kernel:
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/* %rdi page_list
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* %rsi reboot_code_buffer
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* %rdx start address
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* %rcx page_table
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* %r8 arg5
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* %r9 arg6
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*/
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/* zero out flags, and disable interrupts */
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pushq $0
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popfq
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/* set a new stack at the bottom of our page... */
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lea 4096(%rsi), %rsp
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/* store the parameters back on the stack */
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pushq %rdx /* store the start address */
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/* Set cr0 to a known state:
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* 31 1 == Paging enabled
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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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movq %cr0, %rax
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andq $~((1<<18)|(1<<16)|(1<<3)|(1<<2)), %rax
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orl $((1<<31)|(1<<0)), %eax
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movq %rax, %cr0
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/* Set cr4 to a known state:
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* 10 0 == xmm exceptions disabled
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* 9 0 == xmm registers instructions disabled
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* 8 0 == performance monitoring counter disabled
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* 7 0 == page global disabled
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* 6 0 == machine check exceptions disabled
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* 5 1 == physical address extension enabled
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* 4 0 == page size extensions disabled
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* 3 0 == Debug extensions disabled
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* 2 0 == Time stamp disable (disabled)
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* 1 0 == Protected mode virtual interrupts disabled
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* 0 0 == VME disabled
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*/
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movq $((1<<5)), %rax
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movq %rax, %cr4
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jmp 1f
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1:
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/* Switch to the identity mapped page tables,
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* and flush the TLB.
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*/
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movq %rcx, %cr3
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/* Do the copies */
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movq %rdi, %rcx /* Put the page_list in %rcx */
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xorq %rdi, %rdi
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xorq %rsi, %rsi
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jmp 1f
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0: /* top, read another word for the indirection page */
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movq (%rbx), %rcx
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addq $8, %rbx
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1:
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testq $0x1, %rcx /* is it a destination page? */
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jz 2f
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movq %rcx, %rdi
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andq $0xfffffffffffff000, %rdi
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jmp 0b
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2:
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testq $0x2, %rcx /* is it an indirection page? */
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jz 2f
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movq %rcx, %rbx
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andq $0xfffffffffffff000, %rbx
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jmp 0b
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2:
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testq $0x4, %rcx /* 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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testq $0x8, %rcx /* is it the source indicator? */
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jz 0b /* Ignore it otherwise */
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movq %rcx, %rsi /* For ever source page do a copy */
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andq $0xfffffffffffff000, %rsi
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movq $512, %rcx
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rep ; movsq
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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 by reloading %cr3 here, it's handy,
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* and not processor dependent.
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*/
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movq %cr3, %rax
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movq %rax, %cr3
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/* set all of the registers to known values */
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/* leave %rsp alone */
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xorq %rax, %rax
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xorq %rbx, %rbx
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xorq %rcx, %rcx
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xorq %rdx, %rdx
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xorq %rsi, %rsi
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xorq %rdi, %rdi
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xorq %rbp, %rbp
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xorq %r8, %r8
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xorq %r9, %r9
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xorq %r10, %r9
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xorq %r11, %r11
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xorq %r12, %r12
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xorq %r13, %r13
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xorq %r14, %r14
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xorq %r15, %r15
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ret
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relocate_new_kernel_end:
|
||||
|
||||
.globl relocate_new_kernel_size
|
||||
relocate_new_kernel_size:
|
||||
.quad relocate_new_kernel_end - relocate_new_kernel
|
||||
|
|
@ -0,0 +1,28 @@
|
|||
#ifndef _X86_64_KEXEC_H
|
||||
#define _X86_64_KEXEC_H
|
||||
|
||||
#include <asm/page.h>
|
||||
#include <asm/proto.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.
|
||||
*
|
||||
* So far x86_64 is limited to 40 physical address bits.
|
||||
*/
|
||||
|
||||
/* Maximum physical address we can use pages from */
|
||||
#define KEXEC_SOURCE_MEMORY_LIMIT (0xFFFFFFFFFFUL)
|
||||
/* Maximum address we can reach in physical address mode */
|
||||
#define KEXEC_DESTINATION_MEMORY_LIMIT (0xFFFFFFFFFFUL)
|
||||
/* Maximum address we can use for the control pages */
|
||||
#define KEXEC_CONTROL_MEMORY_LIMIT (0xFFFFFFFFFFUL)
|
||||
|
||||
/* Allocate one page for the pdp and the second for the code */
|
||||
#define KEXEC_CONTROL_CODE_SIZE (4096UL + 4096UL)
|
||||
|
||||
/* The native architecture */
|
||||
#define KEXEC_ARCH KEXEC_ARCH_X86_64
|
||||
|
||||
#endif /* _X86_64_KEXEC_H */
|
||||
|
|
@ -552,7 +552,7 @@ __SYSCALL(__NR_mq_notify, sys_mq_notify)
|
|||
#define __NR_mq_getsetattr 245
|
||||
__SYSCALL(__NR_mq_getsetattr, sys_mq_getsetattr)
|
||||
#define __NR_kexec_load 246
|
||||
__SYSCALL(__NR_kexec_load, sys_ni_syscall)
|
||||
__SYSCALL(__NR_kexec_load, sys_kexec_load)
|
||||
#define __NR_waitid 247
|
||||
__SYSCALL(__NR_waitid, sys_waitid)
|
||||
#define __NR_add_key 248
|
||||
|
|
|
|||
Loading…
Reference in New Issue