Commit 5234f5eb authored by Eric W. Biederman's avatar Eric W. Biederman Committed by Linus Torvalds
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[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: 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 d8955958
......@@ -380,6 +380,23 @@ 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.
config SECCOMP
bool "Enable seccomp to safely compute untrusted bytecode"
depends on PROC_FS
......
......@@ -589,7 +589,7 @@ ia32_sys_call_table:
.quad compat_sys_mq_timedreceive /* 280 */
.quad compat_sys_mq_notify
.quad compat_sys_mq_getsetattr
.quad quiet_ni_syscall /* reserved for kexec */
.quad compat_sys_kexec_load /* reserved for kexec */
.quad compat_sys_waitid
.quad quiet_ni_syscall /* sys_altroot */
.quad sys_add_key
......
......@@ -20,6 +20,7 @@ obj-$(CONFIG_SMP) += smp.o smpboot.o trampoline.o
obj-$(CONFIG_X86_LOCAL_APIC) += apic.o nmi.o
obj-$(CONFIG_X86_IO_APIC) += io_apic.o mpparse.o \
genapic.o genapic_cluster.o genapic_flat.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o crash.o
obj-$(CONFIG_PM) += suspend.o
obj-$(CONFIG_SOFTWARE_SUSPEND) += suspend_asm.o
obj-$(CONFIG_CPU_FREQ) += cpufreq/
......
/*
* Architecture specific (x86_64) 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 <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 <linux/string.h>
#include <linux/reboot.h>
#include <asm/pda.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>
#include <asm/hw_irq.h>
#define LEVEL0_SIZE (1UL << 12UL)
#define LEVEL1_SIZE (1UL << 21UL)
#define LEVEL2_SIZE (1UL << 30UL)
#define LEVEL3_SIZE (1UL << 39UL)
#define LEVEL4_SIZE (1UL << 48UL)
#define L0_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
#define L1_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_PSE)
#define L2_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
#define L3_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
static void init_level2_page(
u64 *level2p, unsigned long addr)
{
unsigned long end_addr;
addr &= PAGE_MASK;
end_addr = addr + LEVEL2_SIZE;
while(addr < end_addr) {
*(level2p++) = addr | L1_ATTR;
addr += LEVEL1_SIZE;
}
}
static int init_level3_page(struct kimage *image,
u64 *level3p, unsigned long addr, unsigned long last_addr)
{
unsigned long end_addr;
int result;
result = 0;
addr &= PAGE_MASK;
end_addr = addr + LEVEL3_SIZE;
while((addr < last_addr) && (addr < end_addr)) {
struct page *page;
u64 *level2p;
page = kimage_alloc_control_pages(image, 0);
if (!page) {
result = -ENOMEM;
goto out;
}
level2p = (u64 *)page_address(page);
init_level2_page(level2p, addr);
*(level3p++) = __pa(level2p) | L2_ATTR;
addr += LEVEL2_SIZE;
}
/* clear the unused entries */
while(addr < end_addr) {
*(level3p++) = 0;
addr += LEVEL2_SIZE;
}
out:
return result;
}
static int init_level4_page(struct kimage *image,
u64 *level4p, unsigned long addr, unsigned long last_addr)
{
unsigned long end_addr;
int result;
result = 0;
addr &= PAGE_MASK;
end_addr = addr + LEVEL4_SIZE;
while((addr < last_addr) && (addr < end_addr)) {
struct page *page;
u64 *level3p;
page = kimage_alloc_control_pages(image, 0);
if (!page) {
result = -ENOMEM;
goto out;
}
level3p = (u64 *)page_address(page);
result = init_level3_page(image, level3p, addr, last_addr);
if (result) {
goto out;
}
*(level4p++) = __pa(level3p) | L3_ATTR;
addr += LEVEL3_SIZE;
}
/* clear the unused entries */
while(addr < end_addr) {
*(level4p++) = 0;
addr += LEVEL3_SIZE;
}
out:
return result;
}
static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
{
u64 *level4p;
level4p = (u64 *)__va(start_pgtable);
return init_level4_page(image, level4p, 0, end_pfn << PAGE_SHIFT);
}
static void set_idt(void *newidt, u16 limit)
{
unsigned char curidt[10];
/* x86-64 supports unaliged loads & stores */
(*(u16 *)(curidt)) = limit;
(*(u64 *)(curidt +2)) = (unsigned long)(newidt);
__asm__ __volatile__ (
"lidt %0\n"
: "=m" (curidt)
);
};
static void set_gdt(void *newgdt, u16 limit)
{
unsigned char curgdt[10];
/* x86-64 supports unaligned loads & stores */
(*(u16 *)(curgdt)) = limit;
(*(u64 *)(curgdt +2)) = (unsigned long)(newgdt);
__asm__ __volatile__ (
"lgdt %0\n"
: "=m" (curgdt)
);
};
static void load_segments(void)
{
__asm__ __volatile__ (
"\tmovl $"STR(__KERNEL_DS)",%eax\n"
"\tmovl %eax,%ds\n"
"\tmovl %eax,%es\n"
"\tmovl %eax,%ss\n"
"\tmovl %eax,%fs\n"
"\tmovl %eax,%gs\n"
);
#undef STR
#undef __STR
}
typedef NORET_TYPE void (*relocate_new_kernel_t)(
unsigned long indirection_page, unsigned long control_code_buffer,
unsigned long start_address, unsigned long pgtable) ATTRIB_NORET;
const extern unsigned char relocate_new_kernel[];
const extern unsigned long relocate_new_kernel_size;
int machine_kexec_prepare(struct kimage *image)
{
unsigned long start_pgtable, control_code_buffer;
int result;
/* Calculate the offsets */
start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
control_code_buffer = start_pgtable + 4096UL;
/* Setup the identity mapped 64bit page table */
result = init_pgtable(image, start_pgtable);
if (result) {
return result;
}
/* Place the code in the reboot code buffer */
memcpy(__va(control_code_buffer), relocate_new_kernel, relocate_new_kernel_size);
return 0;
}
void machine_kexec_cleanup(struct kimage *image)
{
return;
}
/*
* 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 control_code_buffer;
unsigned long start_pgtable;
relocate_new_kernel_t rnk;
/* Interrupts aren't acceptable while we reboot */
local_irq_disable();
/* Calculate the offsets */
page_list = image->head;
start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;
control_code_buffer = start_pgtable + 4096UL;
/* Set the low half of the page table to my identity mapped
* page table for kexec. Leave the high half pointing at the
* kernel pages. Don't bother to flush the global pages
* as that will happen when I fully switch to my identity mapped
* page table anyway.
*/
memcpy(__va(read_cr3()), __va(start_pgtable), PAGE_SIZE/2);
__flush_tlb();
/* 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 unless you set the segment to a different selector.
*
* The more common model 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) control_code_buffer;
(*rnk)(page_list, control_code_buffer, image->start, start_pgtable);
}
/*
* relocate_kernel.S - put the kernel image in place to boot
* 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/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
.code64
relocate_new_kernel:
/* %rdi page_list
* %rsi reboot_code_buffer
* %rdx start address
* %rcx page_table
* %r8 arg5
* %r9 arg6
*/
/* zero out flags, and disable interrupts */
pushq $0
popfq
/* set a new stack at the bottom of our page... */
lea 4096(%rsi), %rsp
/* store the parameters back on the stack */
pushq %rdx /* store the start address */
/* Set cr0 to a known state:
* 31 1 == Paging enabled
* 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
*/
movq %cr0, %rax
andq $~((1<<18)|(1<<16)|(1<<3)|(1<<2)), %rax
orl $((1<<31)|(1<<0)), %eax
movq %rax, %cr0
/* Set cr4 to a known state:
* 10 0 == xmm exceptions disabled
* 9 0 == xmm registers instructions disabled
* 8 0 == performance monitoring counter disabled
* 7 0 == page global disabled
* 6 0 == machine check exceptions disabled
* 5 1 == physical address extension enabled
* 4 0 == page size extensions disabled
* 3 0 == Debug extensions disabled
* 2 0 == Time stamp disable (disabled)
* 1 0 == Protected mode virtual interrupts disabled
* 0 0 == VME disabled
*/
movq $((1<<5)), %rax
movq %rax, %cr4
jmp 1f
1:
/* Switch to the identity mapped page tables,
* and flush the TLB.
*/
movq %rcx, %cr3
/* Do the copies */
movq %rdi, %rcx /* Put the page_list in %rcx */
xorq %rdi, %rdi
xorq %rsi, %rsi
jmp 1f
0: /* top, read another word for the indirection page */
movq (%rbx), %rcx
addq $8, %rbx
1:
testq $0x1, %rcx /* is it a destination page? */
jz 2f
movq %rcx, %rdi
andq $0xfffffffffffff000, %rdi
jmp 0b
2:
testq $0x2, %rcx /* is it an indirection page? */
jz 2f
movq %rcx, %rbx
andq $0xfffffffffffff000, %rbx
jmp 0b
2:
testq $0x4, %rcx /* is it the done indicator? */
jz 2f
jmp 3f
2:
testq $0x8, %rcx /* is it the source indicator? */
jz 0b /* Ignore it otherwise */
movq %rcx, %rsi /* For ever source page do a copy */
andq $0xfffffffffffff000, %rsi
movq $512, %rcx
rep ; movsq
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 by reloading %cr3 here, it's handy,
* and not processor dependent.
*/
movq %cr3, %rax
movq %rax, %cr3
/* set all of the registers to known values */
/* leave %rsp alone */
xorq %rax, %rax
xorq %rbx, %rbx
xorq %rcx, %rcx
xorq %rdx, %rdx
xorq %rsi, %rsi
xorq %rdi, %rdi
xorq %rbp, %rbp
xorq %r8, %r8
xorq %r9, %r9
xorq %r10, %r9
xorq %r11, %r11
xorq %r12, %r12
xorq %r13, %r13
xorq %r14, %r14
xorq %r15, %r15
ret
relocate_new_kernel_end:
.globl relocate_new_kernel_size
relocate_new_kernel_size:
.quad relocate_new_kernel_end - relocate_new_kernel
#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
......
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