Commit 4ae362be authored by Vivek Goyal's avatar Vivek Goyal Committed by Linus Torvalds
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[PATCH] kdump: read previous kernel's memory



- Moving the crash_dump.c file to arch dependent part as kmap_atomic_pfn is
  specific to i386 and highmem may not exist in other archs.

- Use ioremap for x86_64 to map the previous kernel memory.

- In copy_oldmem_page(), we now directly copy to the user/kernel buffer and
  avoid the unneccesary copy to a kmalloc'd page.
Signed-off-by: default avatarRachita Kothiyal <rachita@in.ibm.com>
Signed-off-by: default avatarVivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ec9ce0db
......@@ -25,6 +25,7 @@ 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-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_X86_NUMAQ) += numaq.o
obj-$(CONFIG_X86_SUMMIT_NUMA) += summit.o
obj-$(CONFIG_KPROBES) += kprobes.o
......
/*
* kernel/crash_dump.c - Memory preserving reboot related code.
*
* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
* Copyright (C) IBM Corporation, 2004. All rights reserved
*/
#include <linux/errno.h>
#include <linux/highmem.h>
#include <linux/crash_dump.h>
#include <asm/uaccess.h>
static void *kdump_buf_page;
/**
* copy_oldmem_page - copy one page from "oldmem"
* @pfn: page frame number to be copied
* @buf: target memory address for the copy; this can be in kernel address
* space or user address space (see @userbuf)
* @csize: number of bytes to copy
* @offset: offset in bytes into the page (based on pfn) to begin the copy
* @userbuf: if set, @buf is in user address space, use copy_to_user(),
* otherwise @buf is in kernel address space, use memcpy().
*
* Copy a page from "oldmem". For this page, there is no pte mapped
* in the current kernel. We stitch up a pte, similar to kmap_atomic.
*
* Calling copy_to_user() in atomic context is not desirable. Hence first
* copying the data to a pre-allocated kernel page and then copying to user
* space in non-atomic context.
*/
ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
size_t csize, unsigned long offset, int userbuf)
{
void *vaddr;
if (!csize)
return 0;
vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
if (!userbuf) {
memcpy(buf, (vaddr + offset), csize);
kunmap_atomic(vaddr, KM_PTE0);
} else {
if (!kdump_buf_page) {
printk(KERN_WARNING "Kdump: Kdump buffer page not"
" allocated\n");
return -EFAULT;
}
copy_page(kdump_buf_page, vaddr);
kunmap_atomic(vaddr, KM_PTE0);
if (copy_to_user(buf, (kdump_buf_page + offset), csize))
return -EFAULT;
}
return csize;
}
static int __init kdump_buf_page_init(void)
{
int ret = 0;
kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!kdump_buf_page) {
printk(KERN_WARNING "Kdump: Failed to allocate kdump buffer"
" page\n");
ret = -ENOMEM;
}
return ret;
}
arch_initcall(kdump_buf_page_init);
......@@ -22,6 +22,7 @@ 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_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_PM) += suspend.o
obj-$(CONFIG_SOFTWARE_SUSPEND) += suspend_asm.o
obj-$(CONFIG_CPU_FREQ) += cpufreq/
......
......@@ -5,21 +5,12 @@
* Copyright (C) IBM Corporation, 2004. All rights reserved
*/
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/crash_dump.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/kexec.h>
/* Stores the physical address of elf header of crash image. */
unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
#include <asm/io.h>
#ifndef HAVE_ARCH_COPY_OLDMEM_PAGE
/**
* copy_oldmem_page - copy one page from "oldmem"
* @pfn: page frame number to be copied
......@@ -34,31 +25,23 @@ unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
* in the current kernel. We stitch up a pte, similar to kmap_atomic.
*/
ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
size_t csize, unsigned long offset, int userbuf)
size_t csize, unsigned long offset, int userbuf)
{
void *page, *vaddr;
void *vaddr;
if (!csize)
return 0;
page = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!page)
return -ENOMEM;
vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
copy_page(page, vaddr);
kunmap_atomic(vaddr, KM_PTE0);
vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
if (userbuf) {
if (copy_to_user(buf, (page + offset), csize)) {
kfree(page);
if (copy_to_user(buf, (vaddr + offset), csize)) {
iounmap(vaddr);
return -EFAULT;
}
} else {
memcpy(buf, (page + offset), csize);
}
} else
memcpy(buf, (vaddr + offset), csize);
kfree(page);
iounmap(vaddr);
return csize;
}
#endif
......@@ -35,6 +35,9 @@ static size_t elfcorebuf_sz;
/* Total size of vmcore file. */
static u64 vmcore_size;
/* Stores the physical address of elf header of crash image. */
unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
struct proc_dir_entry *proc_vmcore = NULL;
/* Reads a page from the oldmem device from given offset. */
......
......@@ -30,7 +30,6 @@ obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_SYSFS) += ksysfs.o
obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_SECCOMP) += seccomp.o
obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
......
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