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author | 2006-01-09 20:51:50 -0800 | |
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committer | 2006-01-10 08:01:28 -0800 | |
commit | 4ae362be509306eafa6441603686d33fefe321c1 (patch) | |
tree | d16a59e9c85945a6cc4a0945c80c0ecd97815923 /arch/i386 | |
parent | [PATCH] kdump: x86_64 save cpu registers upon crash (diff) | |
download | linux-4ae362be509306eafa6441603686d33fefe321c1.tar.gz linux-4ae362be509306eafa6441603686d33fefe321c1.tar.bz2 linux-4ae362be509306eafa6441603686d33fefe321c1.zip |
[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: Rachita Kothiyal <rachita@in.ibm.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386')
-rw-r--r-- | arch/i386/kernel/Makefile | 1 | ||||
-rw-r--r-- | arch/i386/kernel/crash_dump.c | 74 |
2 files changed, 75 insertions, 0 deletions
diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile index be1880bb75b4..60c3f76dfca4 100644 --- a/arch/i386/kernel/Makefile +++ b/arch/i386/kernel/Makefile @@ -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 diff --git a/arch/i386/kernel/crash_dump.c b/arch/i386/kernel/crash_dump.c new file mode 100644 index 000000000000..3f532df488bc --- /dev/null +++ b/arch/i386/kernel/crash_dump.c @@ -0,0 +1,74 @@ +/* + * 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); |