From 4ae362be509306eafa6441603686d33fefe321c1 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Mon, 9 Jan 2006 20:51:50 -0800 Subject: [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 Signed-off-by: Vivek Goyal Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile index be1880b..60c3f76 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 0000000..3f532df --- /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 +#include +#include + +#include + +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); diff --git a/arch/x86_64/kernel/Makefile b/arch/x86_64/kernel/Makefile index fe4cbd1..12bc540 100644 --- a/arch/x86_64/kernel/Makefile +++ b/arch/x86_64/kernel/Makefile @@ -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/ diff --git a/arch/x86_64/kernel/crash_dump.c b/arch/x86_64/kernel/crash_dump.c new file mode 100644 index 0000000..942deac --- /dev/null +++ b/arch/x86_64/kernel/crash_dump.c @@ -0,0 +1,47 @@ +/* + * 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 +#include + +#include +#include + +/** + * 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. + */ +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 = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE); + + if (userbuf) { + if (copy_to_user(buf, (vaddr + offset), csize)) { + iounmap(vaddr); + return -EFAULT; + } + } else + memcpy(buf, (vaddr + offset), csize); + + iounmap(vaddr); + return csize; +} diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 3b2e7b69..5378d7c7 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -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. */ diff --git a/kernel/Makefile b/kernel/Makefile index a940bac..1e03970 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -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 diff --git a/kernel/crash_dump.c b/kernel/crash_dump.c deleted file mode 100644 index fccb27d..0000000 --- a/kernel/crash_dump.c +++ /dev/null @@ -1,64 +0,0 @@ -/* - * 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 -#include -#include -#include -#include -#include - -#include -#include -#include - -/* Stores the physical address of elf header of crash image. */ -unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX; - -#ifndef HAVE_ARCH_COPY_OLDMEM_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. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, int userbuf) -{ - void *page, *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); - - if (userbuf) { - if (copy_to_user(buf, (page + offset), csize)) { - kfree(page); - return -EFAULT; - } - } else { - memcpy(buf, (page + offset), csize); - } - - kfree(page); - return csize; -} -#endif -- cgit v0.10.2