From mboxrd@z Thu Jan 1 00:00:00 1970 From: ext-mika.1.westerberg@nokia.com (Mika Westerberg) Date: Mon, 29 Mar 2010 12:26:32 +0300 Subject: [RFC 06/10] arm: kdump: implement copy_oldmem_page() In-Reply-To: References: <7b747cd930c20ae4a625c981d88e2773c706fce9.1269854500.git.ext-mika.1.westerberg@nokia.com> <0f8c479602b8957c49db7ac56b8f90ac6f4da5dc.1269854500.git.ext-mika.1.westerberg@nokia.com> <5d4c557a427346c129c8f6cc43c5819177c05ff5.1269854500.git.ext-mika.1.westerberg@nokia.com> Message-ID: <49c5365fe4f794390ca2a4de75365953e211ab3f.1269854500.git.ext-mika.1.westerberg@nokia.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This function is used by vmcore code to read a page from the old kernel memory. Signed-off-by: Mika Westerberg --- arch/arm/kernel/Makefile | 1 + arch/arm/kernel/crash_dump.c | 82 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 83 insertions(+), 0 deletions(-) create mode 100644 arch/arm/kernel/crash_dump.c diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 26d302c..ea023c6 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -39,6 +39,7 @@ obj-$(CONFIG_ARM_THUMBEE) += thumbee.o obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_ARM_UNWIND) += unwind.o obj-$(CONFIG_HAVE_TCM) += tcm.o +obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_CRUNCH) += crunch.o crunch-bits.o AFLAGS_crunch-bits.o := -Wa,-mcpu=ep9312 diff --git a/arch/arm/kernel/crash_dump.c b/arch/arm/kernel/crash_dump.c new file mode 100644 index 0000000..84382d3 --- /dev/null +++ b/arch/arm/kernel/crash_dump.c @@ -0,0 +1,82 @@ +/* + * arch/arm/kernel/crash_dump.c + * + * Copyright (C) 2010 Nokia Corporation. + * + * This code is heavily based on x86 version found in + * arch/x86/kernel/crash_dump_32.c. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Author: Mika Westerberg + */ +#include +#include +#include +#include +#include + +/* buffer used when copying an old page to userspace */ +static void *kdump_buf_page; + +/* stores the physical address of elf header of crash image */ +unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX; + +/** + * copy_oldmem_page() - copy one page from old kernel memory + * @pfn: page frame number to be copied + * @buf: buffer where the copied page is placed + * @csize: number of bytes to copy + * @offset: offset in bytes into the page + * @userbuf: if set, @buf is int he user address space + * + * This function copies one page from old kernel memory into buffer pointed by + * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes + * copied or negative error in case of failure. + */ +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) { + if (!kdump_buf_page) { + printk(KERN_WARNING "Kdump: kdump buffer page not " + "allocated\n"); + kunmap_atomic(vaddr, KM_PTE0); + return -EFAULT; + } + + copy_page(kdump_buf_page, vaddr); + kunmap_atomic(vaddr, KM_PTE0); + + if (copy_to_user(buf, vaddr + offset, csize)) + return -EFAULT; + } else { + memcpy(buf, vaddr + offset, csize); + kunmap_atomic(vaddr, KM_PTE0); + } + + return csize; +} + +static int __init kdump_buf_page_init(void) +{ + kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!kdump_buf_page) { + printk(KERN_WARNING "Kdump: failed to allocate kdump buffer " + "page\n"); + return -ENOMEM; + } + + return 0; +} +arch_initcall(kdump_buf_page_init); -- 1.5.6.5