diff options
| author | Andi Kleen <andi@firstfloor.org> | 2010-11-19 13:30:25 +0100 |
|---|---|---|
| committer | Andi Kleen <ak@linux.intel.com> | 2010-11-19 13:31:39 +0100 |
| commit | cb58f049ae6709ddbab71be199390dc6852018cd (patch) | |
| tree | c298fa1bf42fb1d6b69d50e39e55716e334b1a1b | |
| parent | fe61906edce9e70d02481a77a617ba1397573dce (diff) | |
| download | linux-mce-2.6-mce/crashdump.tar.gz | |
MCE: Disable MCEs during crash dumpmce/crashdump
When a crash kernel is doing a crash dump the previous kernel's
memory might be poisoned. Avoid machine checking in this case,
by disabling machine checks during the access.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
| -rw-r--r-- | arch/x86/kernel/crash_dump_32.c | 5 | ||||
| -rw-r--r-- | arch/x86/kernel/crash_dump_64.c | 36 |
2 files changed, 36 insertions, 5 deletions
diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_32.c index d5cd13945d5a48..04df58e9763051 100644 --- a/arch/x86/kernel/crash_dump_32.c +++ b/arch/x86/kernel/crash_dump_32.c @@ -11,6 +11,7 @@ #include <linux/crash_dump.h> #include <asm/uaccess.h> +#include <asm/mce.h> static void *kdump_buf_page; @@ -64,7 +65,9 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, vaddr = kmap_atomic_pfn(pfn); if (!userbuf) { + mce_disable_error_reporting(); memcpy(buf, (vaddr + offset), csize); + mce_reenable_error_reporting(); kunmap_atomic(vaddr, KM_PTE0); } else { if (!kdump_buf_page) { @@ -73,7 +76,9 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, kunmap_atomic(vaddr, KM_PTE0); return -EFAULT; } + mce_disable_error_reporting(); copy_page(kdump_buf_page, vaddr); + mce_reenable_error_reporting(); kunmap_atomic(vaddr, KM_PTE0); if (copy_to_user(buf, (kdump_buf_page + offset), csize)) return -EFAULT; diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c index 994828899e0983..9cba196221c780 100644 --- a/arch/x86/kernel/crash_dump_64.c +++ b/arch/x86/kernel/crash_dump_64.c @@ -9,6 +9,8 @@ #include <linux/crash_dump.h> #include <linux/uaccess.h> #include <linux/io.h> +#include <linux/mm.h> +#include <asm/mce.h> /* Stores the physical address of elf header of crash image. */ unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX; @@ -30,22 +32,46 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, unsigned long offset, int userbuf) { void *vaddr; + struct page *p[2] = { NULL, NULL }; + unsigned long poff = (unsigned long)buf & ~PAGE_MASK; if (!csize) return 0; + if (userbuf) { + if (get_user_pages_fast((unsigned long)buf, + ((csize + poff) >> PAGE_SHIFT) + 1, + 1, p) < 0) + return -EFAULT; + } vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE); + csize = -ENOMEM; if (!vaddr) - return -ENOMEM; + goto out; + + /* Disable MCEs temporarily so that we don't fault on memory errors */ + get_cpu(); + mce_disable_error_reporting(); if (userbuf) { - if (copy_to_user(buf, vaddr + offset, csize)) { - iounmap(vaddr); - return -EFAULT; - } + unsigned len = min(csize, PAGE_SIZE - poff); + + memcpy(page_address(p[0]) + poff, vaddr + offset, len); + if (p[1]) + memcpy(page_address(p[1]), vaddr + offset + len, + csize - len); } else memcpy(buf, vaddr + offset, csize); + mce_reenable_error_reporting(); + put_cpu(); + +out: + if (p[0]) + put_page(p[0]); + if (p[1]) + put_page(p[1]); + set_iounmap_nonlazy(); iounmap(vaddr); return csize; |