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authorWu Fengguang <fengguang.wu@intel.com>2010-05-26 14:43:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-27 09:12:47 -0700
commit36e15263aa5dcf3b72f1f88437e69497782b7ab8 (patch)
treea1cb0cfabb8069e96df5395ae68d187cd0ed371b /fs
parent57f87869f073929f8e8b3c73748aabb0cece19aa (diff)
kcore: add _text to KCORE_TEXT
Extend KCORE_TEXT to cover the pages between _text and _stext, to allow examining some important page table pages. `readelf -a` output on x86_64 before and after patch: Type Offset VirtAddr PhysAddr before LOAD 0x00007fff8100c000 0xffffffff81009000 0x0000000000000000 after LOAD 0x00007fff81003000 0xffffffff81000000 0x0000000000000000 The newly covered pages are: 0xffffffff81000000 <startup_64> etc. 0xffffffff81001000 <init_level4_pgt> 0xffffffff81002000 <level3_ident_pgt> 0xffffffff81003000 <level3_kernel_pgt> 0xffffffff81004000 <level2_fixmap_pgt> 0xffffffff81005000 <level1_fixmap_pgt> 0xffffffff81006000 <level2_ident_pgt> 0xffffffff81007000 <level2_kernel_pgt> 0xffffffff81008000 <level2_spare_pgt> Before patch, /proc/kcore shows outdated contents for the above page table pages, for example: (gdb) p level3_ident_pgt $1 = {<text variable, no debug info>} 0xffffffff81002000 <level3_ident_pgt> (gdb) p/x *((pud_t *)&level3_ident_pgt)@512 $2 = {{pud = 0x1006063}, {pud = 0x0} <repeats 511 times>} while the real content is: root@hp /home/wfg# hexdump -s 0x1002000 -n 4096 /dev/mem 1002000 6063 0100 0000 0000 8067 0000 0000 0000 1002010 0000 0000 0000 0000 0000 0000 0000 0000 * 1003000 That is, on a x86_64 box with 2GB memory, we can see first-1GB / full-2GB identity mapping before/after patch: (gdb) p/x *((pud_t *)&level3_ident_pgt)@512 before $1 = {{pud = 0x1006063}, {pud = 0x0} <repeats 511 times>} after $1 = {{pud = 0x1006063}, {pud = 0x8067}, {pud = 0x0} <repeats 510 times>} Obviously the content before patch is wrong. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/kcore.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index c837a77351be..6f37c391468d 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -588,7 +588,7 @@ static struct kcore_list kcore_text;
*/
static void __init proc_kcore_text_init(void)
{
- kclist_add(&kcore_text, _stext, _end - _stext, KCORE_TEXT);
+ kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
}
#else
static void __init proc_kcore_text_init(void)