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authorSiddha, Suresh B <suresh.b.siddha@intel.com>2005-11-05 11:25:53 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-14 22:55:14 -0500
commitf6c2e3330d3fdd5474bc3756da46fca889a30e33 (patch)
tree41b7534c39a6aea4ae1f0a75c6eb03f6e4b6312c /arch/i386
parent69d81fcde7797342417591ba7affb372b9c86eae (diff)
[PATCH] x86_64: Unmap NULL during early bootup
We should zap the low mappings, as soon as possible, so that we can catch kernel bugs more effectively. Previously early boot had NULL mapped and didn't trap on NULL references. This patch introduces boot_level4_pgt, which will always have low identity addresses mapped. Druing boot, all the processors will use this as their level4 pgt. On BP, we will switch to init_level4_pgt as soon as we enter C code and zap the low mappings as soon as we are done with the usage of identity low mapped addresses. On AP's we will zap the low mappings as soon as we jump to C code. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386')
-rw-r--r--arch/i386/kernel/acpi/boot.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index 82754bb80e20..f36677241ecd 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -542,7 +542,7 @@ acpi_scan_rsdp(unsigned long start, unsigned long length)
542 * RSDP signature. 542 * RSDP signature.
543 */ 543 */
544 for (offset = 0; offset < length; offset += 16) { 544 for (offset = 0; offset < length; offset += 16) {
545 if (strncmp((char *)(start + offset), "RSD PTR ", sig_len)) 545 if (strncmp((char *)(phys_to_virt(start) + offset), "RSD PTR ", sig_len))
546 continue; 546 continue;
547 return (start + offset); 547 return (start + offset);
548 } 548 }