x86: add hooks for kmemcheck

The hooks that we modify are:
- Page fault handler (to handle kmemcheck faults)
- Debug exception handler (to hide pages after single-stepping
  the instruction that caused the page fault)

Also redefine memset() to use the optimized version if kmemcheck is
enabled.

(Thanks to Pekka Enberg for minimizing the impact on the page fault
handler.)

As kmemcheck doesn't handle MMX/SSE instructions (yet), we also disable
the optimized xor code, and rely instead on the generic C implementation
in order to avoid false-positive warnings.

Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>

[whitespace fixlet]
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 949708d7a481..80cafd76a2bd 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -111,7 +111,7 @@ static pte_t * __init one_page_table_init(pmd_t *pmd)
                 pte_t *page_table = NULL;
 
                 if (after_bootmem) {
-#ifdef CONFIG_DEBUG_PAGEALLOC
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
                         page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
 #endif
                         if (!page_table)