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>
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index c6acc63..baa0e86 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -14,6 +14,7 @@
#include <asm/traps.h> /* dotraplinkage, ... */
#include <asm/pgalloc.h> /* pgd_*(), ... */
+#include <asm/kmemcheck.h> /* kmemcheck_*(), ... */
/*
* Page fault error code bits:
@@ -956,6 +957,13 @@
/* Get the faulting address: */
address = read_cr2();
+ /*
+ * Detect and handle instructions that would cause a page fault for
+ * both a tracked kernel page and a userspace page.
+ */
+ if (kmemcheck_active(regs))
+ kmemcheck_hide(regs);
+
if (unlikely(kmmio_fault(regs, address)))
return;
@@ -973,9 +981,13 @@
* protection error (error_code & 9) == 0.
*/
if (unlikely(fault_in_kernel_space(address))) {
- if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
- vmalloc_fault(address) >= 0)
- return;
+ if (!(error_code & (PF_RSVD | PF_USER | PF_PROT))) {
+ if (vmalloc_fault(address) >= 0)
+ return;
+
+ if (kmemcheck_fault(regs, address, error_code))
+ return;
+ }
/* Can handle a stale RO->RW TLB: */
if (spurious_fault(error_code, address))
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 34c1bfb..f53b57e 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -213,7 +213,7 @@
if (!after_bootmem)
init_gbpages();
-#ifdef CONFIG_DEBUG_PAGEALLOC
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
/*
* For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
* This will simplify cpa(), which otherwise needs to support splitting
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 949708d..80cafd7 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -111,7 +111,7 @@
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)