From f85612967c93b67b10dd240e3e8bf8a0eee9def7 Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Fri, 4 Apr 2008 00:53:23 +0200 Subject: 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 [whitespace fixlet] Signed-off-by: Pekka Enberg Signed-off-by: Ingo Molnar [rebased for mainline inclusion] Signed-off-by: Vegard Nossum --- arch/x86/mm/fault.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'arch/x86/mm/fault.c') diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index c6acc6326374..baa0e86adfbc 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -14,6 +14,7 @@ #include /* dotraplinkage, ... */ #include /* pgd_*(), ... */ +#include /* kmemcheck_*(), ... */ /* * Page fault error code bits: @@ -956,6 +957,13 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code) /* 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 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code) * 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)) -- cgit v1.2.2