From: Ira Weiny ira.weiny@intel.com
Previously if a Protection key fault occurred it indicated something very wrong because user page mappings are not supposed to be in the kernel address space.
Now PKey faults may happen on kernel mappings if the feature is enabled.
Remove the warning in the fault path and allow the oops to occur without extra debugging if PKS is enabled.
Cc: Sean Christopherson seanjc@google.com Cc: Dan Williams dan.j.williams@intel.com Signed-off-by: Ira Weiny ira.weiny@intel.com
--- Changes from V4: From Sean Christopherson Clean up commit message and comment Change cpu_feature_enabled to be in WARN_ON check --- arch/x86/mm/fault.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index a73347e2cdfc..c32d01803e26 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1141,11 +1141,15 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code, unsigned long address) { /* - * Protection keys exceptions only happen on user pages. We - * have no user pages in the kernel portion of the address - * space, so do not expect them here. + * X86_PF_PK (Protection key exceptions) may occur on kernel addresses + * when PKS (PKeys Supervisor) are enabled. + * + * If PKS is not enabled an exception should only happen on user pages. + * Because, we have no user pages in the kernel portion of the address + * space something must have gone very wrong and we should WARN. */ - WARN_ON_ONCE(hw_error_code & X86_PF_PK); + WARN_ON_ONCE(!cpu_feature_enabled(X86_FEATURE_PKS) && + (hw_error_code & X86_PF_PK));
#ifdef CONFIG_X86_32 /*