From: Ira Weiny <[email protected]> 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 <[email protected]> Cc: Dan Williams <[email protected]> Signed-off-by: Ira Weiny <[email protected]> --- Changes from V5: From Dave Hansen Remove 'we' from comment 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..0e0e90968f57 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) is enabled. + * + * However, if PKS is not enabled WARN if this exception is seen + * because there are no user pages in the kernel portion of the address + * space. */ - 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 /* -- 2.28.0.rc0.12.gb6a658bd00c9
