From c0b17b5bd4b7b98e7c6b67c9f69343b64711271b Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 12 Feb 2016 13:02:25 -0800 Subject: [PATCH] x86/mm/pkeys: Dump PKRU with other kernel registers Protection Keys never affect kernel mappings. But, they can affect whether the kernel will fault when it touches a user mapping. The kernel doesn't touch user mappings without some careful choreography and these accesses don't generally result in oopses. But, if one does, we definitely want to have PKRU available so we can figure out if protection keys played a role. Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210225.BF0D4482@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/process_64.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index b9d99e0f82c4..776229e98202 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -116,6 +116,8 @@ void __show_regs(struct pt_regs *regs, int all) printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2); printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7); + if (boot_cpu_has(X86_FEATURE_OSPKE)) + printk(KERN_DEFAULT "PKRU: %08x\n", read_pkru()); } void release_thread(struct task_struct *dead_task) -- 2.30.2