[PATCH 21/34] x86, pkeys: dump PKRU with other kernel registers

[Dave Hansen]

From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>

I'm a bit ambivalent about whether this is needed or not.

Protection Keys never affect kernel mappings.  But, they can
affect whether the kernel will fault when it touches a user
mapping.  But, the kernel doesn't touch user mappings without
some careful choreography and these accesses don't generally
result in oopses.

Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
---

 b/arch/x86/kernel/process_64.c |    2 ++
 1 file changed, 2 insertions(+)

diff -puN arch/x86/kernel/process_64.c~pkeys-30-kernel-error-dumps arch/x86/kernel/process_64.c
--- a/arch/x86/kernel/process_64.c~pkeys-30-kernel-error-dumps	2015-12-03 16:21:27.874773264 -0800
+++ b/arch/x86/kernel/process_64.c	2015-12-03 16:21:27.877773400 -0800
@@ -116,6 +116,8 @@ void __show_regs(struct pt_regs *regs, i
 	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)
_
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