[PATCH 24/37] x86, pkeys: dump PKRU with other kernel registers

From: Dave Hansen
Date: Mon Nov 16 2015 - 22:39:32 EST

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 2015-11-16 12:35:46.445675988 -0800
+++ b/arch/x86/kernel/process_64.c 2015-11-16 12:35:46.449676170 -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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