x86/mm/pkeys: Dump PKRU with other kernel registers

hansendc · Ingo Molnar · commit c0b17b5bd4b7 · 2016-02-18T19:46:29.000+01:00
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 <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20160212210225.BF0D4482@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git 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)

Original file line number	Diff line number	Diff line change
`@@ -116,6 +116,8 @@ void __show_regs(struct pt_regs *regs, int all)`
`116`	`116`	`printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);`
`117`	`117`	`printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);`
`118`	`118`
	`119`	`+ if (boot_cpu_has(X86_FEATURE_OSPKE))`
	`120`	`+ printk(KERN_DEFAULT "PKRU: %08x\n", read_pkru());`
`119`	`121`	`}`
`120`	`122`
`121`	`123`	`void release_thread(struct task_struct *dead_task)`