On Tue, 2012-02-21 at 18:32 +1100, Michael Ellerman wrote:
> In commit 54321242afe ("Disable interrupts early in Program Check"), we
> switched from enabling to disabling interrupts in program_check_common.
> Whereas ENABLE_INTS leaves r3 untouched, if lockdep is enabled DISABLE_INTS
> calls into lockdep code and will clobber r3. That means we pass a bogus
> struct pt_regs* into program_check_exception() and all hell breaks loose.
> So load our regs pointer into r3 after we call DISABLE_INTS.