| Message ID | 1329809550-29336-1-git-send-email-michael@ellerman.id.au (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
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. Ah nice catch, thanks ! Cheers, Ben. > Signed-off-by: Michael Ellerman <michael@ellerman.id.au> > --- > arch/powerpc/kernel/exceptions-64s.S | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S > index 3844ca7..15c5a4f 100644 > --- a/arch/powerpc/kernel/exceptions-64s.S > +++ b/arch/powerpc/kernel/exceptions-64s.S > @@ -774,8 +774,8 @@ alignment_common: > program_check_common: > EXCEPTION_PROLOG_COMMON(0x700, PACA_EXGEN) > bl .save_nvgprs > - addi r3,r1,STACK_FRAME_OVERHEAD > DISABLE_INTS > + addi r3,r1,STACK_FRAME_OVERHEAD > bl .program_check_exception > b .ret_from_except >
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 3844ca7..15c5a4f 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -774,8 +774,8 @@ alignment_common: program_check_common: EXCEPTION_PROLOG_COMMON(0x700, PACA_EXGEN) bl .save_nvgprs - addi r3,r1,STACK_FRAME_OVERHEAD DISABLE_INTS + addi r3,r1,STACK_FRAME_OVERHEAD bl .program_check_exception b .ret_from_except
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. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> --- arch/powerpc/kernel/exceptions-64s.S | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)