| Message ID | 20160425105153.GR2829@codeblueprint.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Apr 25, 2016 at 11:51:53AM +0100, Matt Fleming wrote: > On Mon, 25 Apr, at 11:40:09AM, Mark Rutland wrote: > > > > It looks like irqs_disabled_flags() will do what you expect, and ignore > > everything but the interrupt flag. > > > > However, for ARM that will ignore the other exceptions we've seen FW > > erroneously unmask (e.g. FIQ), which is unfortunate, as fiddling with > > those is just as disastrous. > > Bah, right. > > > Would you be happy with an arch_efi_call_check_flags(before, after), > > instead? That way we can make the flags we check arch-specific. > > Could we just make the flag mask arch-specific instead of the call > since the rest of efi_call_virt_check_flags() is good? Yup, I meant that arch_efi_call_check_flags would only do the flag comparison, only replacing the bit currently in the WARN_ON_ONCE(). > Something like this (uncompiled, untested, half-baked), > > --- > > diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c > index c38b1cfc26e2..057d00bee7d6 100644 > --- a/drivers/firmware/efi/runtime-wrappers.c > +++ b/drivers/firmware/efi/runtime-wrappers.c > @@ -25,9 +25,12 @@ > static void efi_call_virt_check_flags(unsigned long flags, const char *call) > { > unsigned long cur_flags; > + bool mismatch; > > local_save_flags(cur_flags); > - if (!WARN_ON_ONCE(cur_flags != flags)) > + > + mismatch = (cur_flags ^ flags) & ARCH_EFI_IRQ_FLAGS_MASK; > + if (!WARN_ON_ONCE(mismatch)) > return; This style also works for me. Should I respin patch 6 as a series doing the above? I assume that the first 5 patches are fine as-is. Thanks, Mark.
On Mon, 25 Apr, at 12:04:55PM, Mark Rutland wrote: > On Mon, Apr 25, 2016 at 11:51:53AM +0100, Matt Fleming wrote: > > On Mon, 25 Apr, at 11:40:09AM, Mark Rutland wrote: > > > > > > It looks like irqs_disabled_flags() will do what you expect, and ignore > > > everything but the interrupt flag. > > > > > > However, for ARM that will ignore the other exceptions we've seen FW > > > erroneously unmask (e.g. FIQ), which is unfortunate, as fiddling with > > > those is just as disastrous. > > > > Bah, right. > > > > > Would you be happy with an arch_efi_call_check_flags(before, after), > > > instead? That way we can make the flags we check arch-specific. > > > > Could we just make the flag mask arch-specific instead of the call > > since the rest of efi_call_virt_check_flags() is good? > > Yup, I meant that arch_efi_call_check_flags would only do the flag > comparison, only replacing the bit currently in the WARN_ON_ONCE(). > > > Something like this (uncompiled, untested, half-baked), > > > > --- > > > > diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c > > index c38b1cfc26e2..057d00bee7d6 100644 > > --- a/drivers/firmware/efi/runtime-wrappers.c > > +++ b/drivers/firmware/efi/runtime-wrappers.c > > @@ -25,9 +25,12 @@ > > static void efi_call_virt_check_flags(unsigned long flags, const char *call) > > { > > unsigned long cur_flags; > > + bool mismatch; > > > > local_save_flags(cur_flags); > > - if (!WARN_ON_ONCE(cur_flags != flags)) > > + > > + mismatch = (cur_flags ^ flags) & ARCH_EFI_IRQ_FLAGS_MASK; > > + if (!WARN_ON_ONCE(mismatch)) > > return; > > This style also works for me. Cool. One thing that occurred to me after I sent it is that technically we should either, 1) make 'mismatch' an int or 2) do mismatch = !!((cur_flags ^ flags) & ARCH_EFI_IRQ_FLAGS_MASK) Either is fine with me, I just don't want to leave the implicit conversion to C's type system. > Should I respin patch 6 as a series doing the above? > > I assume that the first 5 patches are fine as-is. Yep, they're fine. Sure, go ahead and respin patch 6.
diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c index c38b1cfc26e2..057d00bee7d6 100644 --- a/drivers/firmware/efi/runtime-wrappers.c +++ b/drivers/firmware/efi/runtime-wrappers.c @@ -25,9 +25,12 @@ static void efi_call_virt_check_flags(unsigned long flags, const char *call) { unsigned long cur_flags; + bool mismatch; local_save_flags(cur_flags); - if (!WARN_ON_ONCE(cur_flags != flags)) + + mismatch = (cur_flags ^ flags) & ARCH_EFI_IRQ_FLAGS_MASK; + if (!WARN_ON_ONCE(mismatch)) return; add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE);