On Fri, 22 Apr, at 04:12:59PM, Ard Biesheuvel wrote: > On 22 April 2016 at 15:51, Mark Rutland <mark.rutland@xxxxxxx> wrote: > > Some firmware erroneously unmask IRQs (and potentially other architecture > > specific exceptions) during runtime services functions, in violation of both > > common sense and the UEFI specification. This can result in a number of issues > > if said exceptions are taken when they are expected to be masked, and > > additionally can confuse IRQ tracing if the original mask state is not > > restored prior to returning from firmware. > > > > In practice it's difficult to check that firmware never unmasks exceptions, but > > we can at least check that the IRQ flags are at least consistent upon entry to > > and return from a runtime services function call. This series implements said > > check in the shared EFI runtime wrappers code, after an initial round of > > refactoring such that this can be generic. > > > > I have left ia64 as-is, without this check, as ia64 doesn't currently use the > > generic runtime wrappers, has many special cases for the runtime calls which > > don't fit well with the generic code, and I don't expect a new, buggy ia64 > > firmware to appear soon. > > > > The first time corruption of the IRQ flags is detected, we dump a stack trace, > > and set TAINT_FIRMWARE_WORKAROUND. Additionally, and in all subsequent cases, > > we log (with ratelimiting) the specific corruption of the flags, and restore > > the expected flags to avoid redundant warnings elsewhere. > > > > Since v1 [1]: > > * Fix thinko: s/local_irq_save/local_save_flags/ > > * Remove ifdefs after conversion > > * Remove reundant semicolon from x86 patch > > * Move efi_call_virt_check_flags before first use > > * Add Acked-bys and Reviewed-bys > > > > Ard, I assume that your Reviewed-by still stands for the final patch, even > > though efi_call_virt_check_flags moved. Please shout if that's not the case! > > > > No, that's fine. Thanks for respinning so quickly. > > > Hopefully you're also happy to extend that to the new patch removing the > > ifdefs once they become superfluous. > > > > Matt: in case your review bandwidth is limited atm, I'd much prefer > this series making v4.7 than the GOP stuff or the other stuff i have > been posting over the past weeks. I like this series a lot (well, ignoring the fact that the firmware is trying to eat itself). The runtime call code is much cleaner now, and this is a great precedent for any future multi-architecture quirks we may need. Queued for v4.7, thanks everyone! -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
