On Mon, 25 Apr, at 02:46:29PM, Mark Rutland wrote: > Note: this is largely a rework of the final patch from v2 [2], which now has a > per-arch component (and hence additional patches). The rest of v2 has already > been picked up, and hence dropped from this posting. > > 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 (patches 1-5 of [2]). > > 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. Thanks Mark. I've picked up the series and applied it to the v4.7 queue. -- 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
