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. 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 Since v2 [2]: * Drop the refactoring patches (1-5), which Matt has queued * Add per-arch ARCH_EFI_IRQ_FLAGS_MASK, as discussed for v2 [3,4] As with v2, this has been build-tested for each target, but other than arm64 I don't have a good platform for testing. Hopefully this causes fewer explosions than v2. Thanks, Mark. [1] https://lkml.org/lkml/2016/4/21/260 [2] https://lkml.org/lkml/2016/4/22/542 [3] https://lkml.org/lkml/2016/4/25/230 [4] https://lkml.org/lkml/2016/4/25/243 Mark Rutland (5): efi/runtime-wrappers: detect FW irq flag corruption arm64/efi: enable runtime call flag checking arm/efi: enable runtime call flag checking x86/efi: enable runtime call flag checking efi/runtime-wrappers: remove ARCH_EFI_IRQ_FLAGS_MASK ifdef arch/arm/include/asm/efi.h | 5 +++++ arch/arm64/include/asm/efi.h | 3 +++ arch/x86/include/asm/efi.h | 4 +++- drivers/firmware/efi/runtime-wrappers.c | 25 +++++++++++++++++++++++++ 4 files changed, 36 insertions(+), 1 deletion(-) -- 1.9.1 -- 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
