Hi Ard, On 14/12/2018 16:40, Julien Thierry wrote: > > > On 14/12/2018 15:49, Ard Biesheuvel wrote: >> On Fri, 14 Dec 2018 at 16:23, Julien Thierry <[email protected]> wrote: >>> >>> Hi, >>> >>> On 13/12/2018 15:03, Julien Thierry wrote: >>>> >>>> Argh, not as simple as I had expected. >>>> >>>> Turns out include/linux/efi.h does not include asm/efi.h (including it >>>> at the beginning of the file breaks the build because asm/efi.h misses >>>> the efi type definitions. >>>> >>>> So a thing like: >>>> >>>> #ifndef efi_get_irqflags >>>> #define efi_get_irqflags(flags) local_save_flags(flags) >>>> #endif >>>> >>>> in include/linux/efi.h cannot be overridden. >>>> >>>> Either I would need to introduce the definitions arm, arm64 and x86 (I >>>> don't think there are other arch supporting EFI right now) or I'll need >>>> to come up with another solution. >>>> >>> >> >> It might be a bit nasty, but can we put the #ifndef above in >> runtime-wrappers.c directly? The only reference in linux/efi.h is a >> macro, so that shouldn't matter afaict. >> > > Sadly, in arch/x86/platform/uv/bios_uv.c, uv_bios_call() has a reference > to the macro efi_call_virt_pointer() which wouldn't be able to see the > definition in runtime-wrappers.c > > Otherwise, we could've moved efi_call_virt_pointer() and > __efi_call_virt_pointer in runtime-wrappers.c and things would not have > been as nasty. > > But no, I don't think we can do that without breaking some x86 build :( . >
Since the above does not work, would the solution with the HAVE_GENERIC_EFI_FLAGS below be acceptable to you? Or would you rather I defined helpers in <asm/efi.h> for all arm/arm64/x86? Or neither and I shall find another way? Thanks, Julien >> >>> Would the following patch be acceptable for the EFI generic side? >>> >>> If it is, I'll add it to the next iteration of this series. >>> >>> Thanks, >>> >>> Julien >>> >>> --> >>> >>> From 7acaa8e17142263addafb18ae10bd5d2d49cfb39 Mon Sep 17 00:00:00 2001 >>> From: Julien Thierry <[email protected]> >>> Date: Fri, 14 Dec 2018 14:20:13 +0000 >>> Subject: [RFC] efi: Let architectures decide the flags that should be >>> saved/restored >>> >>> Currently, irqflags are saved before calling runtime services and >>> checked for mismatch on return. >>> >>> Add a config option to let architectures define a set of flags to be >>> checked and (if needed) restored when coming back from runtime services. >>> This allows to use check flags that are not necesarly related to >>> irqflags. >>> >>> Signed-off-by: Julien Thierry <[email protected]> >>> --- >>> arch/Kconfig | 8 ++++++++ >>> drivers/firmware/efi/runtime-wrappers.c | 4 ++-- >>> include/linux/efi.h | 12 ++++++++++-- >>> 3 files changed, 20 insertions(+), 4 deletions(-) >>> >>> diff --git a/arch/Kconfig b/arch/Kconfig >>> index e1e540f..cbec325 100644 >>> --- a/arch/Kconfig >>> +++ b/arch/Kconfig >>> @@ -695,6 +695,14 @@ config HAVE_ARCH_HASH >>> file which provides platform-specific implementations of some >>> functions in <linux/hash.h> or fs/namei.c. >>> >>> +config HAVE_GENERIC_EFI_FLAGS >>> + bool >>> + default n >>> + help >>> + Architecture defines a set of flags that EFI runtime services >>> + should take care to restore when returning to the OS. >>> + If this is not set, the set of flags defaults to the arch >>> irqflags. >>> + >>> config ISA_BUS_API >>> def_bool ISA >>> >>> diff --git a/drivers/firmware/efi/runtime-wrappers.c >>> b/drivers/firmware/efi/runtime-wrappers.c >>> index 8903b9c..6dafa04 100644 >>> --- a/drivers/firmware/efi/runtime-wrappers.c >>> +++ b/drivers/firmware/efi/runtime-wrappers.c >>> @@ -93,7 +93,7 @@ void efi_call_virt_check_flags(unsigned long flags, const >>> char *call) >>> { >>> unsigned long cur_flags, mismatch; >>> >>> - local_save_flags(cur_flags); >>> + efi_save_flags(cur_flags); >>> >>> mismatch = flags ^ cur_flags; >>> if (!WARN_ON_ONCE(mismatch & ARCH_EFI_IRQ_FLAGS_MASK)) >>> @@ -102,7 +102,7 @@ void efi_call_virt_check_flags(unsigned long flags, >>> const char *call) >>> add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_NOW_UNRELIABLE); >>> pr_err_ratelimited(FW_BUG "IRQ flags corrupted (0x%08lx=>0x%08lx) >>> by EFI %s\n", >>> flags, cur_flags, call); >>> - local_irq_restore(flags); >>> + efi_restore_flags(flags); >>> } >>> >>> /* >>> diff --git a/include/linux/efi.h b/include/linux/efi.h >>> index 100ce4a..41c110a 100644 >>> --- a/include/linux/efi.h >>> +++ b/include/linux/efi.h >>> @@ -1594,6 +1594,14 @@ enum efi_secureboot_mode { >>> >>> void efi_retrieve_tpm2_eventlog(efi_system_table_t *sys_table); >>> >>> +#ifdef CONFIG_HAVE_GENERIC_EFI_FLAGS >>> +#define efi_save_flags(state_flags) arch_efi_save_flags(state_flags) >>> +#define efi_restore_flags(state_flags) arch_efi_restore_flags(state_flags) >>> +#else >>> +#define efi_save_flags(state_flags) local_save_flags(state_flags) >>> +#define efi_restore_flags(state_flags) local_irq_restore(state_flags) >>> +#endif >>> + >>> /* >>> * Arch code can implement the following three template macros, avoiding >>> * reptition for the void/non-void return cases of {__,}efi_call_virt(): >>> @@ -1621,7 +1629,7 @@ enum efi_secureboot_mode { >>> \ >>> arch_efi_call_virt_setup(); \ >>> \ >>> - local_save_flags(__flags); \ >>> + efi_save_flags(__flags); \ >>> __s = arch_efi_call_virt(p, f, args); \ >>> efi_call_virt_check_flags(__flags, __stringify(f)); \ >>> \ >>> @@ -1636,7 +1644,7 @@ enum efi_secureboot_mode { >>> \ >>> arch_efi_call_virt_setup(); \ >>> \ >>> - local_save_flags(__flags); \ >>> + efi_save_flags(__flags); \ >>> arch_efi_call_virt(p, f, args); \ >>> efi_call_virt_check_flags(__flags, __stringify(f)); \ >>> \ >>> -- >>> 1.9.1 >>> >>> >>> >>> >>> -- >>> Julien Thierry > -- Julien Thierry
