On Mon, 4 May 2020 at 16:27, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote:
>
> On Mon, May 04, 2020 at 04:15:59PM +0200, Ard Biesheuvel wrote:
> > On Mon, 4 May 2020 at 16:02, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote:
> > >
> > > On Mon, May 04, 2020 at 10:05:23AM +0200, Ard Biesheuvel wrote:
> > > > On Mon, 4 May 2020 at 02:38, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote:
> > > > >
> > > > > Commit
> > > > > 22090f84bc3f ("efi/libstub: unify EFI call wrappers for non-x86")
> > > > >
> > > > > refactored the macros that are used to provide wrappers for mixed-mode
> > > > > calls on x86, allowing us to boot a 64-bit kernel on 32-bit firmware.
> > > > >
> > > > > Unfortunately, this broke mixed mode boot due to the fact that
> > > > > efi_is_native() is not a macro on x86.
> > > > >
> > > > > Fix this by conditioning the generic macro definitions on
> > > > > CONFIG_EFI_MIXED, and removing the wrapper definitions on x86 if
> > > > > CONFIG_EFI_MIXED is not enabled.
> > > > >
> > > > > Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > > > > Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx>
> > > >
> > > > Thanks Arvind.
> > > >
> > > > Currently, CONFIG_EFI_MIXED is never referenced outside of arch/x86,
> > > > and I prefer to keep it that way.
> > >
> > > All these macros go together though -- they should either all be defined
> > > or none, so it makes sense to put them under a single #if.
> >
> > True.
> >
> > > If you think
> > > it's possible that a future architecture might need the wrappers but not
> > > be mixed, we could maybe add an ARCH_NEEDS_EFISTUB_WRAPPERS?
> > >
> >
> > Well, remember that x86 used wrappers for native invocations only two
> > releases ago, but that was mainly because of the SysV vs MS ABI issue,
> > so the issue could emerge again, but it is unlikely.
> >
>
> Yep.
>
> Would the below be more palatable?
>
Yes that looks better. Could you please spin it as a proper patch?
> diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> index cd0c3fbf6156..6b9ab0d8b2a7 100644
> --- a/arch/x86/include/asm/efi.h
> +++ b/arch/x86/include/asm/efi.h
> @@ -225,13 +225,15 @@ efi_status_t efi_set_virtual_address_map(unsigned long memory_map_size,
>
> /* arch specific definitions used by the stub code */
>
> -extern const bool efi_is64;
> +#ifdef CONFIG_EFI_MIXED
> +
> +#define ARCH_HAS_EFISTUB_WRAPPERS
>
> static inline bool efi_is_64bit(void)
> {
> - if (IS_ENABLED(CONFIG_EFI_MIXED))
> - return efi_is64;
> - return IS_ENABLED(CONFIG_X86_64);
> + extern const bool efi_is64;
> +
> + return efi_is64;
> }
>
> static inline bool efi_is_native(void)
> @@ -356,6 +358,15 @@ static inline u32 efi64_convert_status(efi_status_t status)
> runtime), \
> func, __VA_ARGS__))
>
> +#else /* CONFIG_EFI_MIXED */
> +
> +static inline bool efi_is_64bit(void)
> +{
> + return IS_ENABLED(CONFIG_X86_64);
> +}
> +
> +#endif /* CONFIG_EFI_MIXED */
> +
> extern bool efi_reboot_required(void);
> extern bool efi_is_table_address(unsigned long phys_addr);
>
> diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
> index 874233cf8820..4f10a09563f3 100644
> --- a/drivers/firmware/efi/libstub/efistub.h
> +++ b/drivers/firmware/efi/libstub/efistub.h
> @@ -33,20 +33,14 @@ extern bool efi_novamap;
>
> extern const efi_system_table_t *efi_system_table;
>
> -#ifndef efi_bs_call
> +#ifndef ARCH_HAS_EFISTUB_WRAPPERS
> +
> +#define efi_is_native() (true)
> #define efi_bs_call(func, ...) efi_system_table->boottime->func(__VA_ARGS__)
> -#endif
> -#ifndef efi_rt_call
> #define efi_rt_call(func, ...) efi_system_table->runtime->func(__VA_ARGS__)
> -#endif
> -#ifndef efi_is_native
> -#define efi_is_native() (true)
> -#endif
> -#ifndef efi_table_attr
> #define efi_table_attr(inst, attr) (inst->attr)
> -#endif
> -#ifndef efi_call_proto
> #define efi_call_proto(inst, func, ...) inst->func(inst, ##__VA_ARGS__)
> +
> #endif
>
> #define efi_info(msg) do { \
