efi/libstub: Fix mixed mode boot issue after macro refactor

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.

All of these macros should go together, so rather than testing each one
to see if it is defined, condition the generic macro definitions on a
new ARCH_HAS_EFISTUB_WRAPPERS, and remove the wrapper definitions on x86
as well if CONFIG_EFI_MIXED is not enabled.

Fixes: 22090f84bc3f ("efi/libstub: unify EFI call wrappers for non-x86")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200504150248.62482-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

1 files changed, 15 insertions, 4 deletions

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);