From: Ard Biesheuvel <ardb@kernel.org>
Date: Fri, 3 Jan 2020 12:39:36 +0100
Subject: efi/x86: Re-disable RT services for 32-bit kernels running on 64-bit
EFI
Patch-mainline: v5.6-rc1
Git-commit: 6cfcd6f001b42fdbe6948cd113a5024945a8f50f
References: jsc#SLE-16407
Commit a8147dba75b1 ("efi/x86: Rename efi_is_native() to efi_is_mixed()")
renamed and refactored efi_is_native() into efi_is_mixed(), but failed
to take into account that these are not diametrical opposites.
Mixed mode is a construct that permits 64-bit kernels to boot on 32-bit
firmware, but there is another non-native combination which is supported,
i.e., 32-bit kernels booting on 64-bit firmware, but only for boot and not
for runtime services. Also, mixed mode can be disabled in Kconfig, in
which case the 64-bit kernel can still be booted from 32-bit firmware,
but without access to runtime services.
Due to this oversight, efi_runtime_supported() now incorrectly returns
true for such configurations, resulting in crashes at boot. So fix this
by making efi_runtime_supported() aware of this.
As a side effect, some efi_thunk_xxx() stubs have become obsolete, so
remove them as well.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Matthew Garrett <mjg59@google.com>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20200103113953.9571-4-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
arch/x86/include/asm/efi.h | 18 ++----------------
1 file changed, 2 insertions(+), 16 deletions(-)
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -163,10 +163,10 @@ static inline bool efi_is_mixed(void)
static inline bool efi_runtime_supported(void)
{
- if (!efi_is_mixed())
+ if (IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT))
return true;
- if (!efi_enabled(EFI_OLD_MEMMAP))
+ if (IS_ENABLED(CONFIG_EFI_MIXED) && !efi_enabled(EFI_OLD_MEMMAP))
return true;
return false;
@@ -176,7 +176,6 @@ extern void parse_efi_setup(u64 phys_add
extern void efifb_setup_from_dmi(struct screen_info *si, const char *opt);
-#ifdef CONFIG_EFI_MIXED
extern void efi_thunk_runtime_setup(void);
extern efi_status_t efi_thunk_set_virtual_address_map(
void *phys_set_virtual_address_map,
@@ -184,19 +183,6 @@ extern efi_status_t efi_thunk_set_virtua
unsigned long descriptor_size,
u32 descriptor_version,
efi_memory_desc_t *virtual_map);
-#else
-static inline void efi_thunk_runtime_setup(void) {}
-static inline efi_status_t efi_thunk_set_virtual_address_map(
- void *phys_set_virtual_address_map,
- unsigned long memory_map_size,
- unsigned long descriptor_size,
- u32 descriptor_version,
- efi_memory_desc_t *virtual_map)
-{
- return EFI_SUCCESS;
-}
-#endif /* CONFIG_EFI_MIXED */
-
/* arch specific definitions used by the stub code */