efi/arm64: Preserve FP/SIMD registers on UEFI runtime services calls

According to the UEFI spec section 2.3.6.4, the use of FP/SIMD
instructions is allowed, and should adhere to the AAPCS64 calling
convention, which states that 'only the bottom 64 bits of each value
stored in registers v8-v15 need to be preserved' (section 5.1.2).

This applies equally to UEFI Runtime Services called by the kernel, so
make sure the FP/SIMD register file is preserved in this case. We do this
by enabling the wrappers for UEFI Runtime Services (CONFIG_EFI_RUNTIME_WRAPPERS)
and inserting calls to kernel_neon_begin()and kernel_neon_end() into
these wrappers.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7295419..2cc14ce 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -298,6 +298,7 @@ config EFI
        select LIBFDT
        select UCS2_STRING
        select EFI_PARAMS_FROM_FDT
+       select EFI_RUNTIME_WRAPPERS
        default y
        help
          This option provides support for runtime services provided

diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
index 5a46c4e..375ba34 100644 (file)
--- a/arch/arm64/include/asm/efi.h
+++ b/arch/arm64/include/asm/efi.h
@@ -2,6 +2,7 @@
 #define _ASM_EFI_H
 
 #include <asm/io.h>
+#include <asm/neon.h>
 
 #ifdef CONFIG_EFI
 extern void efi_init(void);
@@ -11,4 +12,24 @@ extern void efi_idmap_init(void);
 #define efi_idmap_init()
 #endif
 
+#define efi_call_virt(f, ...)                                          \
+({                                                                     \
+       efi_##f##_t *__f = efi.systab->runtime->f;                      \
+       efi_status_t __s;                                               \
+                                                                       \
+       kernel_neon_begin();                                            \
+       __s = __f(__VA_ARGS__);                                         \
+       kernel_neon_end();                                              \
+       __s;                                                            \
+})
+
+#define __efi_call_virt(f, ...)                                                \
+({                                                                     \
+       efi_##f##_t *__f = efi.systab->runtime->f;                      \
+                                                                       \
+       kernel_neon_begin();                                            \
+       __f(__VA_ARGS__);                                               \
+       kernel_neon_end();                                              \
+})
+
 #endif /* _ASM_EFI_H */

diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 14db1f6..56c3327 100644 (file)
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -449,19 +449,7 @@ static int __init arm64_enter_virtual_mode(void)
 
        /* Set up runtime services function pointers */
        runtime = efi.systab->runtime;
-       efi.get_time = runtime->get_time;
-       efi.set_time = runtime->set_time;
-       efi.get_wakeup_time = runtime->get_wakeup_time;
-       efi.set_wakeup_time = runtime->set_wakeup_time;
-       efi.get_variable = runtime->get_variable;
-       efi.get_next_variable = runtime->get_next_variable;
-       efi.set_variable = runtime->set_variable;
-       efi.query_variable_info = runtime->query_variable_info;
-       efi.update_capsule = runtime->update_capsule;
-       efi.query_capsule_caps = runtime->query_capsule_caps;
-       efi.get_next_high_mono_count = runtime->get_next_high_mono_count;
-       efi.reset_system = runtime->reset_system;
-
+       efi_native_runtime_setup();
        set_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 
        return 0;