x86/efi: Save and restore FPU context around efi_calls (i386)

Do a complete FPU context save/restore around the EFI calls. This required
as runtime EFI firmware may potentially use the FPU.

This change covers only the i386 configuration.

Signed-off-by: Ricardo Neri <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Signed-off-by: Matt Fleming <[e-mail]>

arch/x86/include/asm/efi.h

···
 
 /* Use this macro if your virtual returns a non-void value */
 #define efi_call_virt(f, args...) \
-	((efi_##f##_t __attribute__((regparm(0)))*)efi.systab->runtime->f)(args)
+({									\
+	efi_status_t __s;						\
+	kernel_fpu_begin();						\
+	__s = ((efi_##f##_t __attribute__((regparm(0)))*)		\
+		efi.systab->runtime->f)(args);				\
+	kernel_fpu_end();						\
+	__s;								\
+})
 
 /* Use this macro if your virtual call does not return any value */
-#define __efi_call_virt(f, args...) efi_call_virt(f, args)
+#define __efi_call_virt(f, args...) \
+({									\
+	kernel_fpu_begin();						\
+	((efi_##f##_t __attribute__((regparm(0)))*)			\
+		efi.systab->runtime->f)(args);				\
+	kernel_fpu_end();						\
+})
 
 #define efi_ioremap(addr, size, type, attr)	ioremap_cache(addr, size)