x86/efi: Update efi_thunk() to use the the arch_efi_call_virt*() macros

Currently, the efi_thunk macro has some semi-duplicated code in it that
can be replaced with the arch_efi_call_virt_setup/teardown macros. This
commit simply replaces the duplicated code with those macros.

Suggested-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Alex Thorlton <athorlton@sgi.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roy Franz <roy.franz@linaro.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1466839230-12781-7-git-send-email-matt@codeblueprint.co.uk
[ Renamed variables to the standard __ prefix. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/platform/efi/efi_64.c

@@ -466,22 +466,17 @@ extern efi_status_t efi64_thunk(u32, ...);
 #define efi_thunk(f, ...)						\
 ({									\
 	efi_status_t __s;						\
-	unsigned long flags;						\
-	u32 func;							\
+	unsigned long __flags;						\
+	u32 __func;							\
 									\
-	efi_sync_low_kernel_mappings();					\
-	local_irq_save(flags);						\
+	local_irq_save(__flags);					\
+	arch_efi_call_virt_setup();					\
 									\
-	efi_scratch.prev_cr3 = read_cr3();				\
-	write_cr3((unsigned long)efi_scratch.efi_pgt);			\
-	__flush_tlb_all();						\
+	__func = runtime_service32(f);					\
+	__s = efi64_thunk(__func, __VA_ARGS__);				\
 									\
-	func = runtime_service32(f);					\
-	__s = efi64_thunk(func, __VA_ARGS__);			\
-									\
-	write_cr3(efi_scratch.prev_cr3);				\
-	__flush_tlb_all();						\
-	local_irq_restore(flags);					\
+	arch_efi_call_virt_teardown();					\
+	local_irq_restore(__flags);					\
 									\
 	__s;								\
 })