efi: Convert efi_call_virt() to efi_call_virt_pointer()

This commit makes a few slight modifications to the efi_call_virt() macro
to get it to work with function pointers that are stored in locations
other than efi.systab->runtime, and renames the macro to
efi_call_virt_pointer().  The majority of the changes here are to pull
these macros up into header files so that they can be accessed from
outside of drivers/firmware/efi/runtime-wrappers.c.

The most significant change not directly related to the code move is to
add an extra "p" argument into the appropriate efi_call macros, and use
that new argument in place of the, formerly hard-coded,
efi.systab->runtime pointer.

The last piece of the puzzle was to add an efi_call_virt() macro back into
drivers/firmware/efi/runtime-wrappers.c to wrap around the new
efi_call_virt_pointer() macro - this was mainly to keep the code from
looking too cluttered by adding a bunch of extra references to
efi.systab->runtime everywhere.

Note that I also broke up the code in the efi_call_virt_pointer() macro a
bit in the process of moving it.

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/1466839230-12781-5-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 51 insertions, 0 deletions

diff --git a/include/linux/efi.h b/include/linux/efi.h
index 03009695760d..75d148dc9c3f 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1480,4 +1480,55 @@ efi_status_t efi_setup_gop(efi_system_table_t *sys_table_arg,
 			   unsigned long size);
 
 bool efi_runtime_disabled(void);
+extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
+
+/*
+ * Arch code can implement the following three template macros, avoiding
+ * reptition for the void/non-void return cases of {__,}efi_call_virt():
+ *
+ *  * arch_efi_call_virt_setup()
+ *
+ *    Sets up the environment for the call (e.g. switching page tables,
+ *    allowing kernel-mode use of floating point, if required).
+ *
+ *  * arch_efi_call_virt()
+ *
+ *    Performs the call. The last expression in the macro must be the call
+ *    itself, allowing the logic to be shared by the void and non-void
+ *    cases.
+ *
+ *  * arch_efi_call_virt_teardown()
+ *
+ *    Restores the usual kernel environment once the call has returned.
+ */
+
+#define efi_call_virt_pointer(p, f, args...)				\
+({									\
+	efi_status_t __s;						\
+	unsigned long __flags;						\
+									\
+	arch_efi_call_virt_setup();					\
+									\
+	local_save_flags(__flags);					\
+	__s = arch_efi_call_virt(p, f, args);				\
+	efi_call_virt_check_flags(__flags, __stringify(f));		\
+									\
+	arch_efi_call_virt_teardown();					\
+									\
+	__s;								\
+})
+
+#define __efi_call_virt_pointer(p, f, args...)				\
+({									\
+	unsigned long __flags;						\
+									\
+	arch_efi_call_virt_setup();					\
+									\
+	local_save_flags(__flags);					\
+	arch_efi_call_virt(p, f, args);					\
+	efi_call_virt_check_flags(__flags, __stringify(f));		\
+									\
+	arch_efi_call_virt_teardown();					\
+})
+
 #endif /* _LINUX_EFI_H */