arm/efi: Enable runtime call flag checking

Define ARCH_EFI_IRQ_FLAGS_MASK for arm, which will enable the generic
runtime wrapper code to detect when firmware erroneously modifies flags
over a runtime services function call.

We check all allocated flags, barring those which firmware has
legitimate reason to modify (condition flags and IT state). While in
practice corruption of some flags (e.g. J) would already be fatal, we
include these for consistency and documentation purposes.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.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/1461614832-17633-39-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/arm/include/asm/efi.h

@@ -17,6 +17,7 @@
 #include <asm/mach/map.h>
 #include <asm/mmu_context.h>
 #include <asm/pgtable.h>
+#include <asm/ptrace.h>
 
 #ifdef CONFIG_EFI
 void efi_init(void);
@@ -34,6 +35,10 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
 	__f(args);							\
 })
 
+#define ARCH_EFI_IRQ_FLAGS_MASK \
+	(PSR_J_BIT | PSR_E_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT | \
+	 PSR_T_BIT | MODE_MASK)
+
 static inline void efi_set_pgd(struct mm_struct *mm)
 {
 	check_and_switch_context(mm, NULL);