ARM: 7577/1: arch/add syscall_get_arch

Provide an ARM implementation of syscall_get_arch. This is a pre-requisite
for CONFIG_HAVE_ARCH_SECCOMP_FILTER.
Signed-off-by: NWill Drewry <wad@chromium.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/include/asm/syscall.h

@@ -7,6 +7,8 @@
 #ifndef _ASM_ARM_SYSCALL_H
 #define _ASM_ARM_SYSCALL_H
 
+#include <linux/audit.h> /* for AUDIT_ARCH_* */
+#include <linux/elf.h> /* for ELF_EM */
 #include <linux/err.h>
 #include <linux/sched.h>
 
@@ -95,4 +97,11 @@ static inline void syscall_set_arguments(struct task_struct *task,
 	memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
 }
 
+static inline int syscall_get_arch(struct task_struct *task,
+				   struct pt_regs *regs)
+{
+	/* ARM tasks don't change audit architectures on the fly. */
+	return AUDIT_ARCH_ARM;
+}
+
 #endif /* _ASM_ARM_SYSCALL_H */