arc: define syscall_get_arch()

syscall_get_arch() is required to be implemented on all architectures
in addition to already implemented syscall_get_nr(),
syscall_get_arguments(), syscall_get_error(), and
syscall_get_return_value() functions in order to extend the generic
ptrace API with PTRACE_GET_SYSCALL_INFO request.
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: Elvira Khabirova <lineprinter@altlinux.org>
Cc: Eugene Syromyatnikov <esyr@redhat.com>
Cc: Alexey Brodkin <alexey.brodkin@synopsys.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-audit@redhat.com
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>

arch/arc/include/asm/syscall.h

@@ -9,6 +9,7 @@
 #ifndef _ASM_ARC_SYSCALL_H
 #define _ASM_ARC_SYSCALL_H  1
 
+#include <uapi/linux/audit.h>
 #include <linux/err.h>
 #include <linux/sched.h>
 #include <asm/unistd.h>
@@ -68,4 +69,14 @@ syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
 	}
 }
 
+static inline int
+syscall_get_arch(void)
+{
+	return IS_ENABLED(CONFIG_ISA_ARCOMPACT)
+		? (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)
+			? AUDIT_ARCH_ARCOMPACTBE : AUDIT_ARCH_ARCOMPACT)
+		: (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)
+			? AUDIT_ARCH_ARCV2BE : AUDIT_ARCH_ARCV2);
+}
+
 #endif

include/uapi/linux/audit.h

@@ -375,6 +375,10 @@ enum {
 
 #define AUDIT_ARCH_AARCH64	(EM_AARCH64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
 #define AUDIT_ARCH_ALPHA	(EM_ALPHA|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
+#define AUDIT_ARCH_ARCOMPACT	(EM_ARCOMPACT|__AUDIT_ARCH_LE)
+#define AUDIT_ARCH_ARCOMPACTBE	(EM_ARCOMPACT)
+#define AUDIT_ARCH_ARCV2	(EM_ARCV2|__AUDIT_ARCH_LE)
+#define AUDIT_ARCH_ARCV2BE	(EM_ARCV2)
 #define AUDIT_ARCH_ARM		(EM_ARM|__AUDIT_ARCH_LE)
 #define AUDIT_ARCH_ARMEB	(EM_ARM)
 #define AUDIT_ARCH_CRIS		(EM_CRIS|__AUDIT_ARCH_LE)