powerpc: add little endian flag to syscall_get_arch()

Since both ppc and ppc64 have LE variants which are now reported by uname, add
that flag (__AUDIT_ARCH_LE) to syscall_get_arch() and add AUDIT_ARCH_PPC64LE
variant.

Without this,  perf trace and auditctl fail.

Mainline kernel reports ppc64le (per a058801) but there is no matching
AUDIT_ARCH_PPC64LE.

Since 32-bit PPC LE is not supported by audit, don't advertise it in
AUDIT_ARCH_PPC* variants.

See:
	https://www.redhat.com/archives/linux-audit/2014-August/msg00082.html
	https://www.redhat.com/archives/linux-audit/2014-December/msg00004.html

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/syscall.h

@@ -90,6 +90,10 @@ static inline void syscall_set_arguments(struct task_struct *task,
 
 static inline int syscall_get_arch(void)
 {
-	return is_32bit_task() ? AUDIT_ARCH_PPC : AUDIT_ARCH_PPC64;
+	int arch = is_32bit_task() ? AUDIT_ARCH_PPC : AUDIT_ARCH_PPC64;
+#ifdef __LITTLE_ENDIAN__
+	arch |= __AUDIT_ARCH_LE;
+#endif
+	return arch;
 }
 #endif	/* _ASM_SYSCALL_H */

include/uapi/linux/audit.h

@@ -365,7 +365,9 @@ enum {
 #define AUDIT_ARCH_PARISC	(EM_PARISC)
 #define AUDIT_ARCH_PARISC64	(EM_PARISC|__AUDIT_ARCH_64BIT)
 #define AUDIT_ARCH_PPC		(EM_PPC)
+/* do not define AUDIT_ARCH_PPCLE since it is not supported by audit */
 #define AUDIT_ARCH_PPC64	(EM_PPC64|__AUDIT_ARCH_64BIT)
+#define AUDIT_ARCH_PPC64LE	(EM_PPC64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
 #define AUDIT_ARCH_S390		(EM_S390)
 #define AUDIT_ARCH_S390X	(EM_S390|__AUDIT_ARCH_64BIT)
 #define AUDIT_ARCH_SH		(EM_SH)