powerpc: add little endian flag to syscall_get_arch()

commit 63f13448 upstream.

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 a0588015) 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.htmlSigned-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>
[bwh: Backported to 3.16: arch is passed in by do_syscall_trace_enter()
 rather than queried by calling syscall_get_arch()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

arch/powerpc/kernel/ptrace.c

@@ -1769,6 +1769,7 @@ long arch_ptrace(struct task_struct *child, long request,
 long do_syscall_trace_enter(struct pt_regs *regs)
 {
 	long ret = 0;
+	int arch;
 
 	user_exit();
 
@@ -1786,15 +1787,20 @@ long do_syscall_trace_enter(struct pt_regs *regs)
 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
 		trace_sys_enter(regs, regs->gpr[0]);
 
+	arch = is_32bit_task() ? AUDIT_ARCH_PPC : AUDIT_ARCH_PPC64;
+#ifdef __LITTLE_ENDIAN__
+	arch |= __AUDIT_ARCH_LE;
+#endif
+
 #ifdef CONFIG_PPC64
 	if (!is_32bit_task())
-		audit_syscall_entry(AUDIT_ARCH_PPC64,
+		audit_syscall_entry(arch,
 				    regs->gpr[0],
 				    regs->gpr[3], regs->gpr[4],
 				    regs->gpr[5], regs->gpr[6]);
 	else
 #endif
-		audit_syscall_entry(AUDIT_ARCH_PPC,
+		audit_syscall_entry(arch,
 				    regs->gpr[0],
 				    regs->gpr[3] & 0xffffffff,
 				    regs->gpr[4] & 0xffffffff,

include/uapi/linux/audit.h

@@ -363,7 +363,9 @@ 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)