5 files changed, 26 insertions, 17 deletions

diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index bf57308fcd63..92b2575b0191 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -299,7 +299,17 @@ static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 
 static inline unsigned long regs_return_value(struct pt_regs *regs)
 {
-	return regs->regs[0];
+	unsigned long val = regs->regs[0];
+
+	/*
+	 * Audit currently uses regs_return_value() instead of
+	 * syscall_get_return_value(). Apply the same sign-extension here until
+	 * audit is updated to use syscall_get_return_value().
+	 */
+	if (compat_user_mode(regs))
+		val = sign_extend64(val, 31);
+
+	return val;
 }
 
 static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
index cfc0672013f6..03e20895453a 100644
--- a/arch/arm64/include/asm/syscall.h
+++ b/arch/arm64/include/asm/syscall.h
@@ -29,22 +29,23 @@ static inline void syscall_rollback(struct task_struct *task,
 	regs->regs[0] = regs->orig_x0;
 }
 
-
-static inline long syscall_get_error(struct task_struct *task,
-				     struct pt_regs *regs)
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
 {
-	unsigned long error = regs->regs[0];
+	unsigned long val = regs->regs[0];
 
 	if (is_compat_thread(task_thread_info(task)))
-		error = sign_extend64(error, 31);
+		val = sign_extend64(val, 31);
 
-	return IS_ERR_VALUE(error) ? error : 0;
+	return val;
 }
 
-static inline long syscall_get_return_value(struct task_struct *task,
-					    struct pt_regs *regs)
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
 {
-	return regs->regs[0];
+	unsigned long error = syscall_get_return_value(task, regs);
+
+	return IS_ERR_VALUE(error) ? error : 0;
 }
 
 static inline void syscall_set_return_value(struct task_struct *task,
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 0cfd68577489..8a95a013dfd3 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1868,7 +1868,7 @@ void syscall_trace_exit(struct pt_regs *regs)
 	audit_syscall_exit(regs);
 
 	if (flags & _TIF_SYSCALL_TRACEPOINT)
-		trace_sys_exit(regs, regs_return_value(regs));
+		trace_sys_exit(regs, syscall_get_return_value(current, regs));
 
 	if (flags & (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP))
 		tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index ddb757b2c3e5..f6d3278c1a4e 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -29,6 +29,7 @@
 #include <asm/unistd.h>
 #include <asm/fpsimd.h>
 #include <asm/ptrace.h>
+#include <asm/syscall.h>
 #include <asm/signal32.h>
 #include <asm/traps.h>
 #include <asm/vdso.h>
@@ -868,7 +869,7 @@ static void do_signal(struct pt_regs *regs)
 		     retval == -ERESTART_RESTARTBLOCK ||
 		     (retval == -ERESTARTSYS &&
 		      !(ksig.ka.sa.sa_flags & SA_RESTART)))) {
-			regs->regs[0] = -EINTR;
+			syscall_set_return_value(current, regs, -EINTR, 0);
 			regs->pc = continue_addr;
 		}
 
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index f2d2dbbbfca2..091c11521108 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -50,10 +50,7 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno,
 		ret = do_ni_syscall(regs, scno);
 	}
 
-	if (is_compat_task())
-		ret = lower_32_bits(ret);
-
-	regs->regs[0] = ret;
+	syscall_set_return_value(current, regs, 0, ret);
 }
 
 static inline bool has_syscall_work(unsigned long flags)
@@ -108,7 +105,7 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
 	if (has_syscall_work(flags)) {
 		/* set default errno for user-issued syscall(-1) */
 		if (scno == NO_SYSCALL)
-			regs->regs[0] = -ENOSYS;
+			syscall_set_return_value(current, regs, -ENOSYS, 0);
 		scno = syscall_trace_enter(regs);
 		if (scno == NO_SYSCALL)
 			goto trace_exit;