[PATCH RFC POC 12/50] nios2: commit fds on syscall exit

[Christian Brauner]

Add TIF_FD_SLOTS and test it once the untraced system call has had
its return code translated into the r2 and r7 pair userspace sees.

Signed-off-by: Christian Brauner (Amutable) <brauner@xxxxxxxxxx>
---
 arch/nios2/include/asm/thread_info.h | 2 ++
 arch/nios2/kernel/entry.S            | 5 +++++
 arch/nios2/kernel/ptrace.c           | 3 +++
 3 files changed, 10 insertions(+)

diff --git a/arch/nios2/include/asm/thread_info.h b/arch/nios2/include/asm/thread_info.h
index 83df79286d62..7f5816e1b3d6 100644
--- a/arch/nios2/include/asm/thread_info.h
+++ b/arch/nios2/include/asm/thread_info.h
@@ -78,6 +78,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_SECCOMP		5	/* secure computing */
 #define TIF_SYSCALL_AUDIT	6	/* syscall auditing active */
 #define TIF_NOTIFY_SIGNAL	7	/* signal notifications exist */
+#define TIF_FD_SLOTS		8	/* syscall prepared descriptors */
 #define TIF_RESTORE_SIGMASK	9	/* restore signal mask in do_signal() */
 
 #define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling
@@ -90,6 +91,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_SECCOMP		(1 << TIF_SECCOMP)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
 #define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
+#define _TIF_FD_SLOTS		(1 << TIF_FD_SLOTS)
 #define _TIF_RESTORE_SIGMASK	(1 << TIF_RESTORE_SIGMASK)
 #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
 
diff --git a/arch/nios2/kernel/entry.S b/arch/nios2/kernel/entry.S
index dd40dfd908e5..b3a99a6db379 100644
--- a/arch/nios2/kernel/entry.S
+++ b/arch/nios2/kernel/entry.S
@@ -222,6 +222,11 @@ translate_rc_and_ret:
 	stw	r2, PT_R2(sp)
 	stw	r1, PT_R7(sp)
 end_translate_rc_and_ret:
+	/* Descriptors reserved by the syscall are committed in
+	 * do_syscall_trace_exit, take the traced exit path for them. */
+	GET_THREAD_INFO r11
+	ldw	r11, TI_FLAGS(r11)
+	BTBNZ	r11, r11, TIF_FD_SLOTS, end_translate_rc_and_ret2
 
 ret_from_exception:
 	ldw	r1, PT_ESTATUS(sp)
diff --git a/arch/nios2/kernel/ptrace.c b/arch/nios2/kernel/ptrace.c
index 2cd7e1ecbd74..5cee1b717662 100644
--- a/arch/nios2/kernel/ptrace.c
+++ b/arch/nios2/kernel/ptrace.c
@@ -9,6 +9,7 @@
 
 #include <linux/elf.h>
 #include <linux/errno.h>
+#include <linux/file.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/ptrace.h>
@@ -140,6 +141,8 @@ asmlinkage int do_syscall_trace_enter(void)
 
 asmlinkage void do_syscall_trace_exit(void)
 {
+	if (test_thread_flag(TIF_FD_SLOTS))
+		fd_slots_commit(task_pt_regs(current));
 	if (test_thread_flag(TIF_SYSCALL_TRACE))
 		ptrace_report_syscall_exit(task_pt_regs(current), 0);
 }

-- 
2.53.0