diff mbox series

[3/3] riscv/signal: Fixup additional syscall restarting

Message ID 1554192153-2587-3-git-send-email-guoren@kernel.org (mailing list archive)
State New, archived
Headers show
Series [1/3] csky: Use in_syscall & forget_syscall instead of r11_sig | expand

Commit Message

Guo Ren April 2, 2019, 8:02 a.m. UTC 
From: Guo Ren <ren_guo@c-sky.com>

The function of do_notify_resume called by entry.S could be entered
in loop when SIGPENDING was setted again before sret. So we must add
prevent code to make syscall restart (regs->sepc -= 0x4) or it may
re-execute unexpected instructions.

Just like in_syscall & forget_syscall used by arm.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/riscv/kernel/signal.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Christoph Hellwig April 10, 2019, 6:53 a.m. UTC | #1 
Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
Palmer Dabbelt April 25, 2019, 6:11 p.m. UTC | #2 
On Tue, 09 Apr 2019 23:53:04 PDT (-0700), Christoph Hellwig wrote:
> Looks good,
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Thanks!  I've pulled just this patch into my for-next, as I'm assuming the
c-sky patches will go in seperately.  Given that it's been on the list for a
while I think it's a good candidate for rc7, so unless anyone says something or
testing causes a problem I'll send it up tomorrow.
diff mbox series

Patch

diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 837e164..804d6ee 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -234,6 +234,9 @@  static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 
 	/* Are we from a system call? */
 	if (regs->scause == EXC_SYSCALL) {
+		/* Avoid additional syscall restarting via ret_from_exception */
+		regs->scause = -1UL;
+
 		/* If so, check system call restarting.. */
 		switch (regs->a0) {
 		case -ERESTART_RESTARTBLOCK:
@@ -272,6 +275,9 @@  static void do_signal(struct pt_regs *regs)
 
 	/* Did we come from a system call? */
 	if (regs->scause == EXC_SYSCALL) {
+		/* Avoid additional syscall restarting via ret_from_exception */
+		regs->scause = -1UL;
+
 		/* Restart the system call - no handlers present */
 		switch (regs->a0) {
 		case -ERESTARTNOHAND: