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authorGuo Ren <ren_guo@c-sky.com>2019-04-02 16:02:33 +0800
committerPalmer Dabbelt <palmer@sifive.com>2019-04-25 11:07:36 -0700
commit7a64f3f1cffdc3db2e9de885bc49a6a9851aac62 (patch)
tree64466273a0db2e7553ff94b30d47f1545ac24bb9 /arch/riscv
parent085b7755808aa11f78ab9377257e1dad2e6fa4bb (diff)
riscv/signal: Fixup additional syscall restarting
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> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Diffstat (limited to 'arch/riscv')
-rw-r--r--arch/riscv/kernel/signal.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 837e1646091a..804d6ee4f3c5 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: