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Diffstat (limited to 'arch/riscv/kernel/signal.c')
-rw-r--r--arch/riscv/kernel/signal.c85
1 files changed, 46 insertions, 39 deletions
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index 21a4d0e111bc..88b6220b2608 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -384,30 +384,6 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
sigset_t *oldset = sigmask_to_save();
int ret;
- /* Are we from a system call? */
- if (regs->cause == EXC_SYSCALL) {
- /* Avoid additional syscall restarting via ret_from_exception */
- regs->cause = -1UL;
- /* If so, check system call restarting.. */
- switch (regs->a0) {
- case -ERESTART_RESTARTBLOCK:
- case -ERESTARTNOHAND:
- regs->a0 = -EINTR;
- break;
-
- case -ERESTARTSYS:
- if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
- regs->a0 = -EINTR;
- break;
- }
- fallthrough;
- case -ERESTARTNOINTR:
- regs->a0 = regs->orig_a0;
- regs->epc -= 0x4;
- break;
- }
- }
-
rseq_signal_deliver(ksig, regs);
/* Set up the stack frame */
@@ -421,36 +397,67 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
void arch_do_signal_or_restart(struct pt_regs *regs)
{
+ unsigned long continue_addr = 0, restart_addr = 0;
+ int retval = 0;
struct ksignal ksig;
+ bool syscall = (regs->cause == EXC_SYSCALL);
- if (get_signal(&ksig)) {
- /* Actually deliver the signal */
- handle_signal(&ksig, regs);
- return;
- }
+ /* If we were from a system call, check for system call restarting */
+ if (syscall) {
+ continue_addr = regs->epc;
+ restart_addr = continue_addr - 4;
+ retval = regs->a0;
- /* Did we come from a system call? */
- if (regs->cause == EXC_SYSCALL) {
/* Avoid additional syscall restarting via ret_from_exception */
regs->cause = -1UL;
- /* Restart the system call - no handlers present */
- switch (regs->a0) {
+ /*
+ * Prepare for system call restart. We do this here so that a
+ * debugger will see the already changed PC.
+ */
+ switch (retval) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
- regs->a0 = regs->orig_a0;
- regs->epc -= 0x4;
- break;
case -ERESTART_RESTARTBLOCK:
- regs->a0 = regs->orig_a0;
- regs->a7 = __NR_restart_syscall;
- regs->epc -= 0x4;
+ regs->a0 = regs->orig_a0;
+ regs->epc = restart_addr;
break;
}
}
/*
+ * Get the signal to deliver. When running under ptrace, at this point
+ * the debugger may change all of our registers.
+ */
+ if (get_signal(&ksig)) {
+ /*
+ * Depending on the signal settings, we may need to revert the
+ * decision to restart the system call, but skip this if a
+ * debugger has chosen to restart at a different PC.
+ */
+ if (regs->epc == restart_addr &&
+ (retval == -ERESTARTNOHAND ||
+ retval == -ERESTART_RESTARTBLOCK ||
+ (retval == -ERESTARTSYS &&
+ !(ksig.ka.sa.sa_flags & SA_RESTART)))) {
+ regs->a0 = -EINTR;
+ regs->epc = continue_addr;
+ }
+
+ /* Actually deliver the signal */
+ handle_signal(&ksig, regs);
+ return;
+ }
+
+ /*
+ * Handle restarting a different system call. As above, if a debugger
+ * has chosen to restart at a different PC, ignore the restart.
+ */
+ if (syscall && regs->epc == restart_addr && retval == -ERESTART_RESTARTBLOCK)
+ regs->a7 = __NR_restart_syscall;
+
+ /*
* If there is no signal to deliver, we just put the saved
* sigmask back.
*/