If a task is checkpointed while servicing a restartable system call
like nanosleep, we need to ensure that the syscall is restarted
appropriately after a checkpoint/restart cycle. This gets
cr_tests/sleeptest passing on powerpc.
Signed-off-by: Nathan Lynch <ntl@xxxxxxxxx>
---
arch/powerpc/kernel/checkpoint.c | 25 +++++++++++++++++++++++++
1 files changed, 25 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/kernel/checkpoint.c b/arch/powerpc/kernel/checkpoint.c
index 2634011..cd384df 100644
--- a/arch/powerpc/kernel/checkpoint.c
+++ b/arch/powerpc/kernel/checkpoint.c
@@ -307,6 +307,31 @@ static int restore_gprs(const struct ckpt_hdr_cpu *cpu_hdr,
regs->orig_gpr3 = cpu_hdr->orig_gpr3;
regs->msr = sanitize_msr(regs->msr);
+
+ /* The normal servicing of the freezer's fake signal is
+ * short-circuited by checkpoint/restart. See
+ * arch/powerpc/kernel/signal.c::do_signal_pending().
+ */
+ if (TRAP(regs) != 0x0C00)
+ goto out;
+ if (!(regs->ccr & 0x10000000))
+ goto out;
+
+ switch (regs->gpr[3]) {
+ case ERESTARTNOHAND:
+ case ERESTARTSYS:
+ case ERESTARTNOINTR:
+ regs->gpr[3] = regs->orig_gpr3;
+ break;
+ case ERESTART_RESTARTBLOCK:
+ regs->gpr[0] = __NR_restart_syscall;
+ break;
+ default:
+ goto out;
+ }
+
+ regs->nip -= 4;
+ regs->result = 0;
out:
return rc;
}
--
1.6.0.6
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