sh: Conditionally re-enable IRQs in fault path.
The current kernel behaviour is to reenable interrupts unconditionally
when taking a page fault. This patch changes this to only enable them
if interrupts were previously enabled.
It also fixes a problem seen with this fix in place: the kernel previously
flushed the vsyscall page when handling a signal, which is not only
unncessary, but caused a possible sleep with interrupts disabled.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/mm/fault_32.c b/arch/sh/mm/fault_32.c
index d1fa275..0c776fd 100644
--- a/arch/sh/mm/fault_32.c
+++ b/arch/sh/mm/fault_32.c
@@ -37,16 +37,12 @@
int fault;
siginfo_t info;
- trace_hardirqs_on();
- local_irq_enable();
-
#ifdef CONFIG_SH_KGDB
if (kgdb_nofault && kgdb_bus_err_hook)
kgdb_bus_err_hook();
#endif
tsk = current;
- mm = tsk->mm;
si_code = SEGV_MAPERR;
if (unlikely(address >= TASK_SIZE)) {
@@ -88,6 +84,14 @@
return;
}
+ /* Only enable interrupts if they were on before the fault */
+ if ((regs->sr & SR_IMASK) != SR_IMASK) {
+ trace_hardirqs_on();
+ local_irq_enable();
+ }
+
+ mm = tsk->mm;
+
/*
* If we're in an interrupt or have no user
* context, we must not take the fault..