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-rw-r--r--arch/powerpc/kernel/irq.c80
1 files changed, 77 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 5e37bf14ef2..0bd8c766583 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -64,8 +64,9 @@
#include <asm/ptrace.h>
#include <asm/machdep.h>
#include <asm/udbg.h>
-#ifdef CONFIG_PPC_ISERIES
+#ifdef CONFIG_PPC64
#include <asm/paca.h>
+#include <asm/firmware.h>
#endif
int __irq_offset_value;
@@ -95,6 +96,74 @@ extern atomic_t ipi_sent;
EXPORT_SYMBOL(irq_desc);
int distribute_irqs = 1;
+
+static inline unsigned long get_hard_enabled(void)
+{
+ unsigned long enabled;
+
+ __asm__ __volatile__("lbz %0,%1(13)"
+ : "=r" (enabled) : "i" (offsetof(struct paca_struct, hard_enabled)));
+
+ return enabled;
+}
+
+static inline void set_soft_enabled(unsigned long enable)
+{
+ __asm__ __volatile__("stb %0,%1(13)"
+ : : "r" (enable), "i" (offsetof(struct paca_struct, soft_enabled)));
+}
+
+void local_irq_restore(unsigned long en)
+{
+ /*
+ * get_paca()->soft_enabled = en;
+ * Is it ever valid to use local_irq_restore(0) when soft_enabled is 1?
+ * That was allowed before, and in such a case we do need to take care
+ * that gcc will set soft_enabled directly via r13, not choose to use
+ * an intermediate register, lest we're preempted to a different cpu.
+ */
+ set_soft_enabled(en);
+ if (!en)
+ return;
+
+ if (firmware_has_feature(FW_FEATURE_ISERIES)) {
+ /*
+ * Do we need to disable preemption here? Not really: in the
+ * unlikely event that we're preempted to a different cpu in
+ * between getting r13, loading its lppaca_ptr, and loading
+ * its any_int, we might call iseries_handle_interrupts without
+ * an interrupt pending on the new cpu, but that's no disaster,
+ * is it? And the business of preempting us off the old cpu
+ * would itself involve a local_irq_restore which handles the
+ * interrupt to that cpu.
+ *
+ * But use "local_paca->lppaca_ptr" instead of "get_lppaca()"
+ * to avoid any preemption checking added into get_paca().
+ */
+ if (local_paca->lppaca_ptr->int_dword.any_int)
+ iseries_handle_interrupts();
+ return;
+ }
+
+ /*
+ * if (get_paca()->hard_enabled) return;
+ * But again we need to take care that gcc gets hard_enabled directly
+ * via r13, not choose to use an intermediate register, lest we're
+ * preempted to a different cpu in between the two instructions.
+ */
+ if (get_hard_enabled())
+ return;
+
+ /*
+ * Need to hard-enable interrupts here. Since currently disabled,
+ * no need to take further asm precautions against preemption; but
+ * use local_paca instead of get_paca() to avoid preemption checking.
+ */
+ local_paca->hard_enabled = en;
+ if ((int)mfspr(SPRN_DEC) < 0)
+ mtspr(SPRN_DEC, 1);
+ hard_irq_enable();
+}
#endif /* CONFIG_PPC64 */
int show_interrupts(struct seq_file *p, void *v)
@@ -246,7 +315,8 @@ void do_IRQ(struct pt_regs *regs)
set_irq_regs(old_regs);
#ifdef CONFIG_PPC_ISERIES
- if (get_lppaca()->int_dword.fields.decr_int) {
+ if (firmware_has_feature(FW_FEATURE_ISERIES) &&
+ get_lppaca()->int_dword.fields.decr_int) {
get_lppaca()->int_dword.fields.decr_int = 0;
/* Signal a fake decrementer interrupt */
timer_interrupt(regs);
@@ -626,10 +696,14 @@ EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
void irq_dispose_mapping(unsigned int virq)
{
- struct irq_host *host = irq_map[virq].host;
+ struct irq_host *host;
irq_hw_number_t hwirq;
unsigned long flags;
+ if (virq == NO_IRQ)
+ return;
+
+ host = irq_map[virq].host;
WARN_ON (host == NULL);
if (host == NULL)
return;