1 files changed, 51 insertions, 5 deletions

diff --git a/arch/powerpc/platforms/pseries/xics.c b/arch/powerpc/platforms/pseries/xics.c
index 690f87584f6b..7d01b58f3989 100644
--- a/arch/powerpc/platforms/pseries/xics.c
+++ b/arch/powerpc/platforms/pseries/xics.c
@@ -20,6 +20,7 @@
 #include <linux/cpu.h>
 #include <linux/msi.h>
 #include <linux/of.h>
+#include <linux/percpu.h>
 
 #include <asm/firmware.h>
 #include <asm/io.h>
@@ -46,6 +47,12 @@ static struct irq_host *xics_host;
  */
 #define IPI_PRIORITY            4
 
+/* The least favored priority */
+#define LOWEST_PRIORITY         0xFF
+
+/* The number of priorities defined above */
+#define MAX_NUM_PRIORITIES      3
+
 static unsigned int default_server = 0xFF;
 static unsigned int default_distrib_server = 0;
 static unsigned int interrupt_server_size = 8;
@@ -56,6 +63,12 @@ static int ibm_set_xive;
 static int ibm_int_on;
 static int ibm_int_off;
 
+struct xics_cppr {
+        unsigned char stack[MAX_NUM_PRIORITIES];
+        int index;
+};
+
+static DEFINE_PER_CPU(struct xics_cppr, xics_cppr);
 
 /* Direct hardware low level accessors */
 
@@ -284,6 +297,19 @@ static inline unsigned int xics_xirr_vector(unsigned int xirr)
         return xirr & 0x00ffffff;
 }
 
+static void push_cppr(unsigned int vec)
+{
+        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
+
+        if (WARN_ON(os_cppr->index >= MAX_NUM_PRIORITIES - 1))
+                return;
+
+        if (vec == XICS_IPI)
+                os_cppr->stack[++os_cppr->index] = IPI_PRIORITY;
+        else
+                os_cppr->stack[++os_cppr->index] = DEFAULT_PRIORITY;
+}
+
 static unsigned int xics_get_irq_direct(void)
 {
         unsigned int xirr = direct_xirr_info_get();
@@ -294,8 +320,10 @@ static unsigned int xics_get_irq_direct(void)
                 return NO_IRQ;
 
         irq = irq_radix_revmap_lookup(xics_host, vec);
-        if (likely(irq != NO_IRQ))
+        if (likely(irq != NO_IRQ)) {
+                push_cppr(vec);
                 return irq;
+        }
 
         /* We don't have a linux mapping, so have rtas mask it. */
         xics_mask_unknown_vec(vec);
@@ -315,8 +343,10 @@ static unsigned int xics_get_irq_lpar(void)
                 return NO_IRQ;
 
         irq = irq_radix_revmap_lookup(xics_host, vec);
-        if (likely(irq != NO_IRQ))
+        if (likely(irq != NO_IRQ)) {
+                push_cppr(vec);
                 return irq;
+        }
 
         /* We don't have a linux mapping, so have RTAS mask it. */
         xics_mask_unknown_vec(vec);
@@ -326,12 +356,22 @@ static unsigned int xics_get_irq_lpar(void)
         return NO_IRQ;
 }
 
+static unsigned char pop_cppr(void)
+{
+        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
+
+        if (WARN_ON(os_cppr->index < 1))
+                return LOWEST_PRIORITY;
+
+        return os_cppr->stack[--os_cppr->index];
+}
+
 static void xics_eoi_direct(unsigned int virq)
 {
         unsigned int irq = (unsigned int)irq_map[virq].hwirq;
 
         iosync();
-        direct_xirr_info_set((0xff << 24) | irq);
+        direct_xirr_info_set((pop_cppr() << 24) | irq);
 }
 
 static void xics_eoi_lpar(unsigned int virq)
@@ -339,7 +379,7 @@ static void xics_eoi_lpar(unsigned int virq)
         unsigned int irq = (unsigned int)irq_map[virq].hwirq;
 
         iosync();
-        lpar_xirr_info_set((0xff << 24) | irq);
+        lpar_xirr_info_set((pop_cppr() << 24) | irq);
 }
 
 static int xics_set_affinity(unsigned int virq, const struct cpumask *cpumask)
@@ -746,6 +786,12 @@ void __init xics_init_IRQ(void)
 
 static void xics_set_cpu_priority(unsigned char cppr)
 {
+        struct xics_cppr *os_cppr = &__get_cpu_var(xics_cppr);
+
+        BUG_ON(os_cppr->index != 0);
+
+        os_cppr->stack[os_cppr->index] = cppr;
+
         if (firmware_has_feature(FW_FEATURE_LPAR))
                 lpar_cppr_info(cppr);
         else
@@ -772,7 +818,7 @@ static void xics_set_cpu_giq(unsigned int gserver, unsigned int join)
 
 void xics_setup_cpu(void)
 {
-        xics_set_cpu_priority(0xff);
+        xics_set_cpu_priority(LOWEST_PRIORITY);
 
         xics_set_cpu_giq(default_distrib_server, 1);
 }