Patchwork arm_gic: handle banked enable bits for per-cpu interrupts

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Submitter Rabin Vincent
Date Oct. 28, 2011, 5:40 p.m.
Message ID <1319823613-22903-1-git-send-email-rabin@rab.in>
Download mbox | patch
Permalink /patch/122452/
State New
Headers show

Comments

Rabin Vincent - Oct. 28, 2011, 5:40 p.m.
The first enable set/clear register (which controls the PPIs and SGIs)
is supposed to be banked for each processor.  Currently it is just
handled globally and this prevents recent SMP Linux kernels from
booting, because CPU0 stops receiving localtimer interrupts when CPU1
disables them locally.

To fix this, allow the enable bits to be enabled per-cpu.  For SPIs,
always enable/disable ALL_CPU_MASK.

Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Rabin Vincent <rabin@rab.in>
---
 hw/arm_gic.c |   35 ++++++++++++++++++++---------------
 1 files changed, 20 insertions(+), 15 deletions(-)
Peter Maydell - Nov. 1, 2011, 10:31 p.m.
On 28 October 2011 18:40, Rabin Vincent <rabin@rab.in> wrote:
> The first enable set/clear register (which controls the PPIs and SGIs)
> is supposed to be banked for each processor.  Currently it is just
> handled globally and this prevents recent SMP Linux kernels from
> booting, because CPU0 stops receiving localtimer interrupts when CPU1
> disables them locally.
>
> To fix this, allow the enable bits to be enabled per-cpu.  For SPIs,
> always enable/disable ALL_CPU_MASK.

>  typedef struct gic_irq_state
>  {
> -    /* ??? The documentation seems to imply the enable bits are global, even
> -       for per-cpu interrupts.  This seems strange.  */
> -    unsigned enabled:1;
> +    /* The enable bits are only banked for per-cpu interrupts.  */
> +    unsigned enabled:NCPU;

The ??? comment here is referring to an ambiguity in the 11MPCore
TRM, which doesn't explicitly say that the enable bits for the
per-cpu interrupts are a banked register. (The GIC manual which
covers the A9 and up is clear here that they are banked.)

I have checked with real 11MPCore hardware, and the enable
register is banked between CPUs for the per-cpu interrupt,
so this patch is correct for 11MPCore as well as A9.

Incidentally, this code is shared with the M profile NVIC,
where the first enable register is not special at all. However
since M profile has only one core the special casing is harmless
and this patch only makes it match the other (pending etc)
registers, so I think that's OK.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

-- PMM
Peter Maydell - Nov. 1, 2011, 10:42 p.m.
On 1 November 2011 22:31, Peter Maydell <peter.maydell@linaro.org> wrote:
> On 28 October 2011 18:40, Rabin Vincent <rabin@rab.in> wrote:
>> The first enable set/clear register (which controls the PPIs and SGIs)
>> is supposed to be banked for each processor.  Currently it is just
>> handled globally and this prevents recent SMP Linux kernels from
>> booting, because CPU0 stops receiving localtimer interrupts when CPU1
>> disables them locally.

> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

This has just missed the 1.0rc0 deadline but as it's a bug fix
we can put it into rc1.

-- PMM

Patch

diff --git a/hw/arm_gic.c b/hw/arm_gic.c
index 8dd8742..f3f3516 100644
--- a/hw/arm_gic.c
+++ b/hw/arm_gic.c
@@ -37,9 +37,8 @@  static const uint8_t gic_id[] =
 
 typedef struct gic_irq_state
 {
-    /* ??? The documentation seems to imply the enable bits are global, even
-       for per-cpu interrupts.  This seems strange.  */
-    unsigned enabled:1;
+    /* The enable bits are only banked for per-cpu interrupts.  */
+    unsigned enabled:NCPU;
     unsigned pending:NCPU;
     unsigned active:NCPU;
     unsigned level:NCPU;
@@ -54,9 +53,9 @@  typedef struct gic_irq_state
 #define NUM_CPU(s) 1
 #endif
 
-#define GIC_SET_ENABLED(irq) s->irq_state[irq].enabled = 1
-#define GIC_CLEAR_ENABLED(irq) s->irq_state[irq].enabled = 0
-#define GIC_TEST_ENABLED(irq) s->irq_state[irq].enabled
+#define GIC_SET_ENABLED(irq, cm) s->irq_state[irq].enabled |= (cm)
+#define GIC_CLEAR_ENABLED(irq, cm) s->irq_state[irq].enabled &= ~(cm)
+#define GIC_TEST_ENABLED(irq, cm) ((s->irq_state[irq].enabled & (cm)) != 0)
 #define GIC_SET_PENDING(irq, cm) s->irq_state[irq].pending |= (cm)
 #define GIC_CLEAR_PENDING(irq, cm) s->irq_state[irq].pending &= ~(cm)
 #define GIC_TEST_PENDING(irq, cm) ((s->irq_state[irq].pending & (cm)) != 0)
@@ -128,7 +127,7 @@  static void gic_update(gic_state *s)
         best_prio = 0x100;
         best_irq = 1023;
         for (irq = 0; irq < GIC_NIRQ; irq++) {
-            if (GIC_TEST_ENABLED(irq) && GIC_TEST_PENDING(irq, cm)) {
+            if (GIC_TEST_ENABLED(irq, cm) && GIC_TEST_PENDING(irq, cm)) {
                 if (GIC_GET_PRIORITY(irq, cpu) < best_prio) {
                     best_prio = GIC_GET_PRIORITY(irq, cpu);
                     best_irq = irq;
@@ -171,7 +170,7 @@  static void gic_set_irq(void *opaque, int irq, int level)
 
     if (level) {
         GIC_SET_LEVEL(irq, ALL_CPU_MASK);
-        if (GIC_TEST_TRIGGER(irq) || GIC_TEST_ENABLED(irq)) {
+        if (GIC_TEST_TRIGGER(irq) || GIC_TEST_ENABLED(irq, ALL_CPU_MASK)) {
             DPRINTF("Set %d pending mask %x\n", irq, GIC_TARGET(irq));
             GIC_SET_PENDING(irq, GIC_TARGET(irq));
         }
@@ -221,7 +220,7 @@  static void gic_complete_irq(gic_state * s, int cpu, int irq)
     if (irq != 1023) {
         /* Mark level triggered interrupts as pending if they are still
            raised.  */
-        if (!GIC_TEST_TRIGGER(irq) && GIC_TEST_ENABLED(irq)
+        if (!GIC_TEST_TRIGGER(irq) && GIC_TEST_ENABLED(irq, cm)
                 && GIC_TEST_LEVEL(irq, cm) && (GIC_TARGET(irq) & cm) != 0) {
             DPRINTF("Set %d pending mask %x\n", irq, cm);
             GIC_SET_PENDING(irq, cm);
@@ -280,7 +279,7 @@  static uint32_t gic_dist_readb(void *opaque, target_phys_addr_t offset)
             goto bad_reg;
         res = 0;
         for (i = 0; i < 8; i++) {
-            if (GIC_TEST_ENABLED(irq + i)) {
+            if (GIC_TEST_ENABLED(irq + i, cm)) {
                 res |= (1 << i);
             }
         }
@@ -412,9 +411,12 @@  static void gic_dist_writeb(void *opaque, target_phys_addr_t offset,
         for (i = 0; i < 8; i++) {
             if (value & (1 << i)) {
                 int mask = (irq < 32) ? (1 << cpu) : GIC_TARGET(irq);
-                if (!GIC_TEST_ENABLED(irq + i))
+                int cm = (irq < 32) ? (1 << cpu) : ALL_CPU_MASK;
+
+                if (!GIC_TEST_ENABLED(irq + i, cm)) {
                     DPRINTF("Enabled IRQ %d\n", irq + i);
-                GIC_SET_ENABLED(irq + i);
+                }
+                GIC_SET_ENABLED(irq + i, cm);
                 /* If a raised level triggered IRQ enabled then mark
                    is as pending.  */
                 if (GIC_TEST_LEVEL(irq + i, mask)
@@ -433,9 +435,12 @@  static void gic_dist_writeb(void *opaque, target_phys_addr_t offset,
           value = 0;
         for (i = 0; i < 8; i++) {
             if (value & (1 << i)) {
-                if (GIC_TEST_ENABLED(irq + i))
+                int cm = (irq < 32) ? (1 << cpu) : ALL_CPU_MASK;
+
+                if (GIC_TEST_ENABLED(irq + i, cm)) {
                     DPRINTF("Disabled IRQ %d\n", irq + i);
-                GIC_CLEAR_ENABLED(irq + i);
+                }
+                GIC_CLEAR_ENABLED(irq + i, cm);
             }
         }
     } else if (offset < 0x280) {
@@ -638,7 +643,7 @@  static void gic_reset(gic_state *s)
 #endif
     }
     for (i = 0; i < 16; i++) {
-        GIC_SET_ENABLED(i);
+        GIC_SET_ENABLED(i, ALL_CPU_MASK);
         GIC_SET_TRIGGER(i);
     }
 #ifdef NVIC