[Xen-devel] [PATCH v5 p1 14/14] xen/arm: gic: GICv2 & GICv3 only supports 1020 physical interrupts

[Julien Grall <julien.grall@xxxxxxxxxx>]

From: Julien Grall <julien.grall@xxxxxxxxxx>

GICD_TYPER.ITLinesNumber can encode up to 1024 interrupts. Although,
IRQ 1020-1023 are reserved for special purpose.

The result is used by the callers of gic_number_lines in order to check
the validity of an IRQ.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Frediano Ziglio <frediano.ziglio@xxxxxxxxxx>
Cc: Zoltan Kiss <zoltan.kiss@xxxxxxxxxx>

---
    The GIC HIP04 driver would need a similar if they have some IRQ
    reserved below 512. Maintainers are CCed.

    Changes in v5:
        - Add Ian's ack

    Changes in v4:
        - This patch was formerly sent separatly
        https://patches.linaro.org/45373/
        - s/(unsigned)1020/1020U/
---
 xen/arch/arm/gic-v2.c | 16 ++++++++++------
 xen/arch/arm/gic-v3.c | 16 ++++++++++------
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/xen/arch/arm/gic-v2.c b/xen/arch/arm/gic-v2.c
index 3be4ad6..cfefb39 100644
--- a/xen/arch/arm/gic-v2.c
+++ b/xen/arch/arm/gic-v2.c
@@ -256,6 +256,7 @@ static void __init gicv2_dist_init(void)
     uint32_t type;
     uint32_t cpumask;
     uint32_t gic_cpus;
+    unsigned int nr_lines;
     int i;
 
     cpumask = readl_gicd(GICD_ITARGETSR) & 0xff;
@@ -266,31 +267,34 @@ static void __init gicv2_dist_init(void)
     writel_gicd(0, GICD_CTLR);
 
     type = readl_gicd(GICD_TYPER);
-    gicv2_info.nr_lines = 32 * ((type & GICD_TYPE_LINES) + 1);
+    nr_lines = 32 * ((type & GICD_TYPE_LINES) + 1);
     gic_cpus = 1 + ((type & GICD_TYPE_CPUS) >> 5);
     printk("GICv2: %d lines, %d cpu%s%s (IID %8.8x).\n",
-           gicv2_info.nr_lines, gic_cpus, (gic_cpus == 1) ? "" : "s",
+           nr_lines, gic_cpus, (gic_cpus == 1) ? "" : "s",
            (type & GICD_TYPE_SEC) ? ", secure" : "",
            readl_gicd(GICD_IIDR));
 
     /* Default all global IRQs to level, active low */
-    for ( i = 32; i < gicv2_info.nr_lines; i += 16 )
+    for ( i = 32; i < nr_lines; i += 16 )
         writel_gicd(0x0, GICD_ICFGR + (i / 16) * 4);
 
     /* Route all global IRQs to this CPU */
-    for ( i = 32; i < gicv2_info.nr_lines; i += 4 )
+    for ( i = 32; i < nr_lines; i += 4 )
         writel_gicd(cpumask, GICD_ITARGETSR + (i / 4) * 4);
 
     /* Default priority for global interrupts */
-    for ( i = 32; i < gicv2_info.nr_lines; i += 4 )
+    for ( i = 32; i < nr_lines; i += 4 )
         writel_gicd(GIC_PRI_IRQ << 24 | GIC_PRI_IRQ << 16 |
                     GIC_PRI_IRQ << 8 | GIC_PRI_IRQ,
                     GICD_IPRIORITYR + (i / 4) * 4);
 
     /* Disable all global interrupts */
-    for ( i = 32; i < gicv2_info.nr_lines; i += 32 )
+    for ( i = 32; i < nr_lines; i += 32 )
         writel_gicd(~0x0, GICD_ICENABLER + (i / 32) * 4);
 
+    /* Only 1020 interrupts are supported */
+    gicv2_info.nr_lines = min(1020U, nr_lines);
+
     /* Turn on the distributor */
     writel_gicd(GICD_CTL_ENABLE, GICD_CTLR);
 }
diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index 48772f1..b0f498e 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -528,23 +528,24 @@ static void __init gicv3_dist_init(void)
     uint32_t type;
     uint32_t priority;
     uint64_t affinity;
+    unsigned int nr_lines;
     int i;
 
     /* Disable the distributor */
     writel_relaxed(0, GICD + GICD_CTLR);
 
     type = readl_relaxed(GICD + GICD_TYPER);
-    gicv3_info.nr_lines = 32 * ((type & GICD_TYPE_LINES) + 1);
+    nr_lines = 32 * ((type & GICD_TYPE_LINES) + 1);
 
     printk("GICv3: %d lines, (IID %8.8x).\n",
-           gicv3_info.nr_lines, readl_relaxed(GICD + GICD_IIDR));
+           nr_lines, readl_relaxed(GICD + GICD_IIDR));
 
     /* Default all global IRQs to level, active low */
-    for ( i = NR_GIC_LOCAL_IRQS; i < gicv3_info.nr_lines; i += 16 )
+    for ( i = NR_GIC_LOCAL_IRQS; i < nr_lines; i += 16 )
         writel_relaxed(0, GICD + GICD_ICFGR + (i / 16) * 4);
 
     /* Default priority for global interrupts */
-    for ( i = NR_GIC_LOCAL_IRQS; i < gicv3_info.nr_lines; i += 4 )
+    for ( i = NR_GIC_LOCAL_IRQS; i < nr_lines; i += 4 )
     {
         priority = (GIC_PRI_IRQ << 24 | GIC_PRI_IRQ << 16 |
                     GIC_PRI_IRQ << 8 | GIC_PRI_IRQ);
@@ -552,7 +553,7 @@ static void __init gicv3_dist_init(void)
     }
 
     /* Disable all global interrupts */
-    for ( i = NR_GIC_LOCAL_IRQS; i < gicv3_info.nr_lines; i += 32 )
+    for ( i = NR_GIC_LOCAL_IRQS; i < nr_lines; i += 32 )
         writel_relaxed(0xffffffff, GICD + GICD_ICENABLER + (i / 32) * 4);
 
     gicv3_dist_wait_for_rwp();
@@ -566,8 +567,11 @@ static void __init gicv3_dist_init(void)
     /* Make sure we don't broadcast the interrupt */
     affinity &= ~GICD_IROUTER_SPI_MODE_ANY;
 
-    for ( i = NR_GIC_LOCAL_IRQS; i < gicv3_info.nr_lines; i++ )
+    for ( i = NR_GIC_LOCAL_IRQS; i < nr_lines; i++ )
         writeq_relaxed(affinity, GICD + GICD_IROUTER + i * 8);
+
+    /* Only 1020 interrupts are supported */
+    gicv3_info.nr_lines = min(1020U, nr_lines);
 }
 
 static int gicv3_enable_redist(void)
-- 
2.1.4


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