[PATCH 4.19 48/72] irqchip/mips-gic: Use the correct local interrupt map registers

Greg Kroah-Hartman
2019-07-02T08:07:21Z

From: Paul Burton <paul.burton@mips.com>

commit 6d4d367d0e9ffab4d64a3436256a6a052dc1195d upstream.

The MIPS GIC contains a block of registers used to map local interrupts
to a particular CPU interrupt pin. Since these registers are found at a
consecutive range of addresses we access them using an index, via the
(read|write)_gic_v[lo]_map accessor functions. We currently use values
from enum mips_gic_local_interrupt as those indices.

Unfortunately whilst enum mips_gic_local_interrupt provides the correct
offsets for bits in the pending & mask registers, the ordering of the
map registers is subtly different... Compared with the ordering of
pending & mask bits, the map registers move the FDC from the end of the
list to index 3 after the timer interrupt. As a result the performance
counter & software interrupts are therefore at indices 4-6 rather than
indices 3-5.

Notably this causes problems with performance counter interrupts being
incorrectly mapped on some systems, and presumably will also cause
problems for FDC interrupts.

Introduce a function to map from enum mips_gic_local_interrupt to the
index of the corresponding map register, and use it to ensure we access
the map registers for the correct interrupts.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Fixes: a0dc5cb5e31b ("irqchip: mips-gic: Simplify gic_local_irq_domain_map()")
Fixes: da61fcf9d62a ("irqchip: mips-gic: Use irq_cpu_online to (un)mask all-VP(E) IRQs")
Reported-and-tested-by: Archer Yan <ayan@wavecomp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/mips/include/asm/mips-gic.h | 30 ++++++++++++++++++++++++++++++
drivers/irqchip/irq-mips-gic.c | 4 ++--
2 files changed, 32 insertions(+), 2 deletions(-)

--- a/arch/mips/include/asm/mips-gic.h
+++ b/arch/mips/include/asm/mips-gic.h
@@ -315,6 +315,36 @@ static inline bool mips_gic_present(void
}

/**
+ * mips_gic_vx_map_reg() - Return GIC_Vx_<intr>_MAP register offset
+ * @intr: A GIC local interrupt
+ *
+ * Determine the index of the GIC_VL_<intr>_MAP or GIC_VO_<intr>_MAP register
+ * within the block of GIC map registers. This is almost the same as the order
+ * of interrupts in the pending & mask registers, as used by enum
+ * mips_gic_local_interrupt, but moves the FDC interrupt & thus offsets the
+ * interrupts after it...
+ *
+ * Return: The map register index corresponding to @intr.
+ *
+ * The return value is suitable for use with the (read|write)_gic_v[lo]_map
+ * accessor functions.
+ */
+static inline unsigned int
+mips_gic_vx_map_reg(enum mips_gic_local_interrupt intr)
+{
+ /* WD, Compare & Timer are 1:1 */
+ if (intr <= GIC_LOCAL_INT_TIMER)
+ return intr;
+
+ /* FDC moves to after Timer... */
+ if (intr == GIC_LOCAL_INT_FDC)
+ return GIC_LOCAL_INT_TIMER + 1;
+
+ /* As a result everything else is offset by 1 */
+ return intr + 1;
+}
+
+/**
* gic_get_c0_compare_int() - Return cp0 count/compare interrupt virq
*
* Determine the virq number to use for the coprocessor 0 count/compare
--- a/drivers/irqchip/irq-mips-gic.c
+++ b/drivers/irqchip/irq-mips-gic.c
@@ -388,7 +388,7 @@ static void gic_all_vpes_irq_cpu_online(
intr = GIC_HWIRQ_TO_LOCAL(d->hwirq);
cd = irq_data_get_irq_chip_data(d);

- write_gic_vl_map(intr, cd->map);
+ write_gic_vl_map(mips_gic_vx_map_reg(intr), cd->map);
if (cd->mask)
write_gic_vl_smask(BIT(intr));
}
@@ -517,7 +517,7 @@ static int gic_irq_domain_map(struct irq
spin_lock_irqsave(&gic_lock, flags);
for_each_online_cpu(cpu) {
write_gic_vl_other(mips_cm_vp_id(cpu));
- write_gic_vo_map(intr, map);
+ write_gic_vo_map(mips_gic_vx_map_reg(intr), map);
}
spin_unlock_irqrestore(&gic_lock, flags);