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Subject[PATCH v10 20/25] irqchip/gic-v3: Handle pseudo-NMIs
Date
Provide a higher priority to be used for pseudo-NMIs. When such an
interrupt is received, keep interrupts fully disabled at CPU level to
prevent receiving other pseudo-NMIs while handling the current one.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
---
drivers/irqchip/irq-gic-v3.c | 42 ++++++++++++++++++++++++++++++++++++------
1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index eb9d948..c2767fb 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -41,6 +41,8 @@

#include "irq-gic-common.h"

+#define GICD_INT_NMI_PRI (GICD_INT_DEF_PRI & ~0x80)
+
#define FLAGS_WORKAROUND_GICR_WAKER_MSM8996 (1ULL << 0)

struct redist_region {
@@ -381,12 +383,45 @@ static u64 gic_mpidr_to_affinity(unsigned long mpidr)
return aff;
}

+static void gic_deactivate_unhandled(u32 irqnr)
+{
+ if (static_branch_likely(&supports_deactivate_key)) {
+ if (irqnr < 8192)
+ gic_write_dir(irqnr);
+ } else {
+ gic_write_eoir(irqnr);
+ }
+}
+
+static inline void gic_handle_nmi(u32 irqnr, struct pt_regs *regs)
+{
+ int err;
+
+ if (static_branch_likely(&supports_deactivate_key))
+ gic_write_eoir(irqnr);
+ /*
+ * Leave the PSR.I bit set to prevent other NMIs to be
+ * received while handling this one.
+ * PSR.I will be restored when we ERET to the
+ * interrupted context.
+ */
+ err = handle_domain_nmi(gic_data.domain, irqnr, regs);
+ if (err)
+ gic_deactivate_unhandled(irqnr);
+}
+
static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs)
{
u32 irqnr;

irqnr = gic_read_iar();

+ if (gic_supports_nmi() &&
+ unlikely(gic_read_rpr() == GICD_INT_NMI_PRI)) {
+ gic_handle_nmi(irqnr, regs);
+ return;
+ }
+
if (gic_prio_masking_enabled()) {
gic_pmr_mask_irqs();
gic_arch_enable_irqs();
@@ -403,12 +438,7 @@ static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs
err = handle_domain_irq(gic_data.domain, irqnr, regs);
if (err) {
WARN_ONCE(true, "Unexpected interrupt received!\n");
- if (static_branch_likely(&supports_deactivate_key)) {
- if (irqnr < 8192)
- gic_write_dir(irqnr);
- } else {
- gic_write_eoir(irqnr);
- }
+ gic_deactivate_unhandled(irqnr);
}
return;
}
--
1.9.1
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