From: Robert Richter <rrichter at cavium.com> This patch implements Cavium ThunderX erratum 23154. The gicv3 of ThunderX requires a modified version for reading the IAR status to ensure data synchronization. Since this is in the fast-path and called with each interrupt, runtime patching is used using jump label patching for smallest overhead (no-op). This is the same technique as used for tracepoints. Signed-off-by: Robert Richter <rrichter at cavium.com> Signed-off-by: Vadim Lomovtsev <Vadim.Lomovtsev at caviumnetworks.com> --- drivers/irqchip/irq-gic-v3.c | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index 7857943..9c67bda 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -112,14 +112,38 @@ static void gic_redist_wait_for_rwp(void) } /* Low level accessors */ -static u64 __maybe_unused gic_read_iar(void) +static u64 gic_read_iar_common(void) +{ + u64 irqstat; + + asm volatile("mrs_s %0, " __stringify(ICC_IAR1_EL1) : "=r" (irqstat)); + return irqstat; +} + +/* Cavium ThunderX erratum 23154 */ +static u64 gic_read_iar_cavium_thunderx(void) { u64 irqstat; + asm volatile("nop;nop;nop;nop;"); + asm volatile("nop;nop;nop;nop;"); asm volatile("mrs_s %0, " __stringify(ICC_IAR1_EL1) : "=r" (irqstat)); + asm volatile("nop;nop;nop;nop;"); + mb(); + return irqstat; } +struct static_key is_cavium_thunderx = STATIC_KEY_INIT_FALSE; + +static u64 __maybe_unused gic_read_iar(void) +{ + if (static_key_false(&is_cavium_thunderx)) + return gic_read_iar_common(); + else + return gic_read_iar_cavium_thunderx(); +} + static void __maybe_unused gic_write_pmr(u64 val) { asm volatile("msr_s " __stringify(ICC_PMR_EL1) ", %0" : : "r" (val)); @@ -771,8 +795,19 @@ static const struct irq_domain_ops gic_irq_domain_ops = { .free = gic_irq_domain_free, }; +static void gicv3_enable_cavium_thunderx(void *data) +{ + static_key_slow_inc(&is_cavium_thunderx); +} + static const struct gic_capabilities gicv3_errata[] = { { + .desc = "GIC: Cavium erratum 23154", + .id = 0xa100034c, /* ThunderX pass 1.x */ + .mask = 0xffff0fff, + .init = gicv3_enable_cavium_thunderx, + }, + { } }; -- 2.4.3