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-rw-r--r--arch/arm/include/asm/arch_gicv3.h6
-rw-r--r--arch/arm64/include/asm/arch_gicv3.h6
-rw-r--r--drivers/irqchip/irq-gic-v3.c8
3 files changed, 20 insertions, 0 deletions
diff --git a/arch/arm/include/asm/arch_gicv3.h b/arch/arm/include/asm/arch_gicv3.h
index e08d15184056..dfe4002812da 100644
--- a/arch/arm/include/asm/arch_gicv3.h
+++ b/arch/arm/include/asm/arch_gicv3.h
@@ -34,6 +34,7 @@
#define ICC_CTLR __ACCESS_CP15(c12, 0, c12, 4)
#define ICC_SRE __ACCESS_CP15(c12, 0, c12, 5)
#define ICC_IGRPEN1 __ACCESS_CP15(c12, 0, c12, 7)
+#define ICC_BPR1 __ACCESS_CP15(c12, 0, c12, 3)
#define ICC_HSRE __ACCESS_CP15(c12, 4, c9, 5)
@@ -157,6 +158,11 @@ static inline void gic_write_sre(u32 val)
isb();
}
+static inline void gic_write_bpr1(u32 val)
+{
+ asm volatile("mcr " __stringify(ICC_BPR1) : : "r" (val));
+}
+
/*
* Even in 32bit systems that use LPAE, there is no guarantee that the I/O
* interface provides true 64bit atomic accesses, so using strd/ldrd doesn't
diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h
index 8ec88e5b290f..fc2a0cb47b2c 100644
--- a/arch/arm64/include/asm/arch_gicv3.h
+++ b/arch/arm64/include/asm/arch_gicv3.h
@@ -28,6 +28,7 @@
#define ICC_CTLR_EL1 sys_reg(3, 0, 12, 12, 4)
#define ICC_SRE_EL1 sys_reg(3, 0, 12, 12, 5)
#define ICC_GRPEN1_EL1 sys_reg(3, 0, 12, 12, 7)
+#define ICC_BPR1_EL1 sys_reg(3, 0, 12, 12, 3)
#define ICC_SRE_EL2 sys_reg(3, 4, 12, 9, 5)
@@ -165,6 +166,11 @@ static inline void gic_write_sre(u32 val)
isb();
}
+static inline void gic_write_bpr1(u32 val)
+{
+ asm volatile("msr_s " __stringify(ICC_BPR1_EL1) ", %0" : : "r" (val));
+}
+
#define gic_read_typer(c) readq_relaxed(c)
#define gic_write_irouter(v, c) writeq_relaxed(v, c)
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index ede5672ab34d..ecc5b2360c7a 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -495,6 +495,14 @@ static void gic_cpu_sys_reg_init(void)
/* Set priority mask register */
gic_write_pmr(DEFAULT_PMR_VALUE);
+ /*
+ * Some firmwares hand over to the kernel with the BPR changed from
+ * its reset value (and with a value large enough to prevent
+ * any pre-emptive interrupts from working at all). Writing a zero
+ * to BPR restores is reset value.
+ */
+ gic_write_bpr1(0);
+
if (static_key_true(&supports_deactivate)) {
/* EOI drops priority only (mode 1) */
gic_write_ctlr(ICC_CTLR_EL1_EOImode_drop);