1 files changed, 60 insertions, 14 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 2c9006726450..cb952c073d77 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1879,16 +1879,6 @@ static void its_cpu_init_lpis(void)
 		gic_data_rdist()->pend_page = pend_page;
 	}
 
-	/* Disable LPIs */
-	val = readl_relaxed(rbase + GICR_CTLR);
-	val &= ~GICR_CTLR_ENABLE_LPIS;
-	writel_relaxed(val, rbase + GICR_CTLR);
-
-	/*
-	 * Make sure any change to the table is observable by the GIC.
-	 */
-	dsb(sy);
-
 	/* set PROPBASE */
 	val = (page_to_phys(gic_rdists->prop_page) |
 	       GICR_PROPBASER_InnerShareable |
@@ -3403,13 +3393,69 @@ static bool gic_rdists_supports_plpis(void)
 	return !!(gic_read_typer(gic_data_rdist_rd_base() + GICR_TYPER) & GICR_TYPER_PLPIS);
 }
 
+static int redist_disable_lpis(void)
+{
+	void __iomem *rbase = gic_data_rdist_rd_base();
+	u64 timeout = USEC_PER_SEC;
+	u64 val;
+
+	if (!gic_rdists_supports_plpis()) {
+		pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
+		return -ENXIO;
+	}
+
+	val = readl_relaxed(rbase + GICR_CTLR);
+	if (!(val & GICR_CTLR_ENABLE_LPIS))
+		return 0;
+
+	pr_warn("CPU%d: Booted with LPIs enabled, memory probably corrupted\n",
+		smp_processor_id());
+	add_taint(TAINT_CRAP, LOCKDEP_STILL_OK);
+
+	/* Disable LPIs */
+	val &= ~GICR_CTLR_ENABLE_LPIS;
+	writel_relaxed(val, rbase + GICR_CTLR);
+
+	/* Make sure any change to GICR_CTLR is observable by the GIC */
+	dsb(sy);
+
+	/*
+	 * Software must observe RWP==0 after clearing GICR_CTLR.EnableLPIs
+	 * from 1 to 0 before programming GICR_PEND{PROP}BASER registers.
+	 * Error out if we time out waiting for RWP to clear.
+	 */
+	while (readl_relaxed(rbase + GICR_CTLR) & GICR_CTLR_RWP) {
+		if (!timeout) {
+			pr_err("CPU%d: Timeout while disabling LPIs\n",
+			       smp_processor_id());
+			return -ETIMEDOUT;
+		}
+		udelay(1);
+		timeout--;
+	}
+
+	/*
+	 * After it has been written to 1, it is IMPLEMENTATION
+	 * DEFINED whether GICR_CTLR.EnableLPI becomes RES1 or can be
+	 * cleared to 0. Error out if clearing the bit failed.
+	 */
+	if (readl_relaxed(rbase + GICR_CTLR) & GICR_CTLR_ENABLE_LPIS) {
+		pr_err("CPU%d: Failed to disable LPIs\n", smp_processor_id());
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
 int its_cpu_init(void)
 {
 	if (!list_empty(&its_nodes)) {
-		if (!gic_rdists_supports_plpis()) {
-			pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
-			return -ENXIO;
-		}
+		int ret;
+
+		ret = redist_disable_lpis();
+		if (ret)
+			return ret;
+
 		its_cpu_init_lpis();
 		its_cpu_init_collections();
 	}