- Fix a race condition when clearing error count bits and toggling

the error interrupt throug the same register, in synopsys_edac
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Merge tag 'edac_urgent_for_v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras

Pull EDAC fix from Borislav Petkov:

 - Fix a race condition when clearing error count bits and toggling the
   error interrupt throug the same register, in synopsys_edac

* tag 'edac_urgent_for_v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
  EDAC/synopsys: Fix ECC status and IRQ control race condition

drivers/edac/synopsys_edac.c

@@ -9,6 +9,7 @@
 #include <linux/edac.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/of.h>
 
@@ -299,6 +300,7 @@ struct synps_ecc_status {
 /**
  * struct synps_edac_priv - DDR memory controller private instance data.
  * @baseaddr:		Base address of the DDR controller.
+ * @reglock:		Concurrent CSRs access lock.
  * @message:		Buffer for framing the event specific info.
  * @stat:		ECC status information.
  * @p_data:		Platform data.
@@ -313,6 +315,7 @@ struct synps_ecc_status {
  */
 struct synps_edac_priv {
 	void __iomem *baseaddr;
+	spinlock_t reglock;
 	char message[SYNPS_EDAC_MSG_SIZE];
 	struct synps_ecc_status stat;
 	const struct synps_platform_data *p_data;
@@ -408,7 +411,8 @@ out:
 static int zynqmp_get_error_info(struct synps_edac_priv *priv)
 {
 	struct synps_ecc_status *p;
-	u32 regval, clearval = 0;
+	u32 regval, clearval;
+	unsigned long flags;
 	void __iomem *base;
 
 	base = priv->baseaddr;
@@ -452,10 +456,14 @@ ue_err:
 	p->ueinfo.blknr = (regval & ECC_CEADDR1_BLKNR_MASK);
 	p->ueinfo.data = readl(base + ECC_UESYND0_OFST);
 out:
-	clearval = ECC_CTRL_CLR_CE_ERR | ECC_CTRL_CLR_CE_ERRCNT;
+	spin_lock_irqsave(&priv->reglock, flags);
-	clearval |= ECC_CTRL_CLR_UE_ERR | ECC_CTRL_CLR_UE_ERRCNT;
+
+	clearval = readl(base + ECC_CLR_OFST) |
+		   ECC_CTRL_CLR_CE_ERR | ECC_CTRL_CLR_CE_ERRCNT |
+		   ECC_CTRL_CLR_UE_ERR | ECC_CTRL_CLR_UE_ERRCNT;
 	writel(clearval, base + ECC_CLR_OFST);
-	writel(0x0, base + ECC_CLR_OFST);
+
+	spin_unlock_irqrestore(&priv->reglock, flags);
 
 	return 0;
 }
@@ -515,24 +523,41 @@ static void handle_error(struct mem_ctl_info *mci, struct synps_ecc_status *p)
 
 static void enable_intr(struct synps_edac_priv *priv)
 {
+	unsigned long flags;
+
 	/* Enable UE/CE Interrupts */
-	if (priv->p_data->quirks & DDR_ECC_INTR_SELF_CLEAR)
+	if (!(priv->p_data->quirks & DDR_ECC_INTR_SELF_CLEAR)) {
-		writel(DDR_UE_MASK | DDR_CE_MASK,
-		       priv->baseaddr + ECC_CLR_OFST);
-	else
 		writel(DDR_QOSUE_MASK | DDR_QOSCE_MASK,
 		       priv->baseaddr + DDR_QOS_IRQ_EN_OFST);
 
+		return;
+	}
+
+	spin_lock_irqsave(&priv->reglock, flags);
+
+	writel(DDR_UE_MASK | DDR_CE_MASK,
+	       priv->baseaddr + ECC_CLR_OFST);
+
+	spin_unlock_irqrestore(&priv->reglock, flags);
 }
 
 static void disable_intr(struct synps_edac_priv *priv)
 {
+	unsigned long flags;
+
 	/* Disable UE/CE Interrupts */
-	if (priv->p_data->quirks & DDR_ECC_INTR_SELF_CLEAR)
+	if (!(priv->p_data->quirks & DDR_ECC_INTR_SELF_CLEAR)) {
-		writel(0x0, priv->baseaddr + ECC_CLR_OFST);
-	else
 		writel(DDR_QOSUE_MASK | DDR_QOSCE_MASK,
 		       priv->baseaddr + DDR_QOS_IRQ_DB_OFST);
+
+		return;
+	}
+
+	spin_lock_irqsave(&priv->reglock, flags);
+
+	writel(0, priv->baseaddr + ECC_CLR_OFST);
+
+	spin_unlock_irqrestore(&priv->reglock, flags);
 }
 
 /**
@@ -576,8 +601,6 @@ static irqreturn_t intr_handler(int irq, void *dev_id)
 	/* v3.0 of the controller does not have this register */
 	if (!(priv->p_data->quirks & DDR_ECC_INTR_SELF_CLEAR))
 		writel(regval, priv->baseaddr + DDR_QOS_IRQ_STAT_OFST);
-	else
-		enable_intr(priv);
 
 	return IRQ_HANDLED;
 }
@@ -1357,6 +1380,7 @@ static int mc_probe(struct platform_device *pdev)
 	priv = mci->pvt_info;
 	priv->baseaddr = baseaddr;
 	priv->p_data = p_data;
+	spin_lock_init(&priv->reglock);
 
 	mc_init(mci, pdev);