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From:   Stephen Boyd <sboyd@kernel.org>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     David Collins <collinsd@codeaurora.org>,
        linux-kernel@vger.kernel.org, patches@lists.linux.dev,
        Fenglin Wu <quic_fenglinw@quicinc.com>
Subject: [PATCH 5/9] spmi: pmic-arb: check apid against limits before calling irq handler
Date:   Thu, 29 Sep 2022 17:50:14 -0700
Message-Id: <20220930005019.2663064-6-sboyd@kernel.org>
In-Reply-To: <20220930005019.2663064-1-sboyd@kernel.org>
References: <20220930005019.2663064-1-sboyd@kernel.org>
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From: David Collins <collinsd@codeaurora.org>

Check that the apid for an SPMI interrupt falls between the
min_apid and max_apid that can be handled by the APPS processor
before invoking the per-apid interrupt handler:
periph_interrupt().

This avoids an access violation in rare cases where the status
bit is set for an interrupt that is not owned by the APPS
processor.

Signed-off-by: David Collins <collinsd@codeaurora.org>
Signed-off-by: Fenglin Wu <quic_fenglinw@quicinc.com>
Link: https://lore.kernel.org/r/1655004286-11493-5-git-send-email-quic_fenglinw@quicinc.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
---
 drivers/spmi/spmi-pmic-arb.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/spmi/spmi-pmic-arb.c b/drivers/spmi/spmi-pmic-arb.c
index 2bc3b88f35c9..e19eaec30aa5 100644
--- a/drivers/spmi/spmi-pmic-arb.c
+++ b/drivers/spmi/spmi-pmic-arb.c
@@ -625,21 +625,26 @@ static void pmic_arb_chained_irq(struct irq_desc *desc)
 	struct spmi_pmic_arb *pmic_arb = irq_desc_get_handler_data(desc);
 	const struct pmic_arb_ver_ops *ver_ops = pmic_arb->ver_ops;
 	struct irq_chip *chip = irq_desc_get_chip(desc);
-	int first = pmic_arb->min_apid >> 5;
-	int last = pmic_arb->max_apid >> 5;
+	int first = pmic_arb->min_apid;
+	int last = pmic_arb->max_apid;
 	u8 ee = pmic_arb->ee;
 	u32 status, enable, handled = 0;
 	int i, id, apid;
 
 	chained_irq_enter(chip, desc);
 
-	for (i = first; i <= last; ++i) {
+	for (i = first >> 5; i <= last >> 5; ++i) {
 		status = readl_relaxed(
 				ver_ops->owner_acc_status(pmic_arb, ee, i));
 		while (status) {
 			id = ffs(status) - 1;
 			status &= ~BIT(id);
 			apid = id + i * 32;
+			if (apid < first || apid > last) {
+				WARN_ONCE(true, "spurious spmi irq received for apid=%d\n",
+					apid);
+				continue;
+			}
 			enable = readl_relaxed(
 					ver_ops->acc_enable(pmic_arb, apid));
 			if (enable & SPMI_PIC_ACC_ENABLE_BIT)
-- 
https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git/
https://git.kernel.org/pub/scm/linux/kernel/git/sboyd/spmi.git