[PATCH v3 03/10] spmi: pmic-arb: check apid against limits before calling irq handler

From: Fenglin Wu
Date: Mon Nov 29 2021 - 03:24:54 EST


From: David Collins <collinsd@xxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxx>
Signed-off-by: Fenglin Wu <quic_fenglinw@xxxxxxxxxxx>
---
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 ce7ae99..479f721 100644
--- a/drivers/spmi/spmi-pmic-arb.c
+++ b/drivers/spmi/spmi-pmic-arb.c
@@ -523,21 +523,26 @@ 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)
--
2.7.4