linux-kernel - [PATCH v4 04/14] irqchip/irq-bcm7038-l1: Gate use of CPU logical map to MIPS

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Message-Id: <20211009022023.3796472-5-f.fainelli@gmail.com>
Date:   Fri,  8 Oct 2021 19:20:13 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        bcm-kernel-feedback-list@...adcom.com (maintainer:BROADCOM
        BCM281XX/BCM11XXX/BCM216XX ARM ARCHITE...),
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <maz@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        linux-arm-kernel@...ts.infradead.org (moderated list:ARM
        SUB-ARCHITECTURES), linux-mips@...r.kernel.org (open list:MIPS),
        devicetree@...r.kernel.org (open list:OPEN FIRMWARE AND FLATTENED
        DEVICE TREE)
Subject: [PATCH v4 04/14] irqchip/irq-bcm7038-l1: Gate use of CPU logical map to MIPS

The use of the cpu_logical_map[] array is only relevant for MIPS based
platform where this driver is used as a first level interrupt controller
and contains multiple register groups to map with an associated CPU.

On ARM/ARM64 based systems this interrupt controller is present and used
as a second level interrupt controller hanging off the ARM GIC. That
copy of the interrupt controller contains a single group, resulting in
the intc->cpus[] array to be of size 1.

Things happened to work in that case because we install that interrupt
controller as a chained handler which does not allow it to be affine to
any CPU but the boot CPU which happens to be 0, therefore we never
de-reference past intc->cpus[] but with the current code in place, we do
leave a chance of de-referencing the array past its bounds.

Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
---
 drivers/irqchip/irq-bcm7038-l1.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/irqchip/irq-bcm7038-l1.c b/drivers/irqchip/irq-bcm7038-l1.c
index 14caf32dc23e..3c4e348c661e 100644
--- a/drivers/irqchip/irq-bcm7038-l1.c
+++ b/drivers/irqchip/irq-bcm7038-l1.c
@@ -28,9 +28,6 @@
 #include <linux/irqchip.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/syscore_ops.h>
-#ifdef CONFIG_ARM
-#include <asm/smp_plat.h>
-#endif
 
 #define IRQS_PER_WORD		32
 #define REG_BYTES_PER_IRQ_WORD	(sizeof(u32) * 4)
@@ -127,7 +124,7 @@ static void bcm7038_l1_irq_handle(struct irq_desc *desc)
 	struct irq_chip *chip = irq_desc_get_chip(desc);
 	unsigned int idx;
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) && defined(CONFIG_MIPS)
 	cpu = intc->cpus[cpu_logical_map(smp_processor_id())];
 #else
 	cpu = intc->cpus[0];
@@ -301,7 +298,7 @@ static int bcm7038_l1_suspend(void)
 	u32 val;
 
 	/* Wakeup interrupt should only come from the boot cpu */
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) && defined(CONFIG_MIPS)
 	boot_cpu = cpu_logical_map(0);
 #else
 	boot_cpu = 0;
@@ -325,7 +322,7 @@ static void bcm7038_l1_resume(void)
 	struct bcm7038_l1_chip *intc;
 	int boot_cpu, word;
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) && defined(CONFIG_MIPS)
 	boot_cpu = cpu_logical_map(0);
 #else
 	boot_cpu = 0;
-- 
2.25.1