[PATCH] irqchip/sifive-plic: fix call to __plic_toggle in M-Mode code path

[PATCH] irqchip/sifive-plic: fix call to __plic_toggle in M-Mode code path

[Charles Mirabile]

The code path for M-Mode linux that disables interrupts for other contexts
was missed when refactoring __plic_toggle.

Since the new version caches updates to the state for the primary context,
its use in this codepath is no longer desireable even if it could be made
correct.

Replace the calls to __plic_toggle with a loop that simply disables all of
the interrupts in groups of 32 with a direct mmio write.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202510271316.AQM7gCCy-lkp@intel.com/
Fixes: 14ff9e54dd14 ("irqchip/sifive-plic: Cache the interrupt enable state")

Signed-off-by: Charles Mirabile <cmirabil@redhat.com>
---
 drivers/irqchip/irq-sifive-plic.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index cbd7697bc148..0de3003981f1 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -592,12 +592,12 @@ static int plic_probe(struct fwnode_handle *fwnode)
 		if (parent_hwirq != RV_IRQ_EXT) {
 			/* Disable S-mode enable bits if running in M-mode. */
 			if (IS_ENABLED(CONFIG_RISCV_M_MODE)) {
-				void __iomem *enable_base = priv->regs +
+				u32 __iomem *enable_base = priv->regs +
 					CONTEXT_ENABLE_BASE +
 					i * CONTEXT_ENABLE_SIZE;
 
-				for (hwirq = 1; hwirq <= nr_irqs; hwirq++)
-					__plic_toggle(enable_base, hwirq, 0);
+				for (int j = 0; j <= nr_irqs / 32; j++)
+					writel(0, enable_base + j);
 			}
 			continue;
 		}
-- 
2.43.0


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Re: [PATCH] irqchip/sifive-plic: fix call to __plic_toggle in M-Mode code path

[patchwork-bot+linux-riscv]

Hello:

This patch was applied to riscv/linux.git (fixes)
by Thomas Gleixner <tglx@linutronix.de>:

On Mon,  3 Nov 2025 11:18:13 -0500 you wrote:
> The code path for M-Mode linux that disables interrupts for other contexts
> was missed when refactoring __plic_toggle.
> 
> Since the new version caches updates to the state for the primary context,
> its use in this codepath is no longer desireable even if it could be made
> correct.
> 
> [...]

Here is the summary with links:
  - irqchip/sifive-plic: fix call to __plic_toggle in M-Mode code path
    https://git.kernel.org/riscv/c/a045359e7245

You are awesome, thank you!
-- 
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