arm/gic: disable interrupt before modifying GICD_ICFGRn - #18
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Per the ARM GIC specification, modifying a programmable Int_config field while the corresponding interrupt is enabled results in UNPREDICTABLE behavior. setIRQTrigger currently modifies GICD_ICFGRn (GICv2) and GICD_ICFGR/GICR_ICFGR (GICv3) without first disabling the interrupt. Fix both GICv2 and GICv3 implementations to: 1. Check if the interrupt is currently enabled by reading the GICD_ISENABLER / GICR_ISENABLER register. 2. Disable the interrupt if it was enabled. 3. Modify the configuration register. 4. Re-enable the interrupt if it was previously enabled. While the current sole call site (Arch_invokeIRQControl) configures interrupts before they are enabled, this fix makes setIRQTrigger safe for any future callers that may reconfigure already-enabled interrupts. Resolves seL4#290 Signed-off-by: Kent McLeod <kent.mcleod@kry10.com> Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Per the ARM GIC specification, modifying a programmable Int_config field while the corresponding interrupt is enabled results in UNPREDICTABLE behavior. setIRQTrigger currently modifies GICD_ICFGRn (GICv2) and GICD_ICFGR/GICR_ICFGR (GICv3) without first disabling the interrupt.
Fix both GICv2 and GICv3 implementations to:
While the current sole call site (Arch_invokeIRQControl) configures interrupts before they are enabled, this fix makes setIRQTrigger safe for any future callers that may reconfigure already-enabled interrupts.
Resolves seL4#290