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The current implementation of irq_set_affinity() refuses rightfully to route an interrupt to an offline cpu. But there is a special case, where this is actually desired. Some of the ARM SoCs have per cpu timers which require setting the affinity during cpu startup where the cpu is not yet in the online mask. If we can't do that, then the local timer interrupt for the about to become online cpu is routed to some random online cpu. The developers of the affected machines tried to work around that issue, but that results in a massive mess in that timer code. We have a yet unused argument in the set_affinity callbacks of the irq chips, which I added back then for a similar reason. It was never required so it got not used. But I'm happy that I never removed it. That allows us to implement a sane handling of the above scenario. So the affected SoC drivers can add the required force handling to their interrupt chip, switch the timer code to irq_force_affinity() and things just work. This does not affect any existing user of irq_set_affinity(). Tagged for stable to allow a simple fix of the affected SoC clock event drivers. Reported-and-tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Tomasz Figa <t.figa@samsung.com>, Cc: Daniel Lezcano <daniel.lezcano@linaro.org>, Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: linux-arm-kernel@lists.infradead.org, Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140416143315.717251504@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
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| .. | ||
| autoprobe.c | ||
| chip.c | ||
| debug.h | ||
| devres.c | ||
| dummychip.c | ||
| generic-chip.c | ||
| handle.c | ||
| internals.h | ||
| irqdesc.c | ||
| irqdomain.c | ||
| Kconfig | ||
| Makefile | ||
| manage.c | ||
| migration.c | ||
| pm.c | ||
| proc.c | ||
| resend.c | ||
| settings.h | ||
| spurious.c | ||