linux_dsm_epyc7002/arch/mips/cavium-octeon
Thomas Gleixner 01f8fa4f01 genirq: Allow forcing cpu affinity of interrupts
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>
2014-04-17 23:36:27 +02:00
..
executive MIPS: OCTEON: Supply OCTEON+ USB nodes in internal device trees. 2014-01-23 13:02:35 +01:00
.gitignore MIPS: Octeon: Add device tree source files. 2012-07-23 13:54:52 +01:00
cpu.c MIPS: Octeon: Place cnmips_cu2_setup in __init memory. 2010-10-04 18:34:00 +01:00
csrc-octeon.c MIPS: Optimize current_cpu_type() for better code. 2013-09-17 18:50:53 +02:00
dma-octeon.c x86: Don't panic if can not alloc buffer for swiotlb 2013-01-29 19:36:53 -08:00
flash_setup.c mips/octeon: 16-Bit NOR flash was not being detected during boot 2012-11-09 11:37:16 +01:00
Kconfig MIPS: OCTEON: Get rid of CONFIG_CAVIUM_OCTEON_HW_FIX_UNALIGNED 2013-06-10 18:01:25 +02:00
Makefile Merge branch '3.10-fixes' into mips-for-linux-next 2013-07-12 18:11:43 +02:00
oct_ilm.c MIPS: Octeon: Adding driver to measure interrupt latency on Octeon. 2013-02-15 23:07:37 +01:00
octeon_3xxx.dts MIPS: OCTEON: Supply OCTEON+ USB nodes in internal device trees. 2014-01-23 13:02:35 +01:00
octeon_68xx.dts MIPS: Whitespace cleanup. 2013-02-01 10:00:22 +01:00
octeon_boot.h MIPS: Whitespace cleanup. 2013-02-01 10:00:22 +01:00
octeon-irq.c genirq: Allow forcing cpu affinity of interrupts 2014-04-17 23:36:27 +02:00
octeon-memcpy.S MIPS: Whitespace cleanup. 2013-02-01 10:00:22 +01:00
octeon-platform.c MIPS: OCTEON: Supply OCTEON+ USB nodes in internal device trees. 2014-01-23 13:02:35 +01:00
Platform MIPS: OCTEON: Rename Kconfig CAVIUM_OCTEON_REFERENCE_BOARD to CAVIUM_OCTEON_SOC 2013-06-10 18:01:25 +02:00
setup.c MIPS: Panic messages should not end in \n. 2013-10-29 21:24:19 +01:00
smp.c mips: delete non-required instances of include <linux/init.h> 2014-01-24 22:39:56 +01:00