Valentin Schneider d23bc2bc1d irqchip/gic-v3-its: Postpone LPI pending table freeing and memreserve ... Memory used by the LPI tables have to be made persistent for kexec to have a chance to work, as explained in [1]. If they have been made persistent and we are booting into a kexec'd kernel, we also need to free the pages that were preemptively allocated by the new kernel for those tables. Both of those operations currently happen during its_cpu_init(), which happens in a _STARTING (IOW atomic) cpuhp callback for secondary CPUs. efi_mem_reserve_iomem() issues a GFP_ATOMIC allocation, which unfortunately doesn't work under PREEMPT_RT (this ends up grabbing a non-raw spinlock, which can sleep under PREEMPT_RT). Similarly, freeing the pages ends up grabbing a sleepable spinlock. Since the memreserve is only required by kexec, it doesn't have to be done so early in the secondary boot process. Issue the reservation in a new CPUHP_AP_ONLINE_DYN cpuhp callback, and piggy-back the page freeing on top of it. A CPU gets to run the body of this new callback exactly once. As kexec issues a machine_shutdown() prior to machine_kexec(), it will be serialized vs a CPU being plugged to life by the hotplug machinery - either the CPU will have been brought up and have had its redistributor's pending table memreserved, or it never went online and will have its table allocated by the new kernel. [1]: https://lore.kernel.org/lkml/20180921195954.21574-1-marc.zyngier@arm.com/ Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211027151506.2085066-3-valentin.schneider@arm.com		2021-12-16 13:21:11 +00:00
..
arm-gic-common.h	irqchip/gic: Split vGIC probing information from the GIC code	2021-06-01 10:45:58 +01:00
arm-gic-v3.h	irqchip/gic-v3-its: Postpone LPI pending table freeing and memreserve	2021-12-16 13:21:11 +00:00
arm-gic-v4.h	irqchip/gic-v4.1: Disable vSGI upon (GIC CPUIF < v4.1) detection	2021-04-22 15:55:21 +01:00
arm-gic.h
arm-vgic-info.h	KVM: arm64: vgic: Let an interrupt controller advertise lack of HW deactivation	2021-06-01 10:45:59 +01:00
arm-vic.h	irqchip/vic: Cut down the external API	2020-06-27 11:54:54 +01:00
chained_irq.h
irq-bcm2836.h	irqchip: irq-bcm2836.h: drop a duplicated word	2020-07-27 08:55:03 +01:00
irq-davinci-aintc.h
irq-davinci-cp-intc.h
irq-ixp4xx.h
irq-madera.h
irq-omap-intc.h	include/: replace HTTP links with HTTPS ones	2020-08-12 10:57:59 -07:00
irq-partition-percpu.h
irq-sa11x0.h
mmp.h
mxs.h
versatile-fpga.h
xtensa-mx.h
xtensa-pic.h