From d55c5f28afafb6b1f0a6978916b23338b383faab Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Wed, 12 Jun 2019 13:51:37 +0100 Subject: arm64: smp: disable hotplug on trusted OS resident CPU The trusted OS may reject CPU_OFF calls to its resident CPU, so we must avoid issuing those. We never migrate a Trusted OS and we already take care to prevent CPU_OFF PSCI call. However, this is not reflected explicitly to the userspace. Any user can attempt to hotplug trusted OS resident CPU. The entire motion of going through the various state transitions in the CPU hotplug state machine gets executed and the PSCI layer finally refuses to make CPU_OFF call. This results is unnecessary unwinding of CPU hotplug state machine in the kernel. Instead we can mark the trusted OS resident CPU as not available for hotplug, so that the user attempt or request to do the same will get immediately rejected. Cc: Mark Rutland Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Sudeep Holla Signed-off-by: Will Deacon --- arch/arm64/include/asm/cpu_ops.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/arm64/include/asm') diff --git a/arch/arm64/include/asm/cpu_ops.h b/arch/arm64/include/asm/cpu_ops.h index c09d633c3109..86aabf1e0199 100644 --- a/arch/arm64/include/asm/cpu_ops.h +++ b/arch/arm64/include/asm/cpu_ops.h @@ -23,6 +23,8 @@ * @cpu_boot: Boots a cpu into the kernel. * @cpu_postboot: Optionally, perform any post-boot cleanup or necesary * synchronisation. Called from the cpu being booted. + * @cpu_can_disable: Determines whether a CPU can be disabled based on + * mechanism-specific information. * @cpu_disable: Prepares a cpu to die. May fail for some mechanism-specific * reason, which will cause the hot unplug to be aborted. Called * from the cpu to be killed. @@ -42,6 +44,7 @@ struct cpu_operations { int (*cpu_boot)(unsigned int); void (*cpu_postboot)(void); #ifdef CONFIG_HOTPLUG_CPU + bool (*cpu_can_disable)(unsigned int cpu); int (*cpu_disable)(unsigned int cpu); void (*cpu_die)(unsigned int cpu); int (*cpu_kill)(unsigned int cpu); -- cgit v1.2.3