From ca3fcfe5a17ed901a881f4704f41df552cce419d Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 1 Apr 2015 13:36:57 +0100 Subject: [PATCH] ARM: 8338/1: kexec: Relax SMP validation to improve DT compatibility When trying to kexec into a new kernel on a platform where multiple CPU cores are present, but no SMP bringup code is available yet, the kexec_load system call fails with: kexec_load failed: Invalid argument The SMP test added to machine_kexec_prepare() in commit 4adf9effe3e3d946 ("ARM: 7807/1: kexec: validate CPU hotplug support") wants to prohibit kexec on SMP platforms where it cannot disable secondary CPUs. However, this test is too strict: if the secondary CPUs couldn't be enabled in the first place, there's no need to disable them later at kexec time. Hence skip the test in the absence of SMP bringup code. This allows to add all CPU cores to the DTS from the beginning, without having to implement SMP bringup first, improving DT compatibility. Signed-off-by: Geert Uytterhoeven Acked-by: Stephen Warren Signed-off-by: Russell King --- arch/arm/include/asm/smp_plat.h | 1 + arch/arm/kernel/machine_kexec.c | 3 ++- arch/arm/kernel/smp.c | 5 +++++ 3 files changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h index 0ad7d490ee6f2..993e5224d8f7e 100644 --- a/arch/arm/include/asm/smp_plat.h +++ b/arch/arm/include/asm/smp_plat.h @@ -104,6 +104,7 @@ static inline u32 mpidr_hash_size(void) return 1 << mpidr_hash.bits; } +extern int platform_can_secondary_boot(void); extern int platform_can_cpu_hotplug(void); #endif diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c index de2b085ad7535..8bf3b7c098881 100644 --- a/arch/arm/kernel/machine_kexec.c +++ b/arch/arm/kernel/machine_kexec.c @@ -46,7 +46,8 @@ int machine_kexec_prepare(struct kimage *image) * and implements CPU hotplug for the current HW. If not, we won't be * able to kexec reliably, so fail the prepare operation. */ - if (num_possible_cpus() > 1 && !platform_can_cpu_hotplug()) + if (num_possible_cpus() > 1 && platform_can_secondary_boot() && + !platform_can_cpu_hotplug()) return -EINVAL; /* diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 86ef244c5a24b..cca5b87581855 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -145,6 +145,11 @@ void __init smp_init_cpus(void) smp_ops.smp_init_cpus(); } +int platform_can_secondary_boot(void) +{ + return !!smp_ops.smp_boot_secondary; +} + int platform_can_cpu_hotplug(void) { #ifdef CONFIG_HOTPLUG_CPU -- 2.39.5