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authorThomas Gleixner <tglx@linutronix.de>2019-06-18 22:31:40 +0200
committerPaul Gortmaker <paul.gortmaker@windriver.com>2019-09-16 12:21:49 -0400
commit50d4c6591d254a482c56b0f0f3ee6f79ffe6985a (patch)
treef09f1df621dca55d6b2e0a2a7c53cb6aa28a14ac
parent6129763b4364acec4c5dffba2643f60ebd333e7e (diff)
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x86/microcode: Fix the microcode load on CPU hotplug for real
commit 5423f5ce5ca410b3646f355279e4e937d452e622 upstream. A recent change moved the microcode loader hotplug callback into the early startup phase which is running with interrupts disabled. It missed that the callbacks invoke sysfs functions which might sleep causing nice 'might sleep' splats with proper debugging enabled. Split the callbacks and only load the microcode in the early startup phase and move the sysfs handling back into the later threaded and preemptible bringup phase where it was before. Fixes: 78f4e932f776 ("x86/microcode, cpuhotplug: Add a microcode loader CPU hotplug callback") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: stable@vger.kernel.org Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1906182228350.1766@nanos.tec.linutronix.de
-rw-r--r--arch/x86/kernel/cpu/microcode/core.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index b7027e667604..a96091d44a45 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -790,13 +790,16 @@ static struct syscore_ops mc_syscore_ops = {
.resume = mc_bp_resume,
};
-static int mc_cpu_online(unsigned int cpu)
+static int mc_cpu_starting(unsigned int cpu)
{
- struct device *dev;
-
- dev = get_cpu_device(cpu);
microcode_update_cpu(cpu);
pr_debug("CPU%d added\n", cpu);
+ return 0;
+}
+
+static int mc_cpu_online(unsigned int cpu)
+{
+ struct device *dev = get_cpu_device(cpu);
if (sysfs_create_group(&dev->kobj, &mc_attr_group))
pr_err("Failed to create group for CPU%d\n", cpu);
@@ -873,7 +876,9 @@ int __init microcode_init(void)
goto out_ucode_group;
register_syscore_ops(&mc_syscore_ops);
- cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:online",
+ cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
+ mc_cpu_starting, NULL);
+ cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
mc_cpu_online, mc_cpu_down_prep);
pr_info("Microcode Update Driver: v%s.", DRIVER_VERSION);