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x86/mce/amd: Sanitize thresholding device creation hotplug path

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Drop the stupid threshold_init_device() initcall iterating over all
online CPUs in favor of properly setting up everything on the CPU
hotplug path, when each CPU's callback is invoked.

 [ bp: Write commit message. ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200403161943.1458-5-bp@alien8.de
This commit is contained in:
Thomas Gleixner 2020-03-30 16:21:54 +02:00 committed by Borislav Petkov
parent cca9cc05fe
commit 6e7a41c63a
2 changed files with 27 additions and 41 deletions
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57
arch/x86/kernel/cpu/mce/amd.c
View File

@ -1474,12 +1474,22 @@ int mce_threshold_remove_device(unsigned int cpu)
return 0;
}
/* create dir/files for all valid threshold banks */
/**
* mce_threshold_create_device - Create the per-CPU MCE threshold device
* @cpu: The plugged in CPU
*
* Create directories and files for all valid threshold banks.
*
* This is invoked from the CPU hotplug callback which was installed in
* mcheck_init_device(). The invocation happens in context of the hotplug
* thread running on @cpu. The callback is invoked on all CPUs which are
* online when the callback is installed or during a real hotplug event.
*/
int mce_threshold_create_device(unsigned int cpu)
{
unsigned int bank;
struct threshold_bank **bp;
int err = 0;
int err;
if (!mce_flags.amd_threshold)
return 0;
@ -1500,49 +1510,14 @@ int mce_threshold_create_device(unsigned int cpu)
continue;
err = threshold_create_bank(cpu, bank);
if (err)
goto err;
}
return err;
err:
mce_threshold_remove_device(cpu);
return err;
}
static __init int threshold_init_device(void)
{
unsigned lcpu = 0;
/* to hit CPUs online before the notifier is up */
for_each_online_cpu(lcpu) {
int err = mce_threshold_create_device(lcpu);
if (err)
return err;
goto out_err;
}
if (thresholding_irq_en)
mce_threshold_vector = amd_threshold_interrupt;
return 0;
out_err:
mce_threshold_remove_device(cpu);
return err;
}
/*
* there are 3 funcs which need to be _initcalled in a logic sequence:
* 1. xen_late_init_mcelog
* 2. mcheck_init_device
* 3. threshold_init_device
*
* xen_late_init_mcelog must register xen_mce_chrdev_device before
* native mce_chrdev_device registration if running under xen platform;
*
* mcheck_init_device should be inited before threshold_init_device to
* initialize mce_device, otherwise a NULL ptr dereference will cause panic.
*
* so we use following _initcalls
* 1. device_initcall(xen_late_init_mcelog);
* 2. device_initcall_sync(mcheck_init_device);
* 3. late_initcall(threshold_init_device);
*
* when running under xen, the initcall order is 1,2,3;
* on baremetal, we skip 1 and we do only 2 and 3.
*/
late_initcall(threshold_init_device);

11
arch/x86/kernel/cpu/mce/core.c
View File

@ -2481,6 +2481,13 @@ static __init void mce_init_banks(void)
}
}
/*
* When running on XEN, this initcall is ordered against the XEN mcelog
* initcall:
*
* device_initcall(xen_late_init_mcelog);
* device_initcall_sync(mcheck_init_device);
*/
static __init int mcheck_init_device(void)
{
int err;
@ -2512,6 +2519,10 @@ static __init int mcheck_init_device(void)
if (err)
goto err_out_mem;
/*
* Invokes mce_cpu_online() on all CPUs which are online when
* the state is installed.
*/
err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/mce:online",
mce_cpu_online, mce_cpu_pre_down);
if (err < 0)