Commit 92e26e2a authored by Borislav Petkov's avatar Borislav Petkov
Browse files

x86, MCE, AMD: Remove shared banks sysfs linking 



The code used to create a symlink on all non-BSP cores of a node when
the MCi_MISCj bank is present once per node. (This is generally the
case with bank 4 on AMD). However, these sysfs links cause a bunch
of problems with cpu off-/onlining testing and are, as such, a bit
overengineered. IOW, there's nothing wrong with having normal sysfs
files for the shared banks since the corresponding MSRs are replicated
across each core anyway.

Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
parent 24214449

arch/x86/kernel/cpu/mcheck/mce_amd.c

+7 −98
Original line number Diff line number Diff line
@@ -60,7 +60,6 @@ struct threshold_block { 
struct threshold_bank {

	struct kobject		*kobj;

	struct threshold_block	*blocks;

	cpumask_var_t		cpus;

};

static DEFINE_PER_CPU(struct threshold_bank * [NR_BANKS], threshold_banks);
@@ -224,8 +223,6 @@ void mce_amd_feature_init(struct cpuinfo_x86 *c) 


			if (!block)

				per_cpu(bank_map, cpu) |= (1 << bank);

			if (shared_bank[bank] && c->cpu_core_id)

				break;



			memset(&b, 0, sizeof(b));

			b.cpu			= cpu;
@@ -555,89 +552,35 @@ local_allocate_threshold_blocks(int cpu, unsigned int bank) 
					 MSR_IA32_MC0_MISC + bank * 4);

}



/* symlinks sibling shared banks to first core.  first core owns dir/files. */

static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)

{

	int i, err = 0;

	struct threshold_bank *b = NULL;

	struct device *dev = per_cpu(mce_device, cpu);

	struct threshold_bank *b = NULL;

	char name[32];

	int err = 0;



	sprintf(name, "threshold_bank%i", bank);



#ifdef CONFIG_SMP

	if (cpu_data(cpu).cpu_core_id && shared_bank[bank]) {	/* symlink */

		i = cpumask_first(cpu_llc_shared_mask(cpu));



		/* first core not up yet */

		if (cpu_data(i).cpu_core_id)

			goto out;



		/* already linked */

		if (per_cpu(threshold_banks, cpu)[bank])

			goto out;



		b = per_cpu(threshold_banks, i)[bank];



		if (!b)

			goto out;



		err = sysfs_create_link(&dev->kobj, b->kobj, name);

		if (err)

			goto out;



		cpumask_copy(b->cpus, cpu_llc_shared_mask(cpu));

		per_cpu(threshold_banks, cpu)[bank] = b;



		goto out;

	}

#endif



	b = kzalloc(sizeof(struct threshold_bank), GFP_KERNEL);

	if (!b) {

		err = -ENOMEM;

		goto out;

	}

	if (!zalloc_cpumask_var(&b->cpus, GFP_KERNEL)) {

		kfree(b);

		err = -ENOMEM;

		goto out;

	}



	b->kobj = kobject_create_and_add(name, &dev->kobj);

	if (!b->kobj)

	if (!b->kobj) {

		err = -EINVAL;

		goto out_free;



#ifndef CONFIG_SMP

	cpumask_setall(b->cpus);

#else

	cpumask_set_cpu(cpu, b->cpus);

#endif

	}



	per_cpu(threshold_banks, cpu)[bank] = b;



	err = local_allocate_threshold_blocks(cpu, bank);

	if (err)

		goto out_free;



	for_each_cpu(i, b->cpus) {

		if (i == cpu)

			continue;



		dev = per_cpu(mce_device, i);

		if (dev)

			err = sysfs_create_link(&dev->kobj,b->kobj, name);

		if (err)

			goto out;



		per_cpu(threshold_banks, i)[bank] = b;

	}



	if (!err)

		goto out;



out_free:

	per_cpu(threshold_banks, cpu)[bank] = NULL;

	free_cpumask_var(b->cpus);

	kfree(b);

out:

	return err;
@@ -660,12 +603,6 @@ static __cpuinit int threshold_create_device(unsigned int cpu) 
	return err;

}



/*

 * let's be hotplug friendly.

 * in case of multiple core processors, the first core always takes ownership

 *   of shared sysfs dir/files, and rest of the cores will be symlinked to it.

 */



static void deallocate_threshold_block(unsigned int cpu,

						 unsigned int bank)

{
@@ -689,9 +626,6 @@ static void deallocate_threshold_block(unsigned int cpu, 
static void threshold_remove_bank(unsigned int cpu, int bank)

{

	struct threshold_bank *b;

	struct device *dev;

	char name[32];

	int i = 0;



	b = per_cpu(threshold_banks, cpu)[bank];

	if (!b)
@@ -699,36 +633,11 @@ static void threshold_remove_bank(unsigned int cpu, int bank) 
	if (!b->blocks)

		goto free_out;



	sprintf(name, "threshold_bank%i", bank);



#ifdef CONFIG_SMP

	/* sibling symlink */

	if (shared_bank[bank] && b->blocks->cpu != cpu) {

		dev = per_cpu(mce_device, cpu);

		sysfs_remove_link(&dev->kobj, name);

		per_cpu(threshold_banks, cpu)[bank] = NULL;



		return;

	}

#endif



	/* remove all sibling symlinks before unregistering */

	for_each_cpu(i, b->cpus) {

		if (i == cpu)

			continue;



		dev = per_cpu(mce_device, i);

		if (dev)

			sysfs_remove_link(&dev->kobj, name);

		per_cpu(threshold_banks, i)[bank] = NULL;

	}



	deallocate_threshold_block(cpu, bank);



free_out:

	kobject_del(b->kobj);

	kobject_put(b->kobj);

	free_cpumask_var(b->cpus);

	kfree(b);

	per_cpu(threshold_banks, cpu)[bank] = NULL;

}

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