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: Borislav Petkov <borislav.petkov@amd.com>

diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index f4873a64f46dcb2dac8db0c3585afecc642e70ee..2a5dd30f9969b9c799610e2a4a657ec54d646f0d 100644 (file)
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -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;
-       }
-
-       goto out;
+       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;
 }