[PATCH -v2 2/2] x86, microcode: Make reload interface per system

From: Borislav Petkov
Date: Thu Jun 21 2012 - 08:07:37 EST


From: Borislav Petkov <borislav.petkov@xxxxxxx>

The reload interface should be per-system so that a full system ucode
reload happens (on each core) when doing

echo 1 > /sys/devices/system/cpu/microcode/reload

Move it to the cpu subsys directory instead of it being per-cpu.

Cc: Henrique de Moraes Holschuh <hmh@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <borislav.petkov@xxxxxxx>
---
arch/x86/kernel/microcode_core.c | 36 ++++++++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
index 24b852b61be3..947e4c64b1d8 100644
--- a/arch/x86/kernel/microcode_core.c
+++ b/arch/x86/kernel/microcode_core.c
@@ -301,10 +301,6 @@ static ssize_t reload_store(struct device *dev,
int cpu;
ssize_t ret = 0, tmp_ret;

- /* allow reload only from the BSP */
- if (boot_cpu_data.cpu_index != dev->id)
- return -EINVAL;
-
ret = kstrtoul(buf, 0, &val);
if (ret)
return ret;
@@ -351,7 +347,6 @@ static DEVICE_ATTR(version, 0400, version_show, NULL);
static DEVICE_ATTR(processor_flags, 0400, pf_show, NULL);

static struct attribute *mc_default_attrs[] = {
- &dev_attr_reload.attr,
&dev_attr_version.attr,
&dev_attr_processor_flags.attr,
NULL
@@ -528,6 +523,16 @@ static const struct x86_cpu_id microcode_id[] = {
MODULE_DEVICE_TABLE(x86cpu, microcode_id);
#endif

+static struct attribute *cpu_root_microcode_attrs[] = {
+ &dev_attr_reload.attr,
+ NULL
+};
+
+static struct attribute_group cpu_root_microcode_group = {
+ .name = "microcode",
+ .attrs = cpu_root_microcode_attrs,
+};
+
static int __init microcode_init(void)
{
struct cpuinfo_x86 *c = &cpu_data(0);
@@ -559,9 +564,17 @@ static int __init microcode_init(void)
if (error)
goto out_pdev;

+ error = sysfs_create_group(&cpu_subsys.dev_root->kobj,
+ &cpu_root_microcode_group);
+
+ if (error) {
+ pr_err("Error creating microcode group!\n");
+ goto out_driver;
+ }
+
error = microcode_dev_init();
if (error)
- goto out_driver;
+ goto out_ucode_group;

register_syscore_ops(&mc_syscore_ops);
register_hotcpu_notifier(&mc_cpu_notifier);
@@ -571,7 +584,11 @@ static int __init microcode_init(void)

return 0;

-out_driver:
+ out_ucode_group:
+ sysfs_remove_group(&cpu_subsys.dev_root->kobj,
+ &cpu_root_microcode_group);
+
+ out_driver:
get_online_cpus();
mutex_lock(&microcode_mutex);

@@ -580,7 +597,7 @@ out_driver:
mutex_unlock(&microcode_mutex);
put_online_cpus();

-out_pdev:
+ out_pdev:
platform_device_unregister(microcode_pdev);
return error;

@@ -596,6 +613,9 @@ static void __exit microcode_exit(void)
unregister_hotcpu_notifier(&mc_cpu_notifier);
unregister_syscore_ops(&mc_syscore_ops);

+ sysfs_remove_group(&cpu_subsys.dev_root->kobj,
+ &cpu_root_microcode_group);
+
get_online_cpus();
mutex_lock(&microcode_mutex);

--
1.7.11.rc1

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