[PATCH] x86, microcode: Make reload interface per system

Borislav Petkov
2012-06-15T16:52:14Z

On Fri, Jun 15, 2012 at 02:52:40PM +0200, Borislav Petkov wrote:
> Actually, the BSP thing was more-or-less an arbitrary deal. What we want as an
> endresult is to do:
>
> $ echo 1 > /sys/devices/system/cpu/microcode/reload
>
> (notice this is in the toplevel "cpu" directory in sysfs)
>
> and do the system-wide reload there.

Actually, that was easier than I thought, see below. And it seems to
workie too.

--
From: Borislav Petkov <borislav.petkov@amd.com>
Date: Fri, 15 Jun 2012 18:46:05 +0200
Subject: [PATCH] x86, microcode: Make reload interface per system

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.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
arch/x86/kernel/microcode_core.c | 32 ++++++++++++++++++++++++++++----
1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
index 24b852b61be3..4c6f3b37ed3c 100644
--- a/arch/x86/kernel/microcode_core.c
+++ b/arch/x86/kernel/microcode_core.c
@@ -351,7 +351,6 @@ 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 +527,16 @@ 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 +568,17 @@ 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 +588,11 @@ 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 +601,7 @@ out_driver:
mutex_unlock(&microcode_mutex);
put_online_cpus();

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

@@ -596,6 +617,9 @@ 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

--
Regards/Gruss,
Boris.

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