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

Henrique de Moraes Holschuh
2012-06-19T02:46:44Z

On Fri, 15 Jun 2012, Borislav Petkov wrote:
> 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>

It is a pity this one is much harder to backport to 3.2 and 3.0. I'd
really like to have the new interface there. But it looks good, and we
will support the new /sys/devices/system/cpu/microcode/reload sysfs node
in Debian for the benefit of anyone using a newer kernel than the
distro's (which will be based on 3.2).

So, fwiw, you have my:
Acked-by-unimportant-person: Henrique de Moraes Holschuh <hmh@hmh.eng.br>

> ---
> 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);

--
"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh