Re: [PATCH v4 2/3] acpi, apei, ghes: Make NMI error notification to be GHES architecture extension.

Tomasz Nowicki
2014-07-04T06:52:47Z

On 02.07.2014 14:16, Borislav Petkov wrote:
> On Tue, Jun 24, 2014 at 01:41:34PM +0200, Tomasz Nowicki wrote:
>> Currently APEI depends on x86 architecture. It is because of NMI hardware
>> error notification of GHES which is currently supported by x86 only.
>> However, many other APEI features can be still used perfectly by other
>> architectures.
>>
>> This commit adds two symbols:
>> 1. HAVE_ACPI_APEI for those archs which support APEI.
>> 2. HAVE_ACPI_APEI_NMI which is used for NMI code isolation in ghes.c
>> file. NMI related data and functions are grouped so they can be wrapped
>> inside one #ifdef section. Appropriate function stubs are provided for
>> !NMI case.
>>
>> Note there is no functional changes for x86 due to hard selected
>> HAVE_ACPI_APEI and HAVE_ACPI_APEI_NMI symbols.
>>
>> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
>> ---
>> arch/x86/Kconfig | 2 +
>> drivers/acpi/apei/Kconfig | 8 ++-
>> drivers/acpi/apei/ghes.c | 149 +++++++++++++++++++++++++++++----------------
>> include/linux/nmi.h | 4 ++
>> 4 files changed, 110 insertions(+), 53 deletions(-)
>>
>
> ...
>
>> @@ -894,11 +892,71 @@ static unsigned long ghes_esource_prealloc_size(
>> return prealloc_size;
>> }
>>
>> +static void ghes_estatus_pool_shrink(unsigned long len)
>> +{
>> + ghes_estatus_pool_size_request -= PAGE_ALIGN(len);
>> +}
>> +
>> +static void ghes_nmi_add(struct ghes *ghes)
>> +{
>> + unsigned long len;
>> +
>> + len = ghes_esource_prealloc_size(ghes->generic);
>> + ghes_estatus_pool_expand(len);
>> + mutex_lock(&ghes_list_mutex);
>> + if (list_empty(&ghes_nmi))
>> + register_nmi_handler(NMI_LOCAL, ghes_notify_nmi, 0, "ghes");
>> + list_add_rcu(&ghes->list, &ghes_nmi);
>> + mutex_unlock(&ghes_list_mutex);
>> +}
>> +
>> +static void ghes_nmi_remove(struct ghes *ghes)
>> +{
>> + unsigned long len;
>> +
>> + mutex_lock(&ghes_list_mutex);
>> + list_del_rcu(&ghes->list);
>> + if (list_empty(&ghes_nmi))
>> + unregister_nmi_handler(NMI_LOCAL, "ghes");
>> + mutex_unlock(&ghes_list_mutex);
>> + /*
>> + * To synchronize with NMI handler, ghes can only be
>> + * freed after NMI handler finishes.
>> + */
>> + synchronize_rcu();
>> + len = ghes_esource_prealloc_size(ghes->generic);
>> + ghes_estatus_pool_shrink(len);
>> +}
>> +
>> +static void ghes_nmi_init_cxt(void)
>> +{
>> + init_irq_work(&ghes_proc_irq_work, ghes_proc_in_irq);
>> +}
>> +#else
>
> Markers please to know to which CONFIG_ symbol this #else refers to:
>
> #else /* CONFIG_HAVE_ACPI_APEI_NMI */
>
>> +static inline void ghes_nmi_add(struct ghes *ghes)
>> +{
>> + pr_err(GHES_PFX "ID: %d, trying to add NMI notification which is not supported!\n",
>> + ghes->generic->header.source_id);
>> + BUG();
>> +}
>> +
>> +static inline void ghes_nmi_remove(struct ghes *ghes)
>> +{
>> + pr_err(GHES_PFX "ID: %d, trying to remove NMI notification which is not supported!\n",
>> + ghes->generic->header.source_id);
>> + BUG();
>> +}
>> +
>> +static inline void ghes_nmi_init_cxt(void)
>> +{
>> +}
>> +#endif
>
> Ditto.
>

Right, I will fix that and thanks for all you acks.

BTW, who else should I asked for review to move upstream process one
step further?

Regards,
Tomasz