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

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Date:	Wed, 2 Jul 2014 14:16:45 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Tomasz Nowicki <tomasz.nowicki@...aro.org>
Cc:	rjw@...ysocki.net, lenb@...nel.org, tony.luck@...el.com,
	m.chehab@...sung.com, bp@...e.de, linux-edac@...r.kernel.org,
	x86@...nel.org, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org, linaro-acpi@...ts.linaro.org,
	rric@...nel.org
Subject: Re: [PATCH v4 2/3] acpi, apei, ghes: Make NMI error notification to
 be GHES architecture extension.

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@...aro.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.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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