linux-kernel - Re: [PATCH] ACPI, APEI: Fix BERT resources conflict with ACPI NVS area

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Message-ID: <4305135.N5b65JQej5@aspire.rjw.lan>
Date:   Thu, 16 Feb 2017 00:42 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     "Huang, Ying" <ying.huang@...el.com>, Borislav Petkov <bp@...e.de>
Cc:     Len Brown <lenb@...nel.org>,
        Tomasz Nowicki <tomasz.nowicki@...aro.org>,
        Tony Luck <tony.luck@...el.com>, Fu Wei <fu.wei@...aro.org>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ACPI, APEI: Fix BERT resources conflict with ACPI NVS area

On Tuesday, February 14, 2017 10:01:13 AM Huang, Ying wrote:
> From: Huang Ying <ying.huang@...el.com>
> 
> It was reported that some firmware will use ACPI NVS area for BERT
> address range.  This will cause resources conflict because the ACPI
> NVS area is marked as busy already.  Fix this via excluding ACPI NVS
> area when requesting IO resources for BERT.
> 
> Reported-and-tested-by: Hans Kristian Rosbach <hansr@...kesider.no>
> Signed-off-by: "Huang, Ying" <ying.huang@...el.com>

Boris, what do you think?

> ---
>  drivers/acpi/apei/bert.c | 20 ++++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/acpi/apei/bert.c b/drivers/acpi/apei/bert.c
> index a05b5c0cf181..12771fcf0417 100644
> --- a/drivers/acpi/apei/bert.c
> +++ b/drivers/acpi/apei/bert.c
> @@ -97,6 +97,7 @@ static int __init bert_check_table(struct acpi_table_bert *bert_tab)
>  
>  static int __init bert_init(void)
>  {
> +	struct apei_resources bert_resources;
>  	struct acpi_bert_region *boot_error_region;
>  	struct acpi_table_bert *bert_tab;
>  	unsigned int region_len;
> @@ -127,13 +128,14 @@ static int __init bert_init(void)
>  	}
>  
>  	region_len = bert_tab->region_length;
> -	if (!request_mem_region(bert_tab->address, region_len, "APEI BERT")) {
> -		pr_err("Can't request iomem region <%016llx-%016llx>.\n",
> -		       (unsigned long long)bert_tab->address,
> -		       (unsigned long long)bert_tab->address + region_len - 1);
> -		return -EIO;
> -	}
> -
> +	apei_resources_init(&bert_resources);
> +	rc = apei_resources_add(&bert_resources, bert_tab->address,
> +				region_len, true);
> +	if (rc)
> +		return rc;
> +	rc = apei_resources_request(&bert_resources, "APEI BERT");
> +	if (rc)
> +		goto out_fini;
>  	boot_error_region = ioremap_cache(bert_tab->address, region_len);
>  	if (boot_error_region) {
>  		bert_print_all(boot_error_region, region_len);
> @@ -142,7 +144,9 @@ static int __init bert_init(void)
>  		rc = -ENOMEM;
>  	}
>  
> -	release_mem_region(bert_tab->address, region_len);
> +	apei_resources_release(&bert_resources);
> +out_fini:
> +	apei_resources_fini(&bert_resources);
>  
>  	return rc;
>  }
>