Re: [PATCH v5] acpi, apei: add Boot Error Record Table (BERT) support

[Fu Wei]

Hi Borislav,

On 19 January 2016 at 17:34,  <fu.wei@xxxxxxxxxx> wrote:
> From: Huang Ying <ying.huang@xxxxxxxxx>
>
> ACPI/APEI is designed to verifiy/report H/W errors, like Corrected
> Error(CE) and Uncorrected Error(UC). It contains four tables: HEST,
> ERST, EINJ and BERT. The first three tables have been merged for
> a long time, but because of lacking BIOS support for BERT, the
> support for BERT is pending until now. Recently on ARM 64 platform
> it is has been supported. So here we come.
>
> Under normal circumstances, when a hardware error occurs, kernel will
> be notified via NMI, MCE or some other method, then kernel will
> process the error condition, report it, and recover it if possible.
> But sometime, the situation is so bad, so that firmware may choose to
> reset directly without notifying Linux kernel.
>
> Linux kernel can use the Boot Error Record Table (BERT) to get the
> un-notified hardware errors that occurred in a previous boot. In this
> patch, the error information is reported via printk.
>
> For more information about BERT, please refer to ACPI Specification
> version 6.0, section 18.3.1:
>   http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf
>
> The following log is a BERT record after system reboot because of hitting
> a fatal memory error:
> BERT: Error records from previous boot:
> [Hardware Error]: It has been corrected by h/w and requires no further action
> [Hardware Error]: event severity: corrected
> [Hardware Error]:  Error 0, type: recoverable
> [Hardware Error]:   section_type: memory error
> [Hardware Error]:   error_status: 0x0000000000000400
> [Hardware Error]:   physical_address: 0xffffffffffffffff
> [Hardware Error]:   card: 1 module: 2 bank: 3 row: 1 column: 2 bit_position: 5
> [Hardware Error]:   error_type: 2, single-bit ECC
>
> [Tomasz Nowicki: Clear error status at the end of error handling]
> [Tony: Applied some cleanups suggested by Fu Wei]
> [Fu Wei: delete EXPORT_SYMBOL_GPL(bert_disable), improve the code]
>
> Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx>
> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@xxxxxxxxxx>
> Signed-off-by: Chen, Gong <gong.chen@xxxxxxxxxxxxxxx>
> Tested-by: Jonathan (Zhixiong) Zhang <zjzhang@xxxxxxxxxxxxxx>
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> Signed-off-by: Fu Wei <fu.wei@xxxxxxxxxx>
> Tested-by: Tyler Baicar <tbaicar@xxxxxxxxxxxxxx>
> ---
> Changelog:
> v5: Drop some superfluous comments.
>     Use the introduce of BERT in ACPI Specification instead of original one
>     at the head of bert.c.
>     Fix typo in apei-internal.h
>     Simplify the introduce of bert_disable.
>
> v4: https://lkml.org/lkml/2016/1/8/382
>     Fix the "#undef" bug
>     Improve the instruction of "bert_disable",
>     Delete the useless declaration in include/acpi/apei.h.
>
> v3: https://lkml.org/lkml/2016/1/7/214
>     Merge the two patches
>     Do some improvements according to Borislav's suggestion.
>
> v2: https://lkml.org/lkml/2015/8/18/336
>     Delete EXPORT_SYMBOL_GPL(bert_disable), because "bert_disable" is only
>     used in bert.c for now.
>     Do some code-style cleanups.
>
> v1: The first upstream version submitted in linux-acpi mailing list:
>     http://www.spinics.net/lists/linux-acpi/msg57384.html
>
>  Documentation/kernel-parameters.txt |   3 +
>  drivers/acpi/apei/Makefile          |   2 +-
>  drivers/acpi/apei/apei-internal.h   |   2 +-
>  drivers/acpi/apei/bert.c            | 150 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 155 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index 3ea869d..acb772e 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -564,6 +564,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>
>         bootmem_debug   [KNL] Enable bootmem allocator debug messages.
>
> +       bert_disable    [ACPI]
> +                       Disable BERT OS support on buggy BIOSes.
> +
>         bttv.card=      [HW,V4L] bttv (bt848 + bt878 based grabber cards)
>         bttv.radio=     Most important insmod options are available as
>                         kernel args too.
> diff --git a/drivers/acpi/apei/Makefile b/drivers/acpi/apei/Makefile
> index 5d575a9..e50573d 100644
> --- a/drivers/acpi/apei/Makefile
> +++ b/drivers/acpi/apei/Makefile
> @@ -3,4 +3,4 @@ obj-$(CONFIG_ACPI_APEI_GHES)    += ghes.o
>  obj-$(CONFIG_ACPI_APEI_EINJ)   += einj.o
>  obj-$(CONFIG_ACPI_APEI_ERST_DEBUG) += erst-dbg.o
>
> -apei-y := apei-base.o hest.o erst.o
> +apei-y := apei-base.o hest.o erst.o bert.o
> diff --git a/drivers/acpi/apei/apei-internal.h b/drivers/acpi/apei/apei-internal.h
> index 16129c7..6e9f14c 100644
> --- a/drivers/acpi/apei/apei-internal.h
> +++ b/drivers/acpi/apei/apei-internal.h
> @@ -1,6 +1,6 @@
>  /*
>   * apei-internal.h - ACPI Platform Error Interface internal
> - * definations.
> + * definitions.
>   */
>
>  #ifndef APEI_INTERNAL_H
> diff --git a/drivers/acpi/apei/bert.c b/drivers/acpi/apei/bert.c
> new file mode 100644
> index 0000000..a05b5c0
> --- /dev/null
> +++ b/drivers/acpi/apei/bert.c
> @@ -0,0 +1,150 @@
> +/*
> + * APEI Boot Error Record Table (BERT) support
> + *
> + * Copyright 2011 Intel Corp.
> + *   Author: Huang Ying <ying.huang@xxxxxxxxx>
> + *
> + * Under normal circumstances, when a hardware error occurs, the error
> + * handler receives control and processes the error. This gives OSPM a
> + * chance to process the error condition, report it, and optionally attempt
> + * recovery. In some cases, the system is unable to process an error.
> + * For example, system firmware or a management controller may choose to
> + * reset the system or the system might experience an uncontrolled crash
> + * or reset.The boot error source is used to report unhandled errors that
> + * occurred in a previous boot. This mechanism is described in the BERT
> + * table.
> + *
> + * For more information about BERT, please refer to ACPI Specification
> + * version 4.0, section 17.3.1
> + *
> + * This file is licensed under GPLv2.
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/acpi.h>
> +#include <linux/io.h>
> +
> +#include "apei-internal.h"
> +
> +#undef pr_fmt
> +#define pr_fmt(fmt) "BERT: " fmt
> +
> +static int bert_disable;
> +
> +static void __init bert_print_all(struct acpi_bert_region *region,
> +                                 unsigned int region_len)
> +{
> +       struct acpi_hest_generic_status *estatus =
> +               (struct acpi_hest_generic_status *)region;
> +       int remain = region_len;
> +       u32 estatus_len;
> +
> +       if (!estatus->block_status)
> +               return;
> +
> +       while (remain > sizeof(struct acpi_bert_region)) {
> +               if (cper_estatus_check(estatus)) {
> +                       pr_err(FW_BUG "Invalid error record.\n");
> +                       return;
> +               }
> +
> +               estatus_len = cper_estatus_len(estatus);
> +               if (remain < estatus_len) {
> +                       pr_err(FW_BUG "Truncated status block (length: %u).\n",
> +                              estatus_len);
> +                       return;
> +               }
> +
> +               pr_info_once("Error records from previous boot:\n");
> +
> +               cper_estatus_print(KERN_INFO HW_ERR, estatus);
> +
> +               /*
> +                * Because the boot error source is "one-time polled" type,
> +                * clear Block Status of current Generic Error Status Block,
> +                * once it's printed.
> +                */
> +               estatus->block_status = 0;
> +
> +               estatus = (void *)estatus + estatus_len;
> +               /* No more error records. */
> +               if (!estatus->block_status)
> +                       return;
> +
> +               remain -= estatus_len;
> +       }
> +}
> +
> +static int __init setup_bert_disable(char *str)
> +{
> +       bert_disable = 1;
> +
> +       return 0;
> +}
> +__setup("bert_disable", setup_bert_disable);
> +
> +static int __init bert_check_table(struct acpi_table_bert *bert_tab)
> +{
> +       if (bert_tab->header.length < sizeof(struct acpi_table_bert) ||
> +           bert_tab->region_length < sizeof(struct acpi_bert_region))
> +               return -EINVAL;
> +
> +       return 0;
> +}
> +
> +static int __init bert_init(void)
> +{
> +       struct acpi_bert_region *boot_error_region;
> +       struct acpi_table_bert *bert_tab;
> +       unsigned int region_len;
> +       acpi_status status;
> +       int rc = 0;
> +
> +       if (acpi_disabled)
> +               return 0;
> +
> +       if (bert_disable) {
> +               pr_info("Boot Error Record Table support is disabled.\n");
> +               return 0;
> +       }
> +
> +       status = acpi_get_table(ACPI_SIG_BERT, 0, (struct acpi_table_header **)&bert_tab);
> +       if (status == AE_NOT_FOUND)
> +               return 0;
> +
> +       if (ACPI_FAILURE(status)) {
> +               pr_err("get table failed, %s.\n", acpi_format_exception(status));
> +               return -EINVAL;
> +       }
> +
> +       rc = bert_check_table(bert_tab);
> +       if (rc) {
> +               pr_err(FW_BUG "table invalid.\n");
> +               return rc;
> +       }

I have improved the patch following all your suggestion.

I temporary keep "FW_BUG" here,
But if you still think there is not a good reason to keep this, I will
drop it in my next submission :-)

Thanks for your help

> +
> +       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;
> +       }
> +
> +       boot_error_region = ioremap_cache(bert_tab->address, region_len);
> +       if (boot_error_region) {
> +               bert_print_all(boot_error_region, region_len);
> +               iounmap(boot_error_region);
> +       } else {
> +               rc = -ENOMEM;
> +       }
> +
> +       release_mem_region(bert_tab->address, region_len);
> +
> +       return rc;
> +}
> +
> +late_initcall(bert_init);
> --
> 2.5.0
>



-- 
Best regards,

Fu Wei
Software Engineer
Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch
Ph: +86 21 61221326(direct)
Ph: +86 186 2020 4684 (mobile)
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