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Date: Thu, 7 Jan 2016 02:21:31 +0800
From: Fu Wei <fu.wei@...aro.org>
To: Borislav Petkov <bp@...en8.de>
Cc: Linaro ACPI Mailman List <linaro-acpi@...ts.linaro.org>,
LKML <linux-kernel@...r.kernel.org>,
"Zhang, Jonathan Zhixiong" <zjzhang@...eaurora.org>,
Tony Luck <tony.luck@...el.com>,
"Chen, Gong" <gong.chen@...el.com>,
Huang Ying <ying.huang@...el.com>,
Tomasz Nowicki <tomasz.nowicki@...aro.org>,
Wei Fu <tekkamanninja@...il.com>,
G Gregory <graeme.gregory@...aro.org>,
Al Stone <al.stone@...aro.org>,
Hanjun Guo <hanjun.guo@...aro.org>,
Jon Masters <jcm@...hat.com>,
Mark Rutland <mark.rutland@....com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Rafael Wysocki <rjw@...ysocki.net>,
"matt.fleming" <matt.fleming@...el.com>,
"Chen, Gong" <gong.chen@...ux.intel.com>
Subject: Re: [PATCH v2 1/2] acpi, apei: add Boot Error Record Table (BERT) support
Hi Borislav,
Thanks for your review.
I totally agree all your comment
I have made a new patch, and that is in testing, I will post it ASAP
On 16 December 2015 at 18:29, Borislav Petkov <bp@...en8.de> wrote:
> On Wed, Aug 19, 2015 at 12:44:16AM +0800, fu.wei@...aro.org wrote:
>> From: Huang Ying <ying.huang@...el.com>
>>
>> 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
>>
>> [Tony: Applied some cleanups suggested by Fu Wei]
>> [Fu Wei: delete EXPORT_SYMBOL_GPL(bert_disable), and do some cleanups]
>>
>> Signed-off-by: Huang Ying <ying.huang@...el.com>
>> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@...aro.org>
>> Signed-off-by: Chen, Gong <gong.chen@...ux.intel.com>
>> Tested-by: Jonathan (Zhixiong) Zhang <zjzhang@...eaurora.org>
>> Tested-by: Fu Wei <fu.wei@...aro.org>
>> Signed-off-by: Tony Luck <tony.luck@...el.com>
>> Signed-off-by: Fu Wei <fu.wei@...aro.org>
>> ---
>> Documentation/kernel-parameters.txt | 3 +
>> drivers/acpi/apei/Makefile | 2 +-
>> drivers/acpi/apei/bert.c | 162 ++++++++++++++++++++++++++++++++++++
>> include/acpi/apei.h | 1 +
>> 4 files changed, 167 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
>> index 1d6f045..7c6402c 100644
>> --- a/Documentation/kernel-parameters.txt
>> +++ b/Documentation/kernel-parameters.txt
>> @@ -554,6 +554,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>>
>> bootmem_debug [KNL] Enable bootmem allocator debug messages.
>>
>> + bert_disable [ACPI]
>> + Disable Boot Error Record Table (BERT) support.
>
> Please document what that new parameter is good for.
>
>> +
>> 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/bert.c b/drivers/acpi/apei/bert.c
>> new file mode 100644
>> index 0000000..1426227
>> --- /dev/null
>> +++ b/drivers/acpi/apei/bert.c
>> @@ -0,0 +1,162 @@
>> +/*
>> + * APEI Boot Error Record Table (BERT) support
>> + *
>> + * Copyright 2011 Intel Corp.
>> + * Author: Huang Ying <ying.huang@...el.com>
>> + *
>> + * 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.
>> + *
>> + * 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"
>> +
>> +#define BERT_PFX "BERT: "
>
> This is done with pr_fmt
>
>> +static int bert_disable;
>> +
>> +static void __init bert_print_all(struct acpi_hest_generic_status *region,
>> + unsigned int region_len)
>> +{
>> + struct acpi_hest_generic_status *estatus = region;
>> + int remain = region_len;
>> + u32 estatus_len;
>> + int first = 1;
>
> if (!estatus->block_status)
> return;
>
>> + while (remain > sizeof(struct acpi_hest_generic_status)) {
>> + /* No more error record */
>
> ... records */
>
>> + if (!estatus->block_status)
>> + break;
>
> This test should happen when you enter the function (see above) and when
> you assign to estatus, i.e. below, at the end of the while loop body:
>
> estatus = (void *)estatus + estatus_len;
> if (!estatus->block_status)
> break;
>
>> +
>> + estatus_len = cper_estatus_len(estatus);
>> + if (estatus_len < sizeof(struct acpi_hest_generic_status) ||
>> + remain < estatus_len) {
>> + pr_err(FW_BUG BERT_PFX
>> + "Invalid error status block with length %u\n",
>
> "Invalid status block length (%u)"
>
>> + estatus_len);
>> + return;
>> + }
>> +
>> + if (cper_estatus_check(estatus)) {
>> + pr_err(FW_BUG BERT_PFX "Invalid error status block\n");
>
> "Invalid error record."
>> + goto next;
>> + }
>> +
>> + if (first) {
>> + pr_info(HW_ERR "Error record from previous boot:\n");
>
> Error records<--- plural.
>
>> + first = 0;
>> + }
>
> We have pr_info_once() for this.
>
>> +
>> + cper_estatus_print(KERN_INFO HW_ERR, estatus);
>> +next:
>> + estatus = (void *)estatus + estatus_len;
>> + 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))
>> + return -EINVAL;
>
> \n here
>
>> + if (bert_tab->region_length &&
>
> This test looks redundant if you're going to compare it to the size of
> the BERT region struct below.
>
>> + bert_tab->region_length < sizeof(struct acpi_bert_region))
>> + return -EINVAL;
>> +
>> + return 0;
>> +}
>> +
>> +static int __init bert_init(void)
>> +{
>> + struct acpi_hest_generic_status *bert_region;
>> + struct acpi_table_bert *bert_tab;
>> + unsigned int region_len;
>> + acpi_status status;
>> + struct resource *r;
>> + int rc = -EINVAL;
>> +
>> + if (acpi_disabled)
>> + goto out;
>> +
>> + if (bert_disable) {
>> + pr_info(BERT_PFX "Boot Error Record Table (BERT) support is disabled.\n");
>> + goto out;
>> + }
>> +
>> + status = acpi_get_table(ACPI_SIG_BERT, 0,
>> + (struct acpi_table_header **)&bert_tab);
>
> No need to break that line, just leave it stick out.
>
>> + if (status == AE_NOT_FOUND) {
>> + pr_err(BERT_PFX "Table is not found!\n");
>
> This will get issued on *all* machines which don't have BERT - which
> is the majority now, I'm afraid - and that information is useless to
> people. It's not like they can do anything about it short of overriding
> their own firmware.
>
> So please remove that printk.
>
>> + goto out;
>> + } else if (ACPI_FAILURE(status)) {
>> + const char *msg = acpi_format_exception(status);
>> +
>> + pr_err(BERT_PFX "Failed to get table, %s\n", msg);
>> + goto out;
>> + }
>> +
>> + rc = bert_check_table(bert_tab);
>> + if (rc) {
>> + pr_err(FW_BUG BERT_PFX "BERT table is invalid\n");
>
> Prefix already has "BERT". Either write it out:
>
> "BERT: Boot Error Record Table invalid"
>
> or make it shorter:
>
> "BERT: table invalid."
>
>> + goto out;
>> + }
>> +
>> + region_len = bert_tab->region_length;
>> + if (!region_len) {
>> + rc = 0;
>> + goto out;
>> + }
>
> Huh, we just checked ->region_length in bert_check_table(). This test is
> redundant.
>
>> +
>> + r = request_mem_region(bert_tab->address, region_len, "APEI BERT");
>> + if (!r) {
>> + pr_err(BERT_PFX "Can't request iomem region <%016llx-%016llx>\n",
>> + (unsigned long long)bert_tab->address,
>> + (unsigned long long)bert_tab->address + region_len - 1);
>> + rc = -EIO;
>> + goto out;
>> + }
>> +
>> + bert_region = ioremap_cache(bert_tab->address, region_len);
>> + if (!bert_region) {
>> + rc = -ENOMEM;
>> + goto out_release;
>> + }
>> +
>> + bert_print_all(bert_region, region_len);
>> +
>> + iounmap(bert_region);
>> +
>> +out_release:
>> + release_mem_region(bert_tab->address, region_len);
>> +out:
>> + if (rc)
>> + bert_disable = 1;
>
> This assignment is redundant. We're not testing it anywhere else after
> bert_init() has run.
>
>> +
>> + return rc;
>> +}
>> +
>> +late_initcall(bert_init);
>> diff --git a/include/acpi/apei.h b/include/acpi/apei.h
>> index 76284bb..284801a 100644
>> --- a/include/acpi/apei.h
>> +++ b/include/acpi/apei.h
>> @@ -23,6 +23,7 @@ extern bool ghes_disable;
>> #else
>> #define ghes_disable 1
>> #endif
>> +extern int bert_disable;
>>
>> #ifdef CONFIG_ACPI_APEI
>> void __init acpi_hest_init(void);
>> --
>> 2.4.3
>>
>>
>
> --
> Regards/Gruss,
> Boris.
>
> ECO tip #101: Trim your mails when you reply.
--
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)
Room 1512, Regus One Corporate Avenue,Level 15,
One Corporate Avenue,222 Hubin Road,Huangpu District,
Shanghai,China 200021
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