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@alien8.de wrote:

On Wed, Aug 19, 2015 at 12:44:16AM +0800, fu.wei@linaro.org wrote:

...

From: Huang Ying ying.huang@intel.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@intel.com Signed-off-by: Tomasz Nowicki tomasz.nowicki@linaro.org Signed-off-by: Chen, Gong gong.chen@linux.intel.com Tested-by: Jonathan (Zhixiong) Zhang zjzhang@codeaurora.org Tested-by: Fu Wei fu.wei@linaro.org Signed-off-by: Tony Luck tony.luck@intel.com Signed-off-by: Fu Wei fu.wei@linaro.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@intel.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.