Subject: Re: [PATCH v2 7/8] powerpc/pseries: Read of-config partition via pstore

From: Aruna Balakrishnaiah <[email-masked]>
Date: Thu, 25 Apr 2013 10:40:16 +0530

On Thursday 25 April 2013 02:13 AM, Kees Cook wrote:

Hi Kees,

> On Tue, Apr 23, 2013 at 11:20 PM, Aruna Balakrishnaiah
> <[email-masked]> wrote:
>> This patch set exploits the pstore subsystem to read details of
>> of-config partition in NVRAM to a separate file in /dev/pstore.
>> For instance, of-config partition details will be stored in a
>> file named [of-nvram-5].
>>
>> Signed-off-by: Aruna Balakrishnaiah <[email-masked]>
>> Reviewed-by: Jim Keniston <[email-masked]>
>> ---
>>   arch/powerpc/platforms/pseries/nvram.c |   55 +++++++++++++++++++++++++++-----
>>   fs/pstore/inode.c                      |    3 ++
>>   include/linux/pstore.h                 |    1 +
>>   3 files changed, 50 insertions(+), 9 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
>> index b118382..de448af 100644
>> --- a/arch/powerpc/platforms/pseries/nvram.c
>> +++ b/arch/powerpc/platforms/pseries/nvram.c
>> @@ -132,9 +132,16 @@ static size_t oops_data_sz;
>>   static struct z_stream_s stream;
>>
>>   #ifdef CONFIG_PSTORE
>> +static struct nvram_os_partition of_config_partition = {
>> +       .name = "of-config",
>> +       .index = -1,
>> +       .os_partition = false
>> +};
>> +
>>   static enum pstore_type_id nvram_type_ids[] = {
>>          PSTORE_TYPE_DMESG,
>>          PSTORE_TYPE_RTAS,
>> +       PSTORE_TYPE_OF,
>>          -1
>>   };
>>   static int read_type;
>> @@ -332,10 +339,15 @@ int nvram_read_partition(struct nvram_os_partition *part, char *buff,
>>
>>          tmp_index = part->index;
>>
>> -       rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
>> -       if (rc <= 0) {
>> -               pr_err("%s: Failed nvram_read (%d)\n", __FUNCTION__, rc);
>> -               return rc;
>> +       if (part->os_partition) {
>> +               rc = ppc_md.nvram_read((char *)&info,
>> +                                       sizeof(struct err_log_info),
>> +                                       &tmp_index);
>> +               if (rc <= 0) {
>> +                       pr_err("%s: Failed nvram_read (%d)\n", __FUNCTION__,
>> +                                                                       rc);
>> +                       return rc;
>> +               }
>>          }
>>
>>          rc = ppc_md.nvram_read(buff, length, &tmp_index);
>> @@ -344,8 +356,10 @@ int nvram_read_partition(struct nvram_os_partition *part, char *buff,
>>                  return rc;
>>          }
>>
>> -       *error_log_cnt = info.seq_num;
>> -       *err_type = info.error_type;
>> +       if (part->os_partition) {
>> +               *error_log_cnt = info.seq_num;
>> +               *err_type = info.error_type;
>> +       }
>>
>>          return 0;
>>   }
>> @@ -516,7 +530,7 @@ static int nvram_pstore_write(enum pstore_type_id type,
>>   }
>>
>>   /*
>> - * Reads the oops/panic report and ibm,rtas-log partition.
>> + * Reads the oops/panic report, rtas and of-config partition.
>>    * Returns the length of the data we read from each partition.
>>    * Returns 0 if we've been called before.
>>    */
>> @@ -525,9 +539,11 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
>>                                  struct pstore_info *psi)
>>   {
>>          struct oops_log_info *oops_hdr;
>> -       unsigned int err_type, id_no;
>> +       unsigned int err_type, id_no, size = 0;
>>          struct nvram_os_partition *part = NULL;
>>          char *buff = NULL;
>> +       int sig = 0;
>> +       loff_t p;
>>
>>          read_type++;
>>
>> @@ -542,10 +558,29 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
>>                  time->tv_sec = last_rtas_event;
>>                  time->tv_nsec = 0;
>>                  break;
>> +       case PSTORE_TYPE_OF:
>> +               sig = NVRAM_SIG_OF;
>> +               part = &of_config_partition;
>> +               *type = PSTORE_TYPE_OF;
>> +               *id = PSTORE_TYPE_OF;
>> +               time->tv_sec = 0;
>> +               time->tv_nsec = 0;
>> +               break;
>>          default:
>>                  return 0;
>>          }
>>
>> +       if (!part->os_partition) {
>> +               p = nvram_find_partition(part->name, sig, &size);
>> +               if (p <= 0) {
>> +                       pr_err("nvram: Failed to find partition %s, "
>> +                               "err %d\n", part->name, (int)p);
>> +                       return 0;
>> +               }
>> +               part->index = p;
>> +               part->size = size;
>> +       }
>> +
>>          buff = kmalloc(part->size, GFP_KERNEL);
>>
>>          if (!buff)
>> @@ -557,7 +592,9 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
>>          }
>>
>>          *count = 0;
>> -       *id = id_no;
>> +
>> +       if (part->os_partition)
>> +               *id = id_no;
>>
>>          if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
>>                  oops_hdr = (struct oops_log_info *)buff;
>> diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
>> index ec24f9c..8d4fb65 100644
>> --- a/fs/pstore/inode.c
>> +++ b/fs/pstore/inode.c
>> @@ -327,6 +327,9 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
>>          case PSTORE_TYPE_PPC_RTAS:
>>                  sprintf(name, "rtas-%s-%lld", psname, id);
>>                  break;
>> +       case PSTORE_TYPE_PPC_OF:
>> +               sprintf(name, "of-%s-%lld", psname, id);
>> +               break;
>>          case PSTORE_TYPE_UNKNOWN:
>>                  sprintf(name, "unknown-%s-%lld", psname, id);
>>                  break;
>> diff --git a/include/linux/pstore.h b/include/linux/pstore.h
>> index d7a8fe9..615dc18 100644
>> --- a/include/linux/pstore.h
>> +++ b/include/linux/pstore.h
>> @@ -37,6 +37,7 @@ enum pstore_type_id {
>>          PSTORE_TYPE_FTRACE      = 3,
>>          /* PPC64 partition types */
>>          PSTORE_TYPE_PPC_RTAS    = 4,
>> +       PSTORE_TYPE_PPC_OF      = 5,
>>          PSTORE_TYPE_UNKNOWN     = 255
>>   };
>>
>>
> Should this be named just "PSTORE_TYPE_OF" instead of "...PPC_OF"?

I renamed it from PSTORE_TYPE_OF to PSTORE_TYPE_PPC_OF as per Michael's
suggestion. But I have made a mistake of not changing the new name in nvram.c
file.

Will wait for other review comments and repost the patch.

>
> -Kees
>
> --
> Kees Cook
> Chrome OS Security
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