[PATCH 2/8] Add version and timestamp to oops header

From: Aruna Balakrishnaiah
Date: Wed Apr 10 2013 - 03:21:44 EST


Introduce version and timestamp information in the oops header.
oops_log_info (oops header) holds version (to distinguish between old
and new format oops header), length of the oops text
(compressed or uncompressed) and timestamp.

Signed-off-by: Aruna Balakrishnaiah <aruna@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Jim Keniston <jkenisto@xxxxxxxxxx>
---
arch/powerpc/platforms/pseries/nvram.c | 57 +++++++++++++++++++++-----------
1 file changed, 38 insertions(+), 19 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
index e54a8b7..742735a 100644
--- a/arch/powerpc/platforms/pseries/nvram.c
+++ b/arch/powerpc/platforms/pseries/nvram.c
@@ -29,6 +29,13 @@
/* Max bytes to read/write in one go */
#define NVRW_CNT 0x20

+/*
+ * Set oops header version to distingush between old and new format header.
+ * lnx,oops-log partition max size is 4000, header version > 4000 will
+ * help in identifying new header.
+ */
+#define OOPS_HDR_VERSION 5000
+
static unsigned int nvram_size;
static int nvram_fetch, nvram_store;
static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */
@@ -67,6 +74,12 @@ static const char *pseries_nvram_os_partitions[] = {
NULL
};

+struct oops_log_info {
+ u16 version;
+ u16 report_length;
+ u64 timestamp;
+} __attribute__((packed));
+
static void oops_to_nvram(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason);

@@ -83,28 +96,28 @@ static unsigned long last_unread_rtas_event; /* timestamp */

* big_oops_buf[] holds the uncompressed text we're capturing.
*
- * oops_buf[] holds the compressed text, preceded by a prefix.
- * The prefix is just a u16 holding the length of the compressed* text.
- * (*Or uncompressed, if compression fails.) oops_buf[] gets written
- * to NVRAM.
+ * oops_buf[] holds the compressed text, preceded by a oops header.
+ * oops header has u16 holding the version of oops header (to differentiate
+ * between old and new format header) followed by u16 holding the length of
+ * the compressed* text (*Or uncompressed, if compression fails.) and u64
+ * holding the timestamp. oops_buf[] gets written to NVRAM.
*
- * oops_len points to the prefix. oops_data points to the compressed text.
+ * oops_log_info points to the header. oops_data points to the compressed text.
*
* +- oops_buf
- * | +- oops_data
- * v v
- * +------------+-----------------------------------------------+
- * | length | text |
- * | (2 bytes) | (oops_data_sz bytes) |
- * +------------+-----------------------------------------------+
+ * | +- oops_data
+ * v v
+ * +-----------+-----------+-----------+------------------------+
+ * | version | length | timestamp | text |
+ * | (2 bytes) | (2 bytes) | (8 bytes) | (oops_data_sz bytes) |
+ * +-----------+-----------+-----------+------------------------+
* ^
- * +- oops_len
+ * +- oops_log_info
*
* We preallocate these buffers during init to avoid kmalloc during oops/panic.
*/
static size_t big_oops_buf_sz;
static char *big_oops_buf, *oops_buf;
-static u16 *oops_len;
static char *oops_data;
static size_t oops_data_sz;

@@ -425,9 +438,8 @@ static void __init nvram_init_oops_partition(int rtas_partition_exists)
oops_log_partition.name);
return;
}
- oops_len = (u16*) oops_buf;
- oops_data = oops_buf + sizeof(u16);
- oops_data_sz = oops_log_partition.size - sizeof(u16);
+ oops_data = oops_buf + sizeof(struct oops_log_info);
+ oops_data_sz = oops_log_partition.size - sizeof(struct oops_log_info);

/*
* Figure compression (preceded by elimination of each line's <n>
@@ -555,6 +567,7 @@ error:
/* Compress the text from big_oops_buf into oops_buf. */
static int zip_oops(size_t text_len)
{
+ struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
int zipped_len = nvram_compress(big_oops_buf, oops_data, text_len,
oops_data_sz);
if (zipped_len < 0) {
@@ -562,7 +575,9 @@ static int zip_oops(size_t text_len)
pr_err("nvram: logging uncompressed oops/panic report\n");
return -1;
}
- *oops_len = (u16) zipped_len;
+ oops_hdr->version = OOPS_HDR_VERSION;
+ oops_hdr->report_length = (u16) zipped_len;
+ oops_hdr->timestamp = get_seconds();
return 0;
}

@@ -576,6 +591,7 @@ static int zip_oops(size_t text_len)
static void oops_to_nvram(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason)
{
+ struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
static unsigned int oops_count = 0;
static bool panicking = false;
static DEFINE_SPINLOCK(lock);
@@ -622,11 +638,14 @@ static void oops_to_nvram(struct kmsg_dumper *dumper,
kmsg_dump_get_buffer(dumper, false,
oops_data, oops_data_sz, &text_len);
err_type = ERR_TYPE_KERNEL_PANIC;
- *oops_len = (u16) text_len;
+ oops_hdr->version = OOPS_HDR_VERSION;
+ oops_hdr->report_length = (u16) text_len;
+ oops_hdr->timestamp = get_seconds();
}

(void) nvram_write_os_partition(&oops_log_partition, oops_buf,
- (int) (sizeof(*oops_len) + *oops_len), err_type, ++oops_count);
+ (int) (sizeof(*oops_hdr) + oops_hdr->report_length), err_type,
+ ++oops_count);

spin_unlock_irqrestore(&lock, flags);
}

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