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linux-next/fs/pstore/internal.h
Seiji Aguchi 755d4fe465 efi_pstore: Add a sequence counter to a variable name
[Issue]

Currently, a variable name, which identifies each entry, consists of type, id and ctime.
But if multiple events happens in a short time, a second/third event may fail to log because
efi_pstore can't distinguish each event with current variable name.

[Solution]

A reasonable way to identify all events precisely is introducing a sequence counter to
the variable name.

The sequence counter has already supported in a pstore layer with "oopscount".
So, this patch adds it to a variable name.
Also, it is passed to read/erase callbacks of platform drivers in accordance with
the modification of the variable name.

  <before applying this patch>
 a variable name of first event: dump-type0-1-12345678
 a variable name of second event: dump-type0-1-12345678

  type:0
  id:1
  ctime:12345678

 If multiple events happen in a short time, efi_pstore can't distinguish them because
 variable names are same among them.

  <after applying this patch>

 it can be distinguishable by adding a sequence counter as follows.

 a variable name of first event: dump-type0-1-1-12345678
 a variable name of Second event: dump-type0-1-2-12345678

  type:0
  id:1
  sequence counter: 1(first event), 2(second event)
  ctime:12345678

In case of a write callback executed in pstore_console_write(), "0" is added to
an argument of the write callback because it just logs all kernel messages and
doesn't need to care about multiple events.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-11-26 16:07:44 -08:00

58 lines
1.2 KiB
C

#ifndef __PSTORE_INTERNAL_H__
#define __PSTORE_INTERNAL_H__
#include <linux/types.h>
#include <linux/time.h>
#include <linux/pstore.h>
#if NR_CPUS <= 2 && defined(CONFIG_ARM_THUMB)
#define PSTORE_CPU_IN_IP 0x1
#elif NR_CPUS <= 4 && defined(CONFIG_ARM)
#define PSTORE_CPU_IN_IP 0x3
#endif
struct pstore_ftrace_record {
unsigned long ip;
unsigned long parent_ip;
#ifndef PSTORE_CPU_IN_IP
unsigned int cpu;
#endif
};
static inline void
pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
{
#ifndef PSTORE_CPU_IN_IP
rec->cpu = cpu;
#else
rec->ip |= cpu;
#endif
}
static inline unsigned int
pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
{
#ifndef PSTORE_CPU_IN_IP
return rec->cpu;
#else
return rec->ip & PSTORE_CPU_IN_IP;
#endif
}
#ifdef CONFIG_PSTORE_FTRACE
extern void pstore_register_ftrace(void);
#else
static inline void pstore_register_ftrace(void) {}
#endif
extern struct pstore_info *psinfo;
extern void pstore_set_kmsg_bytes(int);
extern void pstore_get_records(int);
extern int pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
int count, char *data, size_t size,
struct timespec time, struct pstore_info *psi);
extern int pstore_is_mounted(void);
#endif