linux/fs/pstore/internal.h
Anton Vorontsov 65f8c95e46 pstore/ftrace: Convert to its own enable/disable debugfs knob
With this patch we no longer reuse function tracer infrastructure, now
we register our own tracer back-end via a debugfs knob.

It's a bit more code, but that is the only downside. On the bright side we
have:

- Ability to make persistent_ram module removable (when needed, we can
  move ftrace_ops struct into a module). Note that persistent_ram is still
  not removable for other reasons, but with this patch it's just one
  thing less to worry about;

- Pstore part is more isolated from the generic function tracer. We tried
  it already by registering our own tracer in available_tracers, but that
  way we're loosing ability to see the traces while we record them to
  pstore. This solution is somewhere in the middle: we only register
  "internal ftracer" back-end, but not the "front-end";

- When there is only pstore tracing enabled, the kernel will only write
  to the pstore buffer, omitting function tracer buffer (which, of course,
  still can be enabled via 'echo function > current_tracer').

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
2012-09-06 22:16:58 -07:00

57 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,
char *data, size_t size,
struct timespec time, struct pstore_info *psi);
extern int pstore_is_mounted(void);
#endif