From 060287b8c467bf49a594d8d669e1986c6d8d76b0 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Mon, 9 Jul 2012 17:10:41 -0700 Subject: pstore: Add persistent function tracing With this support kernel can save function call chain log into a persistent ram buffer that can be decoded and dumped after reboot through pstore filesystem. It can be used to determine what function was last called before a reset or panic. We store the log in a binary format and then decode it at read time. p.s. Mostly the code comes from trace_persistent.c driver found in the Android git tree, written by Colin Cross (according to sign-off history). I reworked the driver a little bit, and ported it to pstore. Signed-off-by: Anton Vorontsov Signed-off-by: Greg Kroah-Hartman --- fs/pstore/internal.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'fs/pstore/internal.h') diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h index 3bde461c3f34..958c48d8905c 100644 --- a/fs/pstore/internal.h +++ b/fs/pstore/internal.h @@ -1,6 +1,49 @@ +#ifndef __PSTORE_INTERNAL_H__ +#define __PSTORE_INTERNAL_H__ + +#include + +#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 +} + +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 -- cgit v1.2.3