include/linux/pstore.h

   1 /*
   2  * Persistent Storage - pstore.h
   3  *
   4  * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
   5  *
   6  * This code is the generic layer to export data records from platform
   7  * level persistent storage via a file system.
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2 as
  11  *  published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software
  20  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22 #ifndef _LINUX_PSTORE_H
  23 #define _LINUX_PSTORE_H
  24
  25 #include <linux/compiler.h>
  26 #include <linux/errno.h>
  27 #include <linux/kmsg_dump.h>
  28 #include <linux/mutex.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/time.h>
  31 #include <linux/types.h>
  32
  33 /* types */
  34 enum pstore_type_id {
  35         PSTORE_TYPE_DMESG       = 0,
  36         PSTORE_TYPE_MCE         = 1,
  37         PSTORE_TYPE_CONSOLE     = 2,
  38         PSTORE_TYPE_FTRACE      = 3,
  39         /* PPC64 partition types */
  40         PSTORE_TYPE_PPC_RTAS    = 4,
  41         PSTORE_TYPE_PPC_OF      = 5,
  42         PSTORE_TYPE_PPC_COMMON  = 6,
  43         PSTORE_TYPE_PMSG        = 7,
  44         PSTORE_TYPE_PPC_OPAL    = 8,
  45         PSTORE_TYPE_UNKNOWN     = 255
  46 };
  47
  48 struct module;
  49
  50 struct pstore_info {
  51         struct module   *owner;
  52         char            *name;
  53         spinlock_t      buf_lock;       /* serialize access to 'buf' */
  54         char            *buf;
  55         size_t          bufsize;
  56         struct mutex    read_mutex;     /* serialize open/read/close */
  57         int             flags;
  58         int             (*open)(struct pstore_info *psi);
  59         int             (*close)(struct pstore_info *psi);
  60         ssize_t         (*read)(u64 *id, enum pstore_type_id *type,
  61                         int *count, struct timespec *time, char **buf,
  62                         bool *compressed, ssize_t *ecc_notice_size,
  63                         struct pstore_info *psi);
  64         int             (*write)(enum pstore_type_id type,
  65                         enum kmsg_dump_reason reason, u64 *id,
  66                         unsigned int part, int count, bool compressed,
  67                         size_t size, struct pstore_info *psi);
  68         int             (*write_buf)(enum pstore_type_id type,
  69                         enum kmsg_dump_reason reason, u64 *id,
  70                         unsigned int part, const char *buf, bool compressed,
  71                         size_t size, struct pstore_info *psi);
  72         int             (*write_buf_user)(enum pstore_type_id type,
  73                         enum kmsg_dump_reason reason, u64 *id,
  74                         unsigned int part, const char __user *buf,
  75                         bool compressed, size_t size, struct pstore_info *psi);
  76         int             (*erase)(enum pstore_type_id type, u64 id,
  77                         int count, struct timespec time,
  78                         struct pstore_info *psi);
  79         void            *data;
  80 };
  81
  82 #define PSTORE_FLAGS_DMESG      (1 << 0)
  83 #define PSTORE_FLAGS_FRAGILE    PSTORE_FLAGS_DMESG
  84 #define PSTORE_FLAGS_CONSOLE    (1 << 1)
  85 #define PSTORE_FLAGS_FTRACE     (1 << 2)
  86 #define PSTORE_FLAGS_PMSG       (1 << 3)
  87
  88 extern int pstore_register(struct pstore_info *);
  89 extern void pstore_unregister(struct pstore_info *);
  90 extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);
  91
  92 struct pstore_ftrace_record {
  93         unsigned long ip;
  94         unsigned long parent_ip;
  95         u64 ts;
  96 };
  97
  98 /*
  99  * ftrace related stuff: Both backends and frontends need these so expose
 100  * them here.
 101  */
 102
 103 #if NR_CPUS <= 2 && defined(CONFIG_ARM_THUMB)
 104 #define PSTORE_CPU_IN_IP 0x1
 105 #elif NR_CPUS <= 4 && defined(CONFIG_ARM)
 106 #define PSTORE_CPU_IN_IP 0x3
 107 #endif
 108
 109 #define TS_CPU_SHIFT 8
 110 #define TS_CPU_MASK (BIT(TS_CPU_SHIFT) - 1)
 111
 112 /*
 113  * If CPU number can be stored in IP, store it there, otherwise store it in
 114  * the time stamp. This means more timestamp resolution is available when
 115  * the CPU can be stored in the IP.
 116  */
 117 #ifdef PSTORE_CPU_IN_IP
 118 static inline void
 119 pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
 120 {
 121         rec->ip |= cpu;
 122 }
 123
 124 static inline unsigned int
 125 pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
 126 {
 127         return rec->ip & PSTORE_CPU_IN_IP;
 128 }
 129
 130 static inline u64
 131 pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
 132 {
 133         return rec->ts;
 134 }
 135
 136 static inline void
 137 pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
 138 {
 139         rec->ts = val;
 140 }
 141 #else
 142 static inline void
 143 pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
 144 {
 145         rec->ts &= ~(TS_CPU_MASK);
 146         rec->ts |= cpu;
 147 }
 148
 149 static inline unsigned int
 150 pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
 151 {
 152         return rec->ts & TS_CPU_MASK;
 153 }
 154
 155 static inline u64
 156 pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
 157 {
 158         return rec->ts >> TS_CPU_SHIFT;
 159 }
 160
 161 static inline void
 162 pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
 163 {
 164         rec->ts = (rec->ts & TS_CPU_MASK) | (val << TS_CPU_SHIFT);
 165 }
 166 #endif
 167
 168 #endif /*_LINUX_PSTORE_H*/