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fbccdeb8d7
In preparation for merging the per CPU buffers into one buffer when we retrieve the pstore ftrace data, we store the timestamp as a counter in the ftrace pstore record. We store the CPU number as well if !PSTORE_CPU_IN_IP, in this case we shift the counter and may lose ordering there but we preserve the same record size. The timestamp counter is also racy, and not doing any locking or synchronization here results in the benefit of lower overhead. Since we don't care much here for exact ordering of function traces across CPUs, we don't synchronize and may lose some counter updates but I'm ok with that. Using trace_clock() results in much lower performance so avoid using it since we don't want accuracy in timestamp and need a rough ordering to perform merge. Signed-off-by: Joel Fernandes <joelaf@google.com> [kees: updated commit message, added comments] Signed-off-by: Kees Cook <keescook@chromium.org>
168 lines
4.5 KiB
C
168 lines
4.5 KiB
C
/*
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* Persistent Storage - pstore.h
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*
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* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
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*
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* This code is the generic layer to export data records from platform
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* level persistent storage via a file system.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _LINUX_PSTORE_H
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#define _LINUX_PSTORE_H
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#include <linux/compiler.h>
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#include <linux/errno.h>
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#include <linux/kmsg_dump.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/time.h>
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#include <linux/types.h>
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/* types */
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enum pstore_type_id {
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PSTORE_TYPE_DMESG = 0,
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PSTORE_TYPE_MCE = 1,
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PSTORE_TYPE_CONSOLE = 2,
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PSTORE_TYPE_FTRACE = 3,
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/* PPC64 partition types */
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PSTORE_TYPE_PPC_RTAS = 4,
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PSTORE_TYPE_PPC_OF = 5,
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PSTORE_TYPE_PPC_COMMON = 6,
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PSTORE_TYPE_PMSG = 7,
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PSTORE_TYPE_PPC_OPAL = 8,
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PSTORE_TYPE_UNKNOWN = 255
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};
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struct module;
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struct pstore_info {
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struct module *owner;
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char *name;
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spinlock_t buf_lock; /* serialize access to 'buf' */
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char *buf;
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size_t bufsize;
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struct mutex read_mutex; /* serialize open/read/close */
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int flags;
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int (*open)(struct pstore_info *psi);
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int (*close)(struct pstore_info *psi);
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ssize_t (*read)(u64 *id, enum pstore_type_id *type,
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int *count, struct timespec *time, char **buf,
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bool *compressed, ssize_t *ecc_notice_size,
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struct pstore_info *psi);
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int (*write)(enum pstore_type_id type,
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enum kmsg_dump_reason reason, u64 *id,
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unsigned int part, int count, bool compressed,
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size_t size, struct pstore_info *psi);
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int (*write_buf)(enum pstore_type_id type,
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enum kmsg_dump_reason reason, u64 *id,
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unsigned int part, const char *buf, bool compressed,
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size_t size, struct pstore_info *psi);
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int (*write_buf_user)(enum pstore_type_id type,
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enum kmsg_dump_reason reason, u64 *id,
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unsigned int part, const char __user *buf,
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bool compressed, size_t size, struct pstore_info *psi);
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int (*erase)(enum pstore_type_id type, u64 id,
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int count, struct timespec time,
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struct pstore_info *psi);
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void *data;
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};
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#define PSTORE_FLAGS_DMESG (1 << 0)
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#define PSTORE_FLAGS_FRAGILE PSTORE_FLAGS_DMESG
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#define PSTORE_FLAGS_CONSOLE (1 << 1)
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#define PSTORE_FLAGS_FTRACE (1 << 2)
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#define PSTORE_FLAGS_PMSG (1 << 3)
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extern int pstore_register(struct pstore_info *);
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extern void pstore_unregister(struct pstore_info *);
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extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);
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struct pstore_ftrace_record {
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unsigned long ip;
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unsigned long parent_ip;
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u64 ts;
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};
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/*
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* ftrace related stuff: Both backends and frontends need these so expose
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* them here.
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*/
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#if NR_CPUS <= 2 && defined(CONFIG_ARM_THUMB)
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#define PSTORE_CPU_IN_IP 0x1
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#elif NR_CPUS <= 4 && defined(CONFIG_ARM)
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#define PSTORE_CPU_IN_IP 0x3
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#endif
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#define TS_CPU_SHIFT 8
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#define TS_CPU_MASK (BIT(TS_CPU_SHIFT) - 1)
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/*
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* If CPU number can be stored in IP, store it there, otherwise store it in
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* the time stamp. This means more timestamp resolution is available when
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* the CPU can be stored in the IP.
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*/
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#ifdef PSTORE_CPU_IN_IP
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static inline void
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pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
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{
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rec->ip |= cpu;
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}
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static inline unsigned int
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pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
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{
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return rec->ip & PSTORE_CPU_IN_IP;
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}
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static inline u64
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pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
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{
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return rec->ts;
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}
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static inline void
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pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
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{
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rec->ts = val;
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}
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#else
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static inline void
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pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
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{
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rec->ts &= ~(TS_CPU_MASK);
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rec->ts |= cpu;
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}
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static inline unsigned int
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pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
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{
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return rec->ts & TS_CPU_MASK;
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}
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static inline u64
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pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
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{
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return rec->ts >> TS_CPU_SHIFT;
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}
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static inline void
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pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
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{
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rec->ts = (rec->ts & TS_CPU_MASK) | (val << TS_CPU_SHIFT);
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}
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#endif
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#endif /*_LINUX_PSTORE_H*/
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