![Anton Vorontsov](/assets/img/avatar_default.png)
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>
58 lines
1.2 KiB
C
58 lines
1.2 KiB
C
#ifndef __PSTORE_INTERNAL_H__
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#define __PSTORE_INTERNAL_H__
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#include <linux/types.h>
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#include <linux/time.h>
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#include <linux/pstore.h>
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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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struct pstore_ftrace_record {
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unsigned long ip;
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unsigned long parent_ip;
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#ifndef PSTORE_CPU_IN_IP
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unsigned int cpu;
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#endif
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};
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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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#ifndef PSTORE_CPU_IN_IP
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rec->cpu = cpu;
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#else
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rec->ip |= cpu;
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#endif
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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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#ifndef PSTORE_CPU_IN_IP
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return rec->cpu;
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#else
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return rec->ip & PSTORE_CPU_IN_IP;
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#endif
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}
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#ifdef CONFIG_PSTORE_FTRACE
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extern void pstore_register_ftrace(void);
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#else
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static inline void pstore_register_ftrace(void) {}
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#endif
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extern struct pstore_info *psinfo;
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extern void pstore_set_kmsg_bytes(int);
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extern void pstore_get_records(int);
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extern int pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
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char *data, size_t size,
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struct timespec time, struct pstore_info *psi);
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extern int pstore_is_mounted(void);
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#endif
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