Sven Schnelle 533c20b062 ftrace: Add print_function_args()
Add a function to decode argument types with the help of BTF. Will
be used to display arguments in the function and function graph
tracer.

It can only handle simply arguments and up to FTRACE_REGS_MAX_ARGS number
of arguments. When it hits a max, it will print ", ...":

   page_to_skb(vi=0xffff8d53842dc980, rq=0xffff8d53843a0800, page=0xfffffc2e04337c00, offset=6160, len=64, truesize=1536, ...)

And if it hits an argument that is not recognized, it will print the raw
value and the type of argument it is:

   make_vfsuid(idmap=0xffffffff87f99db8, fs_userns=0xffffffff87e543c0, kuid=0x0 (STRUCT))
   __pti_set_user_pgtbl(pgdp=0xffff8d5384ab47f8, pgd=0x110e74067 (STRUCT))

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Guo Ren <guoren@kernel.org>
Cc: Donglin Peng <dolinux.peng@gmail.com>
Cc: Zheng Yejian <zhengyejian@huaweicloud.com>
Link: https://lore.kernel.org/20250227185822.639418500@goodmis.org
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Co-developed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-03-04 11:27:23 -05:00

55 lines
1.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
#ifndef __TRACE_EVENTS_H
#define __TRACE_EVENTS_H
#include <linux/trace_seq.h>
#include "trace.h"
extern enum print_line_t
trace_print_bputs_msg_only(struct trace_iterator *iter);
extern enum print_line_t
trace_print_bprintk_msg_only(struct trace_iterator *iter);
extern enum print_line_t
trace_print_printk_msg_only(struct trace_iterator *iter);
extern int
seq_print_ip_sym(struct trace_seq *s, unsigned long ip,
unsigned long sym_flags);
extern void trace_seq_print_sym(struct trace_seq *s, unsigned long address, bool offset);
extern int trace_print_context(struct trace_iterator *iter);
extern int trace_print_lat_context(struct trace_iterator *iter);
extern enum print_line_t print_event_fields(struct trace_iterator *iter,
struct trace_event *event);
extern void trace_event_read_lock(void);
extern void trace_event_read_unlock(void);
extern struct trace_event *ftrace_find_event(int type);
extern enum print_line_t trace_nop_print(struct trace_iterator *iter,
int flags, struct trace_event *event);
extern int
trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry);
/* used by module unregistering */
extern int __unregister_trace_event(struct trace_event *event);
extern struct rw_semaphore trace_event_sem;
#define SEQ_PUT_FIELD(s, x) \
trace_seq_putmem(s, &(x), sizeof(x))
#define SEQ_PUT_HEX_FIELD(s, x) \
trace_seq_putmem_hex(s, &(x), sizeof(x))
#ifdef CONFIG_FUNCTION_TRACE_ARGS
void print_function_args(struct trace_seq *s, unsigned long *args,
unsigned long func);
#else
static inline void print_function_args(struct trace_seq *s, unsigned long *args,
unsigned long func) {
trace_seq_puts(s, "()");
}
#endif
#endif