diff --git a/include/linux/ftrace_regs.h b/include/linux/ftrace_regs.h index bbc1873ca6b8..15627ceea9bc 100644 --- a/include/linux/ftrace_regs.h +++ b/include/linux/ftrace_regs.h @@ -35,4 +35,9 @@ struct ftrace_regs; #endif /* HAVE_ARCH_FTRACE_REGS */ +/* This can be overridden by the architectures */ +#ifndef FTRACE_REGS_MAX_ARGS +# define FTRACE_REGS_MAX_ARGS 6 +#endif + #endif /* _LINUX_FTRACE_REGS_H */ diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index d570b8b9c0a9..60412c1012ef 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -263,6 +263,12 @@ config FUNCTION_GRAPH_RETADDR the function is called. This feature is off by default, and you can enable it via the trace option funcgraph-retaddr. +config FUNCTION_TRACE_ARGS + bool + depends on HAVE_FUNCTION_ARG_ACCESS_API + depends on DEBUG_INFO_BTF + default y + config DYNAMIC_FTRACE bool "enable/disable function tracing dynamically" depends on FUNCTION_TRACER diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 03d56f711ad1..4b721cd4f21d 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -12,8 +12,11 @@ #include #include #include +#include +#include #include "trace_output.h" +#include "trace_btf.h" /* must be a power of 2 */ #define EVENT_HASHSIZE 128 @@ -684,6 +687,88 @@ int trace_print_lat_context(struct trace_iterator *iter) return !trace_seq_has_overflowed(s); } +#ifdef CONFIG_FUNCTION_TRACE_ARGS +void print_function_args(struct trace_seq *s, unsigned long *args, + unsigned long func) +{ + const struct btf_param *param; + const struct btf_type *t; + const char *param_name; + char name[KSYM_NAME_LEN]; + unsigned long arg; + struct btf *btf; + s32 tid, nr = 0; + int a, p, x; + + trace_seq_printf(s, "("); + + if (!args) + goto out; + if (lookup_symbol_name(func, name)) + goto out; + + /* TODO: Pass module name here too */ + t = btf_find_func_proto(name, &btf); + if (IS_ERR_OR_NULL(t)) + goto out; + + param = btf_get_func_param(t, &nr); + if (!param) + goto out_put; + + for (a = 0, p = 0; p < nr; a++, p++) { + if (p) + trace_seq_puts(s, ", "); + + /* This only prints what the arch allows (6 args by default) */ + if (a == FTRACE_REGS_MAX_ARGS) { + trace_seq_puts(s, "..."); + break; + } + + arg = args[a]; + + param_name = btf_name_by_offset(btf, param[p].name_off); + if (param_name) + trace_seq_printf(s, "%s=", param_name); + t = btf_type_skip_modifiers(btf, param[p].type, &tid); + + switch (t ? BTF_INFO_KIND(t->info) : BTF_KIND_UNKN) { + case BTF_KIND_UNKN: + trace_seq_putc(s, '?'); + /* Still print unknown type values */ + fallthrough; + case BTF_KIND_PTR: + trace_seq_printf(s, "0x%lx", arg); + break; + case BTF_KIND_INT: + trace_seq_printf(s, "%ld", arg); + break; + case BTF_KIND_ENUM: + trace_seq_printf(s, "%ld", arg); + break; + default: + /* This does not handle complex arguments */ + trace_seq_printf(s, "(%s)[0x%lx", btf_type_str(t), arg); + for (x = sizeof(long); x < t->size; x += sizeof(long)) { + trace_seq_putc(s, ':'); + if (++a == FTRACE_REGS_MAX_ARGS) { + trace_seq_puts(s, "...]"); + goto out_put; + } + trace_seq_printf(s, "0x%lx", args[a]); + } + trace_seq_putc(s, ']'); + break; + } + } +out_put: + btf_put(btf); +out: + trace_seq_printf(s, ")"); +} +#endif + /** * ftrace_find_event - find a registered event * @type: the type of event to look for diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h index dca40f1f1da4..2e305364f2a9 100644 --- a/kernel/trace/trace_output.h +++ b/kernel/trace/trace_output.h @@ -41,5 +41,14 @@ extern struct rw_semaphore trace_event_sem; #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