Commit 8be92533 authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
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fprobe: Resolve symbols with ftrace_lookup_symbols 



Using ftrace_lookup_symbols to speed up symbols lookup
in register_fprobe_syms API.

Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220510122616.2652285-4-jolsa@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent bed0d9a5

kernel/trace/fprobe.c

+12 −20
Original line number Diff line number Diff line
@@ -85,39 +85,31 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data, 
}

NOKPROBE_SYMBOL(fprobe_exit_handler);



static int symbols_cmp(const void *a, const void *b)

{

	const char **str_a = (const char **) a;

	const char **str_b = (const char **) b;



	return strcmp(*str_a, *str_b);

}



/* Convert ftrace location address from symbols */

static unsigned long *get_ftrace_locations(const char **syms, int num)

{

	unsigned long addr, size;

	unsigned long *addrs;

	int i;



	/* Convert symbols to symbol address */

	addrs = kcalloc(num, sizeof(*addrs), GFP_KERNEL);

	if (!addrs)

		return ERR_PTR(-ENOMEM);



	for (i = 0; i < num; i++) {

		addr = kallsyms_lookup_name(syms[i]);

		if (!addr)	/* Maybe wrong symbol */

			goto error;



		/* Convert symbol address to ftrace location. */

		if (!kallsyms_lookup_size_offset(addr, &size, NULL) || !size)

			goto error;



		addr = ftrace_location_range(addr, addr + size - 1);

		if (!addr) /* No dynamic ftrace there. */

			goto error;



		addrs[i] = addr;

	}

	/* ftrace_lookup_symbols expects sorted symbols */

	sort(syms, num, sizeof(*syms), symbols_cmp, NULL);



	if (!ftrace_lookup_symbols(syms, num, addrs))

		return addrs;



error:

	kfree(addrs);



	return ERR_PTR(-ENOENT);

}