Commit ef2c6f37 authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
Browse files

tools/resolve_btfids: Add support for 8-byte BTF sets 



A flag is a 4-byte symbol that may follow a BTF ID in a set8. This is
used in the kernel to tag kfuncs in BTF sets with certain flags. Add
support to adjust the sorting code so that it passes size as 8 bytes
for 8-byte BTF sets.

Cc: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220721134245.2450-3-memxor@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent ab21d606

tools/bpf/resolve_btfids/main.c

+34 −6
Original line number Diff line number Diff line
@@ -45,6 +45,19 @@ 
 *             .zero 4

 *             __BTF_ID__func__vfs_fallocate__4:

 *             .zero 4

 *

 *   set8    - store symbol size into first 4 bytes and sort following

 *             ID list

 *

 *             __BTF_ID__set8__list:

 *             .zero 8

 *             list:

 *             __BTF_ID__func__vfs_getattr__3:

 *             .zero 4

 *	       .word (1 << 0) | (1 << 2)

 *             __BTF_ID__func__vfs_fallocate__5:

 *             .zero 4

 *	       .word (1 << 3) | (1 << 1) | (1 << 2)

 */



#define  _GNU_SOURCE
@@ -72,6 +85,7 @@ 
#define BTF_TYPEDEF	"typedef"

#define BTF_FUNC	"func"

#define BTF_SET		"set"

#define BTF_SET8	"set8"



#define ADDR_CNT	100
@@ -84,6 +98,7 @@ struct btf_id { 
	};

	int		 addr_cnt;

	bool		 is_set;

	bool		 is_set8;

	Elf64_Addr	 addr[ADDR_CNT];

};
@@ -231,14 +246,14 @@ static char *get_id(const char *prefix_end) 
	return id;

}



static struct btf_id *add_set(struct object *obj, char *name)

static struct btf_id *add_set(struct object *obj, char *name, bool is_set8)

{

	/*

	 * __BTF_ID__set__name

	 * name =    ^

	 * id   =         ^

	 */

	char *id = name + sizeof(BTF_SET "__") - 1;

	char *id = name + (is_set8 ? sizeof(BTF_SET8 "__") : sizeof(BTF_SET "__")) - 1;

	int len = strlen(name);



	if (id >= name + len) {
@@ -444,9 +459,21 @@ static int symbols_collect(struct object *obj) 
		} else if (!strncmp(prefix, BTF_FUNC, sizeof(BTF_FUNC) - 1)) {

			obj->nr_funcs++;

			id = add_symbol(&obj->funcs, prefix, sizeof(BTF_FUNC) - 1);

		/* set8 */

		} else if (!strncmp(prefix, BTF_SET8, sizeof(BTF_SET8) - 1)) {

			id = add_set(obj, prefix, true);

			/*

			 * SET8 objects store list's count, which is encoded

			 * in symbol's size, together with 'cnt' field hence

			 * that - 1.

			 */

			if (id) {

				id->cnt = sym.st_size / sizeof(uint64_t) - 1;

				id->is_set8 = true;

			}

		/* set */

		} else if (!strncmp(prefix, BTF_SET, sizeof(BTF_SET) - 1)) {

			id = add_set(obj, prefix);

			id = add_set(obj, prefix, false);

			/*

			 * SET objects store list's count, which is encoded

			 * in symbol's size, together with 'cnt' field hence
@@ -571,7 +598,8 @@ static int id_patch(struct object *obj, struct btf_id *id) 
	int *ptr = data->d_buf;

	int i;



	if (!id->id && !id->is_set)

	/* For set, set8, id->id may be 0 */

	if (!id->id && !id->is_set && !id->is_set8)

		pr_err("WARN: resolve_btfids: unresolved symbol %s\n", id->name);



	for (i = 0; i < id->addr_cnt; i++) {
@@ -643,13 +671,13 @@ static int sets_patch(struct object *obj) 
		}



		idx = idx / sizeof(int);

		base = &ptr[idx] + 1;

		base = &ptr[idx] + (id->is_set8 ? 2 : 1);

		cnt = ptr[idx];



		pr_debug("sorting  addr %5lu: cnt %6d [%s]\n",

			 (idx + 1) * sizeof(int), cnt, id->name);



		qsort(base, cnt, sizeof(int), cmp_id);

		qsort(base, cnt, id->is_set8 ? sizeof(uint64_t) : sizeof(int), cmp_id);



		next = rb_next(next);

	}