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

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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: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220721134245.2450-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Kumar Kartikeya Dwivedi 2022-07-21 15:42:34 +02:00 committed by Alexei Starovoitov
parent ab21d6063c
commit ef2c6f370a
1 changed files with 34 additions and 6 deletions
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40
tools/bpf/resolve_btfids/main.c
View file

@ -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);
}