From: Viktor Malik vmalik@redhat.com
[ Upstream commit 9707ac4fe2f5bac6406d2403f8b8a64d7b3d8e43 ]
Instead of using magic offsets to access BTF ID set data, leverage types from btf_ids.h (btf_id_set and btf_id_set8) which define the actual layout of the data. Thanks to this change, set sorting should also continue working if the layout changes.
This requires to sync the definition of 'struct btf_id_set8' from include/linux/btf_ids.h to tools/include/linux/btf_ids.h. We don't sync the rest of the file at the moment, b/c that would require to also sync multiple dependent headers and we don't need any other defs from btf_ids.h.
Signed-off-by: Viktor Malik vmalik@redhat.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Acked-by: Daniel Xu dxu@dxuuu.xyz Link: https://lore.kernel.org/bpf/ff7f062ddf6a00815fda3087957c4ce667f50532.1707223... Stable-dep-of: 903fad439466 ("tools/resolve_btfids: Fix cross-compilation to non-host endianness") Signed-off-by: Sasha Levin sashal@kernel.org --- tools/bpf/resolve_btfids/main.c | 35 ++++++++++++++++++++------------- tools/include/linux/btf_ids.h | 9 +++++++++ 2 files changed, 30 insertions(+), 14 deletions(-)
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c index 27a23196d58e1..32634f00abba4 100644 --- a/tools/bpf/resolve_btfids/main.c +++ b/tools/bpf/resolve_btfids/main.c @@ -70,6 +70,7 @@ #include <sys/stat.h> #include <fcntl.h> #include <errno.h> +#include <linux/btf_ids.h> #include <linux/rbtree.h> #include <linux/zalloc.h> #include <linux/err.h> @@ -78,7 +79,7 @@ #include <subcmd/parse-options.h>
#define BTF_IDS_SECTION ".BTF_ids" -#define BTF_ID "__BTF_ID__" +#define BTF_ID_PREFIX "__BTF_ID__"
#define BTF_STRUCT "struct" #define BTF_UNION "union" @@ -161,7 +162,7 @@ static int eprintf(int level, int var, const char *fmt, ...)
static bool is_btf_id(const char *name) { - return name && !strncmp(name, BTF_ID, sizeof(BTF_ID) - 1); + return name && !strncmp(name, BTF_ID_PREFIX, sizeof(BTF_ID_PREFIX) - 1); }
static struct btf_id *btf_id__find(struct rb_root *root, const char *name) @@ -441,7 +442,7 @@ static int symbols_collect(struct object *obj) * __BTF_ID__TYPE__vfs_truncate__0 * prefix = ^ */ - prefix = name + sizeof(BTF_ID) - 1; + prefix = name + sizeof(BTF_ID_PREFIX) - 1;
/* struct */ if (!strncmp(prefix, BTF_STRUCT, sizeof(BTF_STRUCT) - 1)) { @@ -649,19 +650,18 @@ static int cmp_id(const void *pa, const void *pb) static int sets_patch(struct object *obj) { Elf_Data *data = obj->efile.idlist; - int *ptr = data->d_buf; struct rb_node *next;
next = rb_first(&obj->sets); while (next) { - unsigned long addr, idx; + struct btf_id_set8 *set8; + struct btf_id_set *set; + unsigned long addr, off; struct btf_id *id; - int *base; - int cnt;
id = rb_entry(next, struct btf_id, rb_node); addr = id->addr[0]; - idx = addr - obj->efile.idlist_addr; + off = addr - obj->efile.idlist_addr;
/* sets are unique */ if (id->addr_cnt != 1) { @@ -670,14 +670,21 @@ static int sets_patch(struct object *obj) return -1; }
- idx = idx / sizeof(int); - base = &ptr[idx] + (id->is_set8 ? 2 : 1); - cnt = ptr[idx]; + if (id->is_set) { + set = data->d_buf + off; + qsort(set->ids, set->cnt, sizeof(set->ids[0]), cmp_id); + } else { + set8 = data->d_buf + off; + /* + * Make sure id is at the beginning of the pairs + * struct, otherwise the below qsort would not work. + */ + BUILD_BUG_ON(set8->pairs != &set8->pairs[0].id); + qsort(set8->pairs, set8->cnt, sizeof(set8->pairs[0]), cmp_id); + }
pr_debug("sorting addr %5lu: cnt %6d [%s]\n", - (idx + 1) * sizeof(int), cnt, id->name); - - qsort(base, cnt, id->is_set8 ? sizeof(uint64_t) : sizeof(int), cmp_id); + off, id->is_set ? set->cnt : set8->cnt, id->name);
next = rb_next(next); } diff --git a/tools/include/linux/btf_ids.h b/tools/include/linux/btf_ids.h index 2f882d5cb30f5..72535f00572f6 100644 --- a/tools/include/linux/btf_ids.h +++ b/tools/include/linux/btf_ids.h @@ -8,6 +8,15 @@ struct btf_id_set { u32 ids[]; };
+struct btf_id_set8 { + u32 cnt; + u32 flags; + struct { + u32 id; + u32 flags; + } pairs[]; +}; + #ifdef CONFIG_DEBUG_INFO_BTF
#include <linux/compiler.h> /* for __PASTE */