On 25/08/26 04:15PM, Anton Protopopov wrote:
> On 25/08/25 05:06PM, Eduard Zingerman wrote:
> > On Sat, 2025-08-16 at 18:06 +0000, Anton Protopopov wrote:
> >
> > [...]
> >
> > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > > index fe4fc5438678..a5f04544c09c 100644
> > > --- a/tools/lib/bpf/libbpf.c
> > > +++ b/tools/lib/bpf/libbpf.c
> >
> > [...]
> >
> > > @@ -6101,6 +6124,60 @@ static void poison_kfunc_call(struct bpf_program *prog, int relo_idx,
> > > insn->imm = POISON_CALL_KFUNC_BASE + ext_idx;
> > > }
> > >
> > > +static int create_jt_map(struct bpf_object *obj, int off, int size, int adjust_off)
> > > +{
> > > + static union bpf_attr attr = {
> > > + .map_type = BPF_MAP_TYPE_INSN_ARRAY,
> > > + .key_size = 4,
> > > + .value_size = sizeof(struct bpf_insn_array_value),
> > > + .max_entries = 0,
> > > + };
> > > + struct bpf_insn_array_value val = {};
> > > + int map_fd;
> > > + int err;
> > > + __u32 i;
> > > + __u32 *jt;
> > > +
> > > + attr.max_entries = size / 8;
> > > +
> > > + map_fd = syscall(__NR_bpf, BPF_MAP_CREATE, &attr, sizeof(attr));
> > > + if (map_fd < 0)
> > > + return map_fd;
> > > +
> > > + jt = (__u32 *)(obj->efile.jumptables_data.d_buf + off);
> > ^^^^^^^^^
> > Jump table entries are u64 now, e.g. see test case:
> > https://github.com/llvm/llvm-project/blob/39dc3c41e459e6c847c1e45e7e93c53aaf74c1de/llvm/test/CodeGen/BPF/jump_table_swith_stmt.ll#L68
> >
> > [...]
>
> Yes, thanks, I will change it to u64. (Just in case, it works now
> because the code happens to work properly on little-endian: it uses
> jt[2*i] for i-th element.)
>
> > > @@ -6389,36 +6481,58 @@ static int append_subprog_relos(struct bpf_program *main_prog, struct bpf_progra
> >
> > [...]
> >
> > > static int
> > > bpf_object__append_subprog_code(struct bpf_object *obj, struct bpf_program *main_prog,
> > > - struct bpf_program *subprog)
> > > + struct bpf_program *subprog)
> > > {
> > > - struct bpf_insn *insns;
> > > - size_t new_cnt;
> > > - int err;
> > > + struct bpf_insn *insns;
> > > + size_t new_cnt;
> > > + int err;
> >
> > Could you please extract spaces vs tabs fix for this function as a separate commit?
> > Just to make diff easier to read.
> >
> > [...]
>
> Sure, sorry, I haven't noticed it.
Just in case, this chunk is
@@ -6418,6 +6524,17 @@ bpf_object__append_subprog_code(struct bpf_object *obj, struct bpf_program *main
err = append_subprog_relos(main_prog, subprog);
if (err)
return err;
+
+ /* Save subprogram offsets */
+ if (main_prog->subprog_cnt == ARRAY_SIZE(main_prog->subprog_sec_off)) {
+ pr_warn("prog '%s': number of subprogs exceeds %zu\n",
+ main_prog->name, ARRAY_SIZE(main_prog->subprog_sec_off));
+ return -E2BIG;
+ }
+ main_prog->subprog_sec_off[main_prog->subprog_cnt] = subprog->sec_insn_off;
+ main_prog->subprog_off[main_prog->subprog_cnt] = subprog->sub_insn_off;
+ main_prog->subprog_cnt += 1;
+
return 0;
}
(In v2 it will either change to realloc vs. static allocation, or disappear.)
