powerpc/bpf: Add support for instruction array

On loading the BPF program, the verifier might adjust/omit some
instructions. The adjusted instruction offset is accounted in the
map containing original instruction -> xlated mapping. This patch
add ppc64 JIT support to additionally build the xlated->jitted
mapping for every instruction present in instruction array. This
change is needed to enable support for indirect jumps, added in a
subsequent patch.

Invoke bpf_prog_update_insn_ptrs() with offset pair of xlated_offset
and jited_offset. The offset mapping is already available, which is
being used for bpf_prog_fill_jited_linfo() and can be directly used
for bpf_prog_update_insn_ptrs() as well.

Additional details present at:

commit b4ce592 ("bpf, x86: add new map type: instructions array")

Signed-off-by: Abhishek Dubey <adubey@linux.ibm.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260401152133.42544-2-adubey@linux.ibm.com

Author: Abhishek Dubey

arch/powerpc/net/bpf_jit_comp.c

@@ -373,6 +373,13 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
 			goto out_addrs;
 		}
 		bpf_prog_fill_jited_linfo(fp, addrs);
+		/*
+		 * On ABI V1, executable code starts after the function
+		 * descriptor, so adjust base accordingly.
+		 */
+		bpf_prog_update_insn_ptrs(fp, addrs,
+				(void *)fimage + FUNCTION_DESCR_SIZE);
+
 out_addrs:
 		if (!image && priv_stack_ptr) {
 			fp->aux->priv_stack_ptr = NULL;