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 b4ce5923e780 ("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

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index b2fdf8ff9c604836595e86f84f7d0d83132b7c75..50103b3794fb7314d3ba14b17eb9a287b4081107 100644 (file)
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -373,6 +373,13 @@ skip_init_ctx:
                        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;