powerpc/bpf: implement bpf_arch_text_invalidate for bpf_prog_pack

Implement bpf_arch_text_invalidate and use it to fill unused part of
the bpf_prog_pack with trap instructions when a BPF program is freed.

Signed-off-by: Hari Bathini <[email protected]>
Acked-by: Song Liu <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index c21cb88b09e4..0a5a9758903a 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -292,3 +292,18 @@ void *bpf_arch_text_copy(void *dst, void *src, size_t len)
 
 	return err ? ERR_PTR(err) : dst;
 }
+
+int bpf_arch_text_invalidate(void *dst, size_t len)
+{
+	u32 insn = BREAKPOINT_INSTRUCTION;
+	int ret;
+
+	if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
+		return -EINVAL;
+
+	mutex_lock(&text_mutex);
+	ret = patch_instructions(dst, &insn, len, true);
+	mutex_unlock(&text_mutex);
+
+	return ret;
+}