bpf, arm64: start flushing icache range from header

While recently going over ARM64's BPF code, I noticed that the icache
range we're flushing should start at header already and not at ctx.image.

Reason is that after b569c1c622c5 ("net: bpf: arm64: address randomize
and write protect JIT code"), we also want to make sure to flush the
random-sized trap in front of the start of the actual program (analogous
to x86). No operational differences from user side.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Zi Shen Lim <zlim.lnx@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index ac8b548..64a8bc1 100644 (file)
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -740,7 +740,7 @@ void bpf_int_jit_compile(struct bpf_prog *prog)
        if (bpf_jit_enable > 1)
                bpf_jit_dump(prog->len, image_size, 2, ctx.image);
 
-       bpf_flush_icache(ctx.image, ctx.image + ctx.idx);
+       bpf_flush_icache(header, ctx.image + ctx.idx);
 
        set_memory_ro((unsigned long)header, header->pages);
        prog->bpf_func = (void *)ctx.image;