[PATCH net] bpf, arm: start flushing icache range from header

[Daniel Borkmann]

During review I noticed that the icache range we're flushing should
start at header already and not at ctx.image.

Reason is that after 55309dd3d4cd ("net: bpf: arm: 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 at iogearbox.net>
Tested-by: Nicolas Schichan <nschichan at freebox.fr>
Cc: Alexei Starovoitov <ast at kernel.org>
---
 ( As arm32 fixes usually go via Dave's tree, targeting -net. )

 arch/arm/net/bpf_jit_32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 2f4b14c..591f9db 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -1061,7 +1061,7 @@ void bpf_jit_compile(struct bpf_prog *fp)
 	}
 	build_epilogue(&ctx);
 
-	flush_icache_range((u32)ctx.target, (u32)(ctx.target + ctx.idx));
+	flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx));
 
 #if __LINUX_ARM_ARCH__ < 7
 	if (ctx.imm_count)
-- 
1.9.3