Re: [PATCH v2 bpf-next 11/17] bpf: Reserver space for BPF trampoline in BPF programs
From: Andrii Nakryiko <hidden>
Date: 2019-11-08 05:03:45
Also in:
bpf
On Wed, Nov 6, 2019 at 9:48 PM Alexei Starovoitov [off-list ref] wrote:
BPF trampoline can be made to work with existing 5 bytes of BPF program prologue, but let's add 5 bytes of NOPs to the beginning of every JITed BPF program to make BPF trampoline job easier. They can be removed in the future. Signed-off-by: Alexei Starovoitov <ast@kernel.org> ---
Acked-by: Andrii Nakryiko <redacted>
quoted hunk ↗ jump to hunk
arch/x86/net/bpf_jit_comp.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 44169e8bffc0..260f61276f18 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c@@ -206,7 +206,7 @@ struct jit_context { /* number of bytes emit_call() needs to generate call instruction */ #define X86_CALL_SIZE 5 -#define PROLOGUE_SIZE 20 +#define PROLOGUE_SIZE 25
nit: define as 20 + X86_CALL_SIZE ? [...]