On Thu, Jun 17, 2021 at 01:04:08PM +0200, Daniel Borkmann wrote:
> On 6/16/21 3:34 PM, Jiri Olsa wrote:
> > Removing unused cnt increase from EMIT macro together
> > with cnt declarations. This was introduced in commit [1]
> > to ensure proper code generation. But that code was
> > removed in commit [2] and this extra code was left in.
> >
> > [1] b52f00e6a715 ("x86: bpf_jit: implement bpf_tail_call() helper")
> > [2] ebf7d1f508a7 ("bpf, x64: rework pro/epilogue and tailcall handling in JIT")
> >
> > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > ---
> > arch/x86/net/bpf_jit_comp.c | 39 ++++++++++---------------------------
> > 1 file changed, 10 insertions(+), 29 deletions(-)
> >
> > diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> > index 2a2e290fa5d8..19715542cd9c 100644
> > --- a/arch/x86/net/bpf_jit_comp.c
> > +++ b/arch/x86/net/bpf_jit_comp.c
> > @@ -31,7 +31,7 @@ static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
> > }
> > #define EMIT(bytes, len) \
> > - do { prog = emit_code(prog, bytes, len); cnt += len; } while (0)
> > + do { prog = emit_code(prog, bytes, len); } while (0)
> > #define EMIT1(b1) EMIT(b1, 1)
> > #define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
> > @@ -239,7 +239,6 @@ struct jit_context {
> > static void push_callee_regs(u8 **pprog, bool *callee_regs_used)
> > {
> > u8 *prog = *pprog;
> > - int cnt = 0;
> > if (callee_regs_used[0])
> > EMIT1(0x53); /* push rbx */
> > @@ -255,7 +254,6 @@ static void push_callee_regs(u8 **pprog, bool *callee_regs_used)
> > static void pop_callee_regs(u8 **pprog, bool *callee_regs_used)
> > {
> > u8 *prog = *pprog;
> > - int cnt = 0;
> > if (callee_regs_used[3])
> > EMIT2(0x41, 0x5F); /* pop r15 */
> > @@ -303,7 +301,6 @@ static void emit_prologue(u8 **pprog, u32 stack_depth, bool ebpf_from_cbpf,
>
> nit: In emit_prologue() we also have cnt that we could just replace with X86_PATCH_SIZE
> directly as well.
right, will send v2
thanks,
jirka
>
> > static int emit_patch(u8 **pprog, void *func, void *ip, u8 opcode)
> > {
> > u8 *prog = *pprog;
>
> Otherwise, lgtm.
>
> Thanks,
> Daniel
>
