From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Perches Subject: Re: [PATCH net-next 2/5] s390/bpf: Fix multiple macro expansions Date: Tue, 28 Jul 2015 20:13:41 -0700 Message-ID: <1438139621.2529.31.camel@perches.com> References: <1438092600-16221-1-git-send-email-holzheu@linux.vnet.ibm.com> <1438092600-16221-3-git-send-email-holzheu@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1438092600-16221-3-git-send-email-holzheu@linux.vnet.ibm.com> Sender: netdev-owner@vger.kernel.org List-Archive: List-Post: To: Michael Holzheu Cc: David Miller , Alexei Starovoitov , Martin Schwidefsky , Daniel Borkmann , netdev@vger.kernel.org, linux-s390@vger.kernel.org List-ID: On Tue, 2015-07-28 at 16:09 +0200, Michael Holzheu wrote: > The EMIT6_DISP_LH macro passes the "disp" parameter to the _EMIT6_DISP_LH > macro. The _EMIT6_DISP_LH macro uses the "disp" parameter twice: > > unsigned int __disp_h = ((u32)disp) & 0xff000; > unsigned int __disp_l = ((u32)disp) & 0x00fff; > > The EMIT6_DISP_LH is used several times with EMIT_CONST_U64() as "disp" > parameter. Therefore always two constants are created per usage of > EMIT6_DISP_LH. > > Fix this and add variable "__disp" to avoid multiple expansions. > > Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend") > Signed-off-by: Michael Holzheu > --- > arch/s390/net/bpf_jit_comp.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c > index 01ad166..de0f0bc 100644 > --- a/arch/s390/net/bpf_jit_comp.c > +++ b/arch/s390/net/bpf_jit_comp.c > @@ -221,8 +221,9 @@ static inline void reg_set_seen(struct nbpf_jit *jit, u32 b1) > > #define EMIT6_DISP_LH(op1, op2, b1, b2, b3, disp) \ > ({ \ > + int __disp = (disp); \ > _EMIT6_DISP_LH(op1 | reg(b1, b2) << 16 | \ > - reg_high(b3) << 8, op2, disp); \ > + reg_high(b3) << 8, op2, __disp); \ > REG_SET_SEEN(b1); \ > REG_SET_SEEN(b2); \ > REG_SET_SEEN(b3); \ Perhaps it'd be better to change _EMIT6_DISP_LH --- diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 3a15baa..409e206 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -205,8 +205,9 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1) #define _EMIT6_DISP_LH(op1, op2, disp) \ ({ \ - unsigned int __disp_h = ((u32)disp) & 0xff000; \ - unsigned int __disp_l = ((u32)disp) & 0x00fff; \ + u32 _disp = (u32)disp; \ + unsigned int __disp_h = _disp & 0xff000; \ + unsigned int __disp_l = _disp & 0x00fff; \ _EMIT6(op1 | __disp_l, op2 | __disp_h >> 4); \ })