s390/bpf: Fix multiple macro expansions

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.

* v2: Move "_disp" to _EMIT6_DISP_LH as suggested by Joe Perches

Fixes: 054623105728 ("s390/bpf: Add s390x eBPF JIT compiler backend")
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 01ad166..66926ab 100644 (file)
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -214,8 +214,9 @@ 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);            \
 })