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 <holzheu@xxxxxxxxxxxxxxxxxx>
> ---
> 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); \
})
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