diff options
| author | Nicolas Schichan <nschichan@freebox.fr> | 2013-02-13 17:30:39 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-02-14 13:26:44 -0500 |
| commit | 462738f4f04febe16bf366925559c267130c88f0 (patch) | |
| tree | 3b04e14ad0f6985788c461e04341bf03066c49ce /arch/arm | |
| parent | 3e55f8b306cf305832a4ac78aa82e1b40e818ece (diff) | |
ARM: net: bpf_jit: fix emit_swap16() for non ARMv6+.
The original code was generating an lsl instructions using the value
of ARM_R8 (skb_headlen, possibly uninitialized if no skb_headlen
access was required) as a shift amount.
Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Mircea Gherzan <mgherzan@gmail.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/net/bpf_jit_32.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index a34f1e214116..6828ef6ce80e 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -341,10 +341,17 @@ static void emit_load_be16(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx) static inline void emit_swap16(u8 r_dst, u8 r_src, struct jit_ctx *ctx) { - emit(ARM_LSL_R(ARM_R1, r_src, 8), ctx); - emit(ARM_ORR_S(r_dst, ARM_R1, r_src, SRTYPE_LSL, 8), ctx); - emit(ARM_LSL_I(r_dst, r_dst, 8), ctx); - emit(ARM_LSL_R(r_dst, r_dst, 8), ctx); + /* r_dst = (r_src << 8) | (r_src >> 8) */ + emit(ARM_LSL_I(ARM_R1, r_src, 8), ctx); + emit(ARM_ORR_S(r_dst, ARM_R1, r_src, SRTYPE_LSR, 8), ctx); + + /* + * we need to mask out the bits set in r_dst[23:16] due to + * the first shift instruction. + * + * note that 0x8ff is the encoded immediate 0x00ff0000. + */ + emit(ARM_BIC_I(r_dst, r_dst, 0x8ff), ctx); } #else /* ARMv6+ */ |