[PATCH AUTOSEL for 4.9 137/219] MIPS: BPF: Fix multiple problems in JIT skb access helpers.

Sasha Levin
2018-03-03T22:35:15Z

From: David Daney <david.daney@cavium.com>

[ Upstream commit a81507c79f4ae9a0f9fb1054b59b62a090620dd9 ]

o Socket data is unsigned, so use unsigned accessors instructions.

o Fix path result pointer generation arithmetic.

o Fix half-word byte swapping code for unsigned semantics.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Steven J. Hill <steven.hill@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/15747/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
arch/mips/net/bpf_jit_asm.S | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/mips/net/bpf_jit_asm.S b/arch/mips/net/bpf_jit_asm.S
index 5d2e0c8d29c0..88a2075305d1 100644
--- a/arch/mips/net/bpf_jit_asm.S
+++ b/arch/mips/net/bpf_jit_asm.S
@@ -90,18 +90,14 @@ FEXPORT(sk_load_half_positive)
is_offset_in_header(2, half)
/* Offset within header boundaries */
PTR_ADDU t1, $r_skb_data, offset
- .set reorder
- lh $r_A, 0(t1)
- .set noreorder
+ lhu $r_A, 0(t1)
#ifdef CONFIG_CPU_LITTLE_ENDIAN
# if defined(__mips_isa_rev) && (__mips_isa_rev >= 2)
- wsbh t0, $r_A
- seh $r_A, t0
+ wsbh $r_A, $r_A
# else
- sll t0, $r_A, 24
- andi t1, $r_A, 0xff00
- sra t0, t0, 16
- srl t1, t1, 8
+ sll t0, $r_A, 8
+ srl t1, $r_A, 8
+ andi t0, t0, 0xff00
or $r_A, t0, t1
# endif
#endif
@@ -115,7 +111,7 @@ FEXPORT(sk_load_byte_positive)
is_offset_in_header(1, byte)
/* Offset within header boundaries */
PTR_ADDU t1, $r_skb_data, offset
- lb $r_A, 0(t1)
+ lbu $r_A, 0(t1)
jr $r_ra
move $r_ret, zero
END(sk_load_byte)
@@ -139,6 +135,11 @@ FEXPORT(sk_load_byte_positive)
* (void *to) is returned in r_s0
*
*/
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+#define DS_OFFSET(SIZE) (4 * SZREG)
+#else
+#define DS_OFFSET(SIZE) ((4 * SZREG) + (4 - SIZE))
+#endif
#define bpf_slow_path_common(SIZE) \
/* Quick check. Are we within reasonable boundaries? */ \
LONG_ADDIU $r_s1, $r_skb_len, -SIZE; \
@@ -150,7 +151,7 @@ FEXPORT(sk_load_byte_positive)
PTR_LA t0, skb_copy_bits; \
PTR_S $r_ra, (5 * SZREG)($r_sp); \
/* Assign low slot to a2 */ \
- move a2, $r_sp; \
+ PTR_ADDIU a2, $r_sp, DS_OFFSET(SIZE); \
jalr t0; \
/* Reset our destination slot (DS but it's ok) */ \
INT_S zero, (4 * SZREG)($r_sp); \
--
2.14.1