[dpdk-dev] [PATCH v2 15/16] lpm/arm: implement rte_lpm_lookupx4 using rte_lpm_lookup_bulk on for-x86

[Jan Viktorin <viktorin@rehivetech.com>]

From: Vlastimil Kosar <kosar@rehivetech.com>

LPM function rte_lpm_lookupx4() uses i686/x86_64 SIMD intrinsics. Therefore,
the function is reimplemented using non-vector operations for non-x86
architectures. In the future, each architecture should have vectorized code.
This patch includes rudimentary emulation of intrinsic functions _mm_set_epi32(),
_mm_loadu_si128() and _mm_load_si128() for easy portability of existing
applications.

LPM builds now when on ARM.

FIXME: to be reworked

Signed-off-by: Vlastimil Kosar <kosar@rehivetech.com>
Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
---
 config/defconfig_arm-armv7-a-linuxapp-gcc |  1 -
 lib/librte_lpm/rte_lpm.h                  | 71 +++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/config/defconfig_arm-armv7-a-linuxapp-gcc b/config/defconfig_arm-armv7-a-linuxapp-gcc
index 5b582a8..33afb33 100644
--- a/config/defconfig_arm-armv7-a-linuxapp-gcc
+++ b/config/defconfig_arm-armv7-a-linuxapp-gcc
@@ -58,7 +58,6 @@ CONFIG_XMM_SIZE=16
 
 # fails to compile on ARM
 CONFIG_RTE_LIBRTE_ACL=n
-CONFIG_RTE_LIBRTE_LPM=n
 
 # cannot use those on ARM
 CONFIG_RTE_KNI_KMOD=n
diff --git a/lib/librte_lpm/rte_lpm.h b/lib/librte_lpm/rte_lpm.h
index c299ce2..4619992 100644
--- a/lib/librte_lpm/rte_lpm.h
+++ b/lib/librte_lpm/rte_lpm.h
@@ -47,7 +47,9 @@
 #include <rte_byteorder.h>
 #include <rte_memory.h>
 #include <rte_common.h>
+#if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686)
 #include <rte_vect.h>
+#endif
 
 #ifdef __cplusplus
 extern "C" {
@@ -358,6 +360,7 @@ rte_lpm_lookup_bulk_func(const struct rte_lpm *lpm, const uint32_t * ips,
 	return 0;
 }
 
+#if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686)
 /* Mask four results. */
 #define	 RTE_LPM_MASKX4_RES	UINT64_C(0x00ff00ff00ff00ff)
 
@@ -472,6 +475,74 @@ rte_lpm_lookupx4(const struct rte_lpm *lpm, __m128i ip, uint16_t hop[4],
 	hop[2] = (tbl[2] & RTE_LPM_LOOKUP_SUCCESS) ? (uint8_t)tbl[2] : defv;
 	hop[3] = (tbl[3] & RTE_LPM_LOOKUP_SUCCESS) ? (uint8_t)tbl[3] : defv;
 }
+#else
+// TODO: this code should be reworked.
+
+typedef struct {
+	union uint128 {
+		uint8_t uint8[16];
+		uint32_t uint32[4];
+	} val;
+} __m128i;
+
+static inline __m128i
+_mm_set_epi32(uint32_t v0, uint32_t v1, uint32_t v2, uint32_t v3)
+{
+	__m128i res;
+	res.val.uint32[0] = v0;
+	res.val.uint32[1] = v1;
+	res.val.uint32[2] = v2;
+	res.val.uint32[3] = v3;
+	return res;
+}
+
+static inline __m128i
+_mm_loadu_si128(__m128i * v)
+{
+	__m128i res;
+	res = *v;
+	return res;
+}
+
+static inline __m128i
+_mm_load_si128(__m128i * v)
+{
+	__m128i res;
+	res = *v;
+	return res;
+}
+
+/**
+ * Lookup four IP addresses in an LPM table.
+ *
+ * @param lpm
+ *   LPM object handle
+ * @param ip
+ *   Four IPs to be looked up in the LPM table
+ * @param hop
+ *   Next hop of the most specific rule found for IP (valid on lookup hit only).
+ *   This is an 4 elements array of two byte values.
+ *   If the lookup was succesfull for the given IP, then least significant byte
+ *   of the corresponding element is the  actual next hop and the most
+ *   significant byte is zero.
+ *   If the lookup for the given IP failed, then corresponding element would
+ *   contain default value, see description of then next parameter.
+ * @param defv
+ *   Default value to populate into corresponding element of hop[] array,
+ *   if lookup would fail.
+ */
+static inline void
+rte_lpm_lookupx4(const struct rte_lpm *lpm, __m128i ip, uint16_t hop[4],
+	uint16_t defv)
+{
+	rte_lpm_lookup_bulk(lpm, ip.val.uint32, hop, 4);
+
+	hop[0] = (hop[0] & RTE_LPM_LOOKUP_SUCCESS) ? (uint8_t)hop[0] : defv;
+	hop[1] = (hop[1] & RTE_LPM_LOOKUP_SUCCESS) ? (uint8_t)hop[1] : defv;
+	hop[2] = (hop[2] & RTE_LPM_LOOKUP_SUCCESS) ? (uint8_t)hop[2] : defv;
+	hop[3] = (hop[3] & RTE_LPM_LOOKUP_SUCCESS) ? (uint8_t)hop[3] : defv;
+}
+#endif
 
 #ifdef __cplusplus
 }
-- 
2.6.1