RDMA/cm: Add SET/GET implementations to hide IBA wire format

There is no separation between RDMA-CM wire format as it is declared in
IBTA and kernel logic which implements needed support. Such situation
causes to many mistakes in conversion between big-endian (wire format)
and CPU format used by kernel. It also mixes RDMA core code with
combination of uXX and beXX variables.

The idea that all accesses to IBA definitions will go through special
GET/SET macros to ensure that no conversion mistakes are made. The
shifting and masking required to read the value is automatically deduced
using the field offset description from the tables in the IBA
specification.

This starts with the CM MADs described in IBTA release 1.3 volume 1.

To confirm that the new macros behave the same as the old accessors a
self-test is included in this patch.

Each macro replacing a straightforward struct field compile-time tests
that the new field has the same offsetof() and width as the old field.

For the fields with accessor functions a runtime test, the 'all ones'
value is placed in a dummy message and read back in several ways to
confirm that both approaches give identical results.

Later patches in this series delete the self test.

This creates a tested table of new field name, old field name(s) and some
meta information like BE coding for the functions which will be used in
the next patches.

Link: https://lore.kernel.org/r/20200116170037.30109-3-jgg@ziepe.ca
Link: https://lore.kernel.org/r/20191212093830.316934-5-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Tested-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 146 insertions, 0 deletions

diff --git a/include/rdma/iba.h b/include/rdma/iba.h
new file mode 100644
index 000000000000..6a1115b02a0d
--- /dev/null
+++ b/include/rdma/iba.h
@@ -0,0 +1,146 @@
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/*
+ * Copyright (c) 2020, Mellanox Technologies inc.  All rights reserved.
+ */
+#ifndef _IBA_DEFS_H_
+#define _IBA_DEFS_H_
+
+#include <linux/kernel.h>
+#include <linux/bitfield.h>
+#include <asm/unaligned.h>
+
+static inline u32 _iba_get8(const u8 *ptr)
+{
+	return *ptr;
+}
+
+static inline void _iba_set8(u8 *ptr, u32 mask, u32 prep_value)
+{
+	*ptr = (*ptr & ~mask) | prep_value;
+}
+
+static inline u16 _iba_get16(const __be16 *ptr)
+{
+	return be16_to_cpu(*ptr);
+}
+
+static inline void _iba_set16(__be16 *ptr, u16 mask, u16 prep_value)
+{
+	*ptr = cpu_to_be16((be16_to_cpu(*ptr) & ~mask) | prep_value);
+}
+
+static inline u32 _iba_get32(const __be32 *ptr)
+{
+	return be32_to_cpu(*ptr);
+}
+
+static inline void _iba_set32(__be32 *ptr, u32 mask, u32 prep_value)
+{
+	*ptr = cpu_to_be32((be32_to_cpu(*ptr) & ~mask) | prep_value);
+}
+
+static inline u64 _iba_get64(const __be64 *ptr)
+{
+	/*
+	 * The mads are constructed so that 32 bit and smaller are naturally
+	 * aligned, everything larger has a max alignment of 4 bytes.
+	 */
+	return be64_to_cpu(get_unaligned(ptr));
+}
+
+static inline void _iba_set64(__be64 *ptr, u64 mask, u64 prep_value)
+{
+	put_unaligned(cpu_to_be64((_iba_get64(ptr) & ~mask) | prep_value), ptr);
+}
+
+#define _IBA_SET(field_struct, field_offset, field_mask, num_bits, ptr, value) \
+	({                                                                     \
+		field_struct *_ptr = ptr;                                      \
+		_iba_set##num_bits((void *)_ptr + (field_offset), field_mask,  \
+				   FIELD_PREP(field_mask, value));             \
+	})
+#define IBA_SET(field, ptr, value) _IBA_SET(field, ptr, value)
+
+#define _IBA_GET_MEM_PTR(field_struct, field_offset, type, num_bits, ptr)      \
+	({                                                                     \
+		field_struct *_ptr = ptr;                                      \
+		(type *)((void *)_ptr + (field_offset));                       \
+	})
+#define IBA_GET_MEM_PTR(field, ptr) _IBA_GET_MEM_PTR(field, ptr)
+
+/* FIXME: A set should always set the entire field, meaning we should zero the trailing bytes */
+#define _IBA_SET_MEM(field_struct, field_offset, type, num_bits, ptr, in,      \
+		     bytes)                                                    \
+	({                                                                     \
+		const type *_in_ptr = in;                                      \
+		WARN_ON(bytes * 8 > num_bits);                                 \
+		if (in && bytes)                                               \
+			memcpy(_IBA_GET_MEM_PTR(field_struct, field_offset,    \
+						type, num_bits, ptr),          \
+			       _in_ptr, bytes);                                \
+	})
+#define IBA_SET_MEM(field, ptr, in, bytes) _IBA_SET_MEM(field, ptr, in, bytes)
+
+#define _IBA_GET(field_struct, field_offset, field_mask, num_bits, ptr)        \
+	({                                                                     \
+		const field_struct *_ptr = ptr;                                \
+		(u##num_bits) FIELD_GET(                                       \
+			field_mask, _iba_get##num_bits((const void *)_ptr +    \
+						       (field_offset)));       \
+	})
+#define IBA_GET(field, ptr) _IBA_GET(field, ptr)
+
+#define _IBA_GET_MEM(field_struct, field_offset, type, num_bits, ptr, out,     \
+		     bytes)                                                    \
+	({                                                                     \
+		type *_out_ptr = out;                                          \
+		WARN_ON(bytes * 8 > num_bits);                                 \
+		if (out && bytes)                                              \
+			memcpy(_out_ptr,                                       \
+			       _IBA_GET_MEM_PTR(field_struct, field_offset,    \
+						type, num_bits, ptr),          \
+			       bytes);                                         \
+	})
+#define IBA_GET_MEM(field, ptr, out, bytes) _IBA_GET_MEM(field, ptr, out, bytes)
+
+/*
+ * The generated list becomes the parameters to the macros, the order is:
+ *  - struct this applies to
+ *  - starting offset of the max
+ *  - GENMASK or GENMASK_ULL in CPU order
+ *  - The width of data the mask operations should work on, in bits
+ */
+
+/*
+ * Extraction using a tabular description like table 106. bit_offset is from
+ * the Byte[Bit] notation.
+ */
+#define IBA_FIELD_BLOC(field_struct, byte_offset, bit_offset, num_bits)        \
+	field_struct, byte_offset,                                             \
+		GENMASK(7 - (bit_offset), 7 - (bit_offset) - (num_bits - 1)),  \
+		8
+#define IBA_FIELD8_LOC(field_struct, byte_offset, num_bits)                    \
+	IBA_FIELD_BLOC(field_struct, byte_offset, 0, num_bits)
+
+#define IBA_FIELD16_LOC(field_struct, byte_offset, num_bits)                   \
+	field_struct, (byte_offset)&0xFFFE,                                    \
+		GENMASK(15 - (((byte_offset) % 2) * 8),                        \
+			15 - (((byte_offset) % 2) * 8) - (num_bits - 1)),      \
+		16
+
+#define IBA_FIELD32_LOC(field_struct, byte_offset, num_bits)                   \
+	field_struct, (byte_offset)&0xFFFC,                                    \
+		GENMASK(31 - (((byte_offset) % 4) * 8),                        \
+			31 - (((byte_offset) % 4) * 8) - (num_bits - 1)),      \
+		32
+
+#define IBA_FIELD64_LOC(field_struct, byte_offset)                             \
+	field_struct, byte_offset, GENMASK_ULL(63, 0), 64
+/*
+ * In IBTA spec, everything that is more than 64bits is multiple
+ * of bytes without leftover bits.
+ */
+#define IBA_FIELD_MLOC(field_struct, byte_offset, num_bits, type)              \
+	field_struct, byte_offset, type, num_bits
+
+#endif /* _IBA_DEFS_H_ */