1 files changed, 0 insertions, 265 deletions
diff --git a/arch/riscv/lib/crc-clmul-template.h b/arch/riscv/lib/crc-clmul-template.h
deleted file mode 100644
index 77187e7f1762..000000000000
--- a/arch/riscv/lib/crc-clmul-template.h
+++ /dev/null
@@ -1,265 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/* Copyright 2025 Google LLC */
-
-/*
- * This file is a "template" that generates a CRC function optimized using the
- * RISC-V Zbc (scalar carryless multiplication) extension.  The includer of this
- * file must define the following parameters to specify the type of CRC:
- *
- *	crc_t: the data type of the CRC, e.g. u32 for a 32-bit CRC
- *	LSB_CRC: 0 for a msb (most-significant-bit) first CRC, i.e. natural
- *		 mapping between bits and polynomial coefficients
- *	         1 for a lsb (least-significant-bit) first CRC, i.e. reflected
- *	         mapping between bits and polynomial coefficients
- */
-
-#include <asm/byteorder.h>
-#include <linux/minmax.h>
-
-#define CRC_BITS	(8 * sizeof(crc_t))	/* a.k.a. 'n' */
-
-static inline unsigned long clmul(unsigned long a, unsigned long b)
-{
-	unsigned long res;
-
-	asm(".option push\n"
-	    ".option arch,+zbc\n"
-	    "clmul %0, %1, %2\n"
-	    ".option pop\n"
-	    : "=r" (res) : "r" (a), "r" (b));
-	return res;
-}
-
-static inline unsigned long clmulh(unsigned long a, unsigned long b)
-{
-	unsigned long res;
-
-	asm(".option push\n"
-	    ".option arch,+zbc\n"
-	    "clmulh %0, %1, %2\n"
-	    ".option pop\n"
-	    : "=r" (res) : "r" (a), "r" (b));
-	return res;
-}
-
-static inline unsigned long clmulr(unsigned long a, unsigned long b)
-{
-	unsigned long res;
-
-	asm(".option push\n"
-	    ".option arch,+zbc\n"
-	    "clmulr %0, %1, %2\n"
-	    ".option pop\n"
-	    : "=r" (res) : "r" (a), "r" (b));
-	return res;
-}
-
-/*
- * crc_load_long() loads one "unsigned long" of aligned data bytes, producing a
- * polynomial whose bit order matches the CRC's bit order.
- */
-#ifdef CONFIG_64BIT
-#  if LSB_CRC
-#    define crc_load_long(x)	le64_to_cpup(x)
-#  else
-#    define crc_load_long(x)	be64_to_cpup(x)
-#  endif
-#else
-#  if LSB_CRC
-#    define crc_load_long(x)	le32_to_cpup(x)
-#  else
-#    define crc_load_long(x)	be32_to_cpup(x)
-#  endif
-#endif
-
-/* XOR @crc into the end of @msgpoly that represents the high-order terms. */
-static inline unsigned long
-crc_clmul_prep(crc_t crc, unsigned long msgpoly)
-{
-#if LSB_CRC
-	return msgpoly ^ crc;
-#else
-	return msgpoly ^ ((unsigned long)crc << (BITS_PER_LONG - CRC_BITS));
-#endif
-}
-
-/*
- * Multiply the long-sized @msgpoly by x^n (a.k.a. x^CRC_BITS) and reduce it
- * modulo the generator polynomial G.  This gives the CRC of @msgpoly.
- */
-static inline crc_t
-crc_clmul_long(unsigned long msgpoly, const struct crc_clmul_consts *consts)
-{
-	unsigned long tmp;
-
-	/*
-	 * First step of Barrett reduction with integrated multiplication by
-	 * x^n: calculate floor((msgpoly * x^n) / G).  This is the value by
-	 * which G needs to be multiplied to cancel out the x^n and higher terms
-	 * of msgpoly * x^n.  Do it using the following formula:
-	 *
-	 * msb-first:
-	 *    floor((msgpoly * floor(x^(BITS_PER_LONG-1+n) / G)) / x^(BITS_PER_LONG-1))
-	 * lsb-first:
-	 *    floor((msgpoly * floor(x^(BITS_PER_LONG-1+n) / G) * x) / x^BITS_PER_LONG)
-	 *
-	 * barrett_reduction_const_1 contains floor(x^(BITS_PER_LONG-1+n) / G),
-	 * which fits a long exactly.  Using any lower power of x there would
-	 * not carry enough precision through the calculation, while using any
-	 * higher power of x would require extra instructions to handle a wider
-	 * multiplication.  In the msb-first case, using this power of x results
-	 * in needing a floored division by x^(BITS_PER_LONG-1), which matches
-	 * what clmulr produces.  In the lsb-first case, a factor of x gets
-	 * implicitly introduced by each carryless multiplication (shown as
-	 * '* x' above), and the floored division instead needs to be by
-	 * x^BITS_PER_LONG which matches what clmul produces.
-	 */
-#if LSB_CRC
-	tmp = clmul(msgpoly, consts->barrett_reduction_const_1);
-#else
-	tmp = clmulr(msgpoly, consts->barrett_reduction_const_1);
-#endif
-
-	/*
-	 * Second step of Barrett reduction:
-	 *
-	 *    crc := (msgpoly * x^n) + (G * floor((msgpoly * x^n) / G))
-	 *
-	 * This reduces (msgpoly * x^n) modulo G by adding the appropriate
-	 * multiple of G to it.  The result uses only the x^0..x^(n-1) terms.
-	 * HOWEVER, since the unreduced value (msgpoly * x^n) is zero in those
-	 * terms in the first place, it is more efficient to do the equivalent:
-	 *
-	 *    crc := ((G - x^n) * floor((msgpoly * x^n) / G)) mod x^n
-	 *
-	 * In the lsb-first case further modify it to the following which avoids
-	 * a shift, as the crc ends up in the physically low n bits from clmulr:
-	 *
-	 *    product := ((G - x^n) * x^(BITS_PER_LONG - n)) * floor((msgpoly * x^n) / G) * x
-	 *    crc := floor(product / x^(BITS_PER_LONG + 1 - n)) mod x^n
-	 *
-	 * barrett_reduction_const_2 contains the constant multiplier (G - x^n)
-	 * or (G - x^n) * x^(BITS_PER_LONG - n) from the formulas above.  The
-	 * cast of the result to crc_t is essential, as it applies the mod x^n!
-	 */
-#if LSB_CRC
-	return clmulr(tmp, consts->barrett_reduction_const_2);
-#else
-	return clmul(tmp, consts->barrett_reduction_const_2);
-#endif
-}
-
-/* Update @crc with the data from @msgpoly. */
-static inline crc_t
-crc_clmul_update_long(crc_t crc, unsigned long msgpoly,
-		      const struct crc_clmul_consts *consts)
-{
-	return crc_clmul_long(crc_clmul_prep(crc, msgpoly), consts);
-}
-
-/* Update @crc with 1 <= @len < sizeof(unsigned long) bytes of data. */
-static inline crc_t
-crc_clmul_update_partial(crc_t crc, const u8 *p, size_t len,
-			 const struct crc_clmul_consts *consts)
-{
-	unsigned long msgpoly;
-	size_t i;
-
-#if LSB_CRC
-	msgpoly = (unsigned long)p[0] << (BITS_PER_LONG - 8);
-	for (i = 1; i < len; i++)
-		msgpoly = (msgpoly >> 8) ^ ((unsigned long)p[i] << (BITS_PER_LONG - 8));
-#else
-	msgpoly = p[0];
-	for (i = 1; i < len; i++)
-		msgpoly = (msgpoly << 8) ^ p[i];
-#endif
-
-	if (len >= sizeof(crc_t)) {
-	#if LSB_CRC
-		msgpoly ^= (unsigned long)crc << (BITS_PER_LONG - 8*len);
-	#else
-		msgpoly ^= (unsigned long)crc << (8*len - CRC_BITS);
-	#endif
-		return crc_clmul_long(msgpoly, consts);
-	}
-#if LSB_CRC
-	msgpoly ^= (unsigned long)crc << (BITS_PER_LONG - 8*len);
-	return crc_clmul_long(msgpoly, consts) ^ (crc >> (8*len));
-#else
-	msgpoly ^= crc >> (CRC_BITS - 8*len);
-	return crc_clmul_long(msgpoly, consts) ^ (crc << (8*len));
-#endif
-}
-
-static inline crc_t
-crc_clmul(crc_t crc, const void *p, size_t len,
-	  const struct crc_clmul_consts *consts)
-{
-	size_t align;
-
-	/* This implementation assumes that the CRC fits in an unsigned long. */
-	BUILD_BUG_ON(sizeof(crc_t) > sizeof(unsigned long));
-
-	/* If the buffer is not long-aligned, align it. */
-	align = (unsigned long)p % sizeof(unsigned long);
-	if (align && len) {
-		align = min(sizeof(unsigned long) - align, len);
-		crc = crc_clmul_update_partial(crc, p, align, consts);
-		p += align;
-		len -= align;
-	}
-
-	if (len >= 4 * sizeof(unsigned long)) {
-		unsigned long m0, m1;
-
-		m0 = crc_clmul_prep(crc, crc_load_long(p));
-		m1 = crc_load_long(p + sizeof(unsigned long));
-		p += 2 * sizeof(unsigned long);
-		len -= 2 * sizeof(unsigned long);
-		/*
-		 * Main loop.  Each iteration starts with a message polynomial
-		 * (x^BITS_PER_LONG)*m0 + m1, then logically extends it by two
-		 * more longs of data to form x^(3*BITS_PER_LONG)*m0 +
-		 * x^(2*BITS_PER_LONG)*m1 + x^BITS_PER_LONG*m2 + m3, then
-		 * "folds" that back into a congruent (modulo G) value that uses
-		 * just m0 and m1 again.  This is done by multiplying m0 by the
-		 * precomputed constant (x^(3*BITS_PER_LONG) mod G) and m1 by
-		 * the precomputed constant (x^(2*BITS_PER_LONG) mod G), then
-		 * adding the results to m2 and m3 as appropriate.  Each such
-		 * multiplication produces a result twice the length of a long,
-		 * which in RISC-V is two instructions clmul and clmulh.
-		 *
-		 * This could be changed to fold across more than 2 longs at a
-		 * time if there is a CPU that can take advantage of it.
-		 */
-		do {
-			unsigned long p0, p1, p2, p3;
-
-			p0 = clmulh(m0, consts->fold_across_2_longs_const_hi);
-			p1 = clmul(m0, consts->fold_across_2_longs_const_hi);
-			p2 = clmulh(m1, consts->fold_across_2_longs_const_lo);
-			p3 = clmul(m1, consts->fold_across_2_longs_const_lo);
-			m0 = (LSB_CRC ? p1 ^ p3 : p0 ^ p2) ^ crc_load_long(p);
-			m1 = (LSB_CRC ? p0 ^ p2 : p1 ^ p3) ^
-			     crc_load_long(p + sizeof(unsigned long));
-
-			p += 2 * sizeof(unsigned long);
-			len -= 2 * sizeof(unsigned long);
-		} while (len >= 2 * sizeof(unsigned long));
-
-		crc = crc_clmul_long(m0, consts);
-		crc = crc_clmul_update_long(crc, m1, consts);
-	}
-
-	while (len >= sizeof(unsigned long)) {
-		crc = crc_clmul_update_long(crc, crc_load_long(p), consts);
-		p += sizeof(unsigned long);
-		len -= sizeof(unsigned long);
-	}
-
-	if (len)
-		crc = crc_clmul_update_partial(crc, p, len, consts);
-
-	return crc;
-}