git: 3a909754a10e - stable/13 - Import the arm64 Cortex Strings memset into the kernel

From: Andrew Turner <andrew_at_FreeBSD.org>
Date: Wed, 21 Sep 2022 09:46:49 UTC
The branch stable/13 has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=3a909754a10ead4e6d9e85f2f03ff8b8bcb5b29f

commit 3a909754a10ead4e6d9e85f2f03ff8b8bcb5b29f
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2022-09-07 11:41:13 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2022-09-21 09:45:53 +0000

    Import the arm64 Cortex Strings memset into the kernel
    
    Bring in the last version of the optimized memset from the Cortex
    Strings library that didn't use the VFP registers. While here clean up
    to use the ENTRY/EDIT macros.
    
    This is imported from:
    https://git.linaro.org/toolchain/cortex-strings.git/tree/src/aarch64/memset.S?id=bc654e7a594385071b42db3c9c94bd0fd5fe0da5
    
    Sponsored by:   The FreeBSD Foundation
    
    (cherry picked from commit 949bc17cf28bb0a21b4688f1effad01de63d3318)
---
 sys/arm64/arm64/memset.S | 235 +++++++++++++++++++++++++++++++++++++++++++++++
 sys/conf/files.arm64     |   3 +-
 2 files changed, 236 insertions(+), 2 deletions(-)

diff --git a/sys/arm64/arm64/memset.S b/sys/arm64/arm64/memset.S
new file mode 100644
index 000000000000..aaa196d35278
--- /dev/null
+++ b/sys/arm64/arm64/memset.S
@@ -0,0 +1,235 @@
+/* Copyright (c) 2012, Linaro Limited
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are met:
+       * Redistributions of source code must retain the above copyright
+         notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above copyright
+         notice, this list of conditions and the following disclaimer in the
+         documentation and/or other materials provided with the distribution.
+       * Neither the name of the Linaro nor the
+         names of its contributors may be used to endorse or promote products
+         derived from this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
+
+/* Assumptions:
+ *
+ * ARMv8-a, AArch64
+ * Unaligned accesses
+ *
+ */
+
+#include <machine/asm.h>
+
+
+/* By default we assume that the DC instruction can be used to zero
+   data blocks more efficiently.  In some circumstances this might be
+   unsafe, for example in an asymmetric multiprocessor environment with
+   different DC clear lengths (neither the upper nor lower lengths are
+   safe to use).  The feature can be disabled by defining DONT_USE_DC.
+
+   If code may be run in a virtualized environment, then define
+   MAYBE_VIRT.  This will cause the code to cache the system register
+   values rather than re-reading them each call.  */
+
+#define dstin		x0
+#define val		w1
+#define count		x2
+#define tmp1		x3
+#define tmp1w		w3
+#define tmp2		x4
+#define tmp2w		w4
+#define zva_len_x	x5
+#define zva_len		w5
+#define zva_bits_x	x6
+
+#define A_l		x7
+#define A_lw		w7
+#define dst		x8
+#define tmp3w		w9
+
+ENTRY(memset)
+
+	mov	dst, dstin		/* Preserve return value.  */
+	ands	A_lw, val, #255
+#ifndef DONT_USE_DC
+	b.eq	.Lzero_mem
+#endif
+	orr	A_lw, A_lw, A_lw, lsl #8
+	orr	A_lw, A_lw, A_lw, lsl #16
+	orr	A_l, A_l, A_l, lsl #32
+.Ltail_maybe_long:
+	cmp	count, #64
+	b.ge	.Lnot_short
+.Ltail_maybe_tiny:
+	cmp	count, #15
+	b.le	.Ltail15tiny
+.Ltail63:
+	ands	tmp1, count, #0x30
+	b.eq	.Ltail15
+	add	dst, dst, tmp1
+	cmp	tmp1w, #0x20
+	b.eq	1f
+	b.lt	2f
+	stp	A_l, A_l, [dst, #-48]
+1:
+	stp	A_l, A_l, [dst, #-32]
+2:
+	stp	A_l, A_l, [dst, #-16]
+
+.Ltail15:
+	and	count, count, #15
+	add	dst, dst, count
+	stp	A_l, A_l, [dst, #-16]	/* Repeat some/all of last store. */
+	ret
+
+.Ltail15tiny:
+	/* Set up to 15 bytes.  Does not assume earlier memory
+	   being set.  */
+	tbz	count, #3, 1f
+	str	A_l, [dst], #8
+1:
+	tbz	count, #2, 1f
+	str	A_lw, [dst], #4
+1:
+	tbz	count, #1, 1f
+	strh	A_lw, [dst], #2
+1:
+	tbz	count, #0, 1f
+	strb	A_lw, [dst]
+1:
+	ret
+
+	/* Critical loop.  Start at a new cache line boundary.  Assuming
+	 * 64 bytes per line, this ensures the entire loop is in one line.  */
+	.p2align 6
+.Lnot_short:
+	neg	tmp2, dst
+	ands	tmp2, tmp2, #15
+	b.eq	2f
+	/* Bring DST to 128-bit (16-byte) alignment.  We know that there's
+	 * more than that to set, so we simply store 16 bytes and advance by
+	 * the amount required to reach alignment.  */
+	sub	count, count, tmp2
+	stp	A_l, A_l, [dst]
+	add	dst, dst, tmp2
+	/* There may be less than 63 bytes to go now.  */
+	cmp	count, #63
+	b.le	.Ltail63
+2:
+	sub	dst, dst, #16		/* Pre-bias.  */
+	sub	count, count, #64
+1:
+	stp	A_l, A_l, [dst, #16]
+	stp	A_l, A_l, [dst, #32]
+	stp	A_l, A_l, [dst, #48]
+	stp	A_l, A_l, [dst, #64]!
+	subs	count, count, #64
+	b.ge	1b
+	tst	count, #0x3f
+	add	dst, dst, #16
+	b.ne	.Ltail63
+	ret
+
+#ifndef DONT_USE_DC
+	/* For zeroing memory, check to see if we can use the ZVA feature to
+	 * zero entire 'cache' lines.  */
+.Lzero_mem:
+	mov	A_l, #0
+	cmp	count, #63
+	b.le	.Ltail_maybe_tiny
+	neg	tmp2, dst
+	ands	tmp2, tmp2, #15
+	b.eq	1f
+	sub	count, count, tmp2
+	stp	A_l, A_l, [dst]
+	add	dst, dst, tmp2
+	cmp	count, #63
+	b.le	.Ltail63
+1:
+	/* For zeroing small amounts of memory, it's not worth setting up
+	 * the line-clear code.  */
+	cmp	count, #128
+	b.lt	.Lnot_short
+#ifdef MAYBE_VIRT
+	/* For efficiency when virtualized, we cache the ZVA capability.  */
+	adrp	tmp2, .Lcache_clear
+	ldr	zva_len, [tmp2, #:lo12:.Lcache_clear]
+	tbnz	zva_len, #31, .Lnot_short
+	cbnz	zva_len, .Lzero_by_line
+	mrs	tmp1, dczid_el0
+	tbz	tmp1, #4, 1f
+	/* ZVA not available.  Remember this for next time.  */
+	mov	zva_len, #~0
+	str	zva_len, [tmp2, #:lo12:.Lcache_clear]
+	b	.Lnot_short
+1:
+	mov	tmp3w, #4
+	and	zva_len, tmp1w, #15	/* Safety: other bits reserved.  */
+	lsl	zva_len, tmp3w, zva_len
+	str	zva_len, [tmp2, #:lo12:.Lcache_clear]
+#else
+	mrs	tmp1, dczid_el0
+	tbnz	tmp1, #4, .Lnot_short
+	mov	tmp3w, #4
+	and	zva_len, tmp1w, #15	/* Safety: other bits reserved.  */
+	lsl	zva_len, tmp3w, zva_len
+#endif
+
+.Lzero_by_line:
+	/* Compute how far we need to go to become suitably aligned.  We're
+	 * already at quad-word alignment.  */
+	cmp	count, zva_len_x
+	b.lt	.Lnot_short		/* Not enough to reach alignment.  */
+	sub	zva_bits_x, zva_len_x, #1
+	neg	tmp2, dst
+	ands	tmp2, tmp2, zva_bits_x
+	b.eq	1f			/* Already aligned.  */
+	/* Not aligned, check that there's enough to copy after alignment.  */
+	sub	tmp1, count, tmp2
+	cmp	tmp1, #64
+	ccmp	tmp1, zva_len_x, #8, ge	/* NZCV=0b1000 */
+	b.lt	.Lnot_short
+	/* We know that there's at least 64 bytes to zero and that it's safe
+	 * to overrun by 64 bytes.  */
+	mov	count, tmp1
+2:
+	stp	A_l, A_l, [dst]
+	stp	A_l, A_l, [dst, #16]
+	stp	A_l, A_l, [dst, #32]
+	subs	tmp2, tmp2, #64
+	stp	A_l, A_l, [dst, #48]
+	add	dst, dst, #64
+	b.ge	2b
+	/* We've overrun a bit, so adjust dst downwards.  */
+	add	dst, dst, tmp2
+1:
+	sub	count, count, zva_len_x
+3:
+	dc	zva, dst
+	add	dst, dst, zva_len_x
+	subs	count, count, zva_len_x
+	b.ge	3b
+	ands	count, count, zva_bits_x
+	b.ne	.Ltail_maybe_long
+	ret
+#ifdef MAYBE_VIRT
+	.bss
+	.p2align 2
+.Lcache_clear:
+	.space 4
+#endif
+#endif /* DONT_USE_DC */
+END(memset)
diff --git a/sys/conf/files.arm64 b/sys/conf/files.arm64
index 963ee0aef8f0..221ec6d0e409 100644
--- a/sys/conf/files.arm64
+++ b/sys/conf/files.arm64
@@ -10,8 +10,6 @@ kern/subr_devmap.c				standard
 kern/subr_intr.c				optional intrng
 kern/subr_physmem.c				standard
 libkern/bcmp.c					standard
-libkern/memset.c				standard	\
-	compile-with "${NORMAL_C:N-fsanitize*}"
 libkern/strlen.c		standard
 libkern/arm64/crc32c_armv8.S			standard
 
@@ -60,6 +58,7 @@ arm64/arm64/machdep_boot.c			standard
 arm64/arm64/mem.c				standard
 arm64/arm64/memcmp.S				standard
 arm64/arm64/memcpy.S				standard
+arm64/arm64/memset.S				standard
 arm64/arm64/minidump_machdep.c			standard
 arm64/arm64/mp_machdep.c			optional smp
 arm64/arm64/nexus.c				standard