0061-AArch64-Remove-Falkor-memcpy.patch

From a08ff922946dca0303a270bbfa2557f74caa47aa Mon Sep 17 00:00:00 2001
From: Wilco Dijkstra <wilco.dijkstra@arm.com>
Date: Thu, 26 Oct 2023 17:30:36 +0100
Subject: [PATCH] AArch64: Remove Falkor memcpy

The latest implementations of memcpy are actually faster than the Falkor
implementations [1], so remove the falkor/phecda ifuncs for memcpy and
the now unused IS_FALKOR/IS_PHECDA defines.

[1] https://sourceware.org/pipermail/libc-alpha/2022-December/144227.html

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit 2f5524cc5381eb75fef55f7901bb907bd5628333)
---
 manual/tunables.texi                          |   2 +-
 sysdeps/aarch64/multiarch/Makefile            |   1 -
 sysdeps/aarch64/multiarch/ifunc-impl-list.c   |   2 -
 sysdeps/aarch64/multiarch/memcpy.c            |   4 -
 sysdeps/aarch64/multiarch/memcpy_falkor.S     | 313 ------------------
 sysdeps/aarch64/multiarch/memmove.c           |   4 -
 .../unix/sysv/linux/aarch64/cpu-features.c    |   2 -
 .../unix/sysv/linux/aarch64/cpu-features.h    |   5 -
 8 files changed, 1 insertion(+), 332 deletions(-)
 delete mode 100644 sysdeps/aarch64/multiarch/memcpy_falkor.S

diff --git a/manual/tunables.texi b/manual/tunables.texi
index 4ca0e42a11..bb17fef5bd 100644
--- a/manual/tunables.texi
+++ b/manual/tunables.texi
@@ -529,7 +529,7 @@ This tunable is specific to powerpc, powerpc64 and powerpc64le.
 @deftp Tunable glibc.cpu.name
 The @code{glibc.cpu.name=xxx} tunable allows the user to tell @theglibc{} to
 assume that the CPU is @code{xxx} where xxx may have one of these values:
-@code{generic}, @code{falkor}, @code{thunderxt88}, @code{thunderx2t99},
+@code{generic}, @code{thunderxt88}, @code{thunderx2t99},
 @code{thunderx2t99p1}, @code{ares}, @code{emag}, @code{kunpeng},
 @code{a64fx}.
 
diff --git a/sysdeps/aarch64/multiarch/Makefile b/sysdeps/aarch64/multiarch/Makefile
index 171ca5e4cf..e4720b7468 100644
--- a/sysdeps/aarch64/multiarch/Makefile
+++ b/sysdeps/aarch64/multiarch/Makefile
@@ -3,7 +3,6 @@ sysdep_routines += \
   memchr_generic \
   memchr_nosimd \
   memcpy_a64fx \
-  memcpy_falkor \
   memcpy_generic \
   memcpy_mops \
   memcpy_sve \
diff --git a/sysdeps/aarch64/multiarch/ifunc-impl-list.c b/sysdeps/aarch64/multiarch/ifunc-impl-list.c
index fdd9ea9246..73038ac810 100644
--- a/sysdeps/aarch64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/aarch64/multiarch/ifunc-impl-list.c
@@ -36,7 +36,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   IFUNC_IMPL (i, name, memcpy,
 	      IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_thunderx)
 	      IFUNC_IMPL_ADD (array, i, memcpy, !bti, __memcpy_thunderx2)
-	      IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_falkor)
 #if HAVE_AARCH64_SVE_ASM
 	      IFUNC_IMPL_ADD (array, i, memcpy, sve, __memcpy_a64fx)
 	      IFUNC_IMPL_ADD (array, i, memcpy, sve, __memcpy_sve)
@@ -46,7 +45,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
   IFUNC_IMPL (i, name, memmove,
 	      IFUNC_IMPL_ADD (array, i, memmove, 1, __memmove_thunderx)
 	      IFUNC_IMPL_ADD (array, i, memmove, !bti, __memmove_thunderx2)
-	      IFUNC_IMPL_ADD (array, i, memmove, 1, __memmove_falkor)
 #if HAVE_AARCH64_SVE_ASM
 	      IFUNC_IMPL_ADD (array, i, memmove, sve, __memmove_a64fx)
 	      IFUNC_IMPL_ADD (array, i, memmove, sve, __memmove_sve)
diff --git a/sysdeps/aarch64/multiarch/memcpy.c b/sysdeps/aarch64/multiarch/memcpy.c
index 9aace954cb..6471fe82e3 100644
--- a/sysdeps/aarch64/multiarch/memcpy.c
+++ b/sysdeps/aarch64/multiarch/memcpy.c
@@ -31,7 +31,6 @@ extern __typeof (__redirect_memcpy) __libc_memcpy;
 extern __typeof (__redirect_memcpy) __memcpy_generic attribute_hidden;
 extern __typeof (__redirect_memcpy) __memcpy_thunderx attribute_hidden;
 extern __typeof (__redirect_memcpy) __memcpy_thunderx2 attribute_hidden;
-extern __typeof (__redirect_memcpy) __memcpy_falkor attribute_hidden;
 extern __typeof (__redirect_memcpy) __memcpy_a64fx attribute_hidden;
 extern __typeof (__redirect_memcpy) __memcpy_sve attribute_hidden;
 extern __typeof (__redirect_memcpy) __memcpy_mops attribute_hidden;
@@ -57,9 +56,6 @@ select_memcpy_ifunc (void)
   if (IS_THUNDERX2 (midr) || IS_THUNDERX2PA (midr))
     return __memcpy_thunderx2;
 
-  if (IS_FALKOR (midr) || IS_PHECDA (midr))
-    return __memcpy_falkor;
-
   return __memcpy_generic;
 }
 
diff --git a/sysdeps/aarch64/multiarch/memcpy_falkor.S b/sysdeps/aarch64/multiarch/memcpy_falkor.S
deleted file mode 100644
index 67c4ab34eb..0000000000
--- a/sysdeps/aarch64/multiarch/memcpy_falkor.S
+++ /dev/null
@@ -1,313 +0,0 @@
-/* Optimized memcpy for Qualcomm Falkor processor.
-   Copyright (C) 2017-2023 Free Software Foundation, Inc.
-
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library.  If not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#include <sysdep.h>
-
-/* Assumptions:
-
-   ARMv8-a, AArch64, falkor, unaligned accesses.  */
-
-#define dstin	x0
-#define src	x1
-#define count	x2
-#define dst	x3
-#define srcend	x4
-#define dstend	x5
-#define tmp1	x14
-#define A_x	x6
-#define B_x	x7
-#define A_w	w6
-#define B_w	w7
-
-#define A_q	q0
-#define B_q	q1
-#define C_q	q2
-#define D_q	q3
-#define E_q	q4
-#define F_q	q5
-#define G_q	q6
-#define H_q	q7
-#define Q_q	q6
-#define S_q	q22
-
-/* Copies are split into 3 main cases:
-
-   1. Small copies of up to 32 bytes
-   2. Medium copies of 33..128 bytes which are fully unrolled
-   3. Large copies of more than 128 bytes.
-
-   Large copies align the source to a quad word and use an unrolled loop
-   processing 64 bytes per iteration.
-
-   FALKOR-SPECIFIC DESIGN:
-
-   The smallest copies (32 bytes or less) focus on optimal pipeline usage,
-   which is why the redundant copies of 0-3 bytes have been replaced with
-   conditionals, since the former would unnecessarily break across multiple
-   issue groups.  The medium copy group has been enlarged to 128 bytes since
-   bumping up the small copies up to 32 bytes allows us to do that without
-   cost and also allows us to reduce the size of the prep code before loop64.
-
-   The copy loop uses only one register q0.  This is to ensure that all loads
-   hit a single hardware prefetcher which can get correctly trained to prefetch
-   a single stream.
-
-   The non-temporal stores help optimize cache utilization.  */
-
-#if IS_IN (libc)
-ENTRY (__memcpy_falkor)
-
-	PTR_ARG (0)
-	PTR_ARG (1)
-	SIZE_ARG (2)
-
-	cmp	count, 32
-	add	srcend, src, count
-	add	dstend, dstin, count
-	b.ls	L(copy32)
-	cmp	count, 128
-	b.hi	L(copy_long)
-
-	/* Medium copies: 33..128 bytes.  */
-L(copy128):
-	sub	tmp1, count, 1
-	ldr	A_q, [src]
-	ldr	B_q, [src, 16]
-	ldr	C_q, [srcend, -32]
-	ldr	D_q, [srcend, -16]
-	tbz	tmp1, 6, 1f
-	ldr	E_q, [src, 32]
-	ldr	F_q, [src, 48]
-	ldr	G_q, [srcend, -64]
-	ldr	H_q, [srcend, -48]
-	str	G_q, [dstend, -64]
-	str	H_q, [dstend, -48]
-	str	E_q, [dstin, 32]
-	str	F_q, [dstin, 48]
-1:
-	str	A_q, [dstin]
-	str	B_q, [dstin, 16]
-	str	C_q, [dstend, -32]
-	str	D_q, [dstend, -16]
-	ret
-
-	.p2align 4
-	/* Small copies: 0..32 bytes.  */
-L(copy32):
-	/* 16-32 */
-	cmp	count, 16
-	b.lo	1f
-	ldr	A_q, [src]
-	ldr	B_q, [srcend, -16]
-	str	A_q, [dstin]
-	str	B_q, [dstend, -16]
-	ret
-	.p2align 4
-1:
-	/* 8-15 */
-	tbz	count, 3, 1f
-	ldr	A_x, [src]
-	ldr	B_x, [srcend, -8]
-	str	A_x, [dstin]
-	str	B_x, [dstend, -8]
-	ret
-	.p2align 4
-1:
-	/* 4-7 */
-	tbz	count, 2, 1f
-	ldr	A_w, [src]
-	ldr	B_w, [srcend, -4]
-	str	A_w, [dstin]
-	str	B_w, [dstend, -4]
-	ret
-	.p2align 4
-1:
-	/* 2-3 */
-	tbz	count, 1, 1f
-	ldrh	A_w, [src]
-	ldrh	B_w, [srcend, -2]
-	strh	A_w, [dstin]
-	strh	B_w, [dstend, -2]
-	ret
-	.p2align 4
-1:
-	/* 0-1 */
-	tbz	count, 0, 1f
-	ldrb	A_w, [src]
-	strb	A_w, [dstin]
-1:
-	ret
-
-	/* Align SRC to 16 bytes and copy; that way at least one of the
-	   accesses is aligned throughout the copy sequence.
-
-	   The count is off by 0 to 15 bytes, but this is OK because we trim
-	   off the last 64 bytes to copy off from the end.  Due to this the
-	   loop never runs out of bounds.  */
-
-	.p2align 4
-	nop		/* Align loop64 below.  */
-L(copy_long):
-	ldr	A_q, [src]
-	sub	count, count, 64 + 16
-	and	tmp1, src, 15
-	str	A_q, [dstin]
-	bic	src, src, 15
-	sub	dst, dstin, tmp1
-	add	count, count, tmp1
-
-L(loop64):
-	ldr	A_q, [src, 16]!
-	str	A_q, [dst, 16]
-	ldr	A_q, [src, 16]!
-	subs	count, count, 64
-	str	A_q, [dst, 32]
-	ldr	A_q, [src, 16]!
-	str	A_q, [dst, 48]
-	ldr	A_q, [src, 16]!
-	str	A_q, [dst, 64]!
-	b.hi	L(loop64)
-
-	/* Write the last full set of 64 bytes.  The remainder is at most 64
-	   bytes, so it is safe to always copy 64 bytes from the end even if
-	   there is just 1 byte left.  */
-	ldr	E_q, [srcend, -64]
-	str	E_q, [dstend, -64]
-	ldr	D_q, [srcend, -48]
-	str	D_q, [dstend, -48]
-	ldr	C_q, [srcend, -32]
-	str	C_q, [dstend, -32]
-	ldr	B_q, [srcend, -16]
-	str	B_q, [dstend, -16]
-	ret
-
-END (__memcpy_falkor)
-
-
-/* RATIONALE:
-
-   The move has 4 distinct parts:
-   * Small moves of 32 bytes and under.
-   * Medium sized moves of 33-128 bytes (fully unrolled).
-   * Large moves where the source address is higher than the destination
-     (forward copies)
-   * Large moves where the destination address is higher than the source
-     (copy backward, or move).
-
-   We use only two registers q6 and q22 for the moves and move 32 bytes at a
-   time to correctly train the hardware prefetcher for better throughput.
-
-   For small and medium cases memcpy is used.  */
-
-ENTRY (__memmove_falkor)
-
-	PTR_ARG (0)
-	PTR_ARG (1)
-	SIZE_ARG (2)
-
-	cmp	count, 32
-	add	srcend, src, count
-	add	dstend, dstin, count
-	b.ls	L(copy32)
-	cmp	count, 128
-	b.ls	L(copy128)
-	sub	tmp1, dstin, src
-	ccmp	tmp1, count, 2, hi
-	b.lo	L(move_long)
-
-	/* CASE: Copy Forwards
-
-	   Align src to 16 byte alignment so that we don't cross cache line
-	   boundaries on both loads and stores.  There are at least 128 bytes
-	   to copy, so copy 16 bytes unaligned and then align.  The loop
-	   copies 32 bytes per iteration and prefetches one iteration ahead.  */
-
-	ldr	S_q, [src]
-	and	tmp1, src, 15
-	bic	src, src, 15
-	sub	dst, dstin, tmp1
-	add	count, count, tmp1	/* Count is now 16 too large.  */
-	ldr	Q_q, [src, 16]!
-	str	S_q, [dstin]
-	ldr	S_q, [src, 16]!
-	sub	count, count, 32 + 32 + 16	/* Test and readjust count.  */
-
-	.p2align 4
-1:
-	subs	count, count, 32
-	str	Q_q, [dst, 16]
-	ldr	Q_q, [src, 16]!
-	str	S_q, [dst, 32]!
-	ldr	S_q, [src, 16]!
-	b.hi	1b
-
-	/* Copy 32 bytes from the end before writing the data prefetched in the
-	   last loop iteration.  */
-2:
-	ldr	B_q, [srcend, -32]
-	ldr	C_q, [srcend, -16]
-	str	Q_q, [dst, 16]
-	str	S_q, [dst, 32]
-	str	B_q, [dstend, -32]
-	str	C_q, [dstend, -16]
-	ret
-
-	/* CASE: Copy Backwards
-
-	   Align srcend to 16 byte alignment so that we don't cross cache line
-	   boundaries on both loads and stores.  There are at least 128 bytes
-	   to copy, so copy 16 bytes unaligned and then align.  The loop
-	   copies 32 bytes per iteration and prefetches one iteration ahead.  */
-
-	.p2align 4
-	nop
-	nop
-L(move_long):
-	cbz	tmp1, 3f  /* Return early if src == dstin */
-	ldr	S_q, [srcend, -16]
-	and	tmp1, srcend, 15
-	sub	srcend, srcend, tmp1
-	ldr	Q_q, [srcend, -16]!
-	str	S_q, [dstend, -16]
-	sub	count, count, tmp1
-	ldr	S_q, [srcend, -16]!
-	sub	dstend, dstend, tmp1
-	sub	count, count, 32 + 32
-
-1:
-	subs	count, count, 32
-	str	Q_q, [dstend, -16]
-	ldr	Q_q, [srcend, -16]!
-	str	S_q, [dstend, -32]!
-	ldr	S_q, [srcend, -16]!
-	b.hi	1b
-
-	/* Copy 32 bytes from the start before writing the data prefetched in the
-	   last loop iteration.  */
-
-	ldr	B_q, [src, 16]
-	ldr	C_q, [src]
-	str	Q_q, [dstend, -16]
-	str	S_q, [dstend, -32]
-	str	B_q, [dstin, 16]
-	str	C_q, [dstin]
-3:	ret
-
-END (__memmove_falkor)
-#endif
diff --git a/sysdeps/aarch64/multiarch/memmove.c b/sysdeps/aarch64/multiarch/memmove.c
index fd346e7b73..7602a5d57d 100644
--- a/sysdeps/aarch64/multiarch/memmove.c
+++ b/sysdeps/aarch64/multiarch/memmove.c
@@ -31,7 +31,6 @@ extern __typeof (__redirect_memmove) __libc_memmove;
 extern __typeof (__redirect_memmove) __memmove_generic attribute_hidden;
 extern __typeof (__redirect_memmove) __memmove_thunderx attribute_hidden;
 extern __typeof (__redirect_memmove) __memmove_thunderx2 attribute_hidden;
-extern __typeof (__redirect_memmove) __memmove_falkor attribute_hidden;
 extern __typeof (__redirect_memmove) __memmove_a64fx attribute_hidden;
 extern __typeof (__redirect_memmove) __memmove_sve attribute_hidden;
 extern __typeof (__redirect_memmove) __memmove_mops attribute_hidden;
@@ -57,9 +56,6 @@ select_memmove_ifunc (void)
   if (IS_THUNDERX2 (midr) || IS_THUNDERX2PA (midr))
     return __memmove_thunderx2;
 
-  if (IS_FALKOR (midr) || IS_PHECDA (midr))
-    return __memmove_falkor;
-
   return __memmove_generic;
 }
 
diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
index 233d5b2407..a11a86efab 100644
--- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
+++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
@@ -37,11 +37,9 @@ struct cpu_list
 };
 
 static struct cpu_list cpu_list[] = {
-      {"falkor",	 0x510FC000},
       {"thunderxt88",	 0x430F0A10},
       {"thunderx2t99",   0x431F0AF0},
       {"thunderx2t99p1", 0x420F5160},
-      {"phecda",	 0x680F0000},
       {"ares",		 0x411FD0C0},
       {"emag",		 0x503F0001},
       {"kunpeng920", 	 0x481FD010},
diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.h b/sysdeps/unix/sysv/linux/aarch64/cpu-features.h
index 40b709677d..2cf745cd19 100644
--- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.h
+++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.h
@@ -47,11 +47,6 @@
 #define IS_THUNDERX2(midr) (MIDR_IMPLEMENTOR(midr) == 'C'       \
 			   && MIDR_PARTNUM(midr) == 0xaf)
 
-#define IS_FALKOR(midr) (MIDR_IMPLEMENTOR(midr) == 'Q'			      \
-                        && MIDR_PARTNUM(midr) == 0xc00)
-
-#define IS_PHECDA(midr) (MIDR_IMPLEMENTOR(midr) == 'h'			      \
-                        && MIDR_PARTNUM(midr) == 0x000)
 #define IS_NEOVERSE_N1(midr) (MIDR_IMPLEMENTOR(midr) == 'A'		      \
 			      && MIDR_PARTNUM(midr) == 0xd0c)
 #define IS_NEOVERSE_N2(midr) (MIDR_IMPLEMENTOR(midr) == 'A'		      \
-- 
2.44.0