From: Matteo Croce <[email protected]>
Replace the assembly mem{cpy,move,set} with C equivalent.
Try to access RAM with the largest bit width possible, but without
doing unaligned accesses.
Tested on a BeagleV Starlight with a SiFive U74 core, where the
improvement is noticeable.
v1 -> v2:
- reduce the threshold from 64 to 16 bytes
- fix KASAN build
- optimize memset
Matteo Croce (3):
riscv: optimized memcpy
riscv: optimized memmove
riscv: optimized memset
arch/riscv/include/asm/string.h | 18 ++--
arch/riscv/kernel/Makefile | 1 -
arch/riscv/kernel/riscv_ksyms.c | 17 ----
arch/riscv/lib/Makefile | 4 +-
arch/riscv/lib/memcpy.S | 108 ---------------------
arch/riscv/lib/memmove.S | 64 -------------
arch/riscv/lib/memset.S | 113 ----------------------
arch/riscv/lib/string.c | 162 ++++++++++++++++++++++++++++++++
8 files changed, 172 insertions(+), 315 deletions(-)
delete mode 100644 arch/riscv/kernel/riscv_ksyms.c
delete mode 100644 arch/riscv/lib/memcpy.S
delete mode 100644 arch/riscv/lib/memmove.S
delete mode 100644 arch/riscv/lib/memset.S
create mode 100644 arch/riscv/lib/string.c
--
2.31.1
From: Matteo Croce <[email protected]>
Write a C version of memcpy() which uses the biggest data size allowed,
without generating unaligned accesses.
The procedure is made of three steps:
First copy data one byte at time until the destination buffer is aligned
to a long boundary.
Then copy the data one long at time shifting the current and the next u8
to compose a long at every cycle.
Finally, copy the remainder one byte at time.
On a BeagleV, the TCP RX throughput increased by 45%:
before:
$ iperf3 -c beaglev
Connecting to host beaglev, port 5201
[ 5] local 192.168.85.6 port 44840 connected to 192.168.85.48 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 76.4 MBytes 641 Mbits/sec 27 624 KBytes
[ 5] 1.00-2.00 sec 72.5 MBytes 608 Mbits/sec 0 708 KBytes
[ 5] 2.00-3.00 sec 73.8 MBytes 619 Mbits/sec 10 451 KBytes
[ 5] 3.00-4.00 sec 72.5 MBytes 608 Mbits/sec 0 564 KBytes
[ 5] 4.00-5.00 sec 73.8 MBytes 619 Mbits/sec 0 658 KBytes
[ 5] 5.00-6.00 sec 73.8 MBytes 619 Mbits/sec 14 522 KBytes
[ 5] 6.00-7.00 sec 73.8 MBytes 619 Mbits/sec 0 621 KBytes
[ 5] 7.00-8.00 sec 72.5 MBytes 608 Mbits/sec 0 706 KBytes
[ 5] 8.00-9.00 sec 73.8 MBytes 619 Mbits/sec 20 580 KBytes
[ 5] 9.00-10.00 sec 73.8 MBytes 619 Mbits/sec 0 672 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 736 MBytes 618 Mbits/sec 71 sender
[ 5] 0.00-10.01 sec 733 MBytes 615 Mbits/sec receiver
after:
$ iperf3 -c beaglev
Connecting to host beaglev, port 5201
[ 5] local 192.168.85.6 port 44864 connected to 192.168.85.48 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 109 MBytes 912 Mbits/sec 48 559 KBytes
[ 5] 1.00-2.00 sec 108 MBytes 902 Mbits/sec 0 690 KBytes
[ 5] 2.00-3.00 sec 106 MBytes 891 Mbits/sec 36 396 KBytes
[ 5] 3.00-4.00 sec 108 MBytes 902 Mbits/sec 0 567 KBytes
[ 5] 4.00-5.00 sec 106 MBytes 891 Mbits/sec 0 699 KBytes
[ 5] 5.00-6.00 sec 106 MBytes 891 Mbits/sec 32 414 KBytes
[ 5] 6.00-7.00 sec 106 MBytes 891 Mbits/sec 0 583 KBytes
[ 5] 7.00-8.00 sec 106 MBytes 891 Mbits/sec 0 708 KBytes
[ 5] 8.00-9.00 sec 106 MBytes 891 Mbits/sec 28 433 KBytes
[ 5] 9.00-10.00 sec 108 MBytes 902 Mbits/sec 0 591 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 1.04 GBytes 897 Mbits/sec 144 sender
[ 5] 0.00-10.01 sec 1.04 GBytes 894 Mbits/sec receiver
And the decreased CPU time of the memcpy() is observable with perf top.
This is the `perf top -Ue task-clock` output when doing the test:
before:
Overhead Shared O Symbol
42.22% [kernel] [k] memcpy
35.00% [kernel] [k] __asm_copy_to_user
3.50% [kernel] [k] sifive_l2_flush64_range
2.30% [kernel] [k] stmmac_napi_poll_rx
1.11% [kernel] [k] memset
after:
Overhead Shared O Symbol
45.69% [kernel] [k] __asm_copy_to_user
29.06% [kernel] [k] memcpy
4.09% [kernel] [k] sifive_l2_flush64_range
2.77% [kernel] [k] stmmac_napi_poll_rx
1.24% [kernel] [k] memset
Signed-off-by: Matteo Croce <[email protected]>
---
arch/riscv/include/asm/string.h | 8 ++-
arch/riscv/kernel/riscv_ksyms.c | 2 -
arch/riscv/lib/Makefile | 2 +-
arch/riscv/lib/memcpy.S | 108 --------------------------------
arch/riscv/lib/string.c | 94 +++++++++++++++++++++++++++
5 files changed, 101 insertions(+), 113 deletions(-)
delete mode 100644 arch/riscv/lib/memcpy.S
create mode 100644 arch/riscv/lib/string.c
diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h
index 909049366555..6b5d6fc3eab4 100644
--- a/arch/riscv/include/asm/string.h
+++ b/arch/riscv/include/asm/string.h
@@ -12,9 +12,13 @@
#define __HAVE_ARCH_MEMSET
extern asmlinkage void *memset(void *, int, size_t);
extern asmlinkage void *__memset(void *, int, size_t);
+
+#ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
#define __HAVE_ARCH_MEMCPY
-extern asmlinkage void *memcpy(void *, const void *, size_t);
-extern asmlinkage void *__memcpy(void *, const void *, size_t);
+extern void *memcpy(void *dest, const void *src, size_t count);
+extern void *__memcpy(void *dest, const void *src, size_t count);
+#endif
+
#define __HAVE_ARCH_MEMMOVE
extern asmlinkage void *memmove(void *, const void *, size_t);
extern asmlinkage void *__memmove(void *, const void *, size_t);
diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c
index 5ab1c7e1a6ed..3f6d512a5b97 100644
--- a/arch/riscv/kernel/riscv_ksyms.c
+++ b/arch/riscv/kernel/riscv_ksyms.c
@@ -10,8 +10,6 @@
* Assembly functions that may be used (directly or indirectly) by modules
*/
EXPORT_SYMBOL(memset);
-EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memmove);
EXPORT_SYMBOL(__memset);
-EXPORT_SYMBOL(__memcpy);
EXPORT_SYMBOL(__memmove);
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 25d5c9664e57..2ffe85d4baee 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -1,9 +1,9 @@
# SPDX-License-Identifier: GPL-2.0-only
lib-y += delay.o
-lib-y += memcpy.o
lib-y += memset.o
lib-y += memmove.o
lib-$(CONFIG_MMU) += uaccess.o
lib-$(CONFIG_64BIT) += tishift.o
+lib-$(CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE) += string.o
obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
diff --git a/arch/riscv/lib/memcpy.S b/arch/riscv/lib/memcpy.S
deleted file mode 100644
index 51ab716253fa..000000000000
--- a/arch/riscv/lib/memcpy.S
+++ /dev/null
@@ -1,108 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2013 Regents of the University of California
- */
-
-#include <linux/linkage.h>
-#include <asm/asm.h>
-
-/* void *memcpy(void *, const void *, size_t) */
-ENTRY(__memcpy)
-WEAK(memcpy)
- move t6, a0 /* Preserve return value */
-
- /* Defer to byte-oriented copy for small sizes */
- sltiu a3, a2, 128
- bnez a3, 4f
- /* Use word-oriented copy only if low-order bits match */
- andi a3, t6, SZREG-1
- andi a4, a1, SZREG-1
- bne a3, a4, 4f
-
- beqz a3, 2f /* Skip if already aligned */
- /*
- * Round to nearest double word-aligned address
- * greater than or equal to start address
- */
- andi a3, a1, ~(SZREG-1)
- addi a3, a3, SZREG
- /* Handle initial misalignment */
- sub a4, a3, a1
-1:
- lb a5, 0(a1)
- addi a1, a1, 1
- sb a5, 0(t6)
- addi t6, t6, 1
- bltu a1, a3, 1b
- sub a2, a2, a4 /* Update count */
-
-2:
- andi a4, a2, ~((16*SZREG)-1)
- beqz a4, 4f
- add a3, a1, a4
-3:
- REG_L a4, 0(a1)
- REG_L a5, SZREG(a1)
- REG_L a6, 2*SZREG(a1)
- REG_L a7, 3*SZREG(a1)
- REG_L t0, 4*SZREG(a1)
- REG_L t1, 5*SZREG(a1)
- REG_L t2, 6*SZREG(a1)
- REG_L t3, 7*SZREG(a1)
- REG_L t4, 8*SZREG(a1)
- REG_L t5, 9*SZREG(a1)
- REG_S a4, 0(t6)
- REG_S a5, SZREG(t6)
- REG_S a6, 2*SZREG(t6)
- REG_S a7, 3*SZREG(t6)
- REG_S t0, 4*SZREG(t6)
- REG_S t1, 5*SZREG(t6)
- REG_S t2, 6*SZREG(t6)
- REG_S t3, 7*SZREG(t6)
- REG_S t4, 8*SZREG(t6)
- REG_S t5, 9*SZREG(t6)
- REG_L a4, 10*SZREG(a1)
- REG_L a5, 11*SZREG(a1)
- REG_L a6, 12*SZREG(a1)
- REG_L a7, 13*SZREG(a1)
- REG_L t0, 14*SZREG(a1)
- REG_L t1, 15*SZREG(a1)
- addi a1, a1, 16*SZREG
- REG_S a4, 10*SZREG(t6)
- REG_S a5, 11*SZREG(t6)
- REG_S a6, 12*SZREG(t6)
- REG_S a7, 13*SZREG(t6)
- REG_S t0, 14*SZREG(t6)
- REG_S t1, 15*SZREG(t6)
- addi t6, t6, 16*SZREG
- bltu a1, a3, 3b
- andi a2, a2, (16*SZREG)-1 /* Update count */
-
-4:
- /* Handle trailing misalignment */
- beqz a2, 6f
- add a3, a1, a2
-
- /* Use word-oriented copy if co-aligned to word boundary */
- or a5, a1, t6
- or a5, a5, a3
- andi a5, a5, 3
- bnez a5, 5f
-7:
- lw a4, 0(a1)
- addi a1, a1, 4
- sw a4, 0(t6)
- addi t6, t6, 4
- bltu a1, a3, 7b
-
- ret
-
-5:
- lb a4, 0(a1)
- addi a1, a1, 1
- sb a4, 0(t6)
- addi t6, t6, 1
- bltu a1, a3, 5b
-6:
- ret
-END(__memcpy)
diff --git a/arch/riscv/lib/string.c b/arch/riscv/lib/string.c
new file mode 100644
index 000000000000..694352d21c21
--- /dev/null
+++ b/arch/riscv/lib/string.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * String functions optimized for hardware which doesn't
+ * handle unaligned memory accesses efficiently.
+ *
+ * Copyright (C) 2021 Matteo Croce
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+
+/* Minimum size for a word copy to be convenient */
+#define MIN_THRESHOLD (BITS_PER_LONG / 8 * 2)
+
+/* convenience union to avoid cast between different pointer types */
+union types {
+ u8 *u8;
+ unsigned long *ulong;
+ uintptr_t uptr;
+};
+
+union const_types {
+ const u8 *u8;
+ unsigned long *ulong;
+};
+
+void __weak *memcpy(void *dest, const void *src, size_t count)
+{
+ const int bytes_long = BITS_PER_LONG / 8;
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+ const int mask = bytes_long - 1;
+ const int distance = (src - dest) & mask;
+#endif
+ union const_types s = { .u8 = src };
+ union types d = { .u8 = dest };
+
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+ if (count < MIN_THRESHOLD)
+ goto copy_remainder;
+
+ /* copy a byte at time until destination is aligned */
+ for (; count && d.uptr & mask; count--)
+ *d.u8++ = *s.u8++;
+
+ if (distance) {
+ unsigned long last, next;
+
+ /* move s backward to the previous alignment boundary */
+ s.u8 -= distance;
+
+ /* 32/64 bit wide copy from s to d.
+ * d is aligned now but s is not, so read s alignment wise,
+ * and do proper shift to get the right value.
+ * Works only on Little Endian machines.
+ */
+ for (next = s.ulong[0]; count >= bytes_long + mask; count -= bytes_long) {
+ last = next;
+ next = s.ulong[1];
+
+ d.ulong[0] = last >> (distance * 8) |
+ next << ((bytes_long - distance) * 8);
+
+ d.ulong++;
+ s.ulong++;
+ }
+
+ /* restore s with the original offset */
+ s.u8 += distance;
+ } else
+#endif
+ {
+ /* if the source and dest lower bits are the same, do a simple
+ * 32/64 bit wide copy.
+ */
+ for (; count >= bytes_long; count -= bytes_long)
+ *d.ulong++ = *s.ulong++;
+ }
+
+ /* suppress warning when CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y */
+ goto copy_remainder;
+
+copy_remainder:
+ while (count--)
+ *d.u8++ = *s.u8++;
+
+ return dest;
+}
+EXPORT_SYMBOL(memcpy);
+
+void *__memcpy(void *dest, const void *src, size_t count)
+{
+ return memcpy(dest, src, count);
+}
+EXPORT_SYMBOL(__memcpy);
--
2.31.1
From: Matteo Croce <[email protected]>
The generic memset is defined as a byte at time write. This is always
safe, but it's slower than a 4 byte or even 8 byte write.
Write a generic memset which fills the data one byte at time until the
destination is aligned, then fills using the largest size allowed,
and finally fills the remaining data one byte at time.
Signed-off-by: Matteo Croce <[email protected]>
---
arch/riscv/include/asm/string.h | 10 +--
arch/riscv/kernel/Makefile | 1 -
arch/riscv/kernel/riscv_ksyms.c | 13 ----
arch/riscv/lib/Makefile | 1 -
arch/riscv/lib/memset.S | 113 --------------------------------
arch/riscv/lib/string.c | 42 ++++++++++++
6 files changed, 45 insertions(+), 135 deletions(-)
delete mode 100644 arch/riscv/kernel/riscv_ksyms.c
delete mode 100644 arch/riscv/lib/memset.S
diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h
index 25d9b9078569..90500635035a 100644
--- a/arch/riscv/include/asm/string.h
+++ b/arch/riscv/include/asm/string.h
@@ -6,14 +6,10 @@
#ifndef _ASM_RISCV_STRING_H
#define _ASM_RISCV_STRING_H
-#include <linux/types.h>
-#include <linux/linkage.h>
-
-#define __HAVE_ARCH_MEMSET
-extern asmlinkage void *memset(void *, int, size_t);
-extern asmlinkage void *__memset(void *, int, size_t);
-
#ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
+#define __HAVE_ARCH_MEMSET
+extern void *memset(void *s, int c, size_t count);
+extern void *__memset(void *s, int c, size_t count);
#define __HAVE_ARCH_MEMCPY
extern void *memcpy(void *dest, const void *src, size_t count);
extern void *__memcpy(void *dest, const void *src, size_t count);
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index d3081e4d9600..e635ce1e5645 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -31,7 +31,6 @@ obj-y += syscall_table.o
obj-y += sys_riscv.o
obj-y += time.o
obj-y += traps.o
-obj-y += riscv_ksyms.o
obj-y += stacktrace.o
obj-y += cacheinfo.o
obj-y += patch.o
diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c
deleted file mode 100644
index 361565c4db7e..000000000000
--- a/arch/riscv/kernel/riscv_ksyms.c
+++ /dev/null
@@ -1,13 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright (C) 2017 Zihao Yu
- */
-
-#include <linux/export.h>
-#include <linux/uaccess.h>
-
-/*
- * Assembly functions that may be used (directly or indirectly) by modules
- */
-EXPORT_SYMBOL(memset);
-EXPORT_SYMBOL(__memset);
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 484f5ff7b508..e33263cc622a 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -1,6 +1,5 @@
# SPDX-License-Identifier: GPL-2.0-only
lib-y += delay.o
-lib-y += memset.o
lib-$(CONFIG_MMU) += uaccess.o
lib-$(CONFIG_64BIT) += tishift.o
lib-$(CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE) += string.o
diff --git a/arch/riscv/lib/memset.S b/arch/riscv/lib/memset.S
deleted file mode 100644
index 34c5360c6705..000000000000
--- a/arch/riscv/lib/memset.S
+++ /dev/null
@@ -1,113 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2013 Regents of the University of California
- */
-
-
-#include <linux/linkage.h>
-#include <asm/asm.h>
-
-/* void *memset(void *, int, size_t) */
-ENTRY(__memset)
-WEAK(memset)
- move t0, a0 /* Preserve return value */
-
- /* Defer to byte-oriented fill for small sizes */
- sltiu a3, a2, 16
- bnez a3, 4f
-
- /*
- * Round to nearest XLEN-aligned address
- * greater than or equal to start address
- */
- addi a3, t0, SZREG-1
- andi a3, a3, ~(SZREG-1)
- beq a3, t0, 2f /* Skip if already aligned */
- /* Handle initial misalignment */
- sub a4, a3, t0
-1:
- sb a1, 0(t0)
- addi t0, t0, 1
- bltu t0, a3, 1b
- sub a2, a2, a4 /* Update count */
-
-2: /* Duff's device with 32 XLEN stores per iteration */
- /* Broadcast value into all bytes */
- andi a1, a1, 0xff
- slli a3, a1, 8
- or a1, a3, a1
- slli a3, a1, 16
- or a1, a3, a1
-#ifdef CONFIG_64BIT
- slli a3, a1, 32
- or a1, a3, a1
-#endif
-
- /* Calculate end address */
- andi a4, a2, ~(SZREG-1)
- add a3, t0, a4
-
- andi a4, a4, 31*SZREG /* Calculate remainder */
- beqz a4, 3f /* Shortcut if no remainder */
- neg a4, a4
- addi a4, a4, 32*SZREG /* Calculate initial offset */
-
- /* Adjust start address with offset */
- sub t0, t0, a4
-
- /* Jump into loop body */
- /* Assumes 32-bit instruction lengths */
- la a5, 3f
-#ifdef CONFIG_64BIT
- srli a4, a4, 1
-#endif
- add a5, a5, a4
- jr a5
-3:
- REG_S a1, 0(t0)
- REG_S a1, SZREG(t0)
- REG_S a1, 2*SZREG(t0)
- REG_S a1, 3*SZREG(t0)
- REG_S a1, 4*SZREG(t0)
- REG_S a1, 5*SZREG(t0)
- REG_S a1, 6*SZREG(t0)
- REG_S a1, 7*SZREG(t0)
- REG_S a1, 8*SZREG(t0)
- REG_S a1, 9*SZREG(t0)
- REG_S a1, 10*SZREG(t0)
- REG_S a1, 11*SZREG(t0)
- REG_S a1, 12*SZREG(t0)
- REG_S a1, 13*SZREG(t0)
- REG_S a1, 14*SZREG(t0)
- REG_S a1, 15*SZREG(t0)
- REG_S a1, 16*SZREG(t0)
- REG_S a1, 17*SZREG(t0)
- REG_S a1, 18*SZREG(t0)
- REG_S a1, 19*SZREG(t0)
- REG_S a1, 20*SZREG(t0)
- REG_S a1, 21*SZREG(t0)
- REG_S a1, 22*SZREG(t0)
- REG_S a1, 23*SZREG(t0)
- REG_S a1, 24*SZREG(t0)
- REG_S a1, 25*SZREG(t0)
- REG_S a1, 26*SZREG(t0)
- REG_S a1, 27*SZREG(t0)
- REG_S a1, 28*SZREG(t0)
- REG_S a1, 29*SZREG(t0)
- REG_S a1, 30*SZREG(t0)
- REG_S a1, 31*SZREG(t0)
- addi t0, t0, 32*SZREG
- bltu t0, a3, 3b
- andi a2, a2, SZREG-1 /* Update count */
-
-4:
- /* Handle trailing misalignment */
- beqz a2, 6f
- add a3, t0, a2
-5:
- sb a1, 0(t0)
- addi t0, t0, 1
- bltu t0, a3, 5b
-6:
- ret
-END(__memset)
diff --git a/arch/riscv/lib/string.c b/arch/riscv/lib/string.c
index c932401e365b..3f243a9f6f6c 100644
--- a/arch/riscv/lib/string.c
+++ b/arch/riscv/lib/string.c
@@ -118,3 +118,45 @@ void *__memmove(void *dest, const void *src, size_t count)
return memmove(dest, src, count);
}
EXPORT_SYMBOL(__memmove);
+
+void __weak *memset(void *s, int c, size_t count)
+{
+ union types dest = { .u8 = s };
+
+ if (count >= MIN_THRESHOLD) {
+ const int bytes_long = BITS_PER_LONG / 8;
+ unsigned long cu = (unsigned long)c;
+
+ /* Compose an ulong with 'c' repeated 4/8 times */
+ cu |= cu << 8;
+ cu |= cu << 16;
+#if BITS_PER_LONG == 64
+ cu |= cu << 32;
+#endif
+
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+ /* Fill the buffer one byte at time until the destination
+ * is aligned on a 32/64 bit boundary.
+ */
+ for (; count && dest.uptr % bytes_long; count--)
+ *dest.u8++ = c;
+#endif
+
+ /* Copy using the largest size allowed */
+ for (; count >= bytes_long; count -= bytes_long)
+ *dest.ulong++ = cu;
+ }
+
+ /* copy the remainder */
+ while (count--)
+ *dest.u8++ = c;
+
+ return s;
+}
+EXPORT_SYMBOL(memset);
+
+void *__memset(void *s, int c, size_t count)
+{
+ return memset(s, c, count);
+}
+EXPORT_SYMBOL(__memset);
--
2.31.1