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Subject[PATCH v3 2/7] ARM: Implement memset16, memset32 & memset64
Date
From: Matthew Wilcox <mawilcox@microsoft.com>

ARM is only 32-bit, so it doesn't really need a memset64, but it was
essentially free to add it to the existing implementation.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Russell King <rmk+kernel@armlinux.org.uk>
---
arch/arm/include/asm/string.h | 21 +++++++++++++++++++++
arch/arm/kernel/armksyms.c | 3 +++
arch/arm/lib/memset.S | 44 ++++++++++++++++++++++++++++++++++---------
3 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/arch/arm/include/asm/string.h b/arch/arm/include/asm/string.h
index cf4f3aad0fc1..bc7a1be7a76a 100644
--- a/arch/arm/include/asm/string.h
+++ b/arch/arm/include/asm/string.h
@@ -24,6 +24,27 @@ extern void * memchr(const void *, int, __kernel_size_t);
#define __HAVE_ARCH_MEMSET
extern void * memset(void *, int, __kernel_size_t);

+#define __HAVE_ARCH_MEMSET16
+extern void *__memset16(uint16_t *, uint16_t v, __kernel_size_t);
+static inline void *memset16(uint16_t *p, uint16_t v, __kernel_size_t n)
+{
+ return __memset16(p, v, n * 2);
+}
+
+#define __HAVE_ARCH_MEMSET32
+extern void *__memset32(uint32_t *, uint32_t v, __kernel_size_t);
+static inline void *memset32(uint32_t *p, uint32_t v, __kernel_size_t n)
+{
+ return __memset32(p, v, n * 4);
+}
+
+#define __HAVE_ARCH_MEMSET64
+extern void *__memset64(uint64_t *, uint32_t low, __kernel_size_t, uint32_t hi);
+static inline void *memset64(uint64_t *p, uint64_t v, __kernel_size_t n)
+{
+ return __memset64(p, v, n * 8, v >> 32);
+}
+
extern void __memzero(void *ptr, __kernel_size_t n);

#define memset(p,v,n) \
diff --git a/arch/arm/kernel/armksyms.c b/arch/arm/kernel/armksyms.c
index 8e8d20cdbce7..633341ed0713 100644
--- a/arch/arm/kernel/armksyms.c
+++ b/arch/arm/kernel/armksyms.c
@@ -87,6 +87,9 @@ EXPORT_SYMBOL(__raw_writesl);
EXPORT_SYMBOL(strchr);
EXPORT_SYMBOL(strrchr);
EXPORT_SYMBOL(memset);
+EXPORT_SYMBOL(__memset16);
+EXPORT_SYMBOL(__memset32);
+EXPORT_SYMBOL(__memset64);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memmove);
EXPORT_SYMBOL(memchr);
diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S
index 3c65e3bd790f..9adc9bdf3ffb 100644
--- a/arch/arm/lib/memset.S
+++ b/arch/arm/lib/memset.S
@@ -21,14 +21,14 @@ ENTRY(memset)
UNWIND( .fnstart )
ands r3, r0, #3 @ 1 unaligned?
mov ip, r0 @ preserve r0 as return value
+ orr r1, r1, r1, lsl #8
bne 6f @ 1
/*
* we know that the pointer in ip is aligned to a word boundary.
*/
-1: orr r1, r1, r1, lsl #8
- orr r1, r1, r1, lsl #16
+1: orr r1, r1, r1, lsl #16
mov r3, r1
- cmp r2, #16
+7: cmp r2, #16
blt 4f

#if ! CALGN(1)+0
@@ -41,7 +41,7 @@ UNWIND( .fnend )
UNWIND( .fnstart )
UNWIND( .save {r8, lr} )
mov r8, r1
- mov lr, r1
+ mov lr, r3

2: subs r2, r2, #64
stmgeia ip!, {r1, r3, r8, lr} @ 64 bytes at a time.
@@ -73,11 +73,11 @@ UNWIND( .fnend )
UNWIND( .fnstart )
UNWIND( .save {r4-r8, lr} )
mov r4, r1
- mov r5, r1
+ mov r5, r3
mov r6, r1
- mov r7, r1
+ mov r7, r3
mov r8, r1
- mov lr, r1
+ mov lr, r3

cmp r2, #96
tstgt ip, #31
@@ -114,12 +114,13 @@ UNWIND( .fnstart )
tst r2, #4
strne r1, [ip], #4
/*
- * When we get here, we've got less than 4 bytes to zero. We
+ * When we get here, we've got less than 4 bytes to set. We
* may have an unaligned pointer as well.
*/
5: tst r2, #2
+ movne r3, r1, lsr #8 @ the top half of a 16-bit pattern
strneb r1, [ip], #1
- strneb r1, [ip], #1
+ strneb r3, [ip], #1
tst r2, #1
strneb r1, [ip], #1
ret lr
@@ -135,3 +136,28 @@ UNWIND( .fnstart )
UNWIND( .fnend )
ENDPROC(memset)
ENDPROC(mmioset)
+
+ENTRY(__memset16)
+UNWIND( .fnstart )
+ tst r0, #2 @ pointer unaligned?
+ mov ip, r0 @ preserve r0 as return value
+ beq 1b @ jump into the middle of memset
+ subs r2, r2, #2 @ cope with n == 0
+ movge r3, r1, lsr #8 @ r3 = r1 >> 8
+ strgeb r1, [ip], #1 @ *ip = r1
+ strgeb r3, [ip], #1 @ *ip = r3
+ bgt 1b @ back into memset if n > 0
+ ret lr @ otherwise return
+UNWIND( .fnend )
+ENDPROC(__memset16)
+ENTRY(__memset32)
+UNWIND( .fnstart )
+ mov r3, r1 @ copy r1 to r3 and fall into memset64
+UNWIND( .fnend )
+ENDPROC(__memset32)
+ENTRY(__memset64)
+UNWIND( .fnstart )
+ mov ip, r0 @ preserve r0 as return value
+ b 7b @ jump into the middle of memset
+UNWIND( .fnend )
+ENDPROC(__memset64)
--
2.11.0
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