On Tue, Jan 30, 2024 at 02:07:37PM +0200, Nick Kossifidis wrote:
> On 1/28/24 13:10, Jisheng Zhang wrote:
> > diff --git a/arch/riscv/lib/string.c b/arch/riscv/lib/string.c
> > index 20677c8067da..022edda68f1c 100644
> > --- a/arch/riscv/lib/string.c
> > +++ b/arch/riscv/lib/string.c
> > @@ -144,3 +144,44 @@ void *memmove(void *dest, const void *src, size_t count) __weak __alias(__memmov
> > EXPORT_SYMBOL(memmove);
> > void *__pi_memmove(void *dest, const void *src, size_t count) __alias(__memmove);
> > void *__pi___memmove(void *dest, const void *src, size_t count) __alias(__memmove);
> > +
> > +void *__memset(void *s, int c, size_t count)
> > +{
> > + union types dest = { .as_u8 = s };
> > +
> > + if (count >= MIN_THRESHOLD) {
> > + unsigned long cu = (unsigned long)c;
> > +
> > + /* Compose an ulong with 'c' repeated 4/8 times */
> > +#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
> > + cu *= 0x0101010101010101UL;
Here we need to check BITS_PER_LONG, use 0x01010101UL for rv32
> > +#else
> > + cu |= cu << 8;
> > + cu |= cu << 16;
> > + /* Suppress warning on 32 bit machines */
> > + cu |= (cu << 16) << 16;
> > +#endif
>
> I guess you could check against __SIZEOF_LONG__ here.
Hmm I believe we can remove the | and shift totally, and fall
back to ARCH_HAS_FAST_MULTIPLIER, see
https://lore.kernel.org/linux-riscv/20240125145703.913-1-jszhang@kernel.org/
>
> > + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) {
> > + /*
> > + * Fill the buffer one byte at time until
> > + * the destination is word aligned.
> > + */
> > + for (; count && dest.as_uptr & WORD_MASK; count--)
> > + *dest.as_u8++ = c;
> > + }
> > +
> > + /* Copy using the largest size allowed */
> > + for (; count >= BYTES_LONG; count -= BYTES_LONG)
> > + *dest.as_ulong++ = cu;
> > + }
> > +
> > + /* copy the remainder */
> > + while (count--)
> > + *dest.as_u8++ = c;
> > +
> > + return s;
> > +}
> > +EXPORT_SYMBOL(__memset);
>
> BTW a similar approach could be used for memchr, e.g.:
>
> #if __SIZEOF_LONG__ == 8
> #define HAS_ZERO(_x) (((_x) - 0x0101010101010101ULL) & ~(_x) &
> 0x8080808080808080ULL)
> #else
> #define HAS_ZERO(_x) (((_x) - 0x01010101UL) & ~(_x) & 0x80808080UL)
> #endif
>
> void *
> memchr(const void *src_ptr, int c, size_t len)
> {
> union const_data src = { .as_bytes = src_ptr };
> unsigned char byte = (unsigned char) c;
> unsigned long mask = (unsigned long) c;
> size_t remaining = len;
>
> /* Nothing to do */
> if (!src_ptr || !len)
> return NULL;
>
> if (len < 2 * WORD_SIZE)
> goto trailing;
>
> mask |= mask << 8;
> mask |= mask << 16;
> #if __SIZEOF_LONG__ == 8
> mask |= mask << 32;
> #endif
>
> /* Search by byte up to the src's alignment boundary */
> for(; src.as_uptr & WORD_MASK; remaining--, src.as_bytes++) {
> if (*src.as_bytes == byte)
> return (void*) src.as_bytes;
> }
>
> /* Search word by word using the mask */
> for(; remaining >= WORD_SIZE; remaining -= WORD_SIZE, src.as_ulong++) {
> unsigned long check = *src.as_ulong ^ mask;
> if(HAS_ZERO(check))
> break;
> }
>
> trailing:
> for(; remaining > 0; remaining--, src.as_bytes++) {
> if (*src.as_bytes == byte)
> return (void*) src.as_bytes;
> }
>
> return NULL;
> }
>
> Regards,
> Nick
@@ -10,8 +10,8 @@
#include <linux/linkage.h>
#define __HAVE_ARCH_MEMSET
-extern asmlinkage void *memset(void *, int, size_t);
-extern asmlinkage void *__memset(void *, int, size_t);
+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);
@@ -9,8 +9,6 @@
/*
* Assembly functions that may be used (directly or indirectly) by modules
*/
-EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(strcmp);
EXPORT_SYMBOL(strlen);
EXPORT_SYMBOL(strncmp);
-EXPORT_SYMBOL(__memset);
@@ -1,6 +1,5 @@
# SPDX-License-Identifier: GPL-2.0-only
lib-y += delay.o
-lib-y += memset.o
lib-y += strcmp.o
lib-y += strlen.o
lib-y += string.o
deleted file mode 100644
@@ -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) */
-SYM_FUNC_START(__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
-SYM_FUNC_END(__memset)
-SYM_FUNC_ALIAS_WEAK(memset, __memset)
@@ -144,3 +144,44 @@ void *memmove(void *dest, const void *src, size_t count) __weak __alias(__memmov
EXPORT_SYMBOL(memmove);
void *__pi_memmove(void *dest, const void *src, size_t count) __alias(__memmove);
void *__pi___memmove(void *dest, const void *src, size_t count) __alias(__memmove);
+
+void *__memset(void *s, int c, size_t count)
+{
+ union types dest = { .as_u8 = s };
+
+ if (count >= MIN_THRESHOLD) {
+ unsigned long cu = (unsigned long)c;
+
+ /* Compose an ulong with 'c' repeated 4/8 times */
+#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
+ cu *= 0x0101010101010101UL;
+#else
+ cu |= cu << 8;
+ cu |= cu << 16;
+ /* Suppress warning on 32 bit machines */
+ cu |= (cu << 16) << 16;
+#endif
+ if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) {
+ /*
+ * Fill the buffer one byte at time until
+ * the destination is word aligned.
+ */
+ for (; count && dest.as_uptr & WORD_MASK; count--)
+ *dest.as_u8++ = c;
+ }
+
+ /* Copy using the largest size allowed */
+ for (; count >= BYTES_LONG; count -= BYTES_LONG)
+ *dest.as_ulong++ = cu;
+ }
+
+ /* copy the remainder */
+ while (count--)
+ *dest.as_u8++ = c;
+
+ return s;
+}
+EXPORT_SYMBOL(__memset);
+
+void *memset(void *s, int c, size_t count) __weak __alias(__memset);
+EXPORT_SYMBOL(memset);
@@ -1,7 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
OBJECT_FILES_NON_STANDARD := y
-purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o memset.o
+purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o
purgatory-y += strcmp.o strlen.o strncmp.o riscv_string.o
targets += $(purgatory-y)
@@ -16,9 +16,6 @@ $(obj)/string.o: $(srctree)/lib/string.c FORCE
$(obj)/ctype.o: $(srctree)/lib/ctype.c FORCE
$(call if_changed_rule,cc_o_c)
-$(obj)/memset.o: $(srctree)/arch/riscv/lib/memset.S FORCE
- $(call if_changed_rule,as_o_S)
-
$(obj)/strcmp.o: $(srctree)/arch/riscv/lib/strcmp.S FORCE
$(call if_changed_rule,as_o_S)