d0fdc20b04
DCACHE_WORD_ACCESS uses the word-at-a-time API for optimised string
comparisons in the vfs layer.
This patch implements support for load_unaligned_zeropad in much the
same way as has been done for arm64.
Here is the test program and step:
$ cat tt.c
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#define ITERATIONS 1000000
#define PATH "123456781234567812345678123456781"
int main(void)
{
unsigned long i;
struct stat buf;
for (i = 0; i < ITERATIONS; i++)
stat(PATH, &buf);
return 0;
}
$ gcc -O2 tt.c
$ touch 123456781234567812345678123456781
$ time ./a.out
Per my test on T-HEAD C910 platforms, the above test performance is
improved by about 7.5%.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://lore.kernel.org/r/20231225044207.3821-3-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
86 lines
2.3 KiB
C
86 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __ASM_ASM_EXTABLE_H
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#define __ASM_ASM_EXTABLE_H
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#define EX_TYPE_NONE 0
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#define EX_TYPE_FIXUP 1
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#define EX_TYPE_BPF 2
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#define EX_TYPE_UACCESS_ERR_ZERO 3
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#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 4
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#ifdef CONFIG_MMU
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#ifdef __ASSEMBLY__
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#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
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.pushsection __ex_table, "a"; \
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.balign 4; \
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.long ((insn) - .); \
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.long ((fixup) - .); \
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.short (type); \
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.short (data); \
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.popsection;
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.macro _asm_extable, insn, fixup
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__ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0)
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.endm
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#else /* __ASSEMBLY__ */
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#include <linux/bits.h>
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#include <linux/stringify.h>
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#include <asm/gpr-num.h>
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#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
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".pushsection __ex_table, \"a\"\n" \
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".balign 4\n" \
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".long ((" insn ") - .)\n" \
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".long ((" fixup ") - .)\n" \
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".short (" type ")\n" \
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".short (" data ")\n" \
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".popsection\n"
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#define _ASM_EXTABLE(insn, fixup) \
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__ASM_EXTABLE_RAW(#insn, #fixup, __stringify(EX_TYPE_FIXUP), "0")
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#define EX_DATA_REG_ERR_SHIFT 0
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#define EX_DATA_REG_ERR GENMASK(4, 0)
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#define EX_DATA_REG_ZERO_SHIFT 5
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#define EX_DATA_REG_ZERO GENMASK(9, 5)
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#define EX_DATA_REG_DATA_SHIFT 0
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#define EX_DATA_REG_DATA GENMASK(4, 0)
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#define EX_DATA_REG_ADDR_SHIFT 5
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#define EX_DATA_REG_ADDR GENMASK(9, 5)
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#define EX_DATA_REG(reg, gpr) \
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"((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"
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#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero) \
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__DEFINE_ASM_GPR_NUMS \
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__ASM_EXTABLE_RAW(#insn, #fixup, \
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__stringify(EX_TYPE_UACCESS_ERR_ZERO), \
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"(" \
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EX_DATA_REG(ERR, err) " | " \
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EX_DATA_REG(ZERO, zero) \
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")")
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#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \
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_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)
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#define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr) \
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__DEFINE_ASM_GPR_NUMS \
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__ASM_EXTABLE_RAW(#insn, #fixup, \
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__stringify(EX_TYPE_LOAD_UNALIGNED_ZEROPAD), \
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"(" \
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EX_DATA_REG(DATA, data) " | " \
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EX_DATA_REG(ADDR, addr) \
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")")
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#endif /* __ASSEMBLY__ */
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#else /* CONFIG_MMU */
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#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)
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#endif /* CONFIG_MMU */
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#endif /* __ASM_ASM_EXTABLE_H */
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