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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/riscv/lib/uaccess_vector.S
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/* SPDX-License-Identifier: GPL-2.0-only */

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#include <linux/linkage.h>

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#include <asm/asm.h>

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#include <asm/asm-extable.h>

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#include <asm/csr.h>

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#define pDst a0

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#define pSrc a1

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#define iNum a2

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#define iVL a3

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#define ELEM_LMUL_SETTING m8

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#define vData v0

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	.macro fixup op reg addr lbl

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100:

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	\op \reg, \addr

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	_asm_extable	100b, \lbl

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	.endm

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SYM_FUNC_START(__asm_vector_usercopy)

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	/* Enable access to user memory */

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	li	t6, SR_SUM

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	csrs	CSR_STATUS, t6

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	mv	t6, ra

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	call 	__asm_vector_usercopy_sum_enabled

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	/* Disable access to user memory */

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	mv 	ra, t6

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	li 	t6, SR_SUM

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	csrc	CSR_STATUS, t6

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	ret

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SYM_FUNC_END(__asm_vector_usercopy)

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SYM_FUNC_START(__asm_vector_usercopy_sum_enabled)

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loop:

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	vsetvli iVL, iNum, e8, ELEM_LMUL_SETTING, ta, ma

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	fixup vle8.v vData, (pSrc), 10f

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	sub iNum, iNum, iVL

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	add pSrc, pSrc, iVL

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	fixup vse8.v vData, (pDst), 11f

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	add pDst, pDst, iVL

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	bnez iNum, loop

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	/* Exception fixup for vector load is shared with normal exit */

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10:

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	mv	a0, iNum

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	ret

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	/* Exception fixup code for vector store. */

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11:

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	/* Undo the subtraction after vle8.v */

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	add	iNum, iNum, iVL

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	/* Make sure the scalar fallback skip already processed bytes */

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	csrr	t2, CSR_VSTART

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	sub	iNum, iNum, t2

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	j	10b

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SYM_FUNC_END(__asm_vector_usercopy_sum_enabled)

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