xref: /linux/arch/riscv/lib/riscv_v_helpers.c (revision 06d07429858317ded2db7986113a9e0129cd599b)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2023 SiFive
4  * Author: Andy Chiu <andy.chiu@sifive.com>
5  */
6 #include <linux/linkage.h>
7 #include <asm/asm.h>
8 
9 #include <asm/vector.h>
10 #include <asm/simd.h>
11 
12 #ifdef CONFIG_MMU
13 #include <asm/asm-prototypes.h>
14 #endif
15 
16 #ifdef CONFIG_MMU
17 size_t riscv_v_usercopy_threshold = CONFIG_RISCV_ISA_V_UCOPY_THRESHOLD;
18 int __asm_vector_usercopy(void *dst, void *src, size_t n);
19 int fallback_scalar_usercopy(void *dst, void *src, size_t n);
enter_vector_usercopy(void * dst,void * src,size_t n)20 asmlinkage int enter_vector_usercopy(void *dst, void *src, size_t n)
21 {
22 	size_t remain, copied;
23 
24 	/* skip has_vector() check because it has been done by the asm  */
25 	if (!may_use_simd())
26 		goto fallback;
27 
28 	kernel_vector_begin();
29 	remain = __asm_vector_usercopy(dst, src, n);
30 	kernel_vector_end();
31 
32 	if (remain) {
33 		copied = n - remain;
34 		dst += copied;
35 		src += copied;
36 		n = remain;
37 		goto fallback;
38 	}
39 
40 	return remain;
41 
42 fallback:
43 	return fallback_scalar_usercopy(dst, src, n);
44 }
45 #endif
46