arch/riscv/lib/riscv_v_helpers.c

   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);
  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