copy_from_user.S

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * User memory copy functions for kernel
  4 *
  5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
  6 */
  7
  8/*
  9 * The right way to do this involves valignb
 10 * The easy way to do this is only speed up src/dest similar alignment.
 11 */
 12
 13/*
 14 * Copy to/from user are the same, except that for packets with a load and
 15 * a store, I don't know how to tell which kind of exception we got.
 16 * Therefore, we duplicate the function, and handle faulting addresses
 17 * differently for each function
 18 */
 19
 20/*
 21 * copy from user: loads can fault
 22 */
 23#define src_sav r13
 24#define dst_sav r12
 25#define src_dst_sav r13:12
 26#define d_dbuf r15:14
 27#define w_dbuf r15
 28
 29#define dst r0
 30#define src r1
 31#define bytes r2
 32#define loopcount r5
 33
 34#define FUNCNAME raw_copy_from_user
 35#include "copy_user_template.S"
 36
 37	/* LOAD FAULTS from COPY_FROM_USER */
 38
 39	/* Alignment loop.  r2 has been updated. Return it. */
 40	.falign
 411009:
 422009:
 434009:
 44	{
 45		r0 = r2
 46		jumpr r31
 47	}
 48	/* Normal copy loops. Do epilog. Use src-src_sav to compute distance */
 49	/* X - (A - B) == X + B - A */
 50	.falign
 518089:
 52	{
 53		memd(dst) = d_dbuf
 54		r2 += sub(src_sav,src)
 55	}
 56	{
 57		r0 = r2
 58		jumpr r31
 59	}
 60	.falign
 614089:
 62	{
 63		memw(dst) = w_dbuf
 64		r2 += sub(src_sav,src)
 65	}
 66	{
 67		r0 = r2
 68		jumpr r31
 69	}
 70	.falign
 712089:
 72	{
 73		memh(dst) = w_dbuf
 74		r2 += sub(src_sav,src)
 75	}
 76	{
 77		r0 = r2
 78		jumpr r31
 79	}
 80	.falign
 811089:
 82	{
 83		memb(dst) = w_dbuf
 84		r2 += sub(src_sav,src)
 85	}
 86	{
 87		r0 = r2
 88		jumpr r31
 89	}
 90
 91	/* COPY FROM USER: only loads can fail */
 92
 93	.section __ex_table,"a"
 94	.long 1000b,1009b
 95	.long 2000b,2009b
 96	.long 4000b,4009b
 97	.long 8080b,8089b
 98	.long 4080b,4089b
 99	.long 2080b,2089b
100	.long 1080b,1089b
101	.previous