cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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memmove.S (2017B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
      3
      4#include <linux/linkage.h>
      5#include "sysdep.h"
      6
      7	.weak memmove
      8ENTRY(__memmove)
      9ENTRY(memmove)
     10	subu	r3, r0, r1
     11	cmphs	r3, r2
     12	bt	memcpy
     13
     14	mov	r12, r0
     15	addu	r0, r0, r2
     16	addu	r1, r1, r2
     17
     18	/* Test if len less than 4 bytes.  */
     19	cmplti	r2, 4
     20	bt	.L_copy_by_byte
     21
     22	andi	r13, r0, 3
     23	/* Test if dest is not 4 bytes aligned.  */
     24	bnez	r13, .L_dest_not_aligned
     25	/* Hardware can handle unaligned access directly.  */
     26.L_dest_aligned:
     27	/* If dest is aligned, then copy.  */
     28	zext	r18, r2, 31, 4
     29	/* Test if len less than 16 bytes.  */
     30	bez	r18, .L_len_less_16bytes
     31	movi	r19, 0
     32
     33	/* len > 16 bytes */
     34	LABLE_ALIGN
     35.L_len_larger_16bytes:
     36	subi	r1, 16
     37	subi	r0, 16
     38#if defined(__CK860__)
     39	ldw	r3, (r1, 12)
     40	stw	r3, (r0, 12)
     41	ldw	r3, (r1, 8)
     42	stw	r3, (r0, 8)
     43	ldw	r3, (r1, 4)
     44	stw	r3, (r0, 4)
     45	ldw	r3, (r1, 0)
     46	stw	r3, (r0, 0)
     47#else
     48	ldw	r20, (r1, 0)
     49	ldw	r21, (r1, 4)
     50	ldw	r22, (r1, 8)
     51	ldw	r23, (r1, 12)
     52	stw	r20, (r0, 0)
     53	stw	r21, (r0, 4)
     54	stw	r22, (r0, 8)
     55	stw	r23, (r0, 12)
     56	PRE_BNEZAD (r18)
     57#endif
     58	BNEZAD (r18, .L_len_larger_16bytes)
     59
     60.L_len_less_16bytes:
     61	zext	r18, r2, 3, 2
     62	bez	r18, .L_copy_by_byte
     63.L_len_less_16bytes_loop:
     64	subi	r1, 4
     65	subi	r0, 4
     66	ldw	r3, (r1, 0)
     67	PRE_BNEZAD (r18)
     68	stw	r3, (r0, 0)
     69	BNEZAD (r18, .L_len_less_16bytes_loop)
     70
     71	/* Test if len less than 4 bytes.  */
     72.L_copy_by_byte:
     73	zext	r18, r2, 1, 0
     74	bez	r18, .L_return
     75.L_copy_by_byte_loop:
     76	subi	r1, 1
     77	subi	r0, 1
     78	ldb	r3, (r1, 0)
     79	PRE_BNEZAD (r18)
     80	stb	r3, (r0, 0)
     81	BNEZAD (r18, .L_copy_by_byte_loop)
     82
     83.L_return:
     84	mov	r0, r12
     85	rts
     86
     87	/* If dest is not aligned, just copy some bytes makes the dest
     88	   align.  */
     89.L_dest_not_aligned:
     90	sub	r2, r13
     91.L_dest_not_aligned_loop:
     92	subi	r1, 1
     93	subi	r0, 1
     94	/* Makes the dest align.  */
     95	ldb	r3, (r1, 0)
     96	PRE_BNEZAD (r13)
     97	stb	r3, (r0, 0)
     98	BNEZAD (r13, .L_dest_not_aligned_loop)
     99	cmplti	r2, 4
    100	bt	.L_copy_by_byte
    101	/* Check whether the src is aligned.  */
    102	jbr	.L_dest_aligned
    103ENDPROC(memmove)
    104ENDPROC(__memmove)