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1/*
2 * Copyright (c) 2016-2020, ARM Limited and Contributors. All rights reserved.
3 *
4 * SPDX-License-Identifier: BSD-3-Clause
5 */
6
7#include <arch.h>
8#include <asm_macros.S>
9#include <assert_macros.S>
10
11	.globl	smc
12	.globl	zeromem
13	.globl	zero_normalmem
14	.globl	memcpy4
15	.globl	disable_mmu_icache_secure
16	.globl	disable_mmu_secure
17
18func smc
19	/*
20	 * For AArch32 only r0-r3 will be in the registers;
21	 * rest r4-r6 will be pushed on to the stack. So here, we'll
22	 * have to load them from the stack to registers r4-r6 explicitly.
23	 * Clobbers: r4-r6
24	 */
25	ldm	sp, {r4, r5, r6}
26	smc	#0
27endfunc smc
28
29/* -----------------------------------------------------------------------
30 * void zeromem(void *mem, unsigned int length)
31 *
32 * Initialise a region in normal memory to 0. This functions complies with the
33 * AAPCS and can be called from C code.
34 *
35 * -----------------------------------------------------------------------
36 */
37func zeromem
38	/*
39	 * Readable names for registers
40	 *
41	 * Registers r0, r1 and r2 are also set by zeromem which
42	 * branches into the fallback path directly, so cursor, length and
43	 * stop_address should not be retargeted to other registers.
44	 */
45	cursor       .req r0 /* Start address and then current address */
46	length       .req r1 /* Length in bytes of the region to zero out */
47	/*
48	 * Reusing the r1 register as length is only used at the beginning of
49	 * the function.
50	 */
51	stop_address .req r1  /* Address past the last zeroed byte */
52	zeroreg1     .req r2  /* Source register filled with 0 */
53	zeroreg2     .req r3  /* Source register filled with 0 */
54	tmp	     .req r12 /* Temporary scratch register */
55
56	mov	zeroreg1, #0
57
58	/* stop_address is the address past the last to zero */
59	add	stop_address, cursor, length
60
61	/*
62	 * Length cannot be used anymore as it shares the same register with
63	 * stop_address.
64	 */
65	.unreq	length
66
67	/*
68	 * If the start address is already aligned to 8 bytes, skip this loop.
69	 */
70	tst	cursor, #(8-1)
71	beq	.Lzeromem_8bytes_aligned
72
73	/* Calculate the next address aligned to 8 bytes */
74	orr	tmp, cursor, #(8-1)
75	adds	tmp, tmp, #1
76	/* If it overflows, fallback to byte per byte zeroing */
77	beq	.Lzeromem_1byte_aligned
78	/* If the next aligned address is after the stop address, fall back */
79	cmp	tmp, stop_address
80	bhs	.Lzeromem_1byte_aligned
81
82	/* zero byte per byte */
831:
84	strb	zeroreg1, [cursor], #1
85	cmp	cursor, tmp
86	bne	1b
87
88	/* zero 8 bytes at a time */
89.Lzeromem_8bytes_aligned:
90
91	/* Calculate the last 8 bytes aligned address. */
92	bic	tmp, stop_address, #(8-1)
93
94	cmp	cursor, tmp
95	bhs	2f
96
97	mov	zeroreg2, #0
981:
99	stmia	cursor!, {zeroreg1, zeroreg2}
100	cmp	cursor, tmp
101	blo	1b
1022:
103
104	/* zero byte per byte */
105.Lzeromem_1byte_aligned:
106	cmp	cursor, stop_address
107	beq	2f
1081:
109	strb	zeroreg1, [cursor], #1
110	cmp	cursor, stop_address
111	bne	1b
1122:
113	bx	lr
114
115	.unreq	cursor
116	/*
117	 * length is already unreq'ed to reuse the register for another
118	 * variable.
119	 */
120	.unreq	stop_address
121	.unreq	zeroreg1
122	.unreq	zeroreg2
123	.unreq	tmp
124endfunc zeromem
125
126/*
127 * AArch32 does not have special ways of zeroing normal memory as AArch64 does
128 * using the DC ZVA instruction, so we just alias zero_normalmem to zeromem.
129 */
130.equ	zero_normalmem, zeromem
131
132/* --------------------------------------------------------------------------
133 * void memcpy4(void *dest, const void *src, unsigned int length)
134 *
135 * Copy length bytes from memory area src to memory area dest.
136 * The memory areas should not overlap.
137 * Destination and source addresses must be 4-byte aligned.
138 * --------------------------------------------------------------------------
139 */
140func memcpy4
141#if ENABLE_ASSERTIONS
142	orr	r3, r0, r1
143	tst	r3, #0x3
144	ASM_ASSERT(eq)
145#endif
146/* copy 4 bytes at a time */
147m_loop4:
148	cmp	r2, #4
149	blo	m_loop1
150	ldr	r3, [r1], #4
151	str	r3, [r0], #4
152	subs	r2, r2, #4
153	bne	m_loop4
154	bx	lr
155
156/* copy byte per byte */
157m_loop1:
158	ldrb	r3, [r1], #1
159	strb	r3, [r0], #1
160	subs	r2, r2, #1
161	bne	m_loop1
162	bx	lr
163endfunc memcpy4
164
165/* ---------------------------------------------------------------------------
166 * Disable the MMU in Secure State
167 * ---------------------------------------------------------------------------
168 */
169
170func disable_mmu_secure
171	mov	r1, #(SCTLR_M_BIT | SCTLR_C_BIT)
172do_disable_mmu:
173#if ERRATA_A9_794073
174	stcopr	r0, BPIALL
175	dsb
176#endif
177	ldcopr	r0, SCTLR
178	bic	r0, r0, r1
179	stcopr	r0, SCTLR
180	isb				// ensure MMU is off
181	dsb	sy
182	bx	lr
183endfunc disable_mmu_secure
184
185
186func disable_mmu_icache_secure
187	ldr	r1, =(SCTLR_M_BIT | SCTLR_C_BIT | SCTLR_I_BIT)
188	b	do_disable_mmu
189endfunc disable_mmu_icache_secure
190