1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Switch to non-secure mode
4  *
5  * Copyright (c) 2018 Heinrich Schuchardt
6  *
7  * This module contains the ARMv7 specific code required for leaving the
8  * secure mode before booting an operating system.
9  */
10 
11 #include <common.h>
12 #include <bootm.h>
13 #include <cpu_func.h>
14 #include <log.h>
15 #include <asm/armv7.h>
16 #include <asm/secure.h>
17 #include <asm/setjmp.h>
18 
19 /**
20  * entry_non_secure() - entry point when switching to non-secure mode
21  *
22  * When switching to non-secure mode switch_to_non_secure_mode() calls this
23  * function passing a jump buffer. We use this jump buffer to restore the
24  * original stack and register state.
25  *
26  * @non_secure_jmp:	jump buffer for restoring stack and registers
27  */
entry_non_secure(struct jmp_buf_data * non_secure_jmp)28 static void entry_non_secure(struct jmp_buf_data *non_secure_jmp)
29 {
30 	dcache_enable();
31 	debug("Reached non-secure mode\n");
32 
33 	/* Restore stack and registers saved in switch_to_non_secure_mode() */
34 	longjmp(non_secure_jmp, 1);
35 }
36 
37 /**
38  * switch_to_non_secure_mode() - switch to non-secure mode
39  *
40  * Operating systems may expect to run in non-secure mode. Here we check if
41  * we are running in secure mode and switch to non-secure mode if necessary.
42  */
switch_to_non_secure_mode(void)43 void switch_to_non_secure_mode(void)
44 {
45 	static bool is_nonsec;
46 	struct jmp_buf_data non_secure_jmp;
47 
48 	if (armv7_boot_nonsec() && !is_nonsec) {
49 		if (setjmp(&non_secure_jmp))
50 			return;
51 		dcache_disable();	/* flush cache before switch to HYP */
52 		armv7_init_nonsec();
53 		is_nonsec = true;
54 		secure_ram_addr(_do_nonsec_entry)(entry_non_secure,
55 						  (uintptr_t)&non_secure_jmp,
56 						  0, 0);
57 	}
58 }
59