1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Code shared between SPL and U-Boot proper
4 *
5 * Copyright (c) 2015 Google, Inc
6 * Written by Simon Glass <sjg@chromium.org>
7 */
8
9 #include <common.h>
10 #include <bootstage.h>
11 #include <init.h>
12 #include <asm/global_data.h>
13
14 DECLARE_GLOBAL_DATA_PTR;
15
16 /* Unfortunately x86 or ARM can't compile this code as gd cannot be assigned */
17 #if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
arch_setup_gd(struct global_data * gd_ptr)18 __weak void arch_setup_gd(struct global_data *gd_ptr)
19 {
20 gd = gd_ptr;
21 }
22 #endif /* !CONFIG_X86 && !CONFIG_ARM */
23
24 /**
25 * This function is called from board_init_f_init_reserve to set up
26 * gd->start_addr_sp for stack protection if not already set otherwise
27 */
board_init_f_init_stack_protection_addr(ulong base)28 __weak void board_init_f_init_stack_protection_addr(ulong base)
29 {
30 #if CONFIG_IS_ENABLED(SYS_REPORT_STACK_F_USAGE)
31 /* set up stack pointer for stack usage if not set yet */
32 if (!gd->start_addr_sp)
33 gd->start_addr_sp = base;
34 #endif
35 }
36
37 /**
38 * This function is called after the position of the initial stack is
39 * determined in gd->start_addr_sp. Boards can override it to set up
40 * stack-checking markers.
41 */
board_init_f_init_stack_protection(void)42 __weak void board_init_f_init_stack_protection(void)
43 {
44 #if CONFIG_IS_ENABLED(SYS_REPORT_STACK_F_USAGE)
45 ulong stack_bottom = gd->start_addr_sp -
46 CONFIG_VAL(SIZE_LIMIT_PROVIDE_STACK);
47
48 /* substact some safety margin (0x20) since stack is in use here */
49 memset((void *)stack_bottom, CONFIG_VAL(SYS_STACK_F_CHECK_BYTE),
50 CONFIG_VAL(SIZE_LIMIT_PROVIDE_STACK) - 0x20);
51 #endif
52 }
53
54 /*
55 * Allocate reserved space for use as 'globals' from 'top' address and
56 * return 'bottom' address of allocated space
57 *
58 * Notes:
59 *
60 * Actual reservation cannot be done from within this function as
61 * it requires altering the C stack pointer, so this will be done by
62 * the caller upon return from this function.
63 *
64 * IMPORTANT:
65 *
66 * Alignment constraints may differ for each 'chunk' allocated. For now:
67 *
68 * - GD is aligned down on a 16-byte boundary
69 *
70 * - the early malloc arena is not aligned, therefore it follows the stack
71 * alignment constraint of the architecture for which we are bulding.
72 *
73 * - GD is allocated last, so that the return value of this functions is
74 * both the bottom of the reserved area and the address of GD, should
75 * the calling context need it.
76 */
77
board_init_f_alloc_reserve(ulong top)78 ulong board_init_f_alloc_reserve(ulong top)
79 {
80 /* Reserve early malloc arena */
81 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
82 top -= CONFIG_VAL(SYS_MALLOC_F_LEN);
83 #endif
84 /* LAST : reserve GD (rounded up to a multiple of 16 bytes) */
85 top = rounddown(top-sizeof(struct global_data), 16);
86
87 return top;
88 }
89
90 /*
91 * Initialize reserved space (which has been safely allocated on the C
92 * stack from the C runtime environment handling code).
93 *
94 * Notes:
95 *
96 * Actual reservation was done by the caller; the locations from base
97 * to base+size-1 (where 'size' is the value returned by the allocation
98 * function above) can be accessed freely without risk of corrupting the
99 * C runtime environment.
100 *
101 * IMPORTANT:
102 *
103 * Upon return from the allocation function above, on some architectures
104 * the caller will set gd to the lowest reserved location. Therefore, in
105 * this initialization function, the global data MUST be placed at base.
106 *
107 * ALSO IMPORTANT:
108 *
109 * On some architectures, gd will already be good when entering this
110 * function. On others, it will only be good once arch_setup_gd() returns.
111 * Therefore, global data accesses must be done:
112 *
113 * - through gd_ptr if before the call to arch_setup_gd();
114 *
115 * - through gd once arch_setup_gd() has been called.
116 *
117 * Do not use 'gd->' until arch_setup_gd() has been called!
118 *
119 * IMPORTANT TOO:
120 *
121 * Initialization for each "chunk" (GD, early malloc arena...) ends with
122 * an incrementation line of the form 'base += <some size>'. The last of
123 * these incrementations seems useless, as base will not be used any
124 * more after this incrementation; but if/when a new "chunk" is appended,
125 * this increment will be essential as it will give base right value for
126 * this new chunk (which will have to end with its own incrementation
127 * statement). Besides, the compiler's optimizer will silently detect
128 * and remove the last base incrementation, therefore leaving that last
129 * (seemingly useless) incrementation causes no code increase.
130 */
131
board_init_f_init_reserve(ulong base)132 void board_init_f_init_reserve(ulong base)
133 {
134 struct global_data *gd_ptr;
135
136 /*
137 * clear GD entirely and set it up.
138 * Use gd_ptr, as gd may not be properly set yet.
139 */
140
141 gd_ptr = (struct global_data *)base;
142 /* zero the area */
143 memset(gd_ptr, '\0', sizeof(*gd));
144 /* set GD unless architecture did it already */
145 #if !defined(CONFIG_ARM)
146 arch_setup_gd(gd_ptr);
147 #endif
148
149 if (CONFIG_IS_ENABLED(SYS_REPORT_STACK_F_USAGE))
150 board_init_f_init_stack_protection_addr(base);
151
152 /* next alloc will be higher by one GD plus 16-byte alignment */
153 base += roundup(sizeof(struct global_data), 16);
154
155 /*
156 * record early malloc arena start.
157 * Use gd as it is now properly set for all architectures.
158 */
159
160 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
161 /* go down one 'early malloc arena' */
162 gd->malloc_base = base;
163 #endif
164
165 if (CONFIG_IS_ENABLED(SYS_REPORT_STACK_F_USAGE))
166 board_init_f_init_stack_protection();
167 }
168
169 /*
170 * Board-specific Platform code can reimplement show_boot_progress () if needed
171 */
show_boot_progress(int val)172 __weak void show_boot_progress(int val) {}
173