1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (c) 2016-17 Microsemi Corporation.
4 * Padmarao Begari, Microsemi Corporation <padmarao.begari@microsemi.com>
5 *
6 * Copyright (C) 2017 Andes Technology Corporation
7 * Rick Chen, Andes Technology Corporation <rick@andestech.com>
8 *
9 * Copyright (C) 2019 Sean Anderson <seanga2@gmail.com>
10 */
11
12 #include <linux/compat.h>
13 #include <common.h>
14 #include <efi_loader.h>
15 #include <hang.h>
16 #include <irq_func.h>
17 #include <asm/global_data.h>
18 #include <asm/ptrace.h>
19 #include <asm/system.h>
20 #include <asm/encoding.h>
21 #include <semihosting.h>
22
23 DECLARE_GLOBAL_DATA_PTR;
24
show_efi_loaded_images(uintptr_t epc)25 static void show_efi_loaded_images(uintptr_t epc)
26 {
27 efi_print_image_infos((void *)epc);
28 }
29
show_regs(struct pt_regs * regs)30 static void show_regs(struct pt_regs *regs)
31 {
32 #ifdef CONFIG_SHOW_REGS
33 printf("\nSP: " REG_FMT " GP: " REG_FMT " TP: " REG_FMT "\n",
34 regs->sp, regs->gp, regs->tp);
35 printf("T0: " REG_FMT " T1: " REG_FMT " T2: " REG_FMT "\n",
36 regs->t0, regs->t1, regs->t2);
37 printf("S0: " REG_FMT " S1: " REG_FMT " A0: " REG_FMT "\n",
38 regs->s0, regs->s1, regs->a0);
39 printf("A1: " REG_FMT " A2: " REG_FMT " A3: " REG_FMT "\n",
40 regs->a1, regs->a2, regs->a3);
41 printf("A4: " REG_FMT " A5: " REG_FMT " A6: " REG_FMT "\n",
42 regs->a4, regs->a5, regs->a6);
43 printf("A7: " REG_FMT " S2: " REG_FMT " S3: " REG_FMT "\n",
44 regs->a7, regs->s2, regs->s3);
45 printf("S4: " REG_FMT " S5: " REG_FMT " S6: " REG_FMT "\n",
46 regs->s4, regs->s5, regs->s6);
47 printf("S7: " REG_FMT " S8: " REG_FMT " S9: " REG_FMT "\n",
48 regs->s7, regs->s8, regs->s9);
49 printf("S10: " REG_FMT " S11: " REG_FMT " T3: " REG_FMT "\n",
50 regs->s10, regs->s11, regs->t3);
51 printf("T4: " REG_FMT " T5: " REG_FMT " T6: " REG_FMT "\n",
52 regs->t4, regs->t5, regs->t6);
53 #endif
54 }
55
56 /**
57 * instr_len() - get instruction length
58 *
59 * @i: low 16 bits of the instruction
60 * Return: number of u16 in instruction
61 */
instr_len(u16 i)62 static int instr_len(u16 i)
63 {
64 if ((i & 0x03) != 0x03)
65 return 1;
66 /* Instructions with more than 32 bits are not yet specified */
67 return 2;
68 }
69
70 /**
71 * show_code() - display code leading to exception
72 *
73 * @epc: program counter
74 */
show_code(ulong epc)75 static void show_code(ulong epc)
76 {
77 u16 *pos = (u16 *)(epc & ~1UL);
78 int i, len = instr_len(*pos);
79
80 printf("\nCode: ");
81 for (i = -8; i; ++i)
82 printf("%04x ", pos[i]);
83 printf("(");
84 for (i = 0; i < len; ++i)
85 printf("%04x%s", pos[i], i + 1 == len ? ")\n" : " ");
86 }
87
_exit_trap(ulong code,ulong epc,ulong tval,struct pt_regs * regs)88 static void _exit_trap(ulong code, ulong epc, ulong tval, struct pt_regs *regs)
89 {
90 static const char * const exception_code[] = {
91 "Instruction address misaligned",
92 "Instruction access fault",
93 "Illegal instruction",
94 "Breakpoint",
95 "Load address misaligned",
96 "Load access fault",
97 "Store/AMO address misaligned",
98 "Store/AMO access fault",
99 "Environment call from U-mode",
100 "Environment call from S-mode",
101 "Reserved",
102 "Environment call from M-mode",
103 "Instruction page fault",
104 "Load page fault",
105 "Reserved",
106 "Store/AMO page fault",
107 };
108
109 if (code < ARRAY_SIZE(exception_code))
110 printf("Unhandled exception: %s\n", exception_code[code]);
111 else
112 printf("Unhandled exception code: %ld\n", code);
113
114 printf("EPC: " REG_FMT " RA: " REG_FMT " TVAL: " REG_FMT "\n",
115 epc, regs->ra, tval);
116 /* Print relocation adjustments, but only if gd is initialized */
117 if (gd && gd->flags & GD_FLG_RELOC)
118 printf("EPC: " REG_FMT " RA: " REG_FMT " reloc adjusted\n",
119 epc - gd->reloc_off, regs->ra - gd->reloc_off);
120
121 show_regs(regs);
122 show_code(epc);
123 show_efi_loaded_images(epc);
124 panic("\n");
125 }
126
interrupt_init(void)127 int interrupt_init(void)
128 {
129 return 0;
130 }
131
132 /*
133 * enable interrupts
134 */
enable_interrupts(void)135 void enable_interrupts(void)
136 {
137 }
138
139 /*
140 * disable interrupts
141 */
disable_interrupts(void)142 int disable_interrupts(void)
143 {
144 return 0;
145 }
146
handle_trap(ulong cause,ulong epc,ulong tval,struct pt_regs * regs)147 ulong handle_trap(ulong cause, ulong epc, ulong tval, struct pt_regs *regs)
148 {
149 ulong is_irq, irq;
150
151 /* An UEFI application may have changed gd. Restore U-Boot's gd. */
152 efi_restore_gd();
153
154 if (cause == CAUSE_BREAKPOINT &&
155 CONFIG_IS_ENABLED(SEMIHOSTING_FALLBACK)) {
156 ulong pre_addr = epc - 4, post_addr = epc + 4;
157
158 /* Check for prior and post addresses to be in same page. */
159 if ((pre_addr & ~(PAGE_SIZE - 1)) ==
160 (post_addr & ~(PAGE_SIZE - 1))) {
161 u32 pre = *(u32 *)pre_addr;
162 u32 post = *(u32 *)post_addr;
163
164 /* Check for semihosting, i.e.:
165 * slli zero,zero,0x1f
166 * ebreak
167 * srai zero,zero,0x7
168 */
169 if (pre == 0x01f01013 && post == 0x40705013) {
170 disable_semihosting();
171 epc += 4;
172 return epc;
173 }
174 }
175 }
176
177 is_irq = (cause & MCAUSE_INT);
178 irq = (cause & ~MCAUSE_INT);
179
180 if (is_irq) {
181 switch (irq) {
182 case IRQ_M_EXT:
183 case IRQ_S_EXT:
184 external_interrupt(0); /* handle external interrupt */
185 break;
186 case IRQ_M_TIMER:
187 case IRQ_S_TIMER:
188 timer_interrupt(0); /* handle timer interrupt */
189 break;
190 default:
191 _exit_trap(cause, epc, tval, regs);
192 break;
193 };
194 } else {
195 _exit_trap(cause, epc, tval, regs);
196 }
197
198 return epc;
199 }
200
201 /*
202 *Entry Point for PLIC Interrupt Handler
203 */
external_interrupt(struct pt_regs * regs)204 __attribute__((weak)) void external_interrupt(struct pt_regs *regs)
205 {
206 }
207
timer_interrupt(struct pt_regs * regs)208 __attribute__((weak)) void timer_interrupt(struct pt_regs *regs)
209 {
210 }
211