1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
3
4 #include <linux/sched.h>
5 #include <linux/signal.h>
6 #include <linux/kernel.h>
7 #include <linux/mm.h>
8 #include <linux/module.h>
9 #include <linux/user.h>
10 #include <linux/string.h>
11 #include <linux/linkage.h>
12 #include <linux/init.h>
13 #include <linux/ptrace.h>
14 #include <linux/kallsyms.h>
15 #include <linux/rtc.h>
16 #include <linux/uaccess.h>
17 #include <linux/kprobes.h>
18 #include <linux/kdebug.h>
19 #include <linux/sched/debug.h>
20
21 #include <asm/setup.h>
22 #include <asm/traps.h>
23 #include <asm/pgalloc.h>
24 #include <asm/siginfo.h>
25
26 #include <asm/mmu_context.h>
27
28 #ifdef CONFIG_CPU_HAS_FPU
29 #include <abi/fpu.h>
30 #endif
31
32 int show_unhandled_signals = 1;
33
34 /* Defined in entry.S */
35 asmlinkage void csky_trap(void);
36
37 asmlinkage void csky_systemcall(void);
38 asmlinkage void csky_cmpxchg(void);
39 asmlinkage void csky_get_tls(void);
40 asmlinkage void csky_irq(void);
41
42 asmlinkage void csky_pagefault(void);
43
44 /* Defined in head.S */
45 asmlinkage void _start_smp_secondary(void);
46
pre_trap_init(void)47 void __init pre_trap_init(void)
48 {
49 int i;
50
51 mtcr("vbr", vec_base);
52
53 for (i = 1; i < 128; i++)
54 VEC_INIT(i, csky_trap);
55 }
56
trap_init(void)57 void __init trap_init(void)
58 {
59 VEC_INIT(VEC_AUTOVEC, csky_irq);
60
61 /* setup trap0 trap2 trap3 */
62 VEC_INIT(VEC_TRAP0, csky_systemcall);
63 VEC_INIT(VEC_TRAP2, csky_cmpxchg);
64 VEC_INIT(VEC_TRAP3, csky_get_tls);
65
66 /* setup MMU TLB exception */
67 VEC_INIT(VEC_TLBINVALIDL, csky_pagefault);
68 VEC_INIT(VEC_TLBINVALIDS, csky_pagefault);
69 VEC_INIT(VEC_TLBMODIFIED, csky_pagefault);
70
71 #ifdef CONFIG_CPU_HAS_FPU
72 init_fpu();
73 #endif
74
75 #ifdef CONFIG_SMP
76 mtcr("cr<28, 0>", virt_to_phys(vec_base));
77
78 VEC_INIT(VEC_RESET, (void *)virt_to_phys(_start_smp_secondary));
79 #endif
80 }
81
82 static DEFINE_SPINLOCK(die_lock);
83
die(struct pt_regs * regs,const char * str)84 void die(struct pt_regs *regs, const char *str)
85 {
86 static int die_counter;
87 int ret;
88
89 oops_enter();
90
91 spin_lock_irq(&die_lock);
92 console_verbose();
93 bust_spinlocks(1);
94
95 pr_emerg("%s [#%d]\n", str, ++die_counter);
96 print_modules();
97 show_regs(regs);
98 show_stack(current, (unsigned long *)regs->regs[4], KERN_INFO);
99
100 ret = notify_die(DIE_OOPS, str, regs, 0, trap_no(regs), SIGSEGV);
101
102 bust_spinlocks(0);
103 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
104 spin_unlock_irq(&die_lock);
105 oops_exit();
106
107 if (in_interrupt())
108 panic("Fatal exception in interrupt");
109 if (panic_on_oops)
110 panic("Fatal exception");
111 if (ret != NOTIFY_STOP)
112 do_exit(SIGSEGV);
113 }
114
do_trap(struct pt_regs * regs,int signo,int code,unsigned long addr)115 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
116 {
117 struct task_struct *tsk = current;
118
119 if (show_unhandled_signals && unhandled_signal(tsk, signo)
120 && printk_ratelimit()) {
121 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x%08lx",
122 tsk->comm, task_pid_nr(tsk), signo, code, addr);
123 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
124 pr_cont("\n");
125 show_regs(regs);
126 }
127
128 force_sig_fault(signo, code, (void __user *)addr);
129 }
130
do_trap_error(struct pt_regs * regs,int signo,int code,unsigned long addr,const char * str)131 static void do_trap_error(struct pt_regs *regs, int signo, int code,
132 unsigned long addr, const char *str)
133 {
134 current->thread.trap_no = trap_no(regs);
135
136 if (user_mode(regs)) {
137 do_trap(regs, signo, code, addr);
138 } else {
139 if (!fixup_exception(regs))
140 die(regs, str);
141 }
142 }
143
144 #define DO_ERROR_INFO(name, signo, code, str) \
145 asmlinkage __visible void name(struct pt_regs *regs) \
146 { \
147 do_trap_error(regs, signo, code, regs->pc, "Oops - " str); \
148 }
149
150 DO_ERROR_INFO(do_trap_unknown,
151 SIGILL, ILL_ILLTRP, "unknown exception");
152 DO_ERROR_INFO(do_trap_zdiv,
153 SIGFPE, FPE_INTDIV, "error zero div exception");
154 DO_ERROR_INFO(do_trap_buserr,
155 SIGSEGV, ILL_ILLADR, "error bus error exception");
156
do_trap_misaligned(struct pt_regs * regs)157 asmlinkage void do_trap_misaligned(struct pt_regs *regs)
158 {
159 #ifdef CONFIG_CPU_NEED_SOFTALIGN
160 csky_alignment(regs);
161 #else
162 current->thread.trap_no = trap_no(regs);
163 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->pc,
164 "Oops - load/store address misaligned");
165 #endif
166 }
167
do_trap_bkpt(struct pt_regs * regs)168 asmlinkage void do_trap_bkpt(struct pt_regs *regs)
169 {
170 #ifdef CONFIG_KPROBES
171 if (kprobe_single_step_handler(regs))
172 return;
173 #endif
174 #ifdef CONFIG_UPROBES
175 if (uprobe_single_step_handler(regs))
176 return;
177 #endif
178 if (user_mode(regs)) {
179 send_sig(SIGTRAP, current, 0);
180 return;
181 }
182
183 do_trap_error(regs, SIGILL, ILL_ILLTRP, regs->pc,
184 "Oops - illegal trap exception");
185 }
186
do_trap_illinsn(struct pt_regs * regs)187 asmlinkage void do_trap_illinsn(struct pt_regs *regs)
188 {
189 current->thread.trap_no = trap_no(regs);
190
191 #ifdef CONFIG_KPROBES
192 if (kprobe_breakpoint_handler(regs))
193 return;
194 #endif
195 #ifdef CONFIG_UPROBES
196 if (uprobe_breakpoint_handler(regs))
197 return;
198 #endif
199 #ifndef CONFIG_CPU_NO_USER_BKPT
200 if (*(uint16_t *)instruction_pointer(regs) != USR_BKPT) {
201 send_sig(SIGTRAP, current, 0);
202 return;
203 }
204 #endif
205
206 do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->pc,
207 "Oops - illegal instruction exception");
208 }
209
do_trap_fpe(struct pt_regs * regs)210 asmlinkage void do_trap_fpe(struct pt_regs *regs)
211 {
212 #ifdef CONFIG_CPU_HAS_FP
213 return fpu_fpe(regs);
214 #else
215 do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->pc,
216 "Oops - fpu instruction exception");
217 #endif
218 }
219
do_trap_priv(struct pt_regs * regs)220 asmlinkage void do_trap_priv(struct pt_regs *regs)
221 {
222 #ifdef CONFIG_CPU_HAS_FP
223 if (user_mode(regs) && fpu_libc_helper(regs))
224 return;
225 #endif
226 do_trap_error(regs, SIGILL, ILL_PRVOPC, regs->pc,
227 "Oops - illegal privileged exception");
228 }
229
trap_c(struct pt_regs * regs)230 asmlinkage void trap_c(struct pt_regs *regs)
231 {
232 switch (trap_no(regs)) {
233 case VEC_ZERODIV:
234 do_trap_zdiv(regs);
235 break;
236 case VEC_TRACE:
237 do_trap_bkpt(regs);
238 break;
239 case VEC_ILLEGAL:
240 do_trap_illinsn(regs);
241 break;
242 case VEC_TRAP1:
243 case VEC_BREAKPOINT:
244 do_trap_bkpt(regs);
245 break;
246 case VEC_ACCESS:
247 do_trap_buserr(regs);
248 break;
249 case VEC_ALIGN:
250 do_trap_misaligned(regs);
251 break;
252 case VEC_FPE:
253 do_trap_fpe(regs);
254 break;
255 case VEC_PRIV:
256 do_trap_priv(regs);
257 break;
258 default:
259 do_trap_unknown(regs);
260 break;
261 }
262 }
263