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 		make_task_dead(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_FPU
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_FPU
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