1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * arch/sparc/kernel/traps.c
4 *
5 * Copyright 1995, 2008 David S. Miller (davem@davemloft.net)
6 * Copyright 2000 Jakub Jelinek (jakub@redhat.com)
7 */
8
9 /*
10 * I hate traps on the sparc, grrr...
11 */
12
13 #include <linux/cpu.h>
14 #include <linux/sched/mm.h>
15 #include <linux/sched/debug.h>
16 #include <linux/mm_types.h>
17 #include <linux/kernel.h>
18 #include <linux/signal.h>
19 #include <linux/smp.h>
20 #include <linux/kdebug.h>
21 #include <linux/export.h>
22 #include <linux/pgtable.h>
23
24 #include <asm/delay.h>
25 #include <asm/ptrace.h>
26 #include <asm/oplib.h>
27 #include <asm/page.h>
28 #include <asm/unistd.h>
29 #include <asm/traps.h>
30
31 #include "entry.h"
32 #include "kernel.h"
33
34 /* #define TRAP_DEBUG */
35
instruction_dump(unsigned long * pc)36 static void instruction_dump(unsigned long *pc)
37 {
38 int i;
39
40 if((((unsigned long) pc) & 3))
41 return;
42
43 for(i = -3; i < 6; i++)
44 printk("%c%08lx%c",i?' ':'<',pc[i],i?' ':'>');
45 printk("\n");
46 }
47
48 #define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
49 #define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
50
die_if_kernel(char * str,struct pt_regs * regs)51 void __noreturn die_if_kernel(char *str, struct pt_regs *regs)
52 {
53 static int die_counter;
54 int count = 0;
55
56 /* Amuse the user. */
57 printk(
58 " \\|/ ____ \\|/\n"
59 " \"@'/ ,. \\`@\"\n"
60 " /_| \\__/ |_\\\n"
61 " \\__U_/\n");
62
63 printk("%s(%d): %s [#%d]\n", current->comm, task_pid_nr(current), str, ++die_counter);
64 show_regs(regs);
65 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
66
67 __SAVE; __SAVE; __SAVE; __SAVE;
68 __SAVE; __SAVE; __SAVE; __SAVE;
69 __RESTORE; __RESTORE; __RESTORE; __RESTORE;
70 __RESTORE; __RESTORE; __RESTORE; __RESTORE;
71
72 {
73 struct reg_window32 *rw = (struct reg_window32 *)regs->u_regs[UREG_FP];
74
75 /* Stop the back trace when we hit userland or we
76 * find some badly aligned kernel stack. Set an upper
77 * bound in case our stack is trashed and we loop.
78 */
79 while(rw &&
80 count++ < 30 &&
81 (((unsigned long) rw) >= PAGE_OFFSET) &&
82 !(((unsigned long) rw) & 0x7)) {
83 printk("Caller[%08lx]: %pS\n", rw->ins[7],
84 (void *) rw->ins[7]);
85 rw = (struct reg_window32 *)rw->ins[6];
86 }
87 }
88 printk("Instruction DUMP:");
89 instruction_dump ((unsigned long *) regs->pc);
90 make_task_dead((regs->psr & PSR_PS) ? SIGKILL : SIGSEGV);
91 }
92
do_hw_interrupt(struct pt_regs * regs,unsigned long type)93 void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
94 {
95 if(type < 0x80) {
96 /* Sun OS's puke from bad traps, Linux survives! */
97 printk("Unimplemented Sparc TRAP, type = %02lx\n", type);
98 die_if_kernel("Whee... Hello Mr. Penguin", regs);
99 }
100
101 if(regs->psr & PSR_PS)
102 die_if_kernel("Kernel bad trap", regs);
103
104 force_sig_fault_trapno(SIGILL, ILL_ILLTRP,
105 (void __user *)regs->pc, type - 0x80);
106 }
107
do_illegal_instruction(struct pt_regs * regs,unsigned long pc,unsigned long npc,unsigned long psr)108 void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
109 unsigned long psr)
110 {
111 if(psr & PSR_PS)
112 die_if_kernel("Kernel illegal instruction", regs);
113 #ifdef TRAP_DEBUG
114 printk("Ill instr. at pc=%08lx instruction is %08lx\n",
115 regs->pc, *(unsigned long *)regs->pc);
116 #endif
117
118 send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc, current);
119 }
120
do_priv_instruction(struct pt_regs * regs,unsigned long pc,unsigned long npc,unsigned long psr)121 void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
122 unsigned long psr)
123 {
124 if(psr & PSR_PS)
125 die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
126 send_sig_fault(SIGILL, ILL_PRVOPC, (void __user *)pc, current);
127 }
128
129 /* XXX User may want to be allowed to do this. XXX */
130
do_memaccess_unaligned(struct pt_regs * regs,unsigned long pc,unsigned long npc,unsigned long psr)131 void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned long npc,
132 unsigned long psr)
133 {
134 if(regs->psr & PSR_PS) {
135 printk("KERNEL MNA at pc %08lx npc %08lx called by %08lx\n", pc, npc,
136 regs->u_regs[UREG_RETPC]);
137 die_if_kernel("BOGUS", regs);
138 /* die_if_kernel("Kernel MNA access", regs); */
139 }
140 #if 0
141 show_regs (regs);
142 instruction_dump ((unsigned long *) regs->pc);
143 printk ("do_MNA!\n");
144 #endif
145 send_sig_fault(SIGBUS, BUS_ADRALN,
146 /* FIXME: Should dig out mna address */ (void *)0,
147 current);
148 }
149
150 static unsigned long init_fsr = 0x0UL;
151 static unsigned long init_fregs[32] __attribute__ ((aligned (8))) =
152 { ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
153 ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
154 ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
155 ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL };
156
do_fpd_trap(struct pt_regs * regs,unsigned long pc,unsigned long npc,unsigned long psr)157 void do_fpd_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
158 unsigned long psr)
159 {
160 /* Sanity check... */
161 if(psr & PSR_PS)
162 die_if_kernel("Kernel gets FloatingPenguinUnit disabled trap", regs);
163
164 put_psr(get_psr() | PSR_EF); /* Allow FPU ops. */
165 regs->psr |= PSR_EF;
166 #ifndef CONFIG_SMP
167 if(last_task_used_math == current)
168 return;
169 if(last_task_used_math) {
170 /* Other processes fpu state, save away */
171 struct task_struct *fptask = last_task_used_math;
172 fpsave(&fptask->thread.float_regs[0], &fptask->thread.fsr,
173 &fptask->thread.fpqueue[0], &fptask->thread.fpqdepth);
174 }
175 last_task_used_math = current;
176 if(used_math()) {
177 fpload(¤t->thread.float_regs[0], ¤t->thread.fsr);
178 } else {
179 /* Set initial sane state. */
180 fpload(&init_fregs[0], &init_fsr);
181 set_used_math();
182 }
183 #else
184 if(!used_math()) {
185 fpload(&init_fregs[0], &init_fsr);
186 set_used_math();
187 } else {
188 fpload(¤t->thread.float_regs[0], ¤t->thread.fsr);
189 }
190 set_thread_flag(TIF_USEDFPU);
191 #endif
192 }
193
194 static unsigned long fake_regs[32] __attribute__ ((aligned (8)));
195 static unsigned long fake_fsr;
196 static unsigned long fake_queue[32] __attribute__ ((aligned (8)));
197 static unsigned long fake_depth;
198
do_fpe_trap(struct pt_regs * regs,unsigned long pc,unsigned long npc,unsigned long psr)199 void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
200 unsigned long psr)
201 {
202 static int calls;
203 unsigned long fsr;
204 int ret = 0;
205 int code;
206 #ifndef CONFIG_SMP
207 struct task_struct *fpt = last_task_used_math;
208 #else
209 struct task_struct *fpt = current;
210 #endif
211 put_psr(get_psr() | PSR_EF);
212 /* If nobody owns the fpu right now, just clear the
213 * error into our fake static buffer and hope it don't
214 * happen again. Thank you crashme...
215 */
216 #ifndef CONFIG_SMP
217 if(!fpt) {
218 #else
219 if (!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
220 #endif
221 fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
222 regs->psr &= ~PSR_EF;
223 return;
224 }
225 fpsave(&fpt->thread.float_regs[0], &fpt->thread.fsr,
226 &fpt->thread.fpqueue[0], &fpt->thread.fpqdepth);
227 #ifdef DEBUG_FPU
228 printk("Hmm, FP exception, fsr was %016lx\n", fpt->thread.fsr);
229 #endif
230
231 switch ((fpt->thread.fsr & 0x1c000)) {
232 /* switch on the contents of the ftt [floating point trap type] field */
233 #ifdef DEBUG_FPU
234 case (1 << 14):
235 printk("IEEE_754_exception\n");
236 break;
237 #endif
238 case (2 << 14): /* unfinished_FPop (underflow & co) */
239 case (3 << 14): /* unimplemented_FPop (quad stuff, maybe sqrt) */
240 ret = do_mathemu(regs, fpt);
241 break;
242 #ifdef DEBUG_FPU
243 case (4 << 14):
244 printk("sequence_error (OS bug...)\n");
245 break;
246 case (5 << 14):
247 printk("hardware_error (uhoh!)\n");
248 break;
249 case (6 << 14):
250 printk("invalid_fp_register (user error)\n");
251 break;
252 #endif /* DEBUG_FPU */
253 }
254 /* If we successfully emulated the FPop, we pretend the trap never happened :-> */
255 if (ret) {
256 fpload(¤t->thread.float_regs[0], ¤t->thread.fsr);
257 return;
258 }
259 /* nope, better SIGFPE the offending process... */
260
261 #ifdef CONFIG_SMP
262 clear_tsk_thread_flag(fpt, TIF_USEDFPU);
263 #endif
264 if(psr & PSR_PS) {
265 /* The first fsr store/load we tried trapped,
266 * the second one will not (we hope).
267 */
268 printk("WARNING: FPU exception from kernel mode. at pc=%08lx\n",
269 regs->pc);
270 regs->pc = regs->npc;
271 regs->npc += 4;
272 calls++;
273 if(calls > 2)
274 die_if_kernel("Too many Penguin-FPU traps from kernel mode",
275 regs);
276 return;
277 }
278
279 fsr = fpt->thread.fsr;
280 code = FPE_FLTUNK;
281 if ((fsr & 0x1c000) == (1 << 14)) {
282 if (fsr & 0x10)
283 code = FPE_FLTINV;
284 else if (fsr & 0x08)
285 code = FPE_FLTOVF;
286 else if (fsr & 0x04)
287 code = FPE_FLTUND;
288 else if (fsr & 0x02)
289 code = FPE_FLTDIV;
290 else if (fsr & 0x01)
291 code = FPE_FLTRES;
292 }
293 send_sig_fault(SIGFPE, code, (void __user *)pc, fpt);
294 #ifndef CONFIG_SMP
295 last_task_used_math = NULL;
296 #endif
297 regs->psr &= ~PSR_EF;
298 if(calls > 0)
299 calls=0;
300 }
301
302 void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long npc,
303 unsigned long psr)
304 {
305 if(psr & PSR_PS)
306 die_if_kernel("Penguin overflow trap from kernel mode", regs);
307 send_sig_fault(SIGEMT, EMT_TAGOVF, (void __user *)pc, current);
308 }
309
310 void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
311 unsigned long psr)
312 {
313 #ifdef TRAP_DEBUG
314 printk("Watchpoint detected at PC %08lx NPC %08lx PSR %08lx\n",
315 pc, npc, psr);
316 #endif
317 if(psr & PSR_PS)
318 panic("Tell me what a watchpoint trap is, and I'll then deal "
319 "with such a beast...");
320 }
321
322 void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc,
323 unsigned long psr)
324 {
325 #ifdef TRAP_DEBUG
326 printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
327 pc, npc, psr);
328 #endif
329 force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)pc);
330 }
331
332 void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
333 unsigned long psr)
334 {
335 send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, current);
336 }
337
338 void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
339 unsigned long psr)
340 {
341 #ifdef TRAP_DEBUG
342 printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
343 pc, npc, psr);
344 #endif
345 send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, current);
346 }
347
348 void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
349 unsigned long psr)
350 {
351 send_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)pc, current);
352 }
353
354 #ifdef CONFIG_DEBUG_BUGVERBOSE
355 void do_BUG(const char *file, int line)
356 {
357 // bust_spinlocks(1); XXX Not in our original BUG()
358 printk("kernel BUG at %s:%d!\n", file, line);
359 }
360 EXPORT_SYMBOL(do_BUG);
361 #endif
362
363 /* Since we have our mappings set up, on multiprocessors we can spin them
364 * up here so that timer interrupts work during initialization.
365 */
366
367 void trap_init(void)
368 {
369 extern void thread_info_offsets_are_bolixed_pete(void);
370
371 /* Force linker to barf if mismatched */
372 if (TI_UWINMASK != offsetof(struct thread_info, uwinmask) ||
373 TI_TASK != offsetof(struct thread_info, task) ||
374 TI_FLAGS != offsetof(struct thread_info, flags) ||
375 TI_CPU != offsetof(struct thread_info, cpu) ||
376 TI_PREEMPT != offsetof(struct thread_info, preempt_count) ||
377 TI_SOFTIRQ != offsetof(struct thread_info, softirq_count) ||
378 TI_HARDIRQ != offsetof(struct thread_info, hardirq_count) ||
379 TI_KSP != offsetof(struct thread_info, ksp) ||
380 TI_KPC != offsetof(struct thread_info, kpc) ||
381 TI_KPSR != offsetof(struct thread_info, kpsr) ||
382 TI_KWIM != offsetof(struct thread_info, kwim) ||
383 TI_REG_WINDOW != offsetof(struct thread_info, reg_window) ||
384 TI_RWIN_SPTRS != offsetof(struct thread_info, rwbuf_stkptrs) ||
385 TI_W_SAVED != offsetof(struct thread_info, w_saved))
386 thread_info_offsets_are_bolixed_pete();
387
388 /* Attach to the address space of init_task. */
389 mmgrab(&init_mm);
390 current->active_mm = &init_mm;
391
392 /* NOTE: Other cpus have this done as they are started
393 * up on SMP.
394 */
395 }
396