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