1/*
2 * arch/sparc/kernel/traps.c
3 *
4 * Copyright 1995, 2008 David S. Miller (davem@davemloft.net)
5 * Copyright 2000 Jakub Jelinek (jakub@redhat.com)
6 */
7
8/*
9 * I hate traps on the sparc, grrr...
10 */
11
12#include <linux/sched.h>  /* for jiffies */
13#include <linux/kernel.h>
14#include <linux/signal.h>
15#include <linux/smp.h>
16#include <linux/kdebug.h>
17#include <linux/export.h>
18
19#include <asm/delay.h>
20#include <asm/ptrace.h>
21#include <asm/oplib.h>
22#include <asm/page.h>
23#include <asm/pgtable.h>
24#include <asm/unistd.h>
25#include <asm/traps.h>
26
27#include "entry.h"
28#include "kernel.h"
29
30/* #define TRAP_DEBUG */
31
32static void instruction_dump(unsigned long *pc)
33{
34	int i;
35
36	if((((unsigned long) pc) & 3))
37                return;
38
39	for(i = -3; i < 6; i++)
40		printk("%c%08lx%c",i?' ':'<',pc[i],i?' ':'>');
41	printk("\n");
42}
43
44#define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
45#define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
46
47void die_if_kernel(char *str, struct pt_regs *regs)
48{
49	static int die_counter;
50	int count = 0;
51
52	/* Amuse the user. */
53	printk(
54"              \\|/ ____ \\|/\n"
55"              \"@'/ ,. \\`@\"\n"
56"              /_| \\__/ |_\\\n"
57"                 \\__U_/\n");
58
59	printk("%s(%d): %s [#%d]\n", current->comm, task_pid_nr(current), str, ++die_counter);
60	show_regs(regs);
61	add_taint(TAINT_DIE);
62
63	__SAVE; __SAVE; __SAVE; __SAVE;
64	__SAVE; __SAVE; __SAVE; __SAVE;
65	__RESTORE; __RESTORE; __RESTORE; __RESTORE;
66	__RESTORE; __RESTORE; __RESTORE; __RESTORE;
67
68	{
69		struct reg_window32 *rw = (struct reg_window32 *)regs->u_regs[UREG_FP];
70
71		/* Stop the back trace when we hit userland or we
72		 * find some badly aligned kernel stack. Set an upper
73		 * bound in case our stack is trashed and we loop.
74		 */
75		while(rw					&&
76		      count++ < 30				&&
77                      (((unsigned long) rw) >= PAGE_OFFSET)	&&
78		      !(((unsigned long) rw) & 0x7)) {
79			printk("Caller[%08lx]: %pS\n", rw->ins[7],
80			       (void *) rw->ins[7]);
81			rw = (struct reg_window32 *)rw->ins[6];
82		}
83	}
84	printk("Instruction DUMP:");
85	instruction_dump ((unsigned long *) regs->pc);
86	if(regs->psr & PSR_PS)
87		do_exit(SIGKILL);
88	do_exit(SIGSEGV);
89}
90
91void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
92{
93	siginfo_t info;
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	info.si_signo = SIGILL;
105	info.si_errno = 0;
106	info.si_code = ILL_ILLTRP;
107	info.si_addr = (void __user *)regs->pc;
108	info.si_trapno = type - 0x80;
109	force_sig_info(SIGILL, &info, current);
110}
111
112void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
113			    unsigned long psr)
114{
115	siginfo_t info;
116
117	if(psr & PSR_PS)
118		die_if_kernel("Kernel illegal instruction", regs);
119#ifdef TRAP_DEBUG
120	printk("Ill instr. at pc=%08lx instruction is %08lx\n",
121	       regs->pc, *(unsigned long *)regs->pc);
122#endif
123	if (!do_user_muldiv (regs, pc))
124		return;
125
126	info.si_signo = SIGILL;
127	info.si_errno = 0;
128	info.si_code = ILL_ILLOPC;
129	info.si_addr = (void __user *)pc;
130	info.si_trapno = 0;
131	send_sig_info(SIGILL, &info, current);
132}
133
134void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
135			 unsigned long psr)
136{
137	siginfo_t info;
138
139	if(psr & PSR_PS)
140		die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
141	info.si_signo = SIGILL;
142	info.si_errno = 0;
143	info.si_code = ILL_PRVOPC;
144	info.si_addr = (void __user *)pc;
145	info.si_trapno = 0;
146	send_sig_info(SIGILL, &info, current);
147}
148
149/* XXX User may want to be allowed to do this. XXX */
150
151void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned long npc,
152			    unsigned long psr)
153{
154	siginfo_t info;
155
156	if(regs->psr & PSR_PS) {
157		printk("KERNEL MNA at pc %08lx npc %08lx called by %08lx\n", pc, npc,
158		       regs->u_regs[UREG_RETPC]);
159		die_if_kernel("BOGUS", regs);
160		/* die_if_kernel("Kernel MNA access", regs); */
161	}
162#if 0
163	show_regs (regs);
164	instruction_dump ((unsigned long *) regs->pc);
165	printk ("do_MNA!\n");
166#endif
167	info.si_signo = SIGBUS;
168	info.si_errno = 0;
169	info.si_code = BUS_ADRALN;
170	info.si_addr = /* FIXME: Should dig out mna address */ (void *)0;
171	info.si_trapno = 0;
172	send_sig_info(SIGBUS, &info, current);
173}
174
175static unsigned long init_fsr = 0x0UL;
176static unsigned long init_fregs[32] __attribute__ ((aligned (8))) =
177                { ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
178		  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
179		  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
180		  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL };
181
182void do_fpd_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
183		 unsigned long psr)
184{
185	/* Sanity check... */
186	if(psr & PSR_PS)
187		die_if_kernel("Kernel gets FloatingPenguinUnit disabled trap", regs);
188
189	put_psr(get_psr() | PSR_EF);    /* Allow FPU ops. */
190	regs->psr |= PSR_EF;
191#ifndef CONFIG_SMP
192	if(last_task_used_math == current)
193		return;
194	if(last_task_used_math) {
195		/* Other processes fpu state, save away */
196		struct task_struct *fptask = last_task_used_math;
197		fpsave(&fptask->thread.float_regs[0], &fptask->thread.fsr,
198		       &fptask->thread.fpqueue[0], &fptask->thread.fpqdepth);
199	}
200	last_task_used_math = current;
201	if(used_math()) {
202		fpload(&current->thread.float_regs[0], &current->thread.fsr);
203	} else {
204		/* Set initial sane state. */
205		fpload(&init_fregs[0], &init_fsr);
206		set_used_math();
207	}
208#else
209	if(!used_math()) {
210		fpload(&init_fregs[0], &init_fsr);
211		set_used_math();
212	} else {
213		fpload(&current->thread.float_regs[0], &current->thread.fsr);
214	}
215	set_thread_flag(TIF_USEDFPU);
216#endif
217}
218
219static unsigned long fake_regs[32] __attribute__ ((aligned (8)));
220static unsigned long fake_fsr;
221static unsigned long fake_queue[32] __attribute__ ((aligned (8)));
222static unsigned long fake_depth;
223
224extern int do_mathemu(struct pt_regs *, struct task_struct *);
225
226void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
227		 unsigned long psr)
228{
229	static int calls;
230	siginfo_t info;
231	unsigned long fsr;
232	int ret = 0;
233#ifndef CONFIG_SMP
234	struct task_struct *fpt = last_task_used_math;
235#else
236	struct task_struct *fpt = current;
237#endif
238	put_psr(get_psr() | PSR_EF);
239	/* If nobody owns the fpu right now, just clear the
240	 * error into our fake static buffer and hope it don't
241	 * happen again.  Thank you crashme...
242	 */
243#ifndef CONFIG_SMP
244	if(!fpt) {
245#else
246	if (!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
247#endif
248		fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
249		regs->psr &= ~PSR_EF;
250		return;
251	}
252	fpsave(&fpt->thread.float_regs[0], &fpt->thread.fsr,
253	       &fpt->thread.fpqueue[0], &fpt->thread.fpqdepth);
254#ifdef DEBUG_FPU
255	printk("Hmm, FP exception, fsr was %016lx\n", fpt->thread.fsr);
256#endif
257
258	switch ((fpt->thread.fsr & 0x1c000)) {
259	/* switch on the contents of the ftt [floating point trap type] field */
260#ifdef DEBUG_FPU
261	case (1 << 14):
262		printk("IEEE_754_exception\n");
263		break;
264#endif
265	case (2 << 14):  /* unfinished_FPop (underflow & co) */
266	case (3 << 14):  /* unimplemented_FPop (quad stuff, maybe sqrt) */
267		ret = do_mathemu(regs, fpt);
268		break;
269#ifdef DEBUG_FPU
270	case (4 << 14):
271		printk("sequence_error (OS bug...)\n");
272		break;
273	case (5 << 14):
274		printk("hardware_error (uhoh!)\n");
275		break;
276	case (6 << 14):
277		printk("invalid_fp_register (user error)\n");
278		break;
279#endif /* DEBUG_FPU */
280	}
281	/* If we successfully emulated the FPop, we pretend the trap never happened :-> */
282	if (ret) {
283		fpload(&current->thread.float_regs[0], &current->thread.fsr);
284		return;
285	}
286	/* nope, better SIGFPE the offending process... */
287
288#ifdef CONFIG_SMP
289	clear_tsk_thread_flag(fpt, TIF_USEDFPU);
290#endif
291	if(psr & PSR_PS) {
292		/* The first fsr store/load we tried trapped,
293		 * the second one will not (we hope).
294		 */
295		printk("WARNING: FPU exception from kernel mode. at pc=%08lx\n",
296		       regs->pc);
297		regs->pc = regs->npc;
298		regs->npc += 4;
299		calls++;
300		if(calls > 2)
301			die_if_kernel("Too many Penguin-FPU traps from kernel mode",
302				      regs);
303		return;
304	}
305
306	fsr = fpt->thread.fsr;
307	info.si_signo = SIGFPE;
308	info.si_errno = 0;
309	info.si_addr = (void __user *)pc;
310	info.si_trapno = 0;
311	info.si_code = __SI_FAULT;
312	if ((fsr & 0x1c000) == (1 << 14)) {
313		if (fsr & 0x10)
314			info.si_code = FPE_FLTINV;
315		else if (fsr & 0x08)
316			info.si_code = FPE_FLTOVF;
317		else if (fsr & 0x04)
318			info.si_code = FPE_FLTUND;
319		else if (fsr & 0x02)
320			info.si_code = FPE_FLTDIV;
321		else if (fsr & 0x01)
322			info.si_code = FPE_FLTRES;
323	}
324	send_sig_info(SIGFPE, &info, fpt);
325#ifndef CONFIG_SMP
326	last_task_used_math = NULL;
327#endif
328	regs->psr &= ~PSR_EF;
329	if(calls > 0)
330		calls=0;
331}
332
333void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long npc,
334			 unsigned long psr)
335{
336	siginfo_t info;
337
338	if(psr & PSR_PS)
339		die_if_kernel("Penguin overflow trap from kernel mode", regs);
340	info.si_signo = SIGEMT;
341	info.si_errno = 0;
342	info.si_code = EMT_TAGOVF;
343	info.si_addr = (void __user *)pc;
344	info.si_trapno = 0;
345	send_sig_info(SIGEMT, &info, current);
346}
347
348void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
349		       unsigned long psr)
350{
351#ifdef TRAP_DEBUG
352	printk("Watchpoint detected at PC %08lx NPC %08lx PSR %08lx\n",
353	       pc, npc, psr);
354#endif
355	if(psr & PSR_PS)
356		panic("Tell me what a watchpoint trap is, and I'll then deal "
357		      "with such a beast...");
358}
359
360void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc,
361		       unsigned long psr)
362{
363	siginfo_t info;
364
365#ifdef TRAP_DEBUG
366	printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
367	       pc, npc, psr);
368#endif
369	info.si_signo = SIGBUS;
370	info.si_errno = 0;
371	info.si_code = BUS_OBJERR;
372	info.si_addr = (void __user *)pc;
373	info.si_trapno = 0;
374	force_sig_info(SIGBUS, &info, current);
375}
376
377void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
378			unsigned long psr)
379{
380	siginfo_t info;
381
382	info.si_signo = SIGILL;
383	info.si_errno = 0;
384	info.si_code = ILL_COPROC;
385	info.si_addr = (void __user *)pc;
386	info.si_trapno = 0;
387	send_sig_info(SIGILL, &info, current);
388}
389
390void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
391			 unsigned long psr)
392{
393	siginfo_t info;
394
395#ifdef TRAP_DEBUG
396	printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
397	       pc, npc, psr);
398#endif
399	info.si_signo = SIGILL;
400	info.si_errno = 0;
401	info.si_code = ILL_COPROC;
402	info.si_addr = (void __user *)pc;
403	info.si_trapno = 0;
404	send_sig_info(SIGILL, &info, current);
405}
406
407void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
408		       unsigned long psr)
409{
410	siginfo_t info;
411
412	info.si_signo = SIGFPE;
413	info.si_errno = 0;
414	info.si_code = FPE_INTDIV;
415	info.si_addr = (void __user *)pc;
416	info.si_trapno = 0;
417	send_sig_info(SIGFPE, &info, current);
418}
419
420#ifdef CONFIG_DEBUG_BUGVERBOSE
421void do_BUG(const char *file, int line)
422{
423        // bust_spinlocks(1);   XXX Not in our original BUG()
424        printk("kernel BUG at %s:%d!\n", file, line);
425}
426EXPORT_SYMBOL(do_BUG);
427#endif
428
429/* Since we have our mappings set up, on multiprocessors we can spin them
430 * up here so that timer interrupts work during initialization.
431 */
432
433void trap_init(void)
434{
435	extern void thread_info_offsets_are_bolixed_pete(void);
436
437	/* Force linker to barf if mismatched */
438	if (TI_UWINMASK    != offsetof(struct thread_info, uwinmask) ||
439	    TI_TASK        != offsetof(struct thread_info, task) ||
440	    TI_EXECDOMAIN  != offsetof(struct thread_info, exec_domain) ||
441	    TI_FLAGS       != offsetof(struct thread_info, flags) ||
442	    TI_CPU         != offsetof(struct thread_info, cpu) ||
443	    TI_PREEMPT     != offsetof(struct thread_info, preempt_count) ||
444	    TI_SOFTIRQ     != offsetof(struct thread_info, softirq_count) ||
445	    TI_HARDIRQ     != offsetof(struct thread_info, hardirq_count) ||
446	    TI_KSP         != offsetof(struct thread_info, ksp) ||
447	    TI_KPC         != offsetof(struct thread_info, kpc) ||
448	    TI_KPSR        != offsetof(struct thread_info, kpsr) ||
449	    TI_KWIM        != offsetof(struct thread_info, kwim) ||
450	    TI_REG_WINDOW  != offsetof(struct thread_info, reg_window) ||
451	    TI_RWIN_SPTRS  != offsetof(struct thread_info, rwbuf_stkptrs) ||
452	    TI_W_SAVED     != offsetof(struct thread_info, w_saved))
453		thread_info_offsets_are_bolixed_pete();
454
455	/* Attach to the address space of init_task. */
456	atomic_inc(&init_mm.mm_count);
457	current->active_mm = &init_mm;
458
459	/* NOTE: Other cpus have this done as they are started
460	 *       up on SMP.
461	 */
462}
463