LXR linux/arch/sparc/kernel/traps

   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/mm.h>
  13#include <linux/sched/debug.h>
  14#include <linux/mm_types.h>
  15#include <linux/kernel.h>
  16#include <linux/signal.h>
  17#include <linux/smp.h>
  18#include <linux/kdebug.h>
  19#include <linux/export.h>
  20
  21#include <asm/delay.h>
  22#include <asm/ptrace.h>
  23#include <asm/oplib.h>
  24#include <asm/page.h>
  25#include <asm/pgtable.h>
  26#include <asm/unistd.h>
  27#include <asm/traps.h>
  28
  29#include "entry.h"
  30#include "kernel.h"
  31
  32/* #define TRAP_DEBUG */
  33
  34static void instruction_dump(unsigned long *pc)
  35{
  36        int i;
  37        
  38        if((((unsigned long) pc) & 3))
  39                return;
  40
  41        for(i = -3; i < 6; i++)
  42                printk("%c%08lx%c",i?' ':'<',pc[i],i?' ':'>');
  43        printk("\n");
  44}
  45
  46#define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
  47#define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")
  48
  49void __noreturn die_if_kernel(char *str, struct pt_regs *regs)
  50{
  51        static int die_counter;
  52        int count = 0;
  53
  54        /* Amuse the user. */
  55        printk(
  56"              \\|/ ____ \\|/\n"
  57"              \"@'/ ,. \\`@\"\n"
  58"              /_| \\__/ |_\\\n"
  59"                 \\__U_/\n");
  60
  61        printk("%s(%d): %s [#%d]\n", current->comm, task_pid_nr(current), str, ++die_counter);
  62        show_regs(regs);
  63        add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
  64
  65        __SAVE; __SAVE; __SAVE; __SAVE;
  66        __SAVE; __SAVE; __SAVE; __SAVE;
  67        __RESTORE; __RESTORE; __RESTORE; __RESTORE;
  68        __RESTORE; __RESTORE; __RESTORE; __RESTORE;
  69
  70        {
  71                struct reg_window32 *rw = (struct reg_window32 *)regs->u_regs[UREG_FP];
  72
  73                /* Stop the back trace when we hit userland or we
  74                 * find some badly aligned kernel stack. Set an upper
  75                 * bound in case our stack is trashed and we loop.
  76                 */
  77                while(rw                                        &&
  78                      count++ < 30                              &&
  79                      (((unsigned long) rw) >= PAGE_OFFSET)     &&
  80                      !(((unsigned long) rw) & 0x7)) {
  81                        printk("Caller[%08lx]: %pS\n", rw->ins[7],
  82                               (void *) rw->ins[7]);
  83                        rw = (struct reg_window32 *)rw->ins[6];
  84                }
  85        }
  86        printk("Instruction DUMP:");
  87        instruction_dump ((unsigned long *) regs->pc);
  88        if(regs->psr & PSR_PS)
  89                do_exit(SIGKILL);
  90        do_exit(SIGSEGV);
  91}
  92
  93void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
  94{
  95        siginfo_t info;
  96
  97        if(type < 0x80) {
  98                /* Sun OS's puke from bad traps, Linux survives! */
  99                printk("Unimplemented Sparc TRAP, type = %02lx\n", type);
 100                die_if_kernel("Whee... Hello Mr. Penguin", regs);
 101        }       
 102
 103        if(regs->psr & PSR_PS)
 104                die_if_kernel("Kernel bad trap", regs);
 105
 106        info.si_signo = SIGILL;
 107        info.si_errno = 0;
 108        info.si_code = ILL_ILLTRP;
 109        info.si_addr = (void __user *)regs->pc;
 110        info.si_trapno = type - 0x80;
 111        force_sig_info(SIGILL, &info, current);
 112}
 113
 114void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 115                            unsigned long psr)
 116{
 117        siginfo_t info;
 118
 119        if(psr & PSR_PS)
 120                die_if_kernel("Kernel illegal instruction", regs);
 121#ifdef TRAP_DEBUG
 122        printk("Ill instr. at pc=%08lx instruction is %08lx\n",
 123               regs->pc, *(unsigned long *)regs->pc);
 124#endif
 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
 224void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 225                 unsigned long psr)
 226{
 227        static int calls;
 228        siginfo_t info;
 229        unsigned long fsr;
 230        int ret = 0;
 231#ifndef CONFIG_SMP
 232        struct task_struct *fpt = last_task_used_math;
 233#else
 234        struct task_struct *fpt = current;
 235#endif
 236        put_psr(get_psr() | PSR_EF);
 237        /* If nobody owns the fpu right now, just clear the
 238         * error into our fake static buffer and hope it don't
 239         * happen again.  Thank you crashme...
 240         */
 241#ifndef CONFIG_SMP
 242        if(!fpt) {
 243#else
 244        if (!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
 245#endif
 246                fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
 247                regs->psr &= ~PSR_EF;
 248                return;
 249        }
 250        fpsave(&fpt->thread.float_regs[0], &fpt->thread.fsr,
 251               &fpt->thread.fpqueue[0], &fpt->thread.fpqdepth);
 252#ifdef DEBUG_FPU
 253        printk("Hmm, FP exception, fsr was %016lx\n", fpt->thread.fsr);
 254#endif
 255
 256        switch ((fpt->thread.fsr & 0x1c000)) {
 257        /* switch on the contents of the ftt [floating point trap type] field */
 258#ifdef DEBUG_FPU
 259        case (1 << 14):
 260                printk("IEEE_754_exception\n");
 261                break;
 262#endif
 263        case (2 << 14):  /* unfinished_FPop (underflow & co) */
 264        case (3 << 14):  /* unimplemented_FPop (quad stuff, maybe sqrt) */
 265                ret = do_mathemu(regs, fpt);
 266                break;
 267#ifdef DEBUG_FPU
 268        case (4 << 14):
 269                printk("sequence_error (OS bug...)\n");
 270                break;
 271        case (5 << 14):
 272                printk("hardware_error (uhoh!)\n");
 273                break;
 274        case (6 << 14):
 275                printk("invalid_fp_register (user error)\n");
 276                break;
 277#endif /* DEBUG_FPU */
 278        }
 279        /* If we successfully emulated the FPop, we pretend the trap never happened :-> */
 280        if (ret) {
 281                fpload(&current->thread.float_regs[0], &current->thread.fsr);
 282                return;
 283        }
 284        /* nope, better SIGFPE the offending process... */
 285               
 286#ifdef CONFIG_SMP
 287        clear_tsk_thread_flag(fpt, TIF_USEDFPU);
 288#endif
 289        if(psr & PSR_PS) {
 290                /* The first fsr store/load we tried trapped,
 291                 * the second one will not (we hope).
 292                 */
 293                printk("WARNING: FPU exception from kernel mode. at pc=%08lx\n",
 294                       regs->pc);
 295                regs->pc = regs->npc;
 296                regs->npc += 4;
 297                calls++;
 298                if(calls > 2)
 299                        die_if_kernel("Too many Penguin-FPU traps from kernel mode",
 300                                      regs);
 301                return;
 302        }
 303
 304        fsr = fpt->thread.fsr;
 305        info.si_signo = SIGFPE;
 306        info.si_errno = 0;
 307        info.si_addr = (void __user *)pc;
 308        info.si_trapno = 0;
 309        info.si_code = __SI_FAULT;
 310        if ((fsr & 0x1c000) == (1 << 14)) {
 311                if (fsr & 0x10)
 312                        info.si_code = FPE_FLTINV;
 313                else if (fsr & 0x08)
 314                        info.si_code = FPE_FLTOVF;
 315                else if (fsr & 0x04)
 316                        info.si_code = FPE_FLTUND;
 317                else if (fsr & 0x02)
 318                        info.si_code = FPE_FLTDIV;
 319                else if (fsr & 0x01)
 320                        info.si_code = FPE_FLTRES;
 321        }
 322        send_sig_info(SIGFPE, &info, fpt);
 323#ifndef CONFIG_SMP
 324        last_task_used_math = NULL;
 325#endif
 326        regs->psr &= ~PSR_EF;
 327        if(calls > 0)
 328                calls=0;
 329}
 330
 331void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 332                         unsigned long psr)
 333{
 334        siginfo_t info;
 335
 336        if(psr & PSR_PS)
 337                die_if_kernel("Penguin overflow trap from kernel mode", regs);
 338        info.si_signo = SIGEMT;
 339        info.si_errno = 0;
 340        info.si_code = EMT_TAGOVF;
 341        info.si_addr = (void __user *)pc;
 342        info.si_trapno = 0;
 343        send_sig_info(SIGEMT, &info, current);
 344}
 345
 346void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 347                       unsigned long psr)
 348{
 349#ifdef TRAP_DEBUG
 350        printk("Watchpoint detected at PC %08lx NPC %08lx PSR %08lx\n",
 351               pc, npc, psr);
 352#endif
 353        if(psr & PSR_PS)
 354                panic("Tell me what a watchpoint trap is, and I'll then deal "
 355                      "with such a beast...");
 356}
 357
 358void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 359                       unsigned long psr)
 360{
 361        siginfo_t info;
 362
 363#ifdef TRAP_DEBUG
 364        printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
 365               pc, npc, psr);
 366#endif
 367        info.si_signo = SIGBUS;
 368        info.si_errno = 0;
 369        info.si_code = BUS_OBJERR;
 370        info.si_addr = (void __user *)pc;
 371        info.si_trapno = 0;
 372        force_sig_info(SIGBUS, &info, current);
 373}
 374
 375void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 376                        unsigned long psr)
 377{
 378        siginfo_t info;
 379
 380        info.si_signo = SIGILL;
 381        info.si_errno = 0;
 382        info.si_code = ILL_COPROC;
 383        info.si_addr = (void __user *)pc;
 384        info.si_trapno = 0;
 385        send_sig_info(SIGILL, &info, current);
 386}
 387
 388void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 389                         unsigned long psr)
 390{
 391        siginfo_t info;
 392
 393#ifdef TRAP_DEBUG
 394        printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
 395               pc, npc, psr);
 396#endif
 397        info.si_signo = SIGILL;
 398        info.si_errno = 0;
 399        info.si_code = ILL_COPROC;
 400        info.si_addr = (void __user *)pc;
 401        info.si_trapno = 0;
 402        send_sig_info(SIGILL, &info, current);
 403}
 404
 405void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 406                       unsigned long psr)
 407{
 408        siginfo_t info;
 409
 410        info.si_signo = SIGFPE;
 411        info.si_errno = 0;
 412        info.si_code = FPE_INTDIV;
 413        info.si_addr = (void __user *)pc;
 414        info.si_trapno = 0;
 415        send_sig_info(SIGFPE, &info, current);
 416}
 417
 418#ifdef CONFIG_DEBUG_BUGVERBOSE
 419void do_BUG(const char *file, int line)
 420{
 421        // bust_spinlocks(1);   XXX Not in our original BUG()
 422        printk("kernel BUG at %s:%d!\n", file, line);
 423}
 424EXPORT_SYMBOL(do_BUG);
 425#endif
 426
 427/* Since we have our mappings set up, on multiprocessors we can spin them
 428 * up here so that timer interrupts work during initialization.
 429 */
 430
 431void trap_init(void)
 432{
 433        extern void thread_info_offsets_are_bolixed_pete(void);
 434
 435        /* Force linker to barf if mismatched */
 436        if (TI_UWINMASK    != offsetof(struct thread_info, uwinmask) ||
 437            TI_TASK        != offsetof(struct thread_info, task) ||
 438            TI_FLAGS       != offsetof(struct thread_info, flags) ||
 439            TI_CPU         != offsetof(struct thread_info, cpu) ||
 440            TI_PREEMPT     != offsetof(struct thread_info, preempt_count) ||
 441            TI_SOFTIRQ     != offsetof(struct thread_info, softirq_count) ||
 442            TI_HARDIRQ     != offsetof(struct thread_info, hardirq_count) ||
 443            TI_KSP         != offsetof(struct thread_info, ksp) ||
 444            TI_KPC         != offsetof(struct thread_info, kpc) ||
 445            TI_KPSR        != offsetof(struct thread_info, kpsr) ||
 446            TI_KWIM        != offsetof(struct thread_info, kwim) ||
 447            TI_REG_WINDOW  != offsetof(struct thread_info, reg_window) ||
 448            TI_RWIN_SPTRS  != offsetof(struct thread_info, rwbuf_stkptrs) ||
 449            TI_W_SAVED     != offsetof(struct thread_info, w_saved))
 450                thread_info_offsets_are_bolixed_pete();
 451
 452        /* Attach to the address space of init_task. */
 453        mmgrab(&init_mm);
 454        current->active_mm = &init_mm;
 455
 456        /* NOTE: Other cpus have this done as they are started
 457         *       up on SMP.
 458         */
 459}
 460