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.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 __noreturn 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, LOCKDEP_NOW_UNRELIABLE);
  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
 124        info.si_signo = SIGILL;
 125        info.si_errno = 0;
 126        info.si_code = ILL_ILLOPC;
 127        info.si_addr = (void __user *)pc;
 128        info.si_trapno = 0;
 129        send_sig_info(SIGILL, &info, current);
 130}
 131
 132void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 133                         unsigned long psr)
 134{
 135        siginfo_t info;
 136
 137        if(psr & PSR_PS)
 138                die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
 139        info.si_signo = SIGILL;
 140        info.si_errno = 0;
 141        info.si_code = ILL_PRVOPC;
 142        info.si_addr = (void __user *)pc;
 143        info.si_trapno = 0;
 144        send_sig_info(SIGILL, &info, current);
 145}
 146
 147/* XXX User may want to be allowed to do this. XXX */
 148
 149void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 150                            unsigned long psr)
 151{
 152        siginfo_t info;
 153
 154        if(regs->psr & PSR_PS) {
 155                printk("KERNEL MNA at pc %08lx npc %08lx called by %08lx\n", pc, npc,
 156                       regs->u_regs[UREG_RETPC]);
 157                die_if_kernel("BOGUS", regs);
 158                /* die_if_kernel("Kernel MNA access", regs); */
 159        }
 160#if 0
 161        show_regs (regs);
 162        instruction_dump ((unsigned long *) regs->pc);
 163        printk ("do_MNA!\n");
 164#endif
 165        info.si_signo = SIGBUS;
 166        info.si_errno = 0;
 167        info.si_code = BUS_ADRALN;
 168        info.si_addr = /* FIXME: Should dig out mna address */ (void *)0;
 169        info.si_trapno = 0;
 170        send_sig_info(SIGBUS, &info, current);
 171}
 172
 173static unsigned long init_fsr = 0x0UL;
 174static unsigned long init_fregs[32] __attribute__ ((aligned (8))) =
 175                { ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
 176                  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
 177                  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
 178                  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL };
 179
 180void do_fpd_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 181                 unsigned long psr)
 182{
 183        /* Sanity check... */
 184        if(psr & PSR_PS)
 185                die_if_kernel("Kernel gets FloatingPenguinUnit disabled trap", regs);
 186
 187        put_psr(get_psr() | PSR_EF);    /* Allow FPU ops. */
 188        regs->psr |= PSR_EF;
 189#ifndef CONFIG_SMP
 190        if(last_task_used_math == current)
 191                return;
 192        if(last_task_used_math) {
 193                /* Other processes fpu state, save away */
 194                struct task_struct *fptask = last_task_used_math;
 195                fpsave(&fptask->thread.float_regs[0], &fptask->thread.fsr,
 196                       &fptask->thread.fpqueue[0], &fptask->thread.fpqdepth);
 197        }
 198        last_task_used_math = current;
 199        if(used_math()) {
 200                fpload(&current->thread.float_regs[0], &current->thread.fsr);
 201        } else {
 202                /* Set initial sane state. */
 203                fpload(&init_fregs[0], &init_fsr);
 204                set_used_math();
 205        }
 206#else
 207        if(!used_math()) {
 208                fpload(&init_fregs[0], &init_fsr);
 209                set_used_math();
 210        } else {
 211                fpload(&current->thread.float_regs[0], &current->thread.fsr);
 212        }
 213        set_thread_flag(TIF_USEDFPU);
 214#endif
 215}
 216
 217static unsigned long fake_regs[32] __attribute__ ((aligned (8)));
 218static unsigned long fake_fsr;
 219static unsigned long fake_queue[32] __attribute__ ((aligned (8)));
 220static unsigned long fake_depth;
 221
 222void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 223                 unsigned long psr)
 224{
 225        static int calls;
 226        siginfo_t info;
 227        unsigned long fsr;
 228        int ret = 0;
 229#ifndef CONFIG_SMP
 230        struct task_struct *fpt = last_task_used_math;
 231#else
 232        struct task_struct *fpt = current;
 233#endif
 234        put_psr(get_psr() | PSR_EF);
 235        /* If nobody owns the fpu right now, just clear the
 236         * error into our fake static buffer and hope it don't
 237         * happen again.  Thank you crashme...
 238         */
 239#ifndef CONFIG_SMP
 240        if(!fpt) {
 241#else
 242        if (!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
 243#endif
 244                fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
 245                regs->psr &= ~PSR_EF;
 246                return;
 247        }
 248        fpsave(&fpt->thread.float_regs[0], &fpt->thread.fsr,
 249               &fpt->thread.fpqueue[0], &fpt->thread.fpqdepth);
 250#ifdef DEBUG_FPU
 251        printk("Hmm, FP exception, fsr was %016lx\n", fpt->thread.fsr);
 252#endif
 253
 254        switch ((fpt->thread.fsr & 0x1c000)) {
 255        /* switch on the contents of the ftt [floating point trap type] field */
 256#ifdef DEBUG_FPU
 257        case (1 << 14):
 258                printk("IEEE_754_exception\n");
 259                break;
 260#endif
 261        case (2 << 14):  /* unfinished_FPop (underflow & co) */
 262        case (3 << 14):  /* unimplemented_FPop (quad stuff, maybe sqrt) */
 263                ret = do_mathemu(regs, fpt);
 264                break;
 265#ifdef DEBUG_FPU
 266        case (4 << 14):
 267                printk("sequence_error (OS bug...)\n");
 268                break;
 269        case (5 << 14):
 270                printk("hardware_error (uhoh!)\n");
 271                break;
 272        case (6 << 14):
 273                printk("invalid_fp_register (user error)\n");
 274                break;
 275#endif /* DEBUG_FPU */
 276        }
 277        /* If we successfully emulated the FPop, we pretend the trap never happened :-> */
 278        if (ret) {
 279                fpload(&current->thread.float_regs[0], &current->thread.fsr);
 280                return;
 281        }
 282        /* nope, better SIGFPE the offending process... */
 283               
 284#ifdef CONFIG_SMP
 285        clear_tsk_thread_flag(fpt, TIF_USEDFPU);
 286#endif
 287        if(psr & PSR_PS) {
 288                /* The first fsr store/load we tried trapped,
 289                 * the second one will not (we hope).
 290                 */
 291                printk("WARNING: FPU exception from kernel mode. at pc=%08lx\n",
 292                       regs->pc);
 293                regs->pc = regs->npc;
 294                regs->npc += 4;
 295                calls++;
 296                if(calls > 2)
 297                        die_if_kernel("Too many Penguin-FPU traps from kernel mode",
 298                                      regs);
 299                return;
 300        }
 301
 302        fsr = fpt->thread.fsr;
 303        info.si_signo = SIGFPE;
 304        info.si_errno = 0;
 305        info.si_addr = (void __user *)pc;
 306        info.si_trapno = 0;
 307        info.si_code = __SI_FAULT;
 308        if ((fsr & 0x1c000) == (1 << 14)) {
 309                if (fsr & 0x10)
 310                        info.si_code = FPE_FLTINV;
 311                else if (fsr & 0x08)
 312                        info.si_code = FPE_FLTOVF;
 313                else if (fsr & 0x04)
 314                        info.si_code = FPE_FLTUND;
 315                else if (fsr & 0x02)
 316                        info.si_code = FPE_FLTDIV;
 317                else if (fsr & 0x01)
 318                        info.si_code = FPE_FLTRES;
 319        }
 320        send_sig_info(SIGFPE, &info, fpt);
 321#ifndef CONFIG_SMP
 322        last_task_used_math = NULL;
 323#endif
 324        regs->psr &= ~PSR_EF;
 325        if(calls > 0)
 326                calls=0;
 327}
 328
 329void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 330                         unsigned long psr)
 331{
 332        siginfo_t info;
 333
 334        if(psr & PSR_PS)
 335                die_if_kernel("Penguin overflow trap from kernel mode", regs);
 336        info.si_signo = SIGEMT;
 337        info.si_errno = 0;
 338        info.si_code = EMT_TAGOVF;
 339        info.si_addr = (void __user *)pc;
 340        info.si_trapno = 0;
 341        send_sig_info(SIGEMT, &info, current);
 342}
 343
 344void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 345                       unsigned long psr)
 346{
 347#ifdef TRAP_DEBUG
 348        printk("Watchpoint detected at PC %08lx NPC %08lx PSR %08lx\n",
 349               pc, npc, psr);
 350#endif
 351        if(psr & PSR_PS)
 352                panic("Tell me what a watchpoint trap is, and I'll then deal "
 353                      "with such a beast...");
 354}
 355
 356void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 357                       unsigned long psr)
 358{
 359        siginfo_t info;
 360
 361#ifdef TRAP_DEBUG
 362        printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
 363               pc, npc, psr);
 364#endif
 365        info.si_signo = SIGBUS;
 366        info.si_errno = 0;
 367        info.si_code = BUS_OBJERR;
 368        info.si_addr = (void __user *)pc;
 369        info.si_trapno = 0;
 370        force_sig_info(SIGBUS, &info, current);
 371}
 372
 373void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 374                        unsigned long psr)
 375{
 376        siginfo_t info;
 377
 378        info.si_signo = SIGILL;
 379        info.si_errno = 0;
 380        info.si_code = ILL_COPROC;
 381        info.si_addr = (void __user *)pc;
 382        info.si_trapno = 0;
 383        send_sig_info(SIGILL, &info, current);
 384}
 385
 386void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 387                         unsigned long psr)
 388{
 389        siginfo_t info;
 390
 391#ifdef TRAP_DEBUG
 392        printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
 393               pc, npc, psr);
 394#endif
 395        info.si_signo = SIGILL;
 396        info.si_errno = 0;
 397        info.si_code = ILL_COPROC;
 398        info.si_addr = (void __user *)pc;
 399        info.si_trapno = 0;
 400        send_sig_info(SIGILL, &info, current);
 401}
 402
 403void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 404                       unsigned long psr)
 405{
 406        siginfo_t info;
 407
 408        info.si_signo = SIGFPE;
 409        info.si_errno = 0;
 410        info.si_code = FPE_INTDIV;
 411        info.si_addr = (void __user *)pc;
 412        info.si_trapno = 0;
 413        send_sig_info(SIGFPE, &info, current);
 414}
 415
 416#ifdef CONFIG_DEBUG_BUGVERBOSE
 417void do_BUG(const char *file, int line)
 418{
 419        // bust_spinlocks(1);   XXX Not in our original BUG()
 420        printk("kernel BUG at %s:%d!\n", file, line);
 421}
 422EXPORT_SYMBOL(do_BUG);
 423#endif
 424
 425/* Since we have our mappings set up, on multiprocessors we can spin them
 426 * up here so that timer interrupts work during initialization.
 427 */
 428
 429void trap_init(void)
 430{
 431        extern void thread_info_offsets_are_bolixed_pete(void);
 432
 433        /* Force linker to barf if mismatched */
 434        if (TI_UWINMASK    != offsetof(struct thread_info, uwinmask) ||
 435            TI_TASK        != offsetof(struct thread_info, task) ||
 436            TI_FLAGS       != offsetof(struct thread_info, flags) ||
 437            TI_CPU         != offsetof(struct thread_info, cpu) ||
 438            TI_PREEMPT     != offsetof(struct thread_info, preempt_count) ||
 439            TI_SOFTIRQ     != offsetof(struct thread_info, softirq_count) ||
 440            TI_HARDIRQ     != offsetof(struct thread_info, hardirq_count) ||
 441            TI_KSP         != offsetof(struct thread_info, ksp) ||
 442            TI_KPC         != offsetof(struct thread_info, kpc) ||
 443            TI_KPSR        != offsetof(struct thread_info, kpsr) ||
 444            TI_KWIM        != offsetof(struct thread_info, kwim) ||
 445            TI_REG_WINDOW  != offsetof(struct thread_info, reg_window) ||
 446            TI_RWIN_SPTRS  != offsetof(struct thread_info, rwbuf_stkptrs) ||
 447            TI_W_SAVED     != offsetof(struct thread_info, w_saved))
 448                thread_info_offsets_are_bolixed_pete();
 449
 450        /* Attach to the address space of init_task. */
 451        atomic_inc(&init_mm.mm_count);
 452        current->active_mm = &init_mm;
 453
 454        /* NOTE: Other cpus have this done as they are started
 455         *       up on SMP.
 456         */
 457}
 458