LXR linux/arch/sparc/kernel/traps

   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#include <linux/pgtable.h>
  22
  23#include <asm/delay.h>
  24#include <asm/ptrace.h>
  25#include <asm/oplib.h>
  26#include <asm/page.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
  35static 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
  50void __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        if(regs->psr & PSR_PS)
  90                do_exit(SIGKILL);
  91        do_exit(SIGSEGV);
  92}
  93
  94void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
  95{
  96        if(type < 0x80) {
  97                /* Sun OS's puke from bad traps, Linux survives! */
  98                printk("Unimplemented Sparc TRAP, type = %02lx\n", type);
  99                die_if_kernel("Whee... Hello Mr. Penguin", regs);
 100        }       
 101
 102        if(regs->psr & PSR_PS)
 103                die_if_kernel("Kernel bad trap", regs);
 104
 105        force_sig_fault(SIGILL, ILL_ILLTRP,
 106                        (void __user *)regs->pc, type - 0x80);
 107}
 108
 109void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 110                            unsigned long psr)
 111{
 112        if(psr & PSR_PS)
 113                die_if_kernel("Kernel illegal instruction", regs);
 114#ifdef TRAP_DEBUG
 115        printk("Ill instr. at pc=%08lx instruction is %08lx\n",
 116               regs->pc, *(unsigned long *)regs->pc);
 117#endif
 118
 119        send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)pc, 0, current);
 120}
 121
 122void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 123                         unsigned long psr)
 124{
 125        if(psr & PSR_PS)
 126                die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
 127        send_sig_fault(SIGILL, ILL_PRVOPC, (void __user *)pc, 0, current);
 128}
 129
 130/* XXX User may want to be allowed to do this. XXX */
 131
 132void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 133                            unsigned long psr)
 134{
 135        if(regs->psr & PSR_PS) {
 136                printk("KERNEL MNA at pc %08lx npc %08lx called by %08lx\n", pc, npc,
 137                       regs->u_regs[UREG_RETPC]);
 138                die_if_kernel("BOGUS", regs);
 139                /* die_if_kernel("Kernel MNA access", regs); */
 140        }
 141#if 0
 142        show_regs (regs);
 143        instruction_dump ((unsigned long *) regs->pc);
 144        printk ("do_MNA!\n");
 145#endif
 146        send_sig_fault(SIGBUS, BUS_ADRALN,
 147                       /* FIXME: Should dig out mna address */ (void *)0,
 148                       0, current);
 149}
 150
 151static unsigned long init_fsr = 0x0UL;
 152static unsigned long init_fregs[32] __attribute__ ((aligned (8))) =
 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                  ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL };
 157
 158void do_fpd_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 159                 unsigned long psr)
 160{
 161        /* Sanity check... */
 162        if(psr & PSR_PS)
 163                die_if_kernel("Kernel gets FloatingPenguinUnit disabled trap", regs);
 164
 165        put_psr(get_psr() | PSR_EF);    /* Allow FPU ops. */
 166        regs->psr |= PSR_EF;
 167#ifndef CONFIG_SMP
 168        if(last_task_used_math == current)
 169                return;
 170        if(last_task_used_math) {
 171                /* Other processes fpu state, save away */
 172                struct task_struct *fptask = last_task_used_math;
 173                fpsave(&fptask->thread.float_regs[0], &fptask->thread.fsr,
 174                       &fptask->thread.fpqueue[0], &fptask->thread.fpqdepth);
 175        }
 176        last_task_used_math = current;
 177        if(used_math()) {
 178                fpload(&current->thread.float_regs[0], &current->thread.fsr);
 179        } else {
 180                /* Set initial sane state. */
 181                fpload(&init_fregs[0], &init_fsr);
 182                set_used_math();
 183        }
 184#else
 185        if(!used_math()) {
 186                fpload(&init_fregs[0], &init_fsr);
 187                set_used_math();
 188        } else {
 189                fpload(&current->thread.float_regs[0], &current->thread.fsr);
 190        }
 191        set_thread_flag(TIF_USEDFPU);
 192#endif
 193}
 194
 195static unsigned long fake_regs[32] __attribute__ ((aligned (8)));
 196static unsigned long fake_fsr;
 197static unsigned long fake_queue[32] __attribute__ ((aligned (8)));
 198static unsigned long fake_depth;
 199
 200void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 201                 unsigned long psr)
 202{
 203        static int calls;
 204        unsigned long fsr;
 205        int ret = 0;
 206        int code;
 207#ifndef CONFIG_SMP
 208        struct task_struct *fpt = last_task_used_math;
 209#else
 210        struct task_struct *fpt = current;
 211#endif
 212        put_psr(get_psr() | PSR_EF);
 213        /* If nobody owns the fpu right now, just clear the
 214         * error into our fake static buffer and hope it don't
 215         * happen again.  Thank you crashme...
 216         */
 217#ifndef CONFIG_SMP
 218        if(!fpt) {
 219#else
 220        if (!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
 221#endif
 222                fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
 223                regs->psr &= ~PSR_EF;
 224                return;
 225        }
 226        fpsave(&fpt->thread.float_regs[0], &fpt->thread.fsr,
 227               &fpt->thread.fpqueue[0], &fpt->thread.fpqdepth);
 228#ifdef DEBUG_FPU
 229        printk("Hmm, FP exception, fsr was %016lx\n", fpt->thread.fsr);
 230#endif
 231
 232        switch ((fpt->thread.fsr & 0x1c000)) {
 233        /* switch on the contents of the ftt [floating point trap type] field */
 234#ifdef DEBUG_FPU
 235        case (1 << 14):
 236                printk("IEEE_754_exception\n");
 237                break;
 238#endif
 239        case (2 << 14):  /* unfinished_FPop (underflow & co) */
 240        case (3 << 14):  /* unimplemented_FPop (quad stuff, maybe sqrt) */
 241                ret = do_mathemu(regs, fpt);
 242                break;
 243#ifdef DEBUG_FPU
 244        case (4 << 14):
 245                printk("sequence_error (OS bug...)\n");
 246                break;
 247        case (5 << 14):
 248                printk("hardware_error (uhoh!)\n");
 249                break;
 250        case (6 << 14):
 251                printk("invalid_fp_register (user error)\n");
 252                break;
 253#endif /* DEBUG_FPU */
 254        }
 255        /* If we successfully emulated the FPop, we pretend the trap never happened :-> */
 256        if (ret) {
 257                fpload(&current->thread.float_regs[0], &current->thread.fsr);
 258                return;
 259        }
 260        /* nope, better SIGFPE the offending process... */
 261               
 262#ifdef CONFIG_SMP
 263        clear_tsk_thread_flag(fpt, TIF_USEDFPU);
 264#endif
 265        if(psr & PSR_PS) {
 266                /* The first fsr store/load we tried trapped,
 267                 * the second one will not (we hope).
 268                 */
 269                printk("WARNING: FPU exception from kernel mode. at pc=%08lx\n",
 270                       regs->pc);
 271                regs->pc = regs->npc;
 272                regs->npc += 4;
 273                calls++;
 274                if(calls > 2)
 275                        die_if_kernel("Too many Penguin-FPU traps from kernel mode",
 276                                      regs);
 277                return;
 278        }
 279
 280        fsr = fpt->thread.fsr;
 281        code = FPE_FLTUNK;
 282        if ((fsr & 0x1c000) == (1 << 14)) {
 283                if (fsr & 0x10)
 284                        code = FPE_FLTINV;
 285                else if (fsr & 0x08)
 286                        code = FPE_FLTOVF;
 287                else if (fsr & 0x04)
 288                        code = FPE_FLTUND;
 289                else if (fsr & 0x02)
 290                        code = FPE_FLTDIV;
 291                else if (fsr & 0x01)
 292                        code = FPE_FLTRES;
 293        }
 294        send_sig_fault(SIGFPE, code, (void __user *)pc, 0, fpt);
 295#ifndef CONFIG_SMP
 296        last_task_used_math = NULL;
 297#endif
 298        regs->psr &= ~PSR_EF;
 299        if(calls > 0)
 300                calls=0;
 301}
 302
 303void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 304                         unsigned long psr)
 305{
 306        if(psr & PSR_PS)
 307                die_if_kernel("Penguin overflow trap from kernel mode", regs);
 308        send_sig_fault(SIGEMT, EMT_TAGOVF, (void __user *)pc, 0, current);
 309}
 310
 311void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 312                       unsigned long psr)
 313{
 314#ifdef TRAP_DEBUG
 315        printk("Watchpoint detected at PC %08lx NPC %08lx PSR %08lx\n",
 316               pc, npc, psr);
 317#endif
 318        if(psr & PSR_PS)
 319                panic("Tell me what a watchpoint trap is, and I'll then deal "
 320                      "with such a beast...");
 321}
 322
 323void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 324                       unsigned long psr)
 325{
 326#ifdef TRAP_DEBUG
 327        printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
 328               pc, npc, psr);
 329#endif
 330        force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)pc, 0);
 331}
 332
 333void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 334                        unsigned long psr)
 335{
 336        send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, 0, current);
 337}
 338
 339void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 340                         unsigned long psr)
 341{
 342#ifdef TRAP_DEBUG
 343        printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
 344               pc, npc, psr);
 345#endif
 346        send_sig_fault(SIGILL, ILL_COPROC, (void __user *)pc, 0, current);
 347}
 348
 349void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 350                       unsigned long psr)
 351{
 352        send_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)pc, 0, current);
 353}
 354
 355#ifdef CONFIG_DEBUG_BUGVERBOSE
 356void do_BUG(const char *file, int line)
 357{
 358        // bust_spinlocks(1);   XXX Not in our original BUG()
 359        printk("kernel BUG at %s:%d!\n", file, line);
 360}
 361EXPORT_SYMBOL(do_BUG);
 362#endif
 363
 364/* Since we have our mappings set up, on multiprocessors we can spin them
 365 * up here so that timer interrupts work during initialization.
 366 */
 367
 368void trap_init(void)
 369{
 370        extern void thread_info_offsets_are_bolixed_pete(void);
 371
 372        /* Force linker to barf if mismatched */
 373        if (TI_UWINMASK    != offsetof(struct thread_info, uwinmask) ||
 374            TI_TASK        != offsetof(struct thread_info, task) ||
 375            TI_FLAGS       != offsetof(struct thread_info, flags) ||
 376            TI_CPU         != offsetof(struct thread_info, cpu) ||
 377            TI_PREEMPT     != offsetof(struct thread_info, preempt_count) ||
 378            TI_SOFTIRQ     != offsetof(struct thread_info, softirq_count) ||
 379            TI_HARDIRQ     != offsetof(struct thread_info, hardirq_count) ||
 380            TI_KSP         != offsetof(struct thread_info, ksp) ||
 381            TI_KPC         != offsetof(struct thread_info, kpc) ||
 382            TI_KPSR        != offsetof(struct thread_info, kpsr) ||
 383            TI_KWIM        != offsetof(struct thread_info, kwim) ||
 384            TI_REG_WINDOW  != offsetof(struct thread_info, reg_window) ||
 385            TI_RWIN_SPTRS  != offsetof(struct thread_info, rwbuf_stkptrs) ||
 386            TI_W_SAVED     != offsetof(struct thread_info, w_saved))
 387                thread_info_offsets_are_bolixed_pete();
 388
 389        /* Attach to the address space of init_task. */
 390        mmgrab(&init_mm);
 391        current->active_mm = &init_mm;
 392
 393        /* NOTE: Other cpus have this done as they are started
 394         *       up on SMP.
 395         */
 396}
 397