arch/sparc/kernel/traps_32.c

   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
  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
  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         if(regs->psr & PSR_PS)
  90                 do_exit(SIGKILL);
  91         do_exit(SIGSEGV);
  92 }
  93
  94 void 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
 109 void 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
 122 void 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
 132 void 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
 151 static unsigned long init_fsr = 0x0UL;
 152 static 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
 158 void 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
 195 static unsigned long fake_regs[32] __attribute__ ((aligned (8)));
 196 static unsigned long fake_fsr;
 197 static unsigned long fake_queue[32] __attribute__ ((aligned (8)));
 198 static unsigned long fake_depth;
 199
 200 void 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
 303 void 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
 311 void 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
 323 void 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
 333 void 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
 339 void 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
 349 void 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
 356 void 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 }
 361 EXPORT_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
 368 void 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 }