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