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traps.c

/* $Id: traps.c,v 1.64 2000/09/03 15:00:49 anton Exp $
 * arch/sparc/kernel/traps.c
 *
 * Copyright 1995 David S. Miller (davem@caip.rutgers.edu)
 * Copyright 2000 Jakub Jelinek (jakub@redhat.com)
 */

/*
 * I hate traps on the sparc, grrr...
 */

#include <linux/sched.h>  /* for jiffies */
#include <linux/kernel.h>
#include <linux/kallsyms.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/kdebug.h>

#include <asm/delay.h>
#include <asm/system.h>
#include <asm/ptrace.h>
#include <asm/oplib.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/unistd.h>
#include <asm/traps.h>

/* #define TRAP_DEBUG */

struct trap_trace_entry {
      unsigned long pc;
      unsigned long type;
};

int trap_curbuf = 0;
struct trap_trace_entry trapbuf[1024];

void syscall_trace_entry(struct pt_regs *regs)
{
      printk("%s[%d]: ", current->comm, task_pid_nr(current));
      printk("scall<%d> (could be %d)\n", (int) regs->u_regs[UREG_G1],
             (int) regs->u_regs[UREG_I0]);
}

void syscall_trace_exit(struct pt_regs *regs)
{
}

void sun4m_nmi(struct pt_regs *regs)
{
      unsigned long afsr, afar;

      printk("Aieee: sun4m NMI received!\n");
      /* XXX HyperSparc hack XXX */
      __asm__ __volatile__("mov 0x500, %%g1\n\t"
                       "lda [%%g1] 0x4, %0\n\t"
                       "mov 0x600, %%g1\n\t"
                       "lda [%%g1] 0x4, %1\n\t" :
                       "=r" (afsr), "=r" (afar));
      printk("afsr=%08lx afar=%08lx\n", afsr, afar);
      printk("you lose buddy boy...\n");
      show_regs(regs);
      prom_halt();
}

void sun4d_nmi(struct pt_regs *regs)
{
      printk("Aieee: sun4d NMI received!\n");
      printk("you lose buddy boy...\n");
      show_regs(regs);
      prom_halt();
}

void instruction_dump (unsigned long *pc)
{
      int i;
      
      if((((unsigned long) pc) & 3))
                return;

      for(i = -3; i < 6; i++)
            printk("%c%08lx%c",i?' ':'<',pc[i],i?' ':'>');
      printk("\n");
}

#define __SAVE __asm__ __volatile__("save %sp, -0x40, %sp\n\t")
#define __RESTORE __asm__ __volatile__("restore %g0, %g0, %g0\n\t")

void die_if_kernel(char *str, struct pt_regs *regs)
{
      static int die_counter;
      int count = 0;

      /* Amuse the user. */
      printk(
"              \\|/ ____ \\|/\n"
"              \"@'/ ,. \\`@\"\n"
"              /_| \\__/ |_\\\n"
"                 \\__U_/\n");

      printk("%s(%d): %s [#%d]\n", current->comm, task_pid_nr(current), str, ++die_counter);
      show_regs(regs);
      add_taint(TAINT_DIE);

      __SAVE; __SAVE; __SAVE; __SAVE;
      __SAVE; __SAVE; __SAVE; __SAVE;
      __RESTORE; __RESTORE; __RESTORE; __RESTORE;
      __RESTORE; __RESTORE; __RESTORE; __RESTORE;

      {
            struct reg_window *rw = (struct reg_window *)regs->u_regs[UREG_FP];

            /* Stop the back trace when we hit userland or we
             * find some badly aligned kernel stack. Set an upper
             * bound in case our stack is trashed and we loop.
             */
            while(rw                            &&
                  count++ < 30                        &&
                      (((unsigned long) rw) >= PAGE_OFFSET) &&
                  !(((unsigned long) rw) & 0x7)) {
                  printk("Caller[%08lx]", rw->ins[7]);
                  print_symbol(": %s\n", rw->ins[7]);
                  rw = (struct reg_window *)rw->ins[6];
            }
      }
      printk("Instruction DUMP:");
      instruction_dump ((unsigned long *) regs->pc);
      if(regs->psr & PSR_PS)
            do_exit(SIGKILL);
      do_exit(SIGSEGV);
}

void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
{
      siginfo_t info;

      if(type < 0x80) {
            /* Sun OS's puke from bad traps, Linux survives! */
            printk("Unimplemented Sparc TRAP, type = %02lx\n", type);
            die_if_kernel("Whee... Hello Mr. Penguin", regs);
      }     

      if(regs->psr & PSR_PS)
            die_if_kernel("Kernel bad trap", regs);

      info.si_signo = SIGILL;
      info.si_errno = 0;
      info.si_code = ILL_ILLTRP;
      info.si_addr = (void __user *)regs->pc;
      info.si_trapno = type - 0x80;
      force_sig_info(SIGILL, &info, current);
}

void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                      unsigned long psr)
{
      extern int do_user_muldiv (struct pt_regs *, unsigned long);
      siginfo_t info;

      if(psr & PSR_PS)
            die_if_kernel("Kernel illegal instruction", regs);
#ifdef TRAP_DEBUG
      printk("Ill instr. at pc=%08lx instruction is %08lx\n",
             regs->pc, *(unsigned long *)regs->pc);
#endif
      if (!do_user_muldiv (regs, pc))
            return;

      info.si_signo = SIGILL;
      info.si_errno = 0;
      info.si_code = ILL_ILLOPC;
      info.si_addr = (void __user *)pc;
      info.si_trapno = 0;
      send_sig_info(SIGILL, &info, current);
}

void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                   unsigned long psr)
{
      siginfo_t info;

      if(psr & PSR_PS)
            die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
      info.si_signo = SIGILL;
      info.si_errno = 0;
      info.si_code = ILL_PRVOPC;
      info.si_addr = (void __user *)pc;
      info.si_trapno = 0;
      send_sig_info(SIGILL, &info, current);
}

/* XXX User may want to be allowed to do this. XXX */

void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                      unsigned long psr)
{
      siginfo_t info;

      if(regs->psr & PSR_PS) {
            printk("KERNEL MNA at pc %08lx npc %08lx called by %08lx\n", pc, npc,
                   regs->u_regs[UREG_RETPC]);
            die_if_kernel("BOGUS", regs);
            /* die_if_kernel("Kernel MNA access", regs); */
      }
#if 0
      show_regs (regs);
      instruction_dump ((unsigned long *) regs->pc);
      printk ("do_MNA!\n");
#endif
      info.si_signo = SIGBUS;
      info.si_errno = 0;
      info.si_code = BUS_ADRALN;
      info.si_addr = /* FIXME: Should dig out mna address */ (void *)0;
      info.si_trapno = 0;
      send_sig_info(SIGBUS, &info, current);
}

extern void fpsave(unsigned long *fpregs, unsigned long *fsr,
               void *fpqueue, unsigned long *fpqdepth);
extern void fpload(unsigned long *fpregs, unsigned long *fsr);

static unsigned long init_fsr = 0x0UL;
static unsigned long init_fregs[32] __attribute__ ((aligned (8))) =
                { ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
              ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
              ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL,
              ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL, ~0UL };

void do_fpd_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
             unsigned long psr)
{
      /* Sanity check... */
      if(psr & PSR_PS)
            die_if_kernel("Kernel gets FloatingPenguinUnit disabled trap", regs);

      put_psr(get_psr() | PSR_EF);    /* Allow FPU ops. */
      regs->psr |= PSR_EF;
#ifndef CONFIG_SMP
      if(last_task_used_math == current)
            return;
      if(last_task_used_math) {
            /* Other processes fpu state, save away */
            struct task_struct *fptask = last_task_used_math;
            fpsave(&fptask->thread.float_regs[0], &fptask->thread.fsr,
                   &fptask->thread.fpqueue[0], &fptask->thread.fpqdepth);
      }
      last_task_used_math = current;
      if(used_math()) {
            fpload(&current->thread.float_regs[0], &current->thread.fsr);
      } else {
            /* Set initial sane state. */
            fpload(&init_fregs[0], &init_fsr);
            set_used_math();
      }
#else
      if(!used_math()) {
            fpload(&init_fregs[0], &init_fsr);
            set_used_math();
      } else {
            fpload(&current->thread.float_regs[0], &current->thread.fsr);
      }
      set_thread_flag(TIF_USEDFPU);
#endif
}

static unsigned long fake_regs[32] __attribute__ ((aligned (8)));
static unsigned long fake_fsr;
static unsigned long fake_queue[32] __attribute__ ((aligned (8)));
static unsigned long fake_depth;

extern int do_mathemu(struct pt_regs *, struct task_struct *);

void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
             unsigned long psr)
{
      static int calls;
      siginfo_t info;
      unsigned long fsr;
      int ret = 0;
#ifndef CONFIG_SMP
      struct task_struct *fpt = last_task_used_math;
#else
      struct task_struct *fpt = current;
#endif
      put_psr(get_psr() | PSR_EF);
      /* If nobody owns the fpu right now, just clear the
       * error into our fake static buffer and hope it don't
       * happen again.  Thank you crashme...
       */
#ifndef CONFIG_SMP
      if(!fpt) {
#else
      if (!test_tsk_thread_flag(fpt, TIF_USEDFPU)) {
#endif
            fpsave(&fake_regs[0], &fake_fsr, &fake_queue[0], &fake_depth);
            regs->psr &= ~PSR_EF;
            return;
      }
      fpsave(&fpt->thread.float_regs[0], &fpt->thread.fsr,
             &fpt->thread.fpqueue[0], &fpt->thread.fpqdepth);
#ifdef DEBUG_FPU
      printk("Hmm, FP exception, fsr was %016lx\n", fpt->thread.fsr);
#endif

      switch ((fpt->thread.fsr & 0x1c000)) {
      /* switch on the contents of the ftt [floating point trap type] field */
#ifdef DEBUG_FPU
      case (1 << 14):
            printk("IEEE_754_exception\n");
            break;
#endif
      case (2 << 14):  /* unfinished_FPop (underflow & co) */
      case (3 << 14):  /* unimplemented_FPop (quad stuff, maybe sqrt) */
            ret = do_mathemu(regs, fpt);
            break;
#ifdef DEBUG_FPU
      case (4 << 14):
            printk("sequence_error (OS bug...)\n");
            break;
      case (5 << 14):
            printk("hardware_error (uhoh!)\n");
            break;
      case (6 << 14):
            printk("invalid_fp_register (user error)\n");
            break;
#endif /* DEBUG_FPU */
      }
      /* If we successfully emulated the FPop, we pretend the trap never happened :-> */
      if (ret) {
            fpload(&current->thread.float_regs[0], &current->thread.fsr);
            return;
      }
      /* nope, better SIGFPE the offending process... */
             
#ifdef CONFIG_SMP
      clear_tsk_thread_flag(fpt, TIF_USEDFPU);
#endif
      if(psr & PSR_PS) {
            /* The first fsr store/load we tried trapped,
             * the second one will not (we hope).
             */
            printk("WARNING: FPU exception from kernel mode. at pc=%08lx\n",
                   regs->pc);
            regs->pc = regs->npc;
            regs->npc += 4;
            calls++;
            if(calls > 2)
                  die_if_kernel("Too many Penguin-FPU traps from kernel mode",
                              regs);
            return;
      }

      fsr = fpt->thread.fsr;
      info.si_signo = SIGFPE;
      info.si_errno = 0;
      info.si_addr = (void __user *)pc;
      info.si_trapno = 0;
      info.si_code = __SI_FAULT;
      if ((fsr & 0x1c000) == (1 << 14)) {
            if (fsr & 0x10)
                  info.si_code = FPE_FLTINV;
            else if (fsr & 0x08)
                  info.si_code = FPE_FLTOVF;
            else if (fsr & 0x04)
                  info.si_code = FPE_FLTUND;
            else if (fsr & 0x02)
                  info.si_code = FPE_FLTDIV;
            else if (fsr & 0x01)
                  info.si_code = FPE_FLTRES;
      }
      send_sig_info(SIGFPE, &info, fpt);
#ifndef CONFIG_SMP
      last_task_used_math = NULL;
#endif
      regs->psr &= ~PSR_EF;
      if(calls > 0)
            calls=0;
}

void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                   unsigned long psr)
{
      siginfo_t info;

      if(psr & PSR_PS)
            die_if_kernel("Penguin overflow trap from kernel mode", regs);
      info.si_signo = SIGEMT;
      info.si_errno = 0;
      info.si_code = EMT_TAGOVF;
      info.si_addr = (void __user *)pc;
      info.si_trapno = 0;
      send_sig_info(SIGEMT, &info, current);
}

void handle_watchpoint(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                   unsigned long psr)
{
#ifdef TRAP_DEBUG
      printk("Watchpoint detected at PC %08lx NPC %08lx PSR %08lx\n",
             pc, npc, psr);
#endif
      if(psr & PSR_PS)
            panic("Tell me what a watchpoint trap is, and I'll then deal "
                  "with such a beast...");
}

void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                   unsigned long psr)
{
      siginfo_t info;

#ifdef TRAP_DEBUG
      printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
             pc, npc, psr);
#endif
      info.si_signo = SIGBUS;
      info.si_errno = 0;
      info.si_code = BUS_OBJERR;
      info.si_addr = (void __user *)pc;
      info.si_trapno = 0;
      force_sig_info(SIGBUS, &info, current);
}

void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                  unsigned long psr)
{
      siginfo_t info;

      info.si_signo = SIGILL;
      info.si_errno = 0;
      info.si_code = ILL_COPROC;
      info.si_addr = (void __user *)pc;
      info.si_trapno = 0;
      send_sig_info(SIGILL, &info, current);
}

void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                   unsigned long psr)
{
      siginfo_t info;

#ifdef TRAP_DEBUG
      printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
             pc, npc, psr);
#endif
      info.si_signo = SIGILL;
      info.si_errno = 0;
      info.si_code = ILL_COPROC;
      info.si_addr = (void __user *)pc;
      info.si_trapno = 0;
      send_sig_info(SIGILL, &info, current);
}

void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc,
                   unsigned long psr)
{
      siginfo_t info;

      info.si_signo = SIGFPE;
      info.si_errno = 0;
      info.si_code = FPE_INTDIV;
      info.si_addr = (void __user *)pc;
      info.si_trapno = 0;
      send_sig_info(SIGFPE, &info, current);
}

#ifdef CONFIG_DEBUG_BUGVERBOSE
void do_BUG(const char *file, int line)
{
        // bust_spinlocks(1);   XXX Not in our original BUG()
        printk("kernel BUG at %s:%d!\n", file, line);
}
#endif

/* Since we have our mappings set up, on multiprocessors we can spin them
 * up here so that timer interrupts work during initialization.
 */

extern void sparc_cpu_startup(void);

int linux_smp_still_initting;
unsigned int thiscpus_tbr;
int thiscpus_mid;

void trap_init(void)
{
      extern void thread_info_offsets_are_bolixed_pete(void);

      /* Force linker to barf if mismatched */
      if (TI_UWINMASK    != offsetof(struct thread_info, uwinmask) ||
          TI_TASK        != offsetof(struct thread_info, task) ||
          TI_EXECDOMAIN  != offsetof(struct thread_info, exec_domain) ||
          TI_FLAGS       != offsetof(struct thread_info, flags) ||
          TI_CPU         != offsetof(struct thread_info, cpu) ||
          TI_PREEMPT     != offsetof(struct thread_info, preempt_count) ||
          TI_SOFTIRQ     != offsetof(struct thread_info, softirq_count) ||
          TI_HARDIRQ     != offsetof(struct thread_info, hardirq_count) ||
          TI_KSP         != offsetof(struct thread_info, ksp) ||
          TI_KPC         != offsetof(struct thread_info, kpc) ||
          TI_KPSR        != offsetof(struct thread_info, kpsr) ||
          TI_KWIM        != offsetof(struct thread_info, kwim) ||
          TI_REG_WINDOW  != offsetof(struct thread_info, reg_window) ||
          TI_RWIN_SPTRS  != offsetof(struct thread_info, rwbuf_stkptrs) ||
          TI_W_SAVED     != offsetof(struct thread_info, w_saved))
            thread_info_offsets_are_bolixed_pete();

      /* Attach to the address space of init_task. */
      atomic_inc(&init_mm.mm_count);
      current->active_mm = &init_mm;

      /* NOTE: Other cpus have this done as they are started
       *       up on SMP.
       */
}

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