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  1. /*
  2.  * Copyright (C) 2003-2004 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <arch/exception.h>
  30. #include <arch/interrupt.h>
  31. #include <panic.h>
  32. #include <arch/cp0.h>
  33. #include <arch/types.h>
  34. #include <arch.h>
  35. #include <debug.h>
  36. #include <proc/thread.h>
  37. #include <symtab.h>
  38. #include <print.h>
  39. #include <interrupt.h>
  40. #include <func.h>
  41. #include <console/kconsole.h>
  42. #include <arch/debugger.h>
  43. #include <syscall/syscall.h>
  44.  
  45. static char * exctable[] = {
  46.     "Interrupt","TLB Modified","TLB Invalid","TLB Invalid Store",
  47.         "Address Error - load/instr. fetch",
  48.         "Address Error - store",
  49.         "Bus Error - fetch instruction",
  50.         "Bus Error - data reference",
  51.         "Syscall",
  52.         "BreakPoint",
  53.         "Reserved Instruction",
  54.         "Coprocessor Unusable",
  55.         "Arithmetic Overflow",
  56.         "Trap",
  57.         "Virtual Coherency - instruction",
  58.         "Floating Point",
  59.         NULL, NULL, NULL, NULL, NULL, NULL, NULL,
  60.         "WatchHi/WatchLo", /* 23 */
  61.         NULL, NULL, NULL, NULL, NULL, NULL, NULL,
  62.         "Virtual Coherency - data",
  63. };
  64.  
  65. static void print_regdump(istate_t *istate)
  66. {
  67.     char *pcsymbol = "";
  68.     char *rasymbol = "";
  69.  
  70.     char *s = get_symtab_entry(istate->epc);
  71.     if (s)
  72.         pcsymbol = s;
  73.     s = get_symtab_entry(istate->ra);
  74.     if (s)
  75.         rasymbol = s;
  76.    
  77.     printf("PC: %X(%s) RA: %X(%s), SP(%P)\n",istate->epc,pcsymbol,
  78.            istate->ra,rasymbol, istate->sp);
  79. }
  80.  
  81. static void unhandled_exception(int n, istate_t *istate)
  82. {
  83.     print_regdump(istate);
  84.     panic("unhandled exception %s\n", exctable[n]);
  85. }
  86.  
  87. static void breakpoint_exception(int n, istate_t *istate)
  88. {
  89. #ifdef CONFIG_DEBUG
  90.     debugger_bpoint(istate);
  91. #else
  92.     /* it is necessary to not re-execute BREAK instruction after
  93.        returning from Exception handler
  94.        (see page 138 in R4000 Manual for more information) */
  95.     istate->epc += 4;
  96. #endif
  97. }
  98.  
  99. static void tlbmod_exception(int n, istate_t *istate)
  100. {
  101.     tlb_modified(istate);
  102. }
  103.  
  104. static void tlbinv_exception(int n, istate_t *istate)
  105. {
  106.     tlb_invalid(istate);
  107. }
  108.  
  109. #ifdef CONFIG_FPU_LAZY
  110. static void cpuns_exception(int n, istate_t *istate)
  111. {
  112.     if (cp0_cause_coperr(cp0_cause_read()) == fpu_cop_id)
  113.         scheduler_fpu_lazy_request();
  114.     else
  115.         panic("unhandled Coprocessor Unusable Exception\n");
  116. }
  117. #endif
  118.  
  119. static void interrupt_exception(int n, istate_t *istate)
  120. {
  121.     __u32 cause;
  122.     int i;
  123.    
  124.     /* decode interrupt number and process the interrupt */
  125.     cause = (cp0_cause_read() >> 8) &0xff;
  126.    
  127.     for (i = 0; i < 8; i++)
  128.         if (cause & (1 << i))
  129.             exc_dispatch(i+INT_OFFSET, istate);
  130. }
  131.  
  132. #include <debug.h>
  133. /** Handle syscall userspace call */
  134. static void syscall_exception(int n, istate_t *istate)
  135. {
  136.     interrupts_enable();
  137.     if (istate->t0 < SYSCALL_END)
  138.         istate->v0 = syscall_table[istate->t0](istate->a0,
  139.                                istate->a1,
  140.                                istate->a2,
  141.                                istate->a3);
  142.     else
  143.         panic("Undefined syscall %d", istate->a3);
  144.     istate->epc += 4;
  145.     interrupts_disable();
  146. }
  147.  
  148. void exception(istate_t *istate)
  149. {
  150.     int cause;
  151.     int excno;
  152.  
  153.     ASSERT(CPU != NULL);
  154.  
  155.     /*
  156.      * NOTE ON OPERATION ORDERING
  157.      *
  158.      * On entry, interrupts_disable() must be called before
  159.      * exception bit is cleared.
  160.      */
  161.  
  162.     interrupts_disable();
  163.     cp0_status_write(cp0_status_read() & ~ (cp0_status_exl_exception_bit |
  164.                         cp0_status_um_bit));
  165.  
  166.     /* Save istate so that the threads can access it */
  167.     /* If THREAD->istate is set, this is nested exception,
  168.      * do not rewrite it
  169.      */
  170.     if (THREAD && !THREAD->istate)
  171.         THREAD->istate = istate;
  172.  
  173.     cause = cp0_cause_read();
  174.     excno = cp0_cause_excno(cause);
  175.     /* Dispatch exception */
  176.     exc_dispatch(excno, istate);
  177.  
  178.     /* Set to NULL, so that we can still support nested
  179.      * exceptions
  180.      * TODO: We should probably set EXL bit before this command,
  181.      * nesting. On the other hand, if some exception occurs between
  182.      * here and ERET, it won't set anything on the istate anyway.
  183.      */
  184.     if (THREAD)
  185.         THREAD->istate = NULL;
  186. }
  187.  
  188. void exception_init(void)
  189. {
  190.     int i;
  191.  
  192.     /* Clear exception table */
  193.     for (i=0;i < IVT_ITEMS; i++)
  194.         exc_register(i, "undef", (iroutine) unhandled_exception);
  195.     exc_register(EXC_Bp, "bkpoint", (iroutine) breakpoint_exception);
  196.     exc_register(EXC_Mod, "tlb_mod", (iroutine) tlbmod_exception);
  197.     exc_register(EXC_TLBL, "tlbinvl", (iroutine) tlbinv_exception);
  198.     exc_register(EXC_TLBS, "tlbinvl", (iroutine) tlbinv_exception);
  199.     exc_register(EXC_Int, "interrupt", (iroutine) interrupt_exception);
  200. #ifdef CONFIG_FPU_LAZY
  201.     exc_register(EXC_CpU, "cpunus", (iroutine) cpuns_exception);
  202. #endif
  203.     exc_register(EXC_Sys, "syscall", (iroutine) syscall_exception);
  204. }
  205.