root/kernel/traps.c

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DEFINITIONS

This source file includes following definitions.
  1. console_verbose
  2. die_if_kernel
  3. DO_ERROR
  4. do_debug
  5. math_error
  6. do_coprocessor_error
  7. trap_init

   1 /*
   2  *  linux/kernel/traps.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6 
   7 /*
   8  * 'Traps.c' handles hardware traps and faults after we have saved some
   9  * state in 'asm.s'. Currently mostly a debugging-aid, will be extended
  10  * to mainly kill the offending process (probably by giving it a signal,
  11  * but possibly by killing it outright if necessary).
  12  */
  13 #include <linux/head.h>
  14 #include <linux/sched.h>
  15 #include <linux/kernel.h>
  16 #include <linux/string.h>
  17 #include <linux/errno.h>
  18 #include <linux/segment.h>
  19 #include <linux/ptrace.h>
  20 
  21 #include <asm/system.h>
  22 #include <asm/segment.h>
  23 #include <asm/io.h>
  24 
  25 static inline void console_verbose(void)
     /* [previous][next][first][last][top][bottom][index][help] */
  26 {
  27         extern int console_loglevel;
  28         console_loglevel = 15;
  29 }
  30 
  31 #define DO_ERROR(trapnr, signr, str, name, tsk) \
  32 asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
  33 { \
  34         tsk->tss.error_code = error_code; \
  35         tsk->tss.trap_no = trapnr; \
  36         if (signr == SIGTRAP && current->flags & PF_PTRACED) \
  37                 current->blocked &= ~(1 << (SIGTRAP-1)); \
  38         send_sig(signr, tsk, 1); \
  39         die_if_kernel(str,regs,error_code); \
  40 }
  41 
  42 #define get_seg_byte(seg,addr) ({ \
  43 register char __res; \
  44 __asm__("push %%fs;mov %%ax,%%fs;movb %%fs:%2,%%al;pop %%fs" \
  45         :"=a" (__res):"0" (seg),"m" (*(addr))); \
  46 __res;})
  47 
  48 #define get_seg_long(seg,addr) ({ \
  49 register unsigned long __res; \
  50 __asm__("push %%fs;mov %%ax,%%fs;movl %%fs:%2,%%eax;pop %%fs" \
  51         :"=a" (__res):"0" (seg),"m" (*(addr))); \
  52 __res;})
  53 
  54 #define _fs() ({ \
  55 register unsigned short __res; \
  56 __asm__("mov %%fs,%%ax":"=a" (__res):); \
  57 __res;})
  58 
  59 void page_exception(void);
  60 
  61 asmlinkage void divide_error(void);
  62 asmlinkage void debug(void);
  63 asmlinkage void nmi(void);
  64 asmlinkage void int3(void);
  65 asmlinkage void overflow(void);
  66 asmlinkage void bounds(void);
  67 asmlinkage void invalid_op(void);
  68 asmlinkage void device_not_available(void);
  69 asmlinkage void double_fault(void);
  70 asmlinkage void coprocessor_segment_overrun(void);
  71 asmlinkage void invalid_TSS(void);
  72 asmlinkage void segment_not_present(void);
  73 asmlinkage void stack_segment(void);
  74 asmlinkage void general_protection(void);
  75 asmlinkage void page_fault(void);
  76 asmlinkage void coprocessor_error(void);
  77 asmlinkage void reserved(void);
  78 asmlinkage void alignment_check(void);
  79 
  80 /*static*/ void die_if_kernel(char * str, struct pt_regs * regs, long err)
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  81 {
  82         int i;
  83 
  84         if ((regs->eflags & VM_MASK) || (3 & regs->cs) == 3)
  85                 return;
  86 
  87         console_verbose();
  88         printk("%s: %04lx\n", str, err & 0xffff);
  89         printk("EIP:    %04x:%08lx\nEFLAGS: %08lx\n", 0xffff & regs->cs,regs->eip,regs->eflags);
  90         printk("eax: %08lx   ebx: %08lx   ecx: %08lx   edx: %08lx\n",
  91                 regs->eax, regs->ebx, regs->ecx, regs->edx);
  92         printk("esi: %08lx   edi: %08lx   ebp: %08lx   esp: %08lx\n",
  93                 regs->esi, regs->edi, regs->ebp, regs->esp);
  94         printk("ds: %04x   es: %04x   fs: %04x   gs: %04x\n",
  95                 regs->ds, regs->es, regs->fs, regs->gs);
  96         store_TR(i);
  97         printk("Pid: %d, process nr: %d (%s)\n", current->pid, 0xffff & i, current->comm);
  98         for(i=0;i<20;i++)
  99                 printk("%02x ",0xff & get_seg_byte(regs->cs,(i+(char *)regs->eip)));
 100         printk("\n");
 101 #if 0
 102         for(i=0;i<5;i++)
 103                 printk("%08lx ", get_seg_long(regs->ss,(i+(unsigned long *)regs->esp)));
 104         printk("\n");
 105 #endif
 106         do_exit(SIGSEGV);
 107 }
 108 
 109 DO_ERROR( 0, SIGFPE,  "divide error", divide_error, current)
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 110 DO_ERROR( 3, SIGTRAP, "int3", int3, current)
 111 DO_ERROR( 4, SIGSEGV, "overflow", overflow, current)
 112 DO_ERROR( 5, SIGSEGV, "bounds", bounds, current)
 113 DO_ERROR( 6, SIGILL,  "invalid operand", invalid_op, current)
 114 DO_ERROR( 7, SIGSEGV, "device not available", device_not_available, current)
 115 DO_ERROR( 8, SIGSEGV, "double fault", double_fault, current)
 116 DO_ERROR( 9, SIGFPE,  "coprocessor segment overrun", coprocessor_segment_overrun, last_task_used_math)
 117 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS, current)
 118 DO_ERROR(11, SIGSEGV, "segment not present", segment_not_present, current)
 119 DO_ERROR(12, SIGSEGV, "stack segment", stack_segment, current)
 120 DO_ERROR(13, SIGSEGV, "general protection", general_protection, current)
 121 DO_ERROR(15, SIGSEGV, "reserved", reserved, current)
 122 DO_ERROR(17, SIGSEGV, "alignment check", alignment_check, current)
 123 
 124 asmlinkage void do_nmi(struct pt_regs * regs, long error_code)
 125 {
 126         printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n");
 127         printk("You probably have a hardware problem with your RAM chips\n");
 128 }
 129 
 130 asmlinkage void do_debug(struct pt_regs * regs, long error_code)
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 131 {
 132         if (current->flags & PF_PTRACED)
 133                 current->blocked &= ~(1 << (SIGTRAP-1));
 134         send_sig(SIGTRAP, current, 1);
 135         current->tss.trap_no = 1;
 136         current->tss.error_code = error_code;
 137         if((regs->cs & 3) == 0) {
 138           /* If this is a kernel mode trap, then reset db7 and allow us to continue */
 139           __asm__("movl $0,%%edx\n\t" \
 140                   "movl %%edx,%%db7\n\t" \
 141                   : /* no output */ \
 142                   : /* no input */ :"dx");
 143 
 144           return;
 145         };
 146         die_if_kernel("debug",regs,error_code);
 147 }
 148 
 149 /*
 150  * Allow the process which triggered the interrupt to recover the error
 151  * condition.
 152  *  - the status word is saved in the cs selector.
 153  *  - the tag word is saved in the operand selector.
 154  *  - the status word is then cleared and the tags all set to Empty.
 155  *
 156  * This will give sufficient information for complete recovery provided that
 157  * the affected process knows or can deduce the code and data segments
 158  * which were in force when the exception condition arose.
 159  *
 160  * Note that we play around with the 'TS' bit to hopefully get
 161  * the correct behaviour even in the presense of the asynchronous
 162  * IRQ13 behaviour
 163  */
 164 void math_error(void)
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 165 {
 166         struct i387_hard_struct * env;
 167 
 168         clts();
 169         if (!last_task_used_math) {
 170                 __asm__("fnclex");
 171                 return;
 172         }
 173         env = &last_task_used_math->tss.i387.hard;
 174         send_sig(SIGFPE, last_task_used_math, 1);
 175         last_task_used_math->tss.trap_no = 16;
 176         last_task_used_math->tss.error_code = 0;
 177         __asm__ __volatile__("fnsave %0":"=m" (*env));
 178         last_task_used_math = NULL;
 179         stts();
 180         env->fcs = (env->swd & 0x0000ffff) | (env->fcs & 0xffff0000);
 181         env->fos = env->twd;
 182         env->swd &= 0xffff3800;
 183         env->twd = 0xffffffff;
 184 }
 185 
 186 asmlinkage void do_coprocessor_error(struct pt_regs * regs, long error_code)
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 187 {
 188         ignore_irq13 = 1;
 189         math_error();
 190 }
 191 
 192 void trap_init(void)
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 193 {
 194         int i;
 195 
 196         set_trap_gate(0,&divide_error);
 197         set_trap_gate(1,&debug);
 198         set_trap_gate(2,&nmi);
 199         set_system_gate(3,&int3);       /* int3-5 can be called from all */
 200         set_system_gate(4,&overflow);
 201         set_system_gate(5,&bounds);
 202         set_trap_gate(6,&invalid_op);
 203         set_trap_gate(7,&device_not_available);
 204         set_trap_gate(8,&double_fault);
 205         set_trap_gate(9,&coprocessor_segment_overrun);
 206         set_trap_gate(10,&invalid_TSS);
 207         set_trap_gate(11,&segment_not_present);
 208         set_trap_gate(12,&stack_segment);
 209         set_trap_gate(13,&general_protection);
 210         set_trap_gate(14,&page_fault);
 211         set_trap_gate(15,&reserved);
 212         set_trap_gate(16,&coprocessor_error);
 213         set_trap_gate(17,&alignment_check);
 214         for (i=18;i<48;i++)
 215                 set_trap_gate(i,&reserved);
 216 }

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