kernel/traps.c

/* */
This source file includes following definitions.
console_verbose
die_if_kernel
DO_ERROR
do_nmi
do_debug
math_error
do_coprocessor_error
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)
     /*  */
  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 unsigned 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)
     /*  */
  81 {
  82         int i;
  83         unsigned long esp;
  84         unsigned short ss;
  85 
  86         esp = (unsigned long) &regs->esp;
  87         ss = KERNEL_DS;
  88         if ((regs->eflags & VM_MASK) || (3 & regs->cs) == 3)
  89                 return;
  90         if (regs->cs & 3) {
  91                 esp = regs->esp;
  92                 ss = regs->ss;
  93         }
  94         console_verbose();
  95         printk("%s: %04lx\n", str, err & 0xffff);
  96         printk("EIP:    %04x:%08lx\nEFLAGS: %08lx\n", 0xffff & regs->cs,regs->eip,regs->eflags);
  97         printk("eax: %08lx   ebx: %08lx   ecx: %08lx   edx: %08lx\n",
  98                 regs->eax, regs->ebx, regs->ecx, regs->edx);
  99         printk("esi: %08lx   edi: %08lx   ebp: %08lx   esp: %08lx\n",
 100                 regs->esi, regs->edi, regs->ebp, esp);
 101         printk("ds: %04x   es: %04x   fs: %04x   gs: %04x   ss: %04x\n",
 102                 regs->ds, regs->es, regs->fs, regs->gs, ss);
 103         store_TR(i);
 104         if (STACK_MAGIC != *(unsigned long *)current->kernel_stack_page)
 105                 printk("Corrupted stack page\n");
 106         printk("Process %s (pid: %d, process nr: %d, stackpage=%08lx)\nStack: ",
 107                 current->comm, current->pid, 0xffff & i, current->kernel_stack_page);
 108         for(i=0;i<5;i++)
 109                 printk("%08lx ", get_seg_long(ss,(i+(unsigned long *)esp)));
 110         printk("\nCode: ");
 111         for(i=0;i<20;i++)
 112                 printk("%02x ",0xff & get_seg_byte(regs->cs,(i+(char *)regs->eip)));
 113         printk("\n");
 114         do_exit(SIGSEGV);
 115 }
 116 
 117 DO_ERROR( 0, SIGFPE,  "divide error", divide_error, current)
     /*  */
 118 DO_ERROR( 3, SIGTRAP, "int3", int3, current)
 119 DO_ERROR( 4, SIGSEGV, "overflow", overflow, current)
 120 DO_ERROR( 5, SIGSEGV, "bounds", bounds, current)
 121 DO_ERROR( 6, SIGILL,  "invalid operand", invalid_op, current)
 122 DO_ERROR( 7, SIGSEGV, "device not available", device_not_available, current)
 123 DO_ERROR( 8, SIGSEGV, "double fault", double_fault, current)
 124 DO_ERROR( 9, SIGFPE,  "coprocessor segment overrun", coprocessor_segment_overrun, last_task_used_math)
 125 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS, current)
 126 DO_ERROR(11, SIGBUS,  "segment not present", segment_not_present, current)
 127 DO_ERROR(12, SIGBUS,  "stack segment", stack_segment, current)
 128 DO_ERROR(15, SIGSEGV, "reserved", reserved, current)
 129 DO_ERROR(17, SIGSEGV, "alignment check", alignment_check, current)
 130 
 131 asmlinkage void do_general_protection(struct pt_regs * regs, long error_code)
 132 {
 133         int signr = SIGSEGV;
 134 
 135         if (regs->eflags & VM_MASK) {
 136                 handle_vm86_fault((struct vm86_regs *) regs, error_code);
 137                 return;
 138         }
 139         die_if_kernel("general protection",regs,error_code);
 140         switch (get_seg_byte(regs->cs, (char *)regs->eip)) {
 141                 case 0xCD: /* INT */
 142                 case 0xF4: /* HLT */
 143                 case 0xFA: /* CLI */
 144                 case 0xFB: /* STI */
 145                         signr = SIGILL;
 146         }
 147         current->tss.error_code = error_code;
 148         current->tss.trap_no = 13;
 149         send_sig(signr, current, 1);    
 150 }
 151 
 152 asmlinkage void do_nmi(struct pt_regs * regs, long error_code)
     /*  */
 153 {
 154         printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n");
 155         printk("You probably have a hardware problem with your RAM chips\n");
 156 }
 157 
 158 asmlinkage void do_debug(struct pt_regs * regs, long error_code)
     /*  */
 159 {
 160         if (regs->eflags & VM_MASK) {
 161                 handle_vm86_debug((struct vm86_regs *) regs, error_code);
 162                 return;
 163         }
 164         if (current->flags & PF_PTRACED)
 165                 current->blocked &= ~(1 << (SIGTRAP-1));
 166         send_sig(SIGTRAP, current, 1);
 167         current->tss.trap_no = 1;
 168         current->tss.error_code = error_code;
 169         if ((regs->cs & 3) == 0) {
 170                 /* If this is a kernel mode trap, then reset db7 and allow us to continue */
 171                 __asm__("movl %0,%%db7"
 172                         : /* no output */
 173                         : "r" (0));
 174                 return;
 175         }
 176         die_if_kernel("debug",regs,error_code);
 177 }
 178 
 179 /*
 180  * Allow the process which triggered the interrupt to recover the error
 181  * condition.
 182  *  - the status word is saved in the cs selector.
 183  *  - the tag word is saved in the operand selector.
 184  *  - the status word is then cleared and the tags all set to Empty.
 185  *
 186  * This will give sufficient information for complete recovery provided that
 187  * the affected process knows or can deduce the code and data segments
 188  * which were in force when the exception condition arose.
 189  *
 190  * Note that we play around with the 'TS' bit to hopefully get
 191  * the correct behaviour even in the presence of the asynchronous
 192  * IRQ13 behaviour
 193  */
 194 void math_error(void)
     /*  */
 195 {
 196         struct i387_hard_struct * env;
 197 
 198         clts();
 199         if (!last_task_used_math) {
 200                 __asm__("fnclex");
 201                 return;
 202         }
 203         env = &last_task_used_math->tss.i387.hard;
 204         send_sig(SIGFPE, last_task_used_math, 1);
 205         last_task_used_math->tss.trap_no = 16;
 206         last_task_used_math->tss.error_code = 0;
 207         __asm__ __volatile__("fnsave %0":"=m" (*env));
 208         last_task_used_math = NULL;
 209         stts();
 210         env->fcs = (env->swd & 0x0000ffff) | (env->fcs & 0xffff0000);
 211         env->fos = env->twd;
 212         env->swd &= 0xffff3800;
 213         env->twd = 0xffffffff;
 214 }
 215 
 216 asmlinkage void do_coprocessor_error(struct pt_regs * regs, long error_code)
     /*  */
 217 {
 218         ignore_irq13 = 1;
 219         math_error();
 220 }
 221 
 222 void trap_init(void)
     /*  */
 223 {
 224         int i;
 225 
 226         set_trap_gate(0,&divide_error);
 227         set_trap_gate(1,&debug);
 228         set_trap_gate(2,&nmi);
 229         set_system_gate(3,&int3);       /* int3-5 can be called from all */
 230         set_system_gate(4,&overflow);
 231         set_system_gate(5,&bounds);
 232         set_trap_gate(6,&invalid_op);
 233         set_trap_gate(7,&device_not_available);
 234         set_trap_gate(8,&double_fault);
 235         set_trap_gate(9,&coprocessor_segment_overrun);
 236         set_trap_gate(10,&invalid_TSS);
 237         set_trap_gate(11,&segment_not_present);
 238         set_trap_gate(12,&stack_segment);
 239         set_trap_gate(13,&general_protection);
 240         set_trap_gate(14,&page_fault);
 241         set_trap_gate(15,&reserved);
 242         set_trap_gate(16,&coprocessor_error);
 243         set_trap_gate(17,&alignment_check);
 244         for (i=18;i<48;i++)
 245                 set_trap_gate(i,&reserved);
 246 }
/* */
root/kernel/traps.c

DEFINITIONS
