arch/i386/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
math_state_restore
math_emulate
trap_init
   1 /*
   2  *  linux/arch/i386/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/ptrace.h>
  19 #include <linux/config.h>
  20 #include <linux/timer.h>
  21 #include <linux/mm.h>
  22 
  23 #include <asm/system.h>
  24 #include <asm/segment.h>
  25 #include <asm/io.h>
  26 
  27 asmlinkage int system_call(void);
  28 asmlinkage void lcall7(void);
  29 struct desc_struct default_ldt;
  30 
  31 static inline void console_verbose(void)
     /*  */
  32 {
  33         extern int console_loglevel;
  34         console_loglevel = 15;
  35 }
  36 
  37 #define DO_ERROR(trapnr, signr, str, name, tsk) \
  38 asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
  39 { \
  40         tsk->tss.error_code = error_code; \
  41         tsk->tss.trap_no = trapnr; \
  42         if (signr == SIGTRAP && current->flags & PF_PTRACED) \
  43                 current->blocked &= ~(1 << (SIGTRAP-1)); \
  44         send_sig(signr, tsk, 1); \
  45         die_if_kernel(str,regs,error_code); \
  46 }
  47 
  48 #define get_seg_byte(seg,addr) ({ \
  49 register unsigned char __res; \
  50 __asm__("push %%fs;mov %%ax,%%fs;movb %%fs:%2,%%al;pop %%fs" \
  51         :"=a" (__res):"0" (seg),"m" (*(addr))); \
  52 __res;})
  53 
  54 #define get_seg_long(seg,addr) ({ \
  55 register unsigned long __res; \
  56 __asm__("push %%fs;mov %%ax,%%fs;movl %%fs:%2,%%eax;pop %%fs" \
  57         :"=a" (__res):"0" (seg),"m" (*(addr))); \
  58 __res;})
  59 
  60 #define _fs() ({ \
  61 register unsigned short __res; \
  62 __asm__("mov %%fs,%%ax":"=a" (__res):); \
  63 __res;})
  64 
  65 void page_exception(void);
  66 
  67 asmlinkage void divide_error(void);
  68 asmlinkage void debug(void);
  69 asmlinkage void nmi(void);
  70 asmlinkage void int3(void);
  71 asmlinkage void overflow(void);
  72 asmlinkage void bounds(void);
  73 asmlinkage void invalid_op(void);
  74 asmlinkage void device_not_available(void);
  75 asmlinkage void double_fault(void);
  76 asmlinkage void coprocessor_segment_overrun(void);
  77 asmlinkage void invalid_TSS(void);
  78 asmlinkage void segment_not_present(void);
  79 asmlinkage void stack_segment(void);
  80 asmlinkage void general_protection(void);
  81 asmlinkage void page_fault(void);
  82 asmlinkage void coprocessor_error(void);
  83 asmlinkage void reserved(void);
  84 asmlinkage void alignment_check(void);
  85 
  86 int kstack_depth_to_print = 24;
  87 
  88 /*
  89  * These constants are for searching for possible module text
  90  * segments.  VMALLOC_OFFSET comes from mm/vmalloc.c; MODULE_RANGE is
  91  * a guess of how much space is likely to be vmalloced.
  92  */
  93 #define VMALLOC_OFFSET (8*1024*1024)
  94 #define MODULE_RANGE (8*1024*1024)
  95 
  96 /*static*/ void die_if_kernel(char * str, struct pt_regs * regs, long err)
     /*  */
  97 {
  98         int i;
  99         unsigned long esp;
 100         unsigned short ss;
 101         unsigned long *stack, addr, module_start, module_end;
 102         extern char start_kernel, _etext;
 103 
 104         esp = (unsigned long) &regs->esp;
 105         ss = KERNEL_DS;
 106         if ((regs->eflags & VM_MASK) || (3 & regs->cs) == 3)
 107                 return;
 108         if (regs->cs & 3) {
 109                 esp = regs->esp;
 110                 ss = regs->ss;
 111         }
 112         console_verbose();
 113         printk("%s: %04lx\n", str, err & 0xffff);
 114         printk("EIP:    %04x:%08lx\nEFLAGS: %08lx\n", 0xffff & regs->cs,regs->eip,regs->eflags);
 115         printk("eax: %08lx   ebx: %08lx   ecx: %08lx   edx: %08lx\n",
 116                 regs->eax, regs->ebx, regs->ecx, regs->edx);
 117         printk("esi: %08lx   edi: %08lx   ebp: %08lx   esp: %08lx\n",
 118                 regs->esi, regs->edi, regs->ebp, esp);
 119         printk("ds: %04x   es: %04x   fs: %04x   gs: %04x   ss: %04x\n",
 120                 regs->ds, regs->es, regs->fs, regs->gs, ss);
 121         store_TR(i);
 122         if (STACK_MAGIC != *(unsigned long *)current->kernel_stack_page)
 123                 printk("Corrupted stack page\n");
 124         printk("Process %s (pid: %d, process nr: %d, stackpage=%08lx)\nStack: ",
 125                 current->comm, current->pid, 0xffff & i, current->kernel_stack_page);
 126         stack = (unsigned long *) esp;
 127         for(i=0; i < kstack_depth_to_print; i++) {
 128                 if (((long) stack & 4095) == 0)
 129                         break;
 130                 if (i && ((i % 8) == 0))
 131                         printk("\n       ");
 132                 printk("%08lx ", get_seg_long(ss,stack++));
 133         }
 134         printk("\nCall Trace: ");
 135         stack = (unsigned long *) esp;
 136         i = 1;
 137         module_start = ((high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1));
 138         module_end = module_start + MODULE_RANGE;
 139         while (((long) stack & 4095) != 0) {
 140                 addr = get_seg_long(ss, stack++);
 141                 /*
 142                  * If the address is either in the text segment of the
 143                  * kernel, or in the region which contains vmalloc'ed
 144                  * memory, it *may* be the address of a calling
 145                  * routine; if so, print it so that someone tracing
 146                  * down the cause of the crash will be able to figure
 147                  * out the call path that was taken.
 148                  */
 149                 if (((addr >= (unsigned long) &start_kernel) &&
 150                      (addr <= (unsigned long) &_etext)) ||
 151                     ((addr >= module_start) && (addr <= module_end))) {
 152                         if (i && ((i % 8) == 0))
 153                                 printk("\n       ");
 154                         printk("%08lx ", addr);
 155                         i++;
 156                 }
 157         }
 158         printk("\nCode: ");
 159         for(i=0;i<20;i++)
 160                 printk("%02x ",0xff & get_seg_byte(regs->cs,(i+(char *)regs->eip)));
 161         printk("\n");
 162         do_exit(SIGSEGV);
 163 }
 164 
 165 DO_ERROR( 0, SIGFPE,  "divide error", divide_error, current)
     /*  */
 166 DO_ERROR( 3, SIGTRAP, "int3", int3, current)
 167 DO_ERROR( 4, SIGSEGV, "overflow", overflow, current)
 168 DO_ERROR( 5, SIGSEGV, "bounds", bounds, current)
 169 DO_ERROR( 6, SIGILL,  "invalid operand", invalid_op, current)
 170 DO_ERROR( 7, SIGSEGV, "device not available", device_not_available, current)
 171 DO_ERROR( 8, SIGSEGV, "double fault", double_fault, current)
 172 DO_ERROR( 9, SIGFPE,  "coprocessor segment overrun", coprocessor_segment_overrun, last_task_used_math)
 173 DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS, current)
 174 DO_ERROR(11, SIGBUS,  "segment not present", segment_not_present, current)
 175 DO_ERROR(12, SIGBUS,  "stack segment", stack_segment, current)
 176 DO_ERROR(15, SIGSEGV, "reserved", reserved, current)
 177 DO_ERROR(17, SIGSEGV, "alignment check", alignment_check, current)
 178 
 179 asmlinkage void do_general_protection(struct pt_regs * regs, long error_code)
 180 {
 181         if (regs->eflags & VM_MASK) {
 182                 handle_vm86_fault((struct vm86_regs *) regs, error_code);
 183                 return;
 184         }
 185         die_if_kernel("general protection",regs,error_code);
 186         current->tss.error_code = error_code;
 187         current->tss.trap_no = 13;
 188         send_sig(SIGSEGV, current, 1);  
 189 }
 190 
 191 asmlinkage void do_nmi(struct pt_regs * regs, long error_code)
     /*  */
 192 {
 193 #ifndef CONFIG_IGNORE_NMI
 194         printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n");
 195         printk("You probably have a hardware problem with your RAM chips or a\n");
 196         printk("power saving mode enabled.\n");
 197 #endif  
 198 }
 199 
 200 asmlinkage void do_debug(struct pt_regs * regs, long error_code)
     /*  */
 201 {
 202         if (regs->eflags & VM_MASK) {
 203                 handle_vm86_debug((struct vm86_regs *) regs, error_code);
 204                 return;
 205         }
 206         if (current->flags & PF_PTRACED)
 207                 current->blocked &= ~(1 << (SIGTRAP-1));
 208         send_sig(SIGTRAP, current, 1);
 209         current->tss.trap_no = 1;
 210         current->tss.error_code = error_code;
 211         if ((regs->cs & 3) == 0) {
 212                 /* If this is a kernel mode trap, then reset db7 and allow us to continue */
 213                 __asm__("movl %0,%%db7"
 214                         : /* no output */
 215                         : "r" (0));
 216                 return;
 217         }
 218         die_if_kernel("debug",regs,error_code);
 219 }
 220 
 221 /*
 222  * Allow the process which triggered the interrupt to recover the error
 223  * condition.
 224  *  - the status word is saved in the cs selector.
 225  *  - the tag word is saved in the operand selector.
 226  *  - the status word is then cleared and the tags all set to Empty.
 227  *
 228  * This will give sufficient information for complete recovery provided that
 229  * the affected process knows or can deduce the code and data segments
 230  * which were in force when the exception condition arose.
 231  *
 232  * Note that we play around with the 'TS' bit to hopefully get
 233  * the correct behaviour even in the presence of the asynchronous
 234  * IRQ13 behaviour
 235  */
 236 void math_error(void)
     /*  */
 237 {
 238         struct i387_hard_struct * env;
 239 
 240         clts();
 241         if (!last_task_used_math) {
 242                 __asm__("fnclex");
 243                 return;
 244         }
 245         env = &last_task_used_math->tss.i387.hard;
 246         send_sig(SIGFPE, last_task_used_math, 1);
 247         last_task_used_math->tss.trap_no = 16;
 248         last_task_used_math->tss.error_code = 0;
 249         __asm__ __volatile__("fnsave %0":"=m" (*env));
 250         last_task_used_math = NULL;
 251         stts();
 252         env->fcs = (env->swd & 0x0000ffff) | (env->fcs & 0xffff0000);
 253         env->fos = env->twd;
 254         env->swd &= 0xffff3800;
 255         env->twd = 0xffffffff;
 256 }
 257 
 258 asmlinkage void do_coprocessor_error(struct pt_regs * regs, long error_code)
     /*  */
 259 {
 260         ignore_irq13 = 1;
 261         math_error();
 262 }
 263 
 264 /*
 265  *  'math_state_restore()' saves the current math information in the
 266  * old math state array, and gets the new ones from the current task
 267  *
 268  * Careful.. There are problems with IBM-designed IRQ13 behaviour.
 269  * Don't touch unless you *really* know how it works.
 270  */
 271 asmlinkage void math_state_restore(void)
     /*  */
 272 {
 273         __asm__ __volatile__("clts");
 274         if (last_task_used_math == current)
 275                 return;
 276         timer_table[COPRO_TIMER].expires = jiffies+50;
 277         timer_active |= 1<<COPRO_TIMER; 
 278         if (last_task_used_math)
 279                 __asm__("fnsave %0":"=m" (last_task_used_math->tss.i387));
 280         else
 281                 __asm__("fnclex");
 282         last_task_used_math = current;
 283         if (current->used_math) {
 284                 __asm__("frstor %0": :"m" (current->tss.i387));
 285         } else {
 286                 __asm__("fninit");
 287                 current->used_math=1;
 288         }
 289         timer_active &= ~(1<<COPRO_TIMER);
 290 }
 291 
 292 #ifndef CONFIG_MATH_EMULATION
 293 
 294 asmlinkage void math_emulate(long arg)
     /*  */
 295 {
 296   printk("math-emulation not enabled and no coprocessor found.\n");
 297   printk("killing %s.\n",current->comm);
 298   send_sig(SIGFPE,current,1);
 299   schedule();
 300 }
 301 
 302 #endif /* CONFIG_MATH_EMULATION */
 303 
 304 void trap_init(void)
     /*  */
 305 {
 306         int i;
 307         struct desc_struct * p;
 308 
 309         if (strncmp((char*)0x0FFFD9, "EISA", 4) == 0)
 310                 EISA_bus = 1;
 311         set_call_gate(&default_ldt,lcall7);
 312         set_trap_gate(0,&divide_error);
 313         set_trap_gate(1,&debug);
 314         set_trap_gate(2,&nmi);
 315         set_system_gate(3,&int3);       /* int3-5 can be called from all */
 316         set_system_gate(4,&overflow);
 317         set_system_gate(5,&bounds);
 318         set_trap_gate(6,&invalid_op);
 319         set_trap_gate(7,&device_not_available);
 320         set_trap_gate(8,&double_fault);
 321         set_trap_gate(9,&coprocessor_segment_overrun);
 322         set_trap_gate(10,&invalid_TSS);
 323         set_trap_gate(11,&segment_not_present);
 324         set_trap_gate(12,&stack_segment);
 325         set_trap_gate(13,&general_protection);
 326         set_trap_gate(14,&page_fault);
 327         set_trap_gate(15,&reserved);
 328         set_trap_gate(16,&coprocessor_error);
 329         set_trap_gate(17,&alignment_check);
 330         for (i=18;i<48;i++)
 331                 set_trap_gate(i,&reserved);
 332         set_system_gate(0x80,&system_call);
 333 /* set up GDT task & ldt entries */
 334         p = gdt+FIRST_TSS_ENTRY;
 335         set_tss_desc(p, &init_task.tss);
 336         p++;
 337         set_ldt_desc(p, &default_ldt, 1);
 338         p++;
 339         for(i=1 ; i<NR_TASKS ; i++) {
 340                 p->a=p->b=0;
 341                 p++;
 342                 p->a=p->b=0;
 343                 p++;
 344         }
 345 /* Clear NT, so that we won't have troubles with that later on */
 346         __asm__("pushfl ; andl $0xffffbfff,(%esp) ; popfl");
 347         load_TR(0);
 348         load_ldt(0);
 349 }
/* */
root/arch/i386/kernel/traps.c

DEFINITIONS
