arch/i386/kernel/traps.c /* * linux/arch/i386/traps.c * * Copyright (C) 1991, 1992 Linus Torvalds */ /* * 'Traps.c' handles hardware traps and faults after we have saved some * state in 'asm.s'. Currently mostly a debugging-aid, will be extended * to mainly kill the offending process (probably by giving it a signal, * but possibly by killing it outright if necessary). */ #include <linux/config.h> #include <linux/head.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/errno.h> #include <linux/ptrace.h> #include <linux/config.h> #include <linux/timer.h> #include <linux/mm.h> #include <asm/system.h> #include <asm/segment.h> #include <asm/io.h> asmlinkage int system_call(void); asmlinkage void lcall7(void); struct desc_struct default_ldt = { 0, 0 }; static inline void console_verbose(void) { extern int console_loglevel; console_loglevel = 15; } #define DO_ERROR(trapnr, signr, str, name, tsk) \ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \ { \ tsk->tss.error_code = error_code; \ tsk->tss.trap_no = trapnr; \ force_sig(signr, tsk); \ die_if_kernel(str,regs,error_code); \ } #define get_seg_byte(seg,addr) ({ \ register unsigned char __res; \ __asm__("push %%fs;mov %%ax,%%fs;movb %%fs:%2,%%al;pop %%fs" \ :"=a" (__res):"0" (seg),"m" (*(addr))); \ __res;}) #define get_seg_long(seg,addr) ({ \ register unsigned long __res; \ __asm__("push %%fs;mov %%ax,%%fs;movl %%fs:%2,%%eax;pop %%fs" \ :"=a" (__res):"0" (seg),"m" (*(addr))); \ __res;}) #define _fs() ({ \ register unsigned short __res; \ __asm__("mov %%fs,%%ax":"=a" (__res):); \ __res;}) void page_exception(void); asmlinkage void divide_error(void); asmlinkage void debug(void); asmlinkage void nmi(void); asmlinkage void int3(void); asmlinkage void overflow(void); asmlinkage void bounds(void); asmlinkage void invalid_op(void); asmlinkage void device_not_available(void); asmlinkage void double_fault(void); asmlinkage void coprocessor_segment_overrun(void); asmlinkage void invalid_TSS(void); asmlinkage void segment_not_present(void); asmlinkage void stack_segment(void); asmlinkage void general_protection(void); asmlinkage void page_fault(void); asmlinkage void coprocessor_error(void); asmlinkage void reserved(void); asmlinkage void alignment_check(void); int kstack_depth_to_print = 24; /* * These constants are for searching for possible module text * segments. VMALLOC_OFFSET comes from mm/vmalloc.c; MODULE_RANGE is * a guess of how much space is likely to be vmalloced. */ #define VMALLOC_OFFSET (8*1024*1024) #define MODULE_RANGE (8*1024*1024) /*static*/ void die_if_kernel(const char * str, struct pt_regs * regs, long err) { int i; unsigned long esp; unsigned short ss; unsigned long *stack, addr, module_start, module_end; extern char start_kernel, _etext; esp = (unsigned long) ®s->esp; ss = KERNEL_DS; if ((regs->eflags & VM_MASK) || (3 & regs->cs) == 3) return; if (regs->cs & 3) { esp = regs->esp; ss = regs->ss; } console_verbose(); printk("%s: %04lx\n", str, err & 0xffff); printk("CPU: %d\n", smp_processor_id()); printk("EIP: %04x:[<%08lx>]\nEFLAGS: %08lx\n", 0xffff & regs->cs,regs->eip,regs->eflags); printk("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n", regs->eax, regs->ebx, regs->ecx, regs->edx); printk("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n", regs->esi, regs->edi, regs->ebp, esp); printk("ds: %04x es: %04x fs: %04x gs: %04x ss: %04x\n", regs->ds, regs->es, regs->fs, regs->gs, ss); store_TR(i); if (STACK_MAGIC != *(unsigned long *)current->kernel_stack_page) printk("Corrupted stack page\n"); printk("Process %s (pid: %d, process nr: %d, stackpage=%08lx)\nStack: ", current->comm, current->pid, 0xffff & i, current->kernel_stack_page); stack = (unsigned long *) esp; for(i=0; i < kstack_depth_to_print; i++) { if (((long) stack & 4095) == 0) break; if (i && ((i % 8) == 0)) printk("\n "); printk("%08lx ", get_seg_long(ss,stack++)); } printk("\nCall Trace: "); stack = (unsigned long *) esp; i = 1; module_start = ((high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)); module_end = module_start + MODULE_RANGE; while (((long) stack & 4095) != 0) { addr = get_seg_long(ss, stack++); /* * If the address is either in the text segment of the * kernel, or in the region which contains vmalloc'ed * memory, it *may* be the address of a calling * routine; if so, print it so that someone tracing * down the cause of the crash will be able to figure * out the call path that was taken. */ if (((addr >= (unsigned long) &start_kernel) && (addr <= (unsigned long) &_etext)) || ((addr >= module_start) && (addr <= module_end))) { if (i && ((i % 8) == 0)) printk("\n "); printk("[<%08lx>] ", addr); i++; } } printk("\nCode: "); for(i=0;i<20;i++) printk("%02x ",0xff & get_seg_byte(regs->cs,(i+(char *)regs->eip))); printk("\n"); do_exit(SIGSEGV); } DO_ERROR( 0, SIGFPE, "divide error", divide_error, current) DO_ERROR( 3, SIGTRAP, "int3", int3, current) DO_ERROR( 4, SIGSEGV, "overflow", overflow, current) DO_ERROR( 5, SIGSEGV, "bounds", bounds, current) DO_ERROR( 6, SIGILL, "invalid operand", invalid_op, current) DO_ERROR( 7, SIGSEGV, "device not available", device_not_available, current) DO_ERROR( 8, SIGSEGV, "double fault", double_fault, current) DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun, last_task_used_math) DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS, current) DO_ERROR(11, SIGBUS, "segment not present", segment_not_present, current) DO_ERROR(12, SIGBUS, "stack segment", stack_segment, current) DO_ERROR(17, SIGSEGV, "alignment check", alignment_check, current) asmlinkage void do_reserved(struct pt_regs * regs, long error_code) { printk("Uhhuh.. Reserved trap code, whazzup? (%ld)\n", error_code); } asmlinkage void do_general_protection(struct pt_regs * regs, long error_code) { if (regs->eflags & VM_MASK) { handle_vm86_fault((struct vm86_regs *) regs, error_code); return; } die_if_kernel("general protection",regs,error_code); current->tss.error_code = error_code; current->tss.trap_no = 13; force_sig(SIGSEGV, current); } asmlinkage void do_nmi(struct pt_regs * regs, long error_code) { #ifdef CONFIG_SMP_NMI_INVAL smp_flush_tlb_rcv(); #else #ifndef CONFIG_IGNORE_NMI printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n"); printk("You probably have a hardware problem with your RAM chips or a\n"); printk("power saving mode enabled.\n"); #endif #endif } asmlinkage void do_debug(struct pt_regs * regs, long error_code) { if (regs->eflags & VM_MASK) { handle_vm86_debug((struct vm86_regs *) regs, error_code); return; } force_sig(SIGTRAP, current); current->tss.trap_no = 1; current->tss.error_code = error_code; if ((regs->cs & 3) == 0) { /* If this is a kernel mode trap, then reset db7 and allow us to continue */ __asm__("movl %0,%%db7" : /* no output */ : "r" (0)); return; } die_if_kernel("debug",regs,error_code); } /* * Note that we play around with the 'TS' bit to hopefully get * the correct behaviour even in the presence of the asynchronous * IRQ13 behaviour */ void math_error(void) { struct task_struct * task; clts(); #ifdef __SMP__ task = current; #else task = last_task_used_math; last_task_used_math = NULL; if (!task) { __asm__("fnclex"); return; } #endif /* * Save the info for the exception handler */ __asm__ __volatile__("fnsave %0":"=m" (task->tss.i387.hard)); task->flags&=~PF_USEDFPU; stts(); force_sig(SIGFPE, task); task->tss.trap_no = 16; task->tss.error_code = 0; } asmlinkage void do_coprocessor_error(struct pt_regs * regs, long error_code) { ignore_irq13 = 1; math_error(); } /* * 'math_state_restore()' saves the current math information in the * old math state array, and gets the new ones from the current task * * Careful.. There are problems with IBM-designed IRQ13 behaviour. * Don't touch unless you *really* know how it works. */ asmlinkage void math_state_restore(void) { __asm__ __volatile__("clts"); /* Allow maths ops (or we recurse) */ /* * SMP is actually simpler than uniprocessor for once. Because * we can't pull the delayed FPU switching trick Linus does * we simply have to do the restore each context switch and * set the flag. switch_to() will always save the state in * case we swap processors. We also don't use the coprocessor * timer - IRQ 13 mode isn't used with SMP machines (thank god). */ #ifndef __SMP__ if (last_task_used_math == current) return; if (last_task_used_math) __asm__("fnsave %0":"=m" (last_task_used_math->tss.i387)); else __asm__("fnclex"); last_task_used_math = current; #endif if(current->used_math) __asm__("frstor %0": :"m" (current->tss.i387)); else { /* * Our first FPU usage, clean the chip. */ __asm__("fninit"); current->used_math = 1; } current->flags|=PF_USEDFPU; /* So we fnsave on switch_to() */ } #ifndef CONFIG_MATH_EMULATION asmlinkage void math_emulate(long arg) { printk("math-emulation not enabled and no coprocessor found.\n"); printk("killing %s.\n",current->comm); force_sig(SIGFPE,current); schedule(); } #endif /* CONFIG_MATH_EMULATION */ void trap_init(void) { int i; struct desc_struct * p; static int smptrap=0; if(smptrap) { __asm__("pushfl ; andl $0xffffbfff,(%esp) ; popfl"); load_ldt(0); return; } smptrap++; if (strncmp((char*)0x0FFFD9, "EISA", 4) == 0) EISA_bus = 1; set_call_gate(&default_ldt,lcall7); set_trap_gate(0,÷_error); set_trap_gate(1,&debug); set_trap_gate(2,&nmi); set_system_gate(3,&int3); /* int3-5 can be called from all */ set_system_gate(4,&overflow); set_system_gate(5,&bounds); set_trap_gate(6,&invalid_op); set_trap_gate(7,&device_not_available); set_trap_gate(8,&double_fault); set_trap_gate(9,&coprocessor_segment_overrun); set_trap_gate(10,&invalid_TSS); set_trap_gate(11,&segment_not_present); set_trap_gate(12,&stack_segment); set_trap_gate(13,&general_protection); set_trap_gate(14,&page_fault); set_trap_gate(15,&reserved); set_trap_gate(16,&coprocessor_error); set_trap_gate(17,&alignment_check); for (i=18;i<48;i++) set_trap_gate(i,&reserved); set_system_gate(0x80,&system_call); /* set up GDT task & ldt entries */ p = gdt+FIRST_TSS_ENTRY; set_tss_desc(p, &init_task.tss); p++; set_ldt_desc(p, &default_ldt, 1); p++; for(i=1 ; i<NR_TASKS ; i++) { p->a=p->b=0; p++; p->a=p->b=0; p++; } /* Clear NT, so that we won't have troubles with that later on */ __asm__("pushfl ; andl $0xffffbfff,(%esp) ; popfl"); load_TR(0); load_ldt(0); }