/* * linux/arch/x86-64/traps.c * * Copyright (C) 1991, 1992 Linus Torvalds * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs * * Pentium III FXSR, SSE support * Gareth Hughes <gareth@valinux.com>, May 2000 * * $Id: traps.c,v 1.36 2002/03/24 11:09:10 ak Exp $ */ /* * 'Traps.c' handles hardware traps and faults after we have saved some * state in 'entry.S'. */ #include <linux/config.h> #include <linux/sched.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/errno.h> #include <linux/ptrace.h> #include <linux/timer.h> #include <linux/mm.h> #include <linux/init.h> #include <linux/delay.h> #include <linux/spinlock.h> #include <linux/interrupt.h> #include <linux/module.h> #include <asm/system.h> #include <asm/uaccess.h> #include <asm/io.h> #include <asm/atomic.h> #include <asm/debugreg.h> #include <asm/desc.h> #include <asm/i387.h> #include <asm/kdebug.h> #include <asm/processor.h> #include <asm/smp.h> #include <asm/pgalloc.h> #include <asm/pda.h> #include <linux/irq.h> asmlinkage int system_call(void); asmlinkage int kernel_syscall(void); extern void ia32_syscall(void); extern struct gate_struct idt_table[256]; 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 simd_coprocessor_error(void); asmlinkage void reserved(void); asmlinkage void alignment_check(void); asmlinkage void machine_check(void); asmlinkage void spurious_interrupt_bug(void); asmlinkage void call_debug(void); extern int exception_trace; struct notifier_block *die_chain; static int kstack_depth_to_print = 10; #ifdef CONFIG_KALLSYMS #include <linux/kallsyms.h> int printk_address(unsigned long address) { unsigned long offset = 0, symsize; const char *symname; char *modname; char *delim = ":"; char namebuf[128]; symname = kallsyms_lookup(address, &symsize, &offset, &modname, namebuf); if (!symname) return printk("[<%016lx>]", address); if (!modname) modname = delim = ""; return printk("<%016lx>{%s%s%s%s%+ld}", address,delim,modname,delim,symname,offset); } #else int printk_address(unsigned long address) { return printk("[<%016lx>]", address); } #endif static inline unsigned long *in_exception_stack(int cpu, unsigned long stack) { int k; for (k = 0; k < N_EXCEPTION_STACKS; k++) { unsigned long end = init_tss[cpu].ist[k] + EXCEPTION_STKSZ; if (stack >= init_tss[cpu].ist[k] && stack <= end) return (unsigned long *)end; } return 0; } /* * x86-64 can have upto three kernel stacks: * process stack * interrupt stack * severe exception (double fault, nmi, stack fault) hardware stack * Check and process them in order. */ void show_trace(unsigned long *stack) { unsigned long addr; unsigned long *irqstack, *irqstack_end, *estack_end; /* FIXME: should read the cpuid from the APIC; to still work with bogus %gs */ const int cpu = smp_processor_id(); int i; printk("\nCall Trace:"); i = 0; estack_end = in_exception_stack(cpu, (unsigned long)stack); if (estack_end) { while (stack < estack_end) { addr = *stack++; if (kernel_text_address(addr)) { i += printk_address(addr); i += printk(" "); if (i > 50) { printk("\n"); i = 0; } } } i += printk(" <EOE> "); i += 7; stack = (unsigned long *) estack_end[-2]; } irqstack_end = (unsigned long *) (cpu_pda[cpu].irqstackptr); irqstack = (unsigned long *) (cpu_pda[cpu].irqstackptr - IRQSTACKSIZE + 64); if (stack >= irqstack && stack < irqstack_end) { printk("<IRQ> "); while (stack < irqstack_end) { addr = *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 (kernel_text_address(addr)) { i += printk_address(addr); i += printk(" "); if (i > 50) { printk("\n "); i = 0; } } } stack = (unsigned long *) (irqstack_end[-1]); printk(" <EOI> "); i += 7; } while (((long) stack & (THREAD_SIZE-1)) != 0) { addr = *stack++; if (kernel_text_address(addr)) { i += printk_address(addr); i += printk(" "); if (i > 50) { printk("\n "); i = 0; } } } printk("\n"); } void show_trace_task(struct task_struct *tsk) { unsigned long rsp = tsk->thread.rsp; /* User space on another CPU? */ if ((rsp ^ (unsigned long)tsk->thread_info) & (PAGE_MASK<<1)) return; show_trace((unsigned long *)rsp); } void show_stack(unsigned long * rsp) { unsigned long *stack; int i; const int cpu = smp_processor_id(); unsigned long *irqstack_end = (unsigned long *) (cpu_pda[cpu].irqstackptr); unsigned long *irqstack = (unsigned long *) (cpu_pda[cpu].irqstackptr - IRQSTACKSIZE); // debugging aid: "show_stack(NULL);" prints the // back trace for this cpu. if(rsp==NULL) rsp=(unsigned long*)&rsp; stack = rsp; for(i=0; i < kstack_depth_to_print; i++) { if (stack >= irqstack && stack <= irqstack_end) { if (stack == irqstack_end) { stack = (unsigned long *) (irqstack_end[-1]); printk(" <EOI> "); } } else { if (((long) stack & (THREAD_SIZE-1)) == 0) break; } if (i && ((i % 4) == 0)) printk("\n "); printk("%016lx ", *stack++); } show_trace((unsigned long *)rsp); } /* * The architecture-independent dump_stack generator */ void dump_stack(void) { unsigned long dummy; show_stack(&dummy); } void show_registers(struct pt_regs *regs) { int i; int in_kernel = (regs->cs & 3) == 0; unsigned long rsp; #ifdef CONFIG_SMP /* For SMP should get the APIC id here, just to protect against corrupted GS */ const int cpu = smp_processor_id(); #else const int cpu = 0; #endif struct task_struct *cur = cpu_pda[cpu].pcurrent; rsp = regs->rsp; printk("CPU %d ", cpu); show_regs(regs); printk("Process %s (pid: %d, stackpage=%08lx)\n", cur->comm, cur->pid, 4096+(unsigned long)cur); /* * When in-kernel, we also print out the stack and code at the * time of the fault.. */ if (in_kernel) { printk("Stack: "); show_stack((unsigned long*)rsp); printk("\nCode: "); if(regs->rip < PAGE_OFFSET) goto bad; for(i=0;i<20;i++) { unsigned char c; if(__get_user(c, &((unsigned char*)regs->rip)[i])) { bad: printk(" Bad RIP value."); break; } printk("%02x ", c); } } printk("\n"); } void handle_BUG(struct pt_regs *regs) { struct bug_frame f; char tmp; if (regs->cs & 3) return; if (__copy_from_user(&f, (struct bug_frame *) regs->rip, sizeof(struct bug_frame))) return; if ((unsigned long)f.filename < __PAGE_OFFSET || f.ud2[0] != 0x0f || f.ud2[1] != 0x0b) return; if (__get_user(tmp, f.filename)) f.filename = "unmapped filename"; printk("----------- [cut here ] --------- [please bite here ] ---------\n"); printk("Kernel BUG at %.50s:%d\n", f.filename, f.line); } void out_of_line_bug(void) { BUG(); } spinlock_t die_lock = SPIN_LOCK_UNLOCKED; int die_owner = -1; void die(const char * str, struct pt_regs * regs, long err) { int cpu; struct die_args args = { regs, str, err }; console_verbose(); notifier_call_chain(&die_chain, DIE_DIE, &args); bust_spinlocks(1); handle_BUG(regs); printk("%s: %04lx\n", str, err & 0xffff); cpu = smp_processor_id(); /* racy, but better than risking deadlock. */ local_irq_disable(); if (!spin_trylock(&die_lock)) { if (cpu == die_owner) /* nested oops. should stop eventually */; else spin_lock(&die_lock); } die_owner = cpu; show_registers(regs); bust_spinlocks(0); spin_unlock_irq(&die_lock); notify_die(DIE_OOPS, (char *)str, regs, err); do_exit(SIGSEGV); } static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err) { if (!(regs->eflags & VM_MASK) && (regs->cs == __KERNEL_CS)) die(str, regs, err); } static inline unsigned long get_cr2(void) { unsigned long address; /* get the address */ __asm__("movq %%cr2,%0":"=r" (address)); return address; } static void do_trap(int trapnr, int signr, char *str, struct pt_regs * regs, long error_code, siginfo_t *info) { #ifdef CONFIG_CHECKING { unsigned long gs; struct x8664_pda *pda = cpu_pda + stack_smp_processor_id(); rdmsrl(MSR_GS_BASE, gs); if (gs != (unsigned long)pda) { wrmsrl(MSR_GS_BASE, pda); printk("%s: wrong gs %lx expected %p rip %lx\n", str, gs, pda, regs->rip); } } #endif if ((regs->cs & 3) != 0) { struct task_struct *tsk = current; if (exception_trace && trapnr != 3) printk("%s[%d] trap %s at rip:%lx rsp:%lx err:%lx\n", tsk->comm, tsk->pid, str, regs->rip, regs->rsp, error_code); tsk->thread.error_code = error_code; tsk->thread.trap_no = trapnr; if (info) force_sig_info(signr, info, tsk); else force_sig(signr, tsk); return; } /* kernel trap */ { const struct exception_table_entry *fixup; fixup = search_exception_tables(regs->rip); if (fixup) { extern int exception_trace; if (exception_trace) printk(KERN_ERR "%s: fixed kernel exception at %lx err:%ld\n", current->comm, regs->rip, error_code); regs->rip = fixup->fixup; } else die(str, regs, error_code); return; } } #define DO_ERROR(trapnr, signr, str, name) \ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \ { \ do_trap(trapnr, signr, str, regs, error_code, NULL); \ } #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \ { \ siginfo_t info; \ info.si_signo = signr; \ info.si_errno = 0; \ info.si_code = sicode; \ info.si_addr = (void *)siaddr; \ do_trap(trapnr, signr, str, regs, error_code, &info); \ } DO_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->rip) DO_ERROR( 4, SIGSEGV, "overflow", overflow) DO_ERROR( 5, SIGSEGV, "bounds", bounds) DO_ERROR_INFO( 6, SIGILL, "invalid operand", invalid_op, ILL_ILLOPN, regs->rip) DO_ERROR( 7, SIGSEGV, "device not available", device_not_available) DO_ERROR( 8, SIGSEGV, "double fault", double_fault) DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun) DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS) DO_ERROR(11, SIGBUS, "segment not present", segment_not_present) DO_ERROR(12, SIGBUS, "stack segment", stack_segment) DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, get_cr2()) DO_ERROR(18, SIGSEGV, "reserved", reserved) asmlinkage void do_int3(struct pt_regs * regs, long error_code) { if (notify_die(DIE_INT3, "int3", regs, error_code) == NOTIFY_BAD) return; do_trap(3, SIGTRAP, "int3", regs, error_code, NULL); } asmlinkage void do_general_protection(struct pt_regs * regs, long error_code) { #ifdef CONFIG_CHECKING { unsigned long gs; struct x8664_pda *pda = cpu_pda + stack_smp_processor_id(); rdmsrl(MSR_GS_BASE, gs); if (gs != (unsigned long)pda) { wrmsrl(MSR_GS_BASE, pda); printk("general protection handler: wrong gs %lx expected %p\n", gs, pda); } } #endif if ((regs->cs & 3)!=0) { struct task_struct *tsk = current; if (exception_trace) printk("%s[%d] #gp at rip:%lx rsp:%lx err:%lx\n", tsk->comm, tsk->pid, regs->rip, regs->rsp, error_code); tsk->thread.error_code = error_code; tsk->thread.trap_no = 13; force_sig(SIGSEGV, tsk); return; } /* kernel gp */ { const struct exception_table_entry *fixup; fixup = search_exception_tables(regs->rip); if (fixup) { regs->rip = fixup->fixup; return; } die("general protection fault", regs, error_code); } } static void mem_parity_error(unsigned char reason, struct pt_regs * regs) { printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n"); printk("You probably have a hardware problem with your RAM chips\n"); /* Clear and disable the memory parity error line. */ reason = (reason & 0xf) | 4; outb(reason, 0x61); } static void io_check_error(unsigned char reason, struct pt_regs * regs) { printk("NMI: IOCK error (debug interrupt?)\n"); show_registers(regs); /* Re-enable the IOCK line, wait for a few seconds */ reason = (reason & 0xf) | 8; outb(reason, 0x61); mdelay(2000); reason &= ~8; outb(reason, 0x61); } static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs) { printk("Uhhuh. NMI received for unknown reason %02x.\n", reason); printk("Dazed and confused, but trying to continue\n"); printk("Do you have a strange power saving mode enabled?\n"); } asmlinkage void default_do_nmi(struct pt_regs * regs) { unsigned char reason = inb(0x61); if (!(reason & 0xc0)) { #if CONFIG_X86_LOCAL_APIC /* * Ok, so this is none of the documented NMI sources, * so it must be the NMI watchdog. */ if (nmi_watchdog) { nmi_watchdog_tick(regs); return; } #endif unknown_nmi_error(reason, regs); return; } if (notify_die(DIE_NMI, "nmi", regs, reason) == NOTIFY_BAD) return; if (reason & 0x80) mem_parity_error(reason, regs); if (reason & 0x40) io_check_error(reason, regs); /* * Reassert NMI in case it became active meanwhile * as it's edge-triggered. */ outb(0x8f, 0x70); inb(0x71); /* dummy */ outb(0x0f, 0x70); inb(0x71); /* dummy */ } asmlinkage void do_debug(struct pt_regs * regs, long error_code) { unsigned long condition; struct task_struct *tsk = current; siginfo_t info; #ifdef CONFIG_CHECKING { unsigned long gs; struct x8664_pda *pda = cpu_pda + stack_smp_processor_id(); rdmsrl(MSR_GS_BASE, gs); if (gs != (unsigned long)pda) { wrmsrl(MSR_GS_BASE, pda); printk("debug handler: wrong gs %lx expected %p\n", gs, pda); } } #endif asm("movq %%db6,%0" : "=r" (condition)); if (notify_die(DIE_DEBUG, "debug", regs, error_code) == NOTIFY_BAD) return; /* Mask out spurious debug traps due to lazy DR7 setting */ if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) { if (!tsk->thread.debugreg[7]) { goto clear_dr7; } } tsk->thread.debugreg[6] = condition; /* Mask out spurious TF errors due to lazy TF clearing */ if (condition & DR_STEP) { /* * The TF error should be masked out only if the current * process is not traced and if the TRAP flag has been set * previously by a tracing process (condition detected by * the PT_DTRACE flag); remember that the i386 TRAP flag * can be modified by the process itself in user mode, * allowing programs to debug themselves without the ptrace() * interface. */ if ((regs->cs & 3) == 0) goto clear_TF_reenable; if ((tsk->ptrace & (PT_DTRACE|PT_PTRACED)) == PT_DTRACE) goto clear_TF; } /* Ok, finally something we can handle */ tsk->thread.trap_no = 1; tsk->thread.error_code = error_code; info.si_signo = SIGTRAP; info.si_errno = 0; info.si_code = TRAP_BRKPT; info.si_addr = ((regs->cs & 3) == 0) ? (void *)tsk->thread.rip : (void *)regs->rip; force_sig_info(SIGTRAP, &info, tsk); clear_dr7: asm("movq %0,%%db7"::"r"(0UL)); return; clear_TF_reenable: set_tsk_thread_flag(tsk, TIF_SINGLESTEP); clear_TF: regs->eflags &= ~TF_MASK; return; } /* * Note that we play around with the 'TS' bit in an attempt to get * the correct behaviour even in the presence of the asynchronous * IRQ13 behaviour */ void math_error(void *rip) { struct task_struct * task; siginfo_t info; unsigned short cwd, swd; /* * Save the info for the exception handler and clear the error. */ task = current; save_init_fpu(task); task->thread.trap_no = 16; task->thread.error_code = 0; info.si_signo = SIGFPE; info.si_errno = 0; info.si_code = __SI_FAULT; info.si_addr = rip; /* * (~cwd & swd) will mask out exceptions that are not set to unmasked * status. 0x3f is the exception bits in these regs, 0x200 is the * C1 reg you need in case of a stack fault, 0x040 is the stack * fault bit. We should only be taking one exception at a time, * so if this combination doesn't produce any single exception, * then we have a bad program that isn't syncronizing its FPU usage * and it will suffer the consequences since we won't be able to * fully reproduce the context of the exception */ cwd = get_fpu_cwd(task); swd = get_fpu_swd(task); switch (((~cwd) & swd & 0x3f) | (swd & 0x240)) { case 0x000: default: break; case 0x001: /* Invalid Op */ case 0x040: /* Stack Fault */ case 0x240: /* Stack Fault | Direction */ info.si_code = FPE_FLTINV; break; case 0x002: /* Denormalize */ case 0x010: /* Underflow */ info.si_code = FPE_FLTUND; break; case 0x004: /* Zero Divide */ info.si_code = FPE_FLTDIV; break; case 0x008: /* Overflow */ info.si_code = FPE_FLTOVF; break; case 0x020: /* Precision */ info.si_code = FPE_FLTRES; break; } force_sig_info(SIGFPE, &info, task); } asmlinkage void do_coprocessor_error(struct pt_regs * regs, long error_code) { math_error((void *)regs->rip); } asmlinkage void bad_intr(void) { printk("bad interrupt"); } static inline void simd_math_error(void *rip) { struct task_struct * task; siginfo_t info; unsigned short mxcsr; /* * Save the info for the exception handler and clear the error. */ task = current; save_init_fpu(task); task->thread.trap_no = 19; task->thread.error_code = 0; info.si_signo = SIGFPE; info.si_errno = 0; info.si_code = __SI_FAULT; info.si_addr = rip; /* * The SIMD FPU exceptions are handled a little differently, as there * is only a single status/control register. Thus, to determine which * unmasked exception was caught we must mask the exception mask bits * at 0x1f80, and then use these to mask the exception bits at 0x3f. */ mxcsr = get_fpu_mxcsr(task); switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) { case 0x000: default: break; case 0x001: /* Invalid Op */ info.si_code = FPE_FLTINV; break; case 0x002: /* Denormalize */ case 0x010: /* Underflow */ info.si_code = FPE_FLTUND; break; case 0x004: /* Zero Divide */ info.si_code = FPE_FLTDIV; break; case 0x008: /* Overflow */ info.si_code = FPE_FLTOVF; break; case 0x020: /* Precision */ info.si_code = FPE_FLTRES; break; } force_sig_info(SIGFPE, &info, task); } asmlinkage void do_simd_coprocessor_error(struct pt_regs * regs, long error_code) { simd_math_error((void *)regs->rip); } asmlinkage void do_spurious_interrupt_bug(struct pt_regs * regs) { } /* * '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) { struct task_struct *me = current; clts(); /* Allow maths ops (or we recurse) */ if (!me->used_math) init_fpu(); restore_fpu_checking(&me->thread.i387.fxsave); set_thread_flag(TIF_USEDFPU); } asmlinkage void math_emulate(void) { BUG(); } void do_call_debug(struct pt_regs *regs) { notify_die(DIE_CALL, "debug call", regs, 0); } void __init trap_init(void) { set_intr_gate(0,÷_error); set_intr_gate(1,&debug); set_intr_gate_ist(2,&nmi,NMI_STACK); set_system_gate(3,&int3); /* int3-5 can be called from all */ set_system_gate(4,&overflow); set_system_gate(5,&bounds); set_intr_gate(6,&invalid_op); set_intr_gate(7,&device_not_available); set_intr_gate_ist(8,&double_fault, DOUBLEFAULT_STACK); set_intr_gate(9,&coprocessor_segment_overrun); set_intr_gate(10,&invalid_TSS); set_intr_gate(11,&segment_not_present); set_intr_gate_ist(12,&stack_segment,STACKFAULT_STACK); set_intr_gate(13,&general_protection); set_intr_gate(14,&page_fault); set_intr_gate(15,&spurious_interrupt_bug); set_intr_gate(16,&coprocessor_error); set_intr_gate(17,&alignment_check); set_intr_gate(18,&machine_check); set_intr_gate(19,&simd_coprocessor_error); #ifdef CONFIG_IA32_EMULATION set_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall); #endif set_intr_gate(KDB_VECTOR, call_debug); notify_die(DIE_TRAPINIT, "traps initialized", 0, 0); /* * Should be a barrier for any external CPU state. */ cpu_init(); }