/* * Copyright (C) 1991, 1992 Linus Torvalds * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs * * Pentium III FXSR, SSE support * Gareth Hughes , May 2000 */ /* * 'Traps.c' handles hardware traps and faults after we have saved some * state in 'entry.S'. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if defined(CONFIG_EDAC) #include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include static int ignore_nmis; static inline void conditional_sti(struct pt_regs *regs) { if (regs->flags & X86_EFLAGS_IF) local_irq_enable(); } static inline void preempt_conditional_sti(struct pt_regs *regs) { inc_preempt_count(); if (regs->flags & X86_EFLAGS_IF) local_irq_enable(); } static inline void preempt_conditional_cli(struct pt_regs *regs) { if (regs->flags & X86_EFLAGS_IF) local_irq_disable(); /* Make sure to not schedule here because we could be running on an exception stack. */ dec_preempt_count(); } static void __kprobes do_trap(int trapnr, int signr, char *str, struct pt_regs *regs, long error_code, siginfo_t *info) { struct task_struct *tsk = current; if (!user_mode(regs)) goto kernel_trap; /* * We want error_code and trap_no set for userspace faults and * kernelspace faults which result in die(), but not * kernelspace faults which are fixed up. die() gives the * process no chance to handle the signal and notice the * kernel fault information, so that won't result in polluting * the information about previously queued, but not yet * delivered, faults. See also do_general_protection below. */ tsk->thread.error_code = error_code; tsk->thread.trap_no = trapnr; if (show_unhandled_signals && unhandled_signal(tsk, signr) && printk_ratelimit()) { printk(KERN_INFO "%s[%d] trap %s ip:%lx sp:%lx error:%lx", tsk->comm, tsk->pid, str, regs->ip, regs->sp, error_code); print_vma_addr(" in ", regs->ip); printk("\n"); } if (info) force_sig_info(signr, info, tsk); else force_sig(signr, tsk); return; kernel_trap: if (!fixup_exception(regs)) { tsk->thread.error_code = error_code; tsk->thread.trap_no = trapnr; die(str, regs, error_code); } return; } #define DO_ERROR(trapnr, signr, str, name) \ dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \ { \ if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ == NOTIFY_STOP) \ return; \ conditional_sti(regs); \ do_trap(trapnr, signr, str, regs, error_code, NULL); \ } #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \ dotraplinkage 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 __user *)siaddr; \ if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ == NOTIFY_STOP) \ return; \ conditional_sti(regs); \ do_trap(trapnr, signr, str, regs, error_code, &info); \ } DO_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip) DO_ERROR(4, SIGSEGV, "overflow", overflow) DO_ERROR(5, SIGSEGV, "bounds", bounds) DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip) 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_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0) /* Runs on IST stack */ dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code) { if (notify_die(DIE_TRAP, "stack segment", regs, error_code, 12, SIGBUS) == NOTIFY_STOP) return; preempt_conditional_sti(regs); do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL); preempt_conditional_cli(regs); } dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code) { static const char str[] = "double fault"; struct task_struct *tsk = current; /* Return not checked because double check cannot be ignored */ notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV); tsk->thread.error_code = error_code; tsk->thread.trap_no = 8; /* This is always a kernel trap and never fixable (and thus must never return). */ for (;;) die(str, regs, error_code); } dotraplinkage void __kprobes do_general_protection(struct pt_regs *regs, long error_code) { struct task_struct *tsk; conditional_sti(regs); tsk = current; if (!user_mode(regs)) goto gp_in_kernel; tsk->thread.error_code = error_code; tsk->thread.trap_no = 13; if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) && printk_ratelimit()) { printk(KERN_INFO "%s[%d] general protection ip:%lx sp:%lx error:%lx", tsk->comm, task_pid_nr(tsk), regs->ip, regs->sp, error_code); print_vma_addr(" in ", regs->ip); printk("\n"); } force_sig(SIGSEGV, tsk); return; gp_in_kernel: if (fixup_exception(regs)) return; tsk->thread.error_code = error_code; tsk->thread.trap_no = 13; if (notify_die(DIE_GPF, "general protection fault", regs, error_code, 13, SIGSEGV) == NOTIFY_STOP) return; die("general protection fault", regs, error_code); } static notrace __kprobes void mem_parity_error(unsigned char reason, struct pt_regs *regs) { printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n", reason); printk(KERN_EMERG "You have some hardware problem, likely on the PCI bus.\n"); #if defined(CONFIG_EDAC) if (edac_handler_set()) { edac_atomic_assert_error(); return; } #endif if (panic_on_unrecovered_nmi) panic("NMI: Not continuing"); printk(KERN_EMERG "Dazed and confused, but trying to continue\n"); /* Clear and disable the memory parity error line. */ reason = (reason & 0xf) | 4; outb(reason, 0x61); } static notrace __kprobes void io_check_error(unsigned char reason, struct pt_regs *regs) { unsigned long i; printk(KERN_EMERG "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); i = 2000; while (--i) udelay(1000); reason &= ~8; outb(reason, 0x61); } static notrace __kprobes void unknown_nmi_error(unsigned char reason, struct pt_regs *regs) { if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP) return; printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n", reason); printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n"); if (panic_on_unrecovered_nmi) panic("NMI: Not continuing"); printk(KERN_EMERG "Dazed and confused, but trying to continue\n"); } /* Runs on IST stack. This code must keep interrupts off all the time. Nested NMIs are prevented by the CPU. */ asmlinkage notrace __kprobes void default_do_nmi(struct pt_regs *regs) { unsigned char reason = 0; int cpu; cpu = smp_processor_id(); /* Only the BSP gets external NMIs from the system. */ if (!cpu) reason = get_nmi_reason(); if (!(reason & 0xc0)) { if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT) == NOTIFY_STOP) return; /* * Ok, so this is none of the documented NMI sources, * so it must be the NMI watchdog. */ if (nmi_watchdog_tick(regs, reason)) return; if (!do_nmi_callback(regs, cpu)) unknown_nmi_error(reason, regs); return; } if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP) return; /* AK: following checks seem to be broken on modern chipsets. FIXME */ if (reason & 0x80) mem_parity_error(reason, regs); if (reason & 0x40) io_check_error(reason, regs); } dotraplinkage notrace __kprobes void do_nmi(struct pt_regs *regs, long error_code) { nmi_enter(); add_pda(__nmi_count, 1); if (!ignore_nmis) default_do_nmi(regs); nmi_exit(); } void stop_nmi(void) { acpi_nmi_disable(); ignore_nmis++; } void restart_nmi(void) { ignore_nmis--; acpi_nmi_enable(); } /* runs on IST stack. */ dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code) { if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP) == NOTIFY_STOP) return; preempt_conditional_sti(regs); do_trap(3, SIGTRAP, "int3", regs, error_code, NULL); preempt_conditional_cli(regs); } /* Help handler running on IST stack to switch back to user stack for scheduling or signal handling. The actual stack switch is done in entry.S */ asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs) { struct pt_regs *regs = eregs; /* Did already sync */ if (eregs == (struct pt_regs *)eregs->sp) ; /* Exception from user space */ else if (user_mode(eregs)) regs = task_pt_regs(current); /* Exception from kernel and interrupts are enabled. Move to kernel process stack. */ else if (eregs->flags & X86_EFLAGS_IF) regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs)); if (eregs != regs) *regs = *eregs; return regs; } /* runs on IST stack. */ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) { struct task_struct *tsk = current; unsigned long condition; int si_code; get_debugreg(condition, 6); /* * The processor cleared BTF, so don't mark that we need it set. */ clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR); tsk->thread.debugctlmsr = 0; if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code, SIGTRAP) == NOTIFY_STOP) return; /* It's safe to allow irq's after DR6 has been saved */ preempt_conditional_sti(regs); /* Mask out spurious debug traps due to lazy DR7 setting */ if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) { if (!tsk->thread.debugreg7) goto clear_dr7; } /* Save debug status register where ptrace can see it */ tsk->thread.debugreg6 = condition; /* * Single-stepping through TF: make sure we ignore any events in * kernel space (but re-enable TF when returning to user mode). */ if (condition & DR_STEP) { if (!user_mode(regs)) goto clear_TF_reenable; } si_code = get_si_code(condition); /* Ok, finally something we can handle */ send_sigtrap(tsk, regs, error_code, si_code); /* * Disable additional traps. They'll be re-enabled when * the signal is delivered. */ clear_dr7: set_debugreg(0, 7); preempt_conditional_cli(regs); return; clear_TF_reenable: set_tsk_thread_flag(tsk, TIF_SINGLESTEP); regs->flags &= ~X86_EFLAGS_TF; preempt_conditional_cli(regs); return; } static int kernel_math_error(struct pt_regs *regs, const char *str, int trapnr) { if (fixup_exception(regs)) return 1; notify_die(DIE_GPF, str, regs, 0, trapnr, SIGFPE); /* Illegal floating point operation in the kernel */ current->thread.trap_no = trapnr; die(str, regs, 0); return 0; } /* * 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 __user *ip) { 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 = ip; /* * (~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 synchronizing 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 (swd & ~cwd & 0x3f) { case 0x000: /* No unmasked exception */ default: /* Multiple exceptions */ break; case 0x001: /* Invalid Op */ /* * swd & 0x240 == 0x040: Stack Underflow * swd & 0x240 == 0x240: Stack Overflow * User must clear the SF bit (0x40) if set */ 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); } dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code) { conditional_sti(regs); if (!user_mode(regs) && kernel_math_error(regs, "kernel x87 math error", 16)) return; math_error((void __user *)regs->ip); } asmlinkage void bad_intr(void) { printk("bad interrupt"); } static void simd_math_error(void __user *ip) { 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 = ip; /* * 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); } dotraplinkage void do_simd_coprocessor_error(struct pt_regs *regs, long error_code) { conditional_sti(regs); if (!user_mode(regs) && kernel_math_error(regs, "kernel simd math error", 19)) return; simd_math_error((void __user *)regs->ip); } dotraplinkage void do_spurious_interrupt_bug(struct pt_regs *regs, long error_code) { } asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void) { } asmlinkage void __attribute__((weak)) mce_threshold_interrupt(void) { } /* * '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 thread_info *thread = current_thread_info(); struct task_struct *tsk = thread->task; if (!tsk_used_math(tsk)) { local_irq_enable(); /* * does a slab alloc which can sleep */ if (init_fpu(tsk)) { /* * ran out of memory! */ do_group_exit(SIGKILL); return; } local_irq_disable(); } clts(); /* Allow maths ops (or we recurse) */ /* * Paranoid restore. send a SIGSEGV if we fail to restore the state. */ if (unlikely(restore_fpu_checking(tsk))) { stts(); force_sig(SIGSEGV, tsk); return; } thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */ tsk->fpu_counter++; } EXPORT_SYMBOL_GPL(math_state_restore); dotraplinkage void __kprobes do_device_not_available(struct pt_regs *regs, long error) { math_state_restore(); } void __init trap_init(void) { set_intr_gate(0, ÷_error); set_intr_gate_ist(1, &debug, DEBUG_STACK); set_intr_gate_ist(2, &nmi, NMI_STACK); /* int3 can be called from all */ set_system_intr_gate_ist(3, &int3, DEBUG_STACK); /* int4 can be called from all */ set_system_intr_gate(4, &overflow); set_intr_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); #ifdef CONFIG_X86_MCE set_intr_gate_ist(18, &machine_check, MCE_STACK); #endif set_intr_gate(19, &simd_coprocessor_error); #ifdef CONFIG_IA32_EMULATION set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall); #endif /* * Should be a barrier for any external CPU state: */ cpu_init(); }