/* * Copyright (C) 1991, 1992 Linus Torvalds * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs * * Pentium III FXSR, SSE support * Gareth Hughes , May 2000 */ /* * Handle hardware traps and faults. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_EISA #include #include #endif #ifdef CONFIG_MCA #include #endif #if defined(CONFIG_EDAC) #include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "cpu/mcheck/mce.h" DECLARE_BITMAP(used_vectors, NR_VECTORS); EXPORT_SYMBOL_GPL(used_vectors); asmlinkage int system_call(void); /* Do we ignore FPU interrupts ? */ char ignore_fpu_irq; /* * The IDT has to be page-aligned to simplify the Pentium * F0 0F bug workaround.. We have a special link segment * for this. */ gate_desc idt_table[256] __attribute__((__section__(".data.idt"))) = { { { { 0, 0 } } }, }; 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(); dec_preempt_count(); } static inline void die_if_kernel(const char *str, struct pt_regs *regs, long err) { if (!user_mode_vm(regs)) die(str, regs, err); } /* * Perform the lazy TSS's I/O bitmap copy. If the TSS has an * invalid offset set (the LAZY one) and the faulting thread has * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS, * we set the offset field correctly and return 1. */ static int lazy_iobitmap_copy(void) { struct thread_struct *thread; struct tss_struct *tss; int cpu; cpu = get_cpu(); tss = &per_cpu(init_tss, cpu); thread = ¤t->thread; if (tss->x86_tss.io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY && thread->io_bitmap_ptr) { memcpy(tss->io_bitmap, thread->io_bitmap_ptr, thread->io_bitmap_max); /* * If the previously set map was extending to higher ports * than the current one, pad extra space with 0xff (no access). */ if (thread->io_bitmap_max < tss->io_bitmap_max) { memset((char *) tss->io_bitmap + thread->io_bitmap_max, 0xff, tss->io_bitmap_max - thread->io_bitmap_max); } tss->io_bitmap_max = thread->io_bitmap_max; tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET; tss->io_bitmap_owner = thread; put_cpu(); return 1; } put_cpu(); return 0; } 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 (regs->flags & X86_VM_MASK) { /* * traps 0, 1, 3, 4, and 5 should be forwarded to vm86. * On nmi (interrupt 2), do_trap should not be called. */ if (trapnr < 6) goto vm86_trap; goto trap_signal; } if (!user_mode(regs)) goto kernel_trap; trap_signal: /* * 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 (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; vm86_trap: if (handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr)) goto trap_signal; 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(12, SIGBUS, "stack segment", stack_segment) DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0) dotraplinkage void __kprobes do_general_protection(struct pt_regs *regs, long error_code) { struct task_struct *tsk; conditional_sti(regs); if (lazy_iobitmap_copy()) { /* restart the faulting instruction */ return; } if (regs->flags & X86_VM_MASK) goto gp_in_vm86; 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_vm86: local_irq_enable(); handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code); 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 on CPU %d.\n", reason, smp_processor_id()); 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; #ifdef CONFIG_MCA /* * Might actually be able to figure out what the guilty party * is: */ if (MCA_bus) { mca_handle_nmi(); return; } #endif printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n", reason, smp_processor_id()); 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"); } static DEFINE_SPINLOCK(nmi_print_lock); void notrace __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic) { if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP) return; spin_lock(&nmi_print_lock); /* * We are in trouble anyway, lets at least try * to get a message out: */ bust_spinlocks(1); printk(KERN_EMERG "%s", str); printk(" on CPU%d, ip %08lx, registers:\n", smp_processor_id(), regs->ip); show_registers(regs); if (do_panic) panic("Non maskable interrupt"); console_silent(); spin_unlock(&nmi_print_lock); bust_spinlocks(0); /* * If we are in kernel we are probably nested up pretty bad * and might aswell get out now while we still can: */ if (!user_mode_vm(regs)) { current->thread.trap_no = 2; crash_kexec(regs); } do_exit(SIGSEGV); } static 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; #ifdef CONFIG_X86_LOCAL_APIC /* * 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); #else unknown_nmi_error(reason, regs); #endif 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); /* * Reassert NMI in case it became active meanwhile * as it's edge-triggered: */ reassert_nmi(); } dotraplinkage notrace __kprobes void do_nmi(struct pt_regs *regs, long error_code) { nmi_enter(); { int cpu; cpu = smp_processor_id(); ++nmi_count(cpu); } 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(); } /* May run on IST stack. */ dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code) { #ifdef CONFIG_KPROBES if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP) == NOTIFY_STOP) return; #else if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP) == NOTIFY_STOP) return; #endif preempt_conditional_sti(regs); do_trap(3, SIGTRAP, "int3", regs, error_code, NULL); preempt_conditional_cli(regs); } /* * Our handling of the processor debug registers is non-trivial. * We do not clear them on entry and exit from the kernel. Therefore * it is possible to get a watchpoint trap here from inside the kernel. * However, the code in ./ptrace.c has ensured that the user can * only set watchpoints on userspace addresses. Therefore the in-kernel * watchpoint trap can only occur in code which is reading/writing * from user space. Such code must not hold kernel locks (since it * can equally take a page fault), therefore it is safe to call * force_sig_info even though that claims and releases locks. * * Code in ./signal.c ensures that the debug control register * is restored before we deliver any signal, and therefore that * user code runs with the correct debug control register even though * we clear it here. * * Being careful here means that we don't have to be as careful in a * lot of more complicated places (task switching can be a bit lazy * about restoring all the debug state, and ptrace doesn't have to * find every occurrence of the TF bit that could be saved away even * by user code) * * May run 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; } if (regs->flags & X86_VM_MASK) goto debug_vm86; /* 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; debug_vm86: handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1); 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; } /* * 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 */ return; 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); ignore_fpu_irq = 1; math_error((void __user *)regs->ip); } 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 (cpu_has_xmm) { /* Handle SIMD FPU exceptions on PIII+ processors. */ ignore_fpu_irq = 1; simd_math_error((void __user *)regs->ip); return; } /* * Handle strange cache flush from user space exception * in all other cases. This is undocumented behaviour. */ if (regs->flags & X86_VM_MASK) { handle_vm86_fault((struct kernel_vm86_regs *)regs, error_code); return; } current->thread.trap_no = 19; current->thread.error_code = error_code; die_if_kernel("cache flush denied", regs, error_code); force_sig(SIGSEGV, current); } dotraplinkage void do_spurious_interrupt_bug(struct pt_regs *regs, long error_code) { conditional_sti(regs); #if 0 /* No need to warn about this any longer. */ printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n"); #endif } unsigned long patch_espfix_desc(unsigned long uesp, unsigned long kesp) { struct desc_struct *gdt = get_cpu_gdt_table(smp_processor_id()); unsigned long base = (kesp - uesp) & -THREAD_SIZE; unsigned long new_kesp = kesp - base; unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT; __u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS]; /* Set up base for espfix segment */ desc &= 0x00f0ff0000000000ULL; desc |= ((((__u64)base) << 16) & 0x000000ffffff0000ULL) | ((((__u64)base) << 32) & 0xff00000000000000ULL) | ((((__u64)lim_pages) << 32) & 0x000f000000000000ULL) | (lim_pages & 0xffff); *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc; return new_kesp; } /* * '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. * * Must be called with kernel preemption disabled (in this case, * local interrupts are disabled at the call-site in entry.S). */ 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) */ restore_fpu(tsk); thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */ tsk->fpu_counter++; } EXPORT_SYMBOL_GPL(math_state_restore); #ifndef CONFIG_MATH_EMULATION asmlinkage void math_emulate(long arg) { printk(KERN_EMERG "math-emulation not enabled and no coprocessor found.\n"); printk(KERN_EMERG "killing %s.\n", current->comm); force_sig(SIGFPE, current); schedule(); } #endif /* CONFIG_MATH_EMULATION */ dotraplinkage void __kprobes do_device_not_available(struct pt_regs *regs, long error) { if (read_cr0() & X86_CR0_EM) { conditional_sti(regs); math_emulate(0); } else { math_state_restore(); /* interrupts still off */ conditional_sti(regs); } } #ifdef CONFIG_X86_MCE dotraplinkage void __kprobes do_machine_check(struct pt_regs *regs, long error) { conditional_sti(regs); machine_check_vector(regs, error); } #endif dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) { siginfo_t info; local_irq_enable(); info.si_signo = SIGILL; info.si_errno = 0; info.si_code = ILL_BADSTK; info.si_addr = 0; if (notify_die(DIE_TRAP, "iret exception", regs, error_code, 32, SIGILL) == NOTIFY_STOP) return; do_trap(32, SIGILL, "iret exception", regs, error_code, &info); } void __init trap_init(void) { int i; #ifdef CONFIG_EISA void __iomem *p = early_ioremap(0x0FFFD9, 4); if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24)) EISA_bus = 1; early_iounmap(p, 4); #endif 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_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS); 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); if (cpu_has_fxsr) { printk(KERN_INFO "Enabling fast FPU save and restore... "); set_in_cr4(X86_CR4_OSFXSR); printk("done.\n"); } if (cpu_has_xmm) { printk(KERN_INFO "Enabling unmasked SIMD FPU exception support... "); set_in_cr4(X86_CR4_OSXMMEXCPT); printk("done.\n"); } set_system_trap_gate(SYSCALL_VECTOR, &system_call); /* Reserve all the builtin and the syscall vector: */ for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++) set_bit(i, used_vectors); set_bit(SYSCALL_VECTOR, used_vectors); /* * Should be a barrier for any external CPU state: */ cpu_init(); trap_init_hook(); }