/* * linux/arch/i386/traps.c * * Copyright (C) 1991, 1992 Linus Torvalds * * Pentium III FXSR, SSE support * Gareth Hughes , May 2000 */ /* * 'Traps.c' handles hardware traps and faults after we have saved some * state in 'asm.s'. */ #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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "mach_traps.h" asmlinkage int system_call(void); struct desc_struct default_ldt[] = { { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 }, { 0, 0 } }; /* Do we ignore FPU interrupts ? */ char ignore_fpu_irq = 0; /* * The IDT has to be page-aligned to simplify the Pentium * F0 0F bug workaround.. We have a special link segment * for this. */ struct desc_struct idt_table[256] __attribute__((__section__(".data.idt"))) = { {0, 0}, }; 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 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 alignment_check(void); asmlinkage void spurious_interrupt_bug(void); asmlinkage void machine_check(void); static int kstack_depth_to_print = 24; static int call_trace = 1; ATOMIC_NOTIFIER_HEAD(i386die_chain); int register_die_notifier(struct notifier_block *nb) { vmalloc_sync_all(); return atomic_notifier_chain_register(&i386die_chain, nb); } EXPORT_SYMBOL(register_die_notifier); /* used modular by kdb */ int unregister_die_notifier(struct notifier_block *nb) { return atomic_notifier_chain_unregister(&i386die_chain, nb); } EXPORT_SYMBOL(unregister_die_notifier); /* used modular by kdb */ static inline int valid_stack_ptr(struct thread_info *tinfo, void *p) { return p > (void *)tinfo && p < (void *)tinfo + THREAD_SIZE - 3; } /* * Print one address/symbol entries per line. */ static inline void print_addr_and_symbol(unsigned long addr, char *log_lvl) { printk(" [<%08lx>] ", addr); print_symbol("%s\n", addr); } static inline unsigned long print_context_stack(struct thread_info *tinfo, unsigned long *stack, unsigned long ebp, char *log_lvl) { unsigned long addr; #ifdef CONFIG_FRAME_POINTER while (valid_stack_ptr(tinfo, (void *)ebp)) { addr = *(unsigned long *)(ebp + 4); print_addr_and_symbol(addr, log_lvl); /* * break out of recursive entries (such as * end_of_stack_stop_unwind_function): */ if (ebp == *(unsigned long *)ebp) break; ebp = *(unsigned long *)ebp; } #else while (valid_stack_ptr(tinfo, stack)) { addr = *stack++; if (__kernel_text_address(addr)) print_addr_and_symbol(addr, log_lvl); } #endif return ebp; } static asmlinkage int show_trace_unwind(struct unwind_frame_info *info, void *log_lvl) { int n = 0; while (unwind(info) == 0 && UNW_PC(info)) { n++; print_addr_and_symbol(UNW_PC(info), log_lvl); if (arch_unw_user_mode(info)) break; } return n; } static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, unsigned long *stack, char *log_lvl) { unsigned long ebp; if (!task) task = current; if (call_trace >= 0) { int unw_ret = 0; struct unwind_frame_info info; if (regs) { if (unwind_init_frame_info(&info, task, regs) == 0) unw_ret = show_trace_unwind(&info, log_lvl); } else if (task == current) unw_ret = unwind_init_running(&info, show_trace_unwind, log_lvl); else { if (unwind_init_blocked(&info, task) == 0) unw_ret = show_trace_unwind(&info, log_lvl); } if (unw_ret > 0 && !arch_unw_user_mode(&info)) { #ifdef CONFIG_STACK_UNWIND print_symbol("DWARF2 unwinder stuck at %s\n", UNW_PC(info.regs)); if (call_trace == 1) { printk("Leftover inexact backtrace:\n"); if (UNW_SP(info.regs)) stack = (void *)UNW_SP(info.regs); } else if (call_trace > 1) return; else printk("Full inexact backtrace again:\n"); #else printk("Inexact backtrace:\n"); #endif } } if (task == current) { /* Grab ebp right from our regs */ asm ("movl %%ebp, %0" : "=r" (ebp) : ); } else { /* ebp is the last reg pushed by switch_to */ ebp = *(unsigned long *) task->thread.esp; } while (1) { struct thread_info *context; context = (struct thread_info *) ((unsigned long)stack & (~(THREAD_SIZE - 1))); ebp = print_context_stack(context, stack, ebp, log_lvl); stack = (unsigned long*)context->previous_esp; if (!stack) break; printk("%s =======================\n", log_lvl); } } void show_trace(struct task_struct *task, struct pt_regs *regs, unsigned long * stack) { show_trace_log_lvl(task, regs, stack, ""); } static void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, unsigned long *esp, char *log_lvl) { unsigned long *stack; int i; if (esp == NULL) { if (task) esp = (unsigned long*)task->thread.esp; else esp = (unsigned long *)&esp; } stack = esp; for(i = 0; i < kstack_depth_to_print; i++) { if (kstack_end(stack)) break; if (i && ((i % 8) == 0)) printk("\n%s ", log_lvl); printk("%08lx ", *stack++); } printk("\n%sCall Trace:\n", log_lvl); show_trace_log_lvl(task, regs, esp, log_lvl); } void show_stack(struct task_struct *task, unsigned long *esp) { printk(" "); show_stack_log_lvl(task, NULL, esp, ""); } /* * The architecture-independent dump_stack generator */ void dump_stack(void) { unsigned long stack; show_trace(current, NULL, &stack); } EXPORT_SYMBOL(dump_stack); void show_registers(struct pt_regs *regs) { int i; int in_kernel = 1; unsigned long esp; unsigned short ss; esp = (unsigned long) (®s->esp); savesegment(ss, ss); if (user_mode_vm(regs)) { in_kernel = 0; esp = regs->esp; ss = regs->xss & 0xffff; } print_modules(); printk(KERN_EMERG "CPU: %d\nEIP: %04x:[<%08lx>] %s VLI\n" "EFLAGS: %08lx (%s %.*s) \n", smp_processor_id(), 0xffff & regs->xcs, regs->eip, print_tainted(), regs->eflags, system_utsname.release, (int)strcspn(system_utsname.version, " "), system_utsname.version); print_symbol(KERN_EMERG "EIP is at %s\n", regs->eip); printk(KERN_EMERG "eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n", regs->eax, regs->ebx, regs->ecx, regs->edx); printk(KERN_EMERG "esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n", regs->esi, regs->edi, regs->ebp, esp); printk(KERN_EMERG "ds: %04x es: %04x ss: %04x\n", regs->xds & 0xffff, regs->xes & 0xffff, ss); printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)", TASK_COMM_LEN, current->comm, current->pid, current_thread_info(), current, current->thread_info); /* * When in-kernel, we also print out the stack and code at the * time of the fault.. */ if (in_kernel) { u8 __user *eip; printk("\n" KERN_EMERG "Stack: "); show_stack_log_lvl(NULL, regs, (unsigned long *)esp, KERN_EMERG); printk(KERN_EMERG "Code: "); eip = (u8 __user *)regs->eip - 43; for (i = 0; i < 64; i++, eip++) { unsigned char c; if (eip < (u8 __user *)PAGE_OFFSET || __get_user(c, eip)) { printk(" Bad EIP value."); break; } if (eip == (u8 __user *)regs->eip) printk("<%02x> ", c); else printk("%02x ", c); } } printk("\n"); } static void handle_BUG(struct pt_regs *regs) { unsigned long eip = regs->eip; unsigned short ud2; if (eip < PAGE_OFFSET) return; if (__get_user(ud2, (unsigned short __user *)eip)) return; if (ud2 != 0x0b0f) return; printk(KERN_EMERG "------------[ cut here ]------------\n"); #ifdef CONFIG_DEBUG_BUGVERBOSE do { unsigned short line; char *file; char c; if (__get_user(line, (unsigned short __user *)(eip + 2))) break; if (__get_user(file, (char * __user *)(eip + 4)) || (unsigned long)file < PAGE_OFFSET || __get_user(c, file)) file = ""; printk(KERN_EMERG "kernel BUG at %s:%d!\n", file, line); return; } while (0); #endif printk(KERN_EMERG "Kernel BUG at [verbose debug info unavailable]\n"); } /* This is gone through when something in the kernel * has done something bad and is about to be terminated. */ void die(const char * str, struct pt_regs * regs, long err) { static struct { spinlock_t lock; u32 lock_owner; int lock_owner_depth; } die = { .lock = SPIN_LOCK_UNLOCKED, .lock_owner = -1, .lock_owner_depth = 0 }; static int die_counter; unsigned long flags; oops_enter(); if (die.lock_owner != raw_smp_processor_id()) { console_verbose(); spin_lock_irqsave(&die.lock, flags); die.lock_owner = smp_processor_id(); die.lock_owner_depth = 0; bust_spinlocks(1); } else local_save_flags(flags); if (++die.lock_owner_depth < 3) { int nl = 0; unsigned long esp; unsigned short ss; handle_BUG(regs); printk(KERN_EMERG "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter); #ifdef CONFIG_PREEMPT printk(KERN_EMERG "PREEMPT "); nl = 1; #endif #ifdef CONFIG_SMP if (!nl) printk(KERN_EMERG); printk("SMP "); nl = 1; #endif #ifdef CONFIG_DEBUG_PAGEALLOC if (!nl) printk(KERN_EMERG); printk("DEBUG_PAGEALLOC"); nl = 1; #endif if (nl) printk("\n"); if (notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV) != NOTIFY_STOP) { show_registers(regs); /* Executive summary in case the oops scrolled away */ esp = (unsigned long) (®s->esp); savesegment(ss, ss); if (user_mode(regs)) { esp = regs->esp; ss = regs->xss & 0xffff; } printk(KERN_EMERG "EIP: [<%08lx>] ", regs->eip); print_symbol("%s", regs->eip); printk(" SS:ESP %04x:%08lx\n", ss, esp); } else regs = NULL; } else printk(KERN_EMERG "Recursive die() failure, output suppressed\n"); bust_spinlocks(0); die.lock_owner = -1; spin_unlock_irqrestore(&die.lock, flags); if (!regs) return; if (kexec_should_crash(current)) crash_kexec(regs); if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) { printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n"); ssleep(5); panic("Fatal exception"); } oops_exit(); do_exit(SIGSEGV); } static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err) { if (!user_mode_vm(regs)) die(str, regs, err); } static void __kprobes do_trap(int trapnr, int signr, char *str, int vm86, struct pt_regs * regs, long error_code, siginfo_t *info) { struct task_struct *tsk = current; tsk->thread.error_code = error_code; tsk->thread.trap_no = trapnr; if (regs->eflags & VM_MASK) { if (vm86) goto vm86_trap; goto trap_signal; } if (!user_mode(regs)) goto kernel_trap; trap_signal: { if (info) force_sig_info(signr, info, tsk); else force_sig(signr, tsk); return; } kernel_trap: { if (!fixup_exception(regs)) die(str, regs, error_code); return; } vm86_trap: { int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr); if (ret) goto trap_signal; return; } } #define DO_ERROR(trapnr, signr, str, name) \ fastcall void do_##name(struct pt_regs * regs, long error_code) \ { \ if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ == NOTIFY_STOP) \ return; \ do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \ } #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \ fastcall 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; \ do_trap(trapnr, signr, str, 0, regs, error_code, &info); \ } #define DO_VM86_ERROR(trapnr, signr, str, name) \ fastcall void do_##name(struct pt_regs * regs, long error_code) \ { \ if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \ == NOTIFY_STOP) \ return; \ do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \ } #define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \ fastcall 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; \ do_trap(trapnr, signr, str, 1, regs, error_code, &info); \ } DO_VM86_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->eip) #ifndef CONFIG_KPROBES DO_VM86_ERROR( 3, SIGTRAP, "int3", int3) #endif DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow) DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds) DO_ERROR_INFO( 6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->eip) 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) DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0) fastcall void __kprobes do_general_protection(struct pt_regs * regs, long error_code) { int cpu = get_cpu(); struct tss_struct *tss = &per_cpu(init_tss, cpu); struct thread_struct *thread = ¤t->thread; /* * 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 * and we set the offset field correctly. Then we let the CPU to * restart the faulting instruction. */ if (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->io_bitmap_base = IO_BITMAP_OFFSET; tss->io_bitmap_owner = thread; put_cpu(); return; } put_cpu(); current->thread.error_code = error_code; current->thread.trap_no = 13; if (regs->eflags & VM_MASK) goto gp_in_vm86; if (!user_mode(regs)) goto gp_in_kernel; current->thread.error_code = error_code; current->thread.trap_no = 13; force_sig(SIGSEGV, current); 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)) { if (notify_die(DIE_GPF, "general protection fault", regs, error_code, 13, SIGSEGV) == NOTIFY_STOP) return; die("general protection fault", regs, error_code); } } static void mem_parity_error(unsigned char reason, struct pt_regs * regs) { printk(KERN_EMERG "Uhhuh. NMI received. Dazed and confused, but trying " "to continue\n"); printk(KERN_EMERG "You probably have a hardware problem with your RAM " "chips\n"); /* Clear and disable the memory parity error line. */ clear_mem_error(reason); } static 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 void unknown_nmi_error(unsigned char reason, struct pt_regs * regs) { #ifdef CONFIG_MCA /* Might actually be able to figure out what the guilty party * is. */ if( MCA_bus ) { mca_handle_nmi(); return; } #endif printk("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n", reason, smp_processor_id()); printk("Dazed and confused, but trying to continue\n"); printk("Do you have a strange power saving mode enabled?\n"); } static DEFINE_SPINLOCK(nmi_print_lock); void die_nmi (struct pt_regs *regs, const char *msg) { if (notify_die(DIE_NMIWATCHDOG, msg, 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", msg); printk(" on CPU%d, eip %08lx, registers:\n", smp_processor_id(), regs->eip); show_registers(regs); printk(KERN_EMERG "console shuts up ...\n"); 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 void default_do_nmi(struct pt_regs * regs) { unsigned char reason = 0; /* Only the BSP gets external NMIs from the system. */ if (!smp_processor_id()) 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) { nmi_watchdog_tick(regs); return; } #endif unknown_nmi_error(reason, regs); return; } if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP) 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. */ reassert_nmi(); } static int dummy_nmi_callback(struct pt_regs * regs, int cpu) { return 0; } static nmi_callback_t nmi_callback = dummy_nmi_callback; fastcall void do_nmi(struct pt_regs * regs, long error_code) { int cpu; nmi_enter(); cpu = smp_processor_id(); ++nmi_count(cpu); if (!rcu_dereference(nmi_callback)(regs, cpu)) default_do_nmi(regs); nmi_exit(); } void set_nmi_callback(nmi_callback_t callback) { vmalloc_sync_all(); rcu_assign_pointer(nmi_callback, callback); } EXPORT_SYMBOL_GPL(set_nmi_callback); void unset_nmi_callback(void) { nmi_callback = dummy_nmi_callback; } EXPORT_SYMBOL_GPL(unset_nmi_callback); #ifdef CONFIG_KPROBES fastcall 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; /* This is an interrupt gate, because kprobes wants interrupts disabled. Normal trap handlers don't. */ restore_interrupts(regs); do_trap(3, SIGTRAP, "int3", 1, regs, error_code, NULL); } #endif /* * 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) */ fastcall void __kprobes do_debug(struct pt_regs * regs, long error_code) { unsigned int condition; struct task_struct *tsk = current; get_debugreg(condition, 6); 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 */ if (regs->eflags & X86_EFLAGS_IF) local_irq_enable(); /* 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; } if (regs->eflags & VM_MASK) goto debug_vm86; /* Save debug status register where ptrace can see it */ tsk->thread.debugreg[6] = 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) { /* * We already checked v86 mode above, so we can * check for kernel mode by just checking the CPL * of CS. */ if (!user_mode(regs)) goto clear_TF_reenable; } /* Ok, finally something we can handle */ send_sigtrap(tsk, regs, error_code); /* Disable additional traps. They'll be re-enabled when * the signal is delivered. */ clear_dr7: set_debugreg(0, 7); return; debug_vm86: handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1); return; clear_TF_reenable: set_tsk_thread_flag(tsk, TIF_SINGLESTEP); 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 __user *eip) { 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 = eip; /* * (~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 (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); } fastcall void do_coprocessor_error(struct pt_regs * regs, long error_code) { ignore_fpu_irq = 1; math_error((void __user *)regs->eip); } static void simd_math_error(void __user *eip) { 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 = eip; /* * 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); } fastcall void do_simd_coprocessor_error(struct pt_regs * regs, long error_code) { if (cpu_has_xmm) { /* Handle SIMD FPU exceptions on PIII+ processors. */ ignore_fpu_irq = 1; simd_math_error((void __user *)regs->eip); } else { /* * Handle strange cache flush from user space exception * in all other cases. This is undocumented behaviour. */ if (regs->eflags & 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); } } fastcall void do_spurious_interrupt_bug(struct pt_regs * regs, long error_code) { #if 0 /* No need to warn about this any longer. */ printk("Ignoring P6 Local APIC Spurious Interrupt Bug...\n"); #endif } fastcall void setup_x86_bogus_stack(unsigned char * stk) { unsigned long *switch16_ptr, *switch32_ptr; struct pt_regs *regs; unsigned long stack_top, stack_bot; unsigned short iret_frame16_off; int cpu = smp_processor_id(); /* reserve the space on 32bit stack for the magic switch16 pointer */ memmove(stk, stk + 8, sizeof(struct pt_regs)); switch16_ptr = (unsigned long *)(stk + sizeof(struct pt_regs)); regs = (struct pt_regs *)stk; /* now the switch32 on 16bit stack */ stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu); stack_top = stack_bot + CPU_16BIT_STACK_SIZE; switch32_ptr = (unsigned long *)(stack_top - 8); iret_frame16_off = CPU_16BIT_STACK_SIZE - 8 - 20; /* copy iret frame on 16bit stack */ memcpy((void *)(stack_bot + iret_frame16_off), ®s->eip, 20); /* fill in the switch pointers */ switch16_ptr[0] = (regs->esp & 0xffff0000) | iret_frame16_off; switch16_ptr[1] = __ESPFIX_SS; switch32_ptr[0] = (unsigned long)stk + sizeof(struct pt_regs) + 8 - CPU_16BIT_STACK_SIZE; switch32_ptr[1] = __KERNEL_DS; } fastcall unsigned char * fixup_x86_bogus_stack(unsigned short sp) { unsigned long *switch32_ptr; unsigned char *stack16, *stack32; unsigned long stack_top, stack_bot; int len; int cpu = smp_processor_id(); stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu); stack_top = stack_bot + CPU_16BIT_STACK_SIZE; switch32_ptr = (unsigned long *)(stack_top - 8); /* copy the data from 16bit stack to 32bit stack */ len = CPU_16BIT_STACK_SIZE - 8 - sp; stack16 = (unsigned char *)(stack_bot + sp); stack32 = (unsigned char *) (switch32_ptr[0] + CPU_16BIT_STACK_SIZE - 8 - len); memcpy(stack32, stack16, len); return stack32; } /* * '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(struct pt_regs regs) { struct thread_info *thread = current_thread_info(); struct task_struct *tsk = thread->task; clts(); /* Allow maths ops (or we recurse) */ if (!tsk_used_math(tsk)) init_fpu(tsk); restore_fpu(tsk); thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */ } #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 */ #ifdef CONFIG_X86_F00F_BUG void __init trap_init_f00f_bug(void) { __set_fixmap(FIX_F00F_IDT, __pa(&idt_table), PAGE_KERNEL_RO); /* * Update the IDT descriptor and reload the IDT so that * it uses the read-only mapped virtual address. */ idt_descr.address = fix_to_virt(FIX_F00F_IDT); load_idt(&idt_descr); } #endif #define _set_gate(gate_addr,type,dpl,addr,seg) \ do { \ int __d0, __d1; \ __asm__ __volatile__ ("movw %%dx,%%ax\n\t" \ "movw %4,%%dx\n\t" \ "movl %%eax,%0\n\t" \ "movl %%edx,%1" \ :"=m" (*((long *) (gate_addr))), \ "=m" (*(1+(long *) (gate_addr))), "=&a" (__d0), "=&d" (__d1) \ :"i" ((short) (0x8000+(dpl<<13)+(type<<8))), \ "3" ((char *) (addr)),"2" ((seg) << 16)); \ } while (0) /* * This needs to use 'idt_table' rather than 'idt', and * thus use the _nonmapped_ version of the IDT, as the * Pentium F0 0F bugfix can have resulted in the mapped * IDT being write-protected. */ void set_intr_gate(unsigned int n, void *addr) { _set_gate(idt_table+n,14,0,addr,__KERNEL_CS); } /* * This routine sets up an interrupt gate at directory privilege level 3. */ static inline void set_system_intr_gate(unsigned int n, void *addr) { _set_gate(idt_table+n, 14, 3, addr, __KERNEL_CS); } static void __init set_trap_gate(unsigned int n, void *addr) { _set_gate(idt_table+n,15,0,addr,__KERNEL_CS); } static void __init set_system_gate(unsigned int n, void *addr) { _set_gate(idt_table+n,15,3,addr,__KERNEL_CS); } static void __init set_task_gate(unsigned int n, unsigned int gdt_entry) { _set_gate(idt_table+n,5,0,0,(gdt_entry<<3)); } void __init trap_init(void) { #ifdef CONFIG_EISA void __iomem *p = ioremap(0x0FFFD9, 4); if (readl(p) == 'E'+('I'<<8)+('S'<<16)+('A'<<24)) { EISA_bus = 1; } iounmap(p); #endif #ifdef CONFIG_X86_LOCAL_APIC init_apic_mappings(); #endif set_trap_gate(0,÷_error); set_intr_gate(1,&debug); set_intr_gate(2,&nmi); set_system_intr_gate(3, &int3); /* int3/4 can be called from all */ set_system_gate(4,&overflow); set_trap_gate(5,&bounds); set_trap_gate(6,&invalid_op); set_trap_gate(7,&device_not_available); set_task_gate(8,GDT_ENTRY_DOUBLEFAULT_TSS); 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_intr_gate(14,&page_fault); set_trap_gate(15,&spurious_interrupt_bug); set_trap_gate(16,&coprocessor_error); set_trap_gate(17,&alignment_check); #ifdef CONFIG_X86_MCE set_trap_gate(18,&machine_check); #endif set_trap_gate(19,&simd_coprocessor_error); if (cpu_has_fxsr) { /* * Verify that the FXSAVE/FXRSTOR data will be 16-byte aligned. * Generates a compile-time "error: zero width for bit-field" if * the alignment is wrong. */ struct fxsrAlignAssert { int _:!(offsetof(struct task_struct, thread.i387.fxsave) & 15); }; 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_gate(SYSCALL_VECTOR,&system_call); /* * Should be a barrier for any external CPU state. */ cpu_init(); trap_init_hook(); } static int __init kstack_setup(char *s) { kstack_depth_to_print = simple_strtoul(s, NULL, 0); return 1; } __setup("kstack=", kstack_setup); static int __init call_trace_setup(char *s) { if (strcmp(s, "old") == 0) call_trace = -1; else if (strcmp(s, "both") == 0) call_trace = 0; else if (strcmp(s, "new") == 0) call_trace = 1; return 1; } __setup("call_trace=", call_trace_setup);