/* * 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 'asm.s'. */ #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 "mach_traps.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 } } }, }; int panic_on_unrecovered_nmi; int kstack_depth_to_print = 24; static unsigned int code_bytes = 64; static int ignore_nmis; static int die_counter; void printk_address(unsigned long address, int reliable) { #ifdef CONFIG_KALLSYMS unsigned long offset = 0; unsigned long symsize; const char *symname; char *modname; char *delim = ":"; char namebuf[KSYM_NAME_LEN]; char reliab[4] = ""; symname = kallsyms_lookup(address, &symsize, &offset, &modname, namebuf); if (!symname) { printk(" [<%08lx>]\n", address); return; } if (!reliable) strcpy(reliab, "? "); if (!modname) modname = delim = ""; printk(" [<%08lx>] %s%s%s%s%s+0x%lx/0x%lx\n", address, reliab, delim, modname, delim, symname, offset, symsize); #else printk(" [<%08lx>]\n", address); #endif } static inline int valid_stack_ptr(struct thread_info *tinfo, void *p, unsigned int size) { void *t = tinfo; return p > t && p <= t + THREAD_SIZE - size; } /* The form of the top of the frame on the stack */ struct stack_frame { struct stack_frame *next_frame; unsigned long return_address; }; static inline unsigned long print_context_stack(struct thread_info *tinfo, unsigned long *stack, unsigned long bp, const struct stacktrace_ops *ops, void *data) { struct stack_frame *frame = (struct stack_frame *)bp; while (valid_stack_ptr(tinfo, stack, sizeof(*stack))) { unsigned long addr; addr = *stack; if (__kernel_text_address(addr)) { if ((unsigned long) stack == bp + 4) { ops->address(data, addr, 1); frame = frame->next_frame; bp = (unsigned long) frame; } else { ops->address(data, addr, bp == 0); } } stack++; } return bp; } void dump_trace(struct task_struct *task, struct pt_regs *regs, unsigned long *stack, unsigned long bp, const struct stacktrace_ops *ops, void *data) { if (!task) task = current; if (!stack) { unsigned long dummy; stack = &dummy; if (task != current) stack = (unsigned long *)task->thread.sp; } #ifdef CONFIG_FRAME_POINTER if (!bp) { if (task == current) { /* Grab bp right from our regs */ asm("movl %%ebp, %0" : "=r" (bp) :); } else { /* bp is the last reg pushed by switch_to */ bp = *(unsigned long *) task->thread.sp; } } #endif for (;;) { struct thread_info *context; context = (struct thread_info *) ((unsigned long)stack & (~(THREAD_SIZE - 1))); bp = print_context_stack(context, stack, bp, ops, data); /* * Should be after the line below, but somewhere * in early boot context comes out corrupted and we * can't reference it: */ if (ops->stack(data, "IRQ") < 0) break; stack = (unsigned long *)context->previous_esp; if (!stack) break; touch_nmi_watchdog(); } } EXPORT_SYMBOL(dump_trace); static void print_trace_warning_symbol(void *data, char *msg, unsigned long symbol) { printk(data); print_symbol(msg, symbol); printk("\n"); } static void print_trace_warning(void *data, char *msg) { printk("%s%s\n", (char *)data, msg); } static int print_trace_stack(void *data, char *name) { return 0; } /* * Print one address/symbol entries per line. */ static void print_trace_address(void *data, unsigned long addr, int reliable) { printk("%s [<%08lx>] ", (char *)data, addr); if (!reliable) printk("? "); print_symbol("%s\n", addr); touch_nmi_watchdog(); } static const struct stacktrace_ops print_trace_ops = { .warning = print_trace_warning, .warning_symbol = print_trace_warning_symbol, .stack = print_trace_stack, .address = print_trace_address, }; static void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, unsigned long *stack, unsigned long bp, char *log_lvl) { dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl); printk("%s =======================\n", log_lvl); } void show_trace(struct task_struct *task, struct pt_regs *regs, unsigned long *stack, unsigned long bp) { show_trace_log_lvl(task, regs, stack, bp, ""); } static void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, unsigned long *sp, unsigned long bp, char *log_lvl) { unsigned long *stack; int i; if (sp == NULL) { if (task) sp = (unsigned long *)task->thread.sp; else sp = (unsigned long *)&sp; } stack = sp; 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, sp, bp, log_lvl); } void show_stack(struct task_struct *task, unsigned long *sp) { printk(" "); show_stack_log_lvl(task, NULL, sp, 0, ""); } /* * The architecture-independent dump_stack generator */ void dump_stack(void) { unsigned long bp = 0; unsigned long stack; #ifdef CONFIG_FRAME_POINTER if (!bp) asm("movl %%ebp, %0" : "=r" (bp):); #endif printk("Pid: %d, comm: %.20s %s %s %.*s\n", current->pid, current->comm, print_tainted(), init_utsname()->release, (int)strcspn(init_utsname()->version, " "), init_utsname()->version); show_trace(current, NULL, &stack, bp); } EXPORT_SYMBOL(dump_stack); void show_registers(struct pt_regs *regs) { int i; print_modules(); __show_registers(regs, 0); printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)", TASK_COMM_LEN, current->comm, task_pid_nr(current), current_thread_info(), current, task_thread_info(current)); /* * When in-kernel, we also print out the stack and code at the * time of the fault.. */ if (!user_mode_vm(regs)) { unsigned int code_prologue = code_bytes * 43 / 64; unsigned int code_len = code_bytes; unsigned char c; u8 *ip; printk("\n" KERN_EMERG "Stack: "); show_stack_log_lvl(NULL, regs, ®s->sp, 0, KERN_EMERG); printk(KERN_EMERG "Code: "); ip = (u8 *)regs->ip - code_prologue; if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) { /* try starting at EIP */ ip = (u8 *)regs->ip; code_len = code_len - code_prologue + 1; } for (i = 0; i < code_len; i++, ip++) { if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) { printk(" Bad EIP value."); break; } if (ip == (u8 *)regs->ip) printk("<%02x> ", c); else printk("%02x ", c); } } printk("\n"); } int is_valid_bugaddr(unsigned long ip) { unsigned short ud2; if (ip < PAGE_OFFSET) return 0; if (probe_kernel_address((unsigned short *)ip, ud2)) return 0; return ud2 == 0x0b0f; } static raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED; static int die_owner = -1; static unsigned int die_nest_count; unsigned __kprobes long oops_begin(void) { unsigned long flags; oops_enter(); if (die_owner != raw_smp_processor_id()) { console_verbose(); raw_local_irq_save(flags); __raw_spin_lock(&die_lock); die_owner = smp_processor_id(); die_nest_count = 0; bust_spinlocks(1); } else { raw_local_irq_save(flags); } die_nest_count++; return flags; } void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr) { bust_spinlocks(0); die_owner = -1; add_taint(TAINT_DIE); __raw_spin_unlock(&die_lock); raw_local_irq_restore(flags); if (!regs) return; if (kexec_should_crash(current)) crash_kexec(regs); if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); oops_exit(); do_exit(signr); } int __kprobes __die(const char *str, struct pt_regs *regs, long err) { unsigned short ss; unsigned long sp; printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter); #ifdef CONFIG_PREEMPT printk("PREEMPT "); #endif #ifdef CONFIG_SMP printk("SMP "); #endif #ifdef CONFIG_DEBUG_PAGEALLOC printk("DEBUG_PAGEALLOC"); #endif printk("\n"); if (notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV) == NOTIFY_STOP) return 1; show_registers(regs); /* Executive summary in case the oops scrolled away */ sp = (unsigned long) (®s->sp); savesegment(ss, ss); if (user_mode(regs)) { sp = regs->sp; ss = regs->ss & 0xffff; } printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip); print_symbol("%s", regs->ip); printk(" SS:ESP %04x:%08lx\n", ss, sp); return 0; } /* * 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) { unsigned long flags = oops_begin(); if (die_nest_count < 3) { report_bug(regs->ip, regs); if (__die(str, regs, err)) regs = NULL; } else { printk(KERN_EMERG "Recursive die() failure, output suppressed\n"); } oops_end(flags, regs, 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; if (regs->flags & X86_VM_MASK) { if (vm86) 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) \ void do_##name(struct pt_regs *regs, long error_code) \ { \ trace_hardirqs_fixup(); \ 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, irq) \ void do_##name(struct pt_regs *regs, long error_code) \ { \ siginfo_t info; \ if (irq) \ local_irq_enable(); \ 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) \ 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) \ 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; \ trace_hardirqs_fixup(); \ 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->ip) #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->ip, 0) 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, 0) DO_ERROR_INFO(32, SIGILL, "iret exception", iret_error, ILL_BADSTK, 0, 1) void __kprobes do_general_protection(struct pt_regs *regs, long error_code) { struct task_struct *tsk; struct thread_struct *thread; struct tss_struct *tss; int cpu; cpu = get_cpu(); tss = &per_cpu(init_tss, cpu); 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->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; } put_cpu(); 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. */ clear_mem_error(reason); } 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(); } notrace __kprobes void do_nmi(struct pt_regs *regs, long error_code) { int cpu; nmi_enter(); 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(); } #ifdef CONFIG_KPROBES void __kprobes do_int3(struct pt_regs *regs, long error_code) { trace_hardirqs_fixup(); 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) */ void __kprobes do_debug(struct pt_regs *regs, long error_code) { struct task_struct *tsk = current; unsigned int condition; trace_hardirqs_fixup(); 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 */ if (regs->flags & 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.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) { /* * 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->flags &= ~X86_EFLAGS_TF; 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); } void do_coprocessor_error(struct pt_regs *regs, long error_code) { 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); } 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->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); } void do_spurious_interrupt_bug(struct pt_regs *regs, long error_code) { #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 */ 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_trap_gate(0, ÷_error); set_intr_gate(1, &debug); set_intr_gate(2, &nmi); set_system_intr_gate(3, &int3); /* int3 can be called from all */ set_system_gate(4, &overflow); /* int4 can be called from all */ 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) { 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); /* 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); init_thread_xstate(); /* * 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 code_bytes_setup(char *s) { code_bytes = simple_strtoul(s, NULL, 0); if (code_bytes > 8192) code_bytes = 8192; return 1; } __setup("code_bytes=", code_bytes_setup);