|  | /* | 
|  | *  linux/arch/arm/kernel/traps.c | 
|  | * | 
|  | *  Copyright (C) 1995-2009 Russell King | 
|  | *  Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds | 
|  | * | 
|  | * This program is free software; you can redistribute it and/or modify | 
|  | * it under the terms of the GNU General Public License version 2 as | 
|  | * published by the Free Software Foundation. | 
|  | * | 
|  | *  'traps.c' handles hardware exceptions after we have saved some state in | 
|  | *  'linux/arch/arm/lib/traps.S'.  Mostly a debugging aid, but will probably | 
|  | *  kill the offending process. | 
|  | */ | 
|  | #include <linux/signal.h> | 
|  | #include <linux/personality.h> | 
|  | #include <linux/kallsyms.h> | 
|  | #include <linux/spinlock.h> | 
|  | #include <linux/uaccess.h> | 
|  | #include <linux/hardirq.h> | 
|  | #include <linux/kdebug.h> | 
|  | #include <linux/module.h> | 
|  | #include <linux/kexec.h> | 
|  | #include <linux/bug.h> | 
|  | #include <linux/delay.h> | 
|  | #include <linux/init.h> | 
|  | #include <linux/sched.h> | 
|  | #include <linux/irq.h> | 
|  |  | 
|  | #include <linux/atomic.h> | 
|  | #include <asm/cacheflush.h> | 
|  | #include <asm/exception.h> | 
|  | #include <asm/unistd.h> | 
|  | #include <asm/traps.h> | 
|  | #include <asm/ptrace.h> | 
|  | #include <asm/unwind.h> | 
|  | #include <asm/tls.h> | 
|  | #include <asm/system_misc.h> | 
|  | #include <asm/opcodes.h> | 
|  |  | 
|  |  | 
|  | static const char *handler[]= { | 
|  | "prefetch abort", | 
|  | "data abort", | 
|  | "address exception", | 
|  | "interrupt", | 
|  | "undefined instruction", | 
|  | }; | 
|  |  | 
|  | void *vectors_page; | 
|  |  | 
|  | #ifdef CONFIG_DEBUG_USER | 
|  | unsigned int user_debug; | 
|  |  | 
|  | static int __init user_debug_setup(char *str) | 
|  | { | 
|  | get_option(&str, &user_debug); | 
|  | return 1; | 
|  | } | 
|  | __setup("user_debug=", user_debug_setup); | 
|  | #endif | 
|  |  | 
|  | static void dump_mem(const char *, const char *, unsigned long, unsigned long); | 
|  |  | 
|  | void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) | 
|  | { | 
|  | #ifdef CONFIG_KALLSYMS | 
|  | printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from); | 
|  | #else | 
|  | printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); | 
|  | #endif | 
|  |  | 
|  | if (in_exception_text(where)) | 
|  | dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); | 
|  | } | 
|  |  | 
|  | #ifndef CONFIG_ARM_UNWIND | 
|  | /* | 
|  | * Stack pointers should always be within the kernels view of | 
|  | * physical memory.  If it is not there, then we can't dump | 
|  | * out any information relating to the stack. | 
|  | */ | 
|  | static int verify_stack(unsigned long sp) | 
|  | { | 
|  | if (sp < PAGE_OFFSET || | 
|  | (sp > (unsigned long)high_memory && high_memory != NULL)) | 
|  | return -EFAULT; | 
|  |  | 
|  | return 0; | 
|  | } | 
|  | #endif | 
|  |  | 
|  | /* | 
|  | * Dump out the contents of some memory nicely... | 
|  | */ | 
|  | static void dump_mem(const char *lvl, const char *str, unsigned long bottom, | 
|  | unsigned long top) | 
|  | { | 
|  | unsigned long first; | 
|  | mm_segment_t fs; | 
|  | int i; | 
|  |  | 
|  | /* | 
|  | * We need to switch to kernel mode so that we can use __get_user | 
|  | * to safely read from kernel space.  Note that we now dump the | 
|  | * code first, just in case the backtrace kills us. | 
|  | */ | 
|  | fs = get_fs(); | 
|  | set_fs(KERNEL_DS); | 
|  |  | 
|  | printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top); | 
|  |  | 
|  | for (first = bottom & ~31; first < top; first += 32) { | 
|  | unsigned long p; | 
|  | char str[sizeof(" 12345678") * 8 + 1]; | 
|  |  | 
|  | memset(str, ' ', sizeof(str)); | 
|  | str[sizeof(str) - 1] = '\0'; | 
|  |  | 
|  | for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { | 
|  | if (p >= bottom && p < top) { | 
|  | unsigned long val; | 
|  | if (__get_user(val, (unsigned long *)p) == 0) | 
|  | sprintf(str + i * 9, " %08lx", val); | 
|  | else | 
|  | sprintf(str + i * 9, " ????????"); | 
|  | } | 
|  | } | 
|  | printk("%s%04lx:%s\n", lvl, first & 0xffff, str); | 
|  | } | 
|  |  | 
|  | set_fs(fs); | 
|  | } | 
|  |  | 
|  | static void dump_instr(const char *lvl, struct pt_regs *regs) | 
|  | { | 
|  | unsigned long addr = instruction_pointer(regs); | 
|  | const int thumb = thumb_mode(regs); | 
|  | const int width = thumb ? 4 : 8; | 
|  | mm_segment_t fs; | 
|  | char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; | 
|  | int i; | 
|  |  | 
|  | /* | 
|  | * We need to switch to kernel mode so that we can use __get_user | 
|  | * to safely read from kernel space.  Note that we now dump the | 
|  | * code first, just in case the backtrace kills us. | 
|  | */ | 
|  | fs = get_fs(); | 
|  | set_fs(KERNEL_DS); | 
|  |  | 
|  | for (i = -4; i < 1 + !!thumb; i++) { | 
|  | unsigned int val, bad; | 
|  |  | 
|  | if (thumb) | 
|  | bad = __get_user(val, &((u16 *)addr)[i]); | 
|  | else | 
|  | bad = __get_user(val, &((u32 *)addr)[i]); | 
|  |  | 
|  | if (!bad) | 
|  | p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ", | 
|  | width, val); | 
|  | else { | 
|  | p += sprintf(p, "bad PC value"); | 
|  | break; | 
|  | } | 
|  | } | 
|  | printk("%sCode: %s\n", lvl, str); | 
|  |  | 
|  | set_fs(fs); | 
|  | } | 
|  |  | 
|  | #ifdef CONFIG_ARM_UNWIND | 
|  | static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) | 
|  | { | 
|  | unwind_backtrace(regs, tsk); | 
|  | } | 
|  | #else | 
|  | static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) | 
|  | { | 
|  | unsigned int fp, mode; | 
|  | int ok = 1; | 
|  |  | 
|  | printk("Backtrace: "); | 
|  |  | 
|  | if (!tsk) | 
|  | tsk = current; | 
|  |  | 
|  | if (regs) { | 
|  | fp = frame_pointer(regs); | 
|  | mode = processor_mode(regs); | 
|  | } else if (tsk != current) { | 
|  | fp = thread_saved_fp(tsk); | 
|  | mode = 0x10; | 
|  | } else { | 
|  | asm("mov %0, fp" : "=r" (fp) : : "cc"); | 
|  | mode = 0x10; | 
|  | } | 
|  |  | 
|  | if (!fp) { | 
|  | pr_cont("no frame pointer"); | 
|  | ok = 0; | 
|  | } else if (verify_stack(fp)) { | 
|  | pr_cont("invalid frame pointer 0x%08x", fp); | 
|  | ok = 0; | 
|  | } else if (fp < (unsigned long)end_of_stack(tsk)) | 
|  | pr_cont("frame pointer underflow"); | 
|  | pr_cont("\n"); | 
|  |  | 
|  | if (ok) | 
|  | c_backtrace(fp, mode); | 
|  | } | 
|  | #endif | 
|  |  | 
|  | void show_stack(struct task_struct *tsk, unsigned long *sp) | 
|  | { | 
|  | dump_backtrace(NULL, tsk); | 
|  | barrier(); | 
|  | } | 
|  |  | 
|  | #ifdef CONFIG_PREEMPT | 
|  | #define S_PREEMPT " PREEMPT" | 
|  | #else | 
|  | #define S_PREEMPT "" | 
|  | #endif | 
|  | #ifdef CONFIG_SMP | 
|  | #define S_SMP " SMP" | 
|  | #else | 
|  | #define S_SMP "" | 
|  | #endif | 
|  | #ifdef CONFIG_THUMB2_KERNEL | 
|  | #define S_ISA " THUMB2" | 
|  | #else | 
|  | #define S_ISA " ARM" | 
|  | #endif | 
|  |  | 
|  | static int __die(const char *str, int err, struct pt_regs *regs) | 
|  | { | 
|  | struct task_struct *tsk = current; | 
|  | static int die_counter; | 
|  | int ret; | 
|  |  | 
|  | pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n", | 
|  | str, err, ++die_counter); | 
|  |  | 
|  | /* trap and error numbers are mostly meaningless on ARM */ | 
|  | ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV); | 
|  | if (ret == NOTIFY_STOP) | 
|  | return 1; | 
|  |  | 
|  | print_modules(); | 
|  | __show_regs(regs); | 
|  | pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", | 
|  | TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); | 
|  |  | 
|  | if (!user_mode(regs) || in_interrupt()) { | 
|  | dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp, | 
|  | THREAD_SIZE + (unsigned long)task_stack_page(tsk)); | 
|  | dump_backtrace(regs, tsk); | 
|  | dump_instr(KERN_EMERG, regs); | 
|  | } | 
|  |  | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED; | 
|  | static int die_owner = -1; | 
|  | static unsigned int die_nest_count; | 
|  |  | 
|  | static unsigned long oops_begin(void) | 
|  | { | 
|  | int cpu; | 
|  | unsigned long flags; | 
|  |  | 
|  | oops_enter(); | 
|  |  | 
|  | /* racy, but better than risking deadlock. */ | 
|  | raw_local_irq_save(flags); | 
|  | cpu = smp_processor_id(); | 
|  | if (!arch_spin_trylock(&die_lock)) { | 
|  | if (cpu == die_owner) | 
|  | /* nested oops. should stop eventually */; | 
|  | else | 
|  | arch_spin_lock(&die_lock); | 
|  | } | 
|  | die_nest_count++; | 
|  | die_owner = cpu; | 
|  | console_verbose(); | 
|  | bust_spinlocks(1); | 
|  | return flags; | 
|  | } | 
|  |  | 
|  | static void oops_end(unsigned long flags, struct pt_regs *regs, int signr) | 
|  | { | 
|  | if (regs && kexec_should_crash(current)) | 
|  | crash_kexec(regs); | 
|  |  | 
|  | bust_spinlocks(0); | 
|  | die_owner = -1; | 
|  | add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); | 
|  | die_nest_count--; | 
|  | if (!die_nest_count) | 
|  | /* Nest count reaches zero, release the lock. */ | 
|  | arch_spin_unlock(&die_lock); | 
|  | raw_local_irq_restore(flags); | 
|  | oops_exit(); | 
|  |  | 
|  | if (in_interrupt()) | 
|  | panic("Fatal exception in interrupt"); | 
|  | if (panic_on_oops) | 
|  | panic("Fatal exception"); | 
|  | if (signr) | 
|  | do_exit(signr); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * This function is protected against re-entrancy. | 
|  | */ | 
|  | void die(const char *str, struct pt_regs *regs, int err) | 
|  | { | 
|  | enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE; | 
|  | unsigned long flags = oops_begin(); | 
|  | int sig = SIGSEGV; | 
|  |  | 
|  | if (!user_mode(regs)) | 
|  | bug_type = report_bug(regs->ARM_pc, regs); | 
|  | if (bug_type != BUG_TRAP_TYPE_NONE) | 
|  | str = "Oops - BUG"; | 
|  |  | 
|  | if (__die(str, err, regs)) | 
|  | sig = 0; | 
|  |  | 
|  | oops_end(flags, regs, sig); | 
|  | } | 
|  |  | 
|  | void arm_notify_die(const char *str, struct pt_regs *regs, | 
|  | struct siginfo *info, unsigned long err, unsigned long trap) | 
|  | { | 
|  | if (user_mode(regs)) { | 
|  | current->thread.error_code = err; | 
|  | current->thread.trap_no = trap; | 
|  |  | 
|  | force_sig_info(info->si_signo, info, current); | 
|  | } else { | 
|  | die(str, regs, err); | 
|  | } | 
|  | } | 
|  |  | 
|  | #ifdef CONFIG_GENERIC_BUG | 
|  |  | 
|  | int is_valid_bugaddr(unsigned long pc) | 
|  | { | 
|  | #ifdef CONFIG_THUMB2_KERNEL | 
|  | u16 bkpt; | 
|  | u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE); | 
|  | #else | 
|  | u32 bkpt; | 
|  | u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE); | 
|  | #endif | 
|  |  | 
|  | if (probe_kernel_address((unsigned *)pc, bkpt)) | 
|  | return 0; | 
|  |  | 
|  | return bkpt == insn; | 
|  | } | 
|  |  | 
|  | #endif | 
|  |  | 
|  | static LIST_HEAD(undef_hook); | 
|  | static DEFINE_RAW_SPINLOCK(undef_lock); | 
|  |  | 
|  | void register_undef_hook(struct undef_hook *hook) | 
|  | { | 
|  | unsigned long flags; | 
|  |  | 
|  | raw_spin_lock_irqsave(&undef_lock, flags); | 
|  | list_add(&hook->node, &undef_hook); | 
|  | raw_spin_unlock_irqrestore(&undef_lock, flags); | 
|  | } | 
|  |  | 
|  | void unregister_undef_hook(struct undef_hook *hook) | 
|  | { | 
|  | unsigned long flags; | 
|  |  | 
|  | raw_spin_lock_irqsave(&undef_lock, flags); | 
|  | list_del(&hook->node); | 
|  | raw_spin_unlock_irqrestore(&undef_lock, flags); | 
|  | } | 
|  |  | 
|  | static int call_undef_hook(struct pt_regs *regs, unsigned int instr) | 
|  | { | 
|  | struct undef_hook *hook; | 
|  | unsigned long flags; | 
|  | int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL; | 
|  |  | 
|  | raw_spin_lock_irqsave(&undef_lock, flags); | 
|  | list_for_each_entry(hook, &undef_hook, node) | 
|  | if ((instr & hook->instr_mask) == hook->instr_val && | 
|  | (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) | 
|  | fn = hook->fn; | 
|  | raw_spin_unlock_irqrestore(&undef_lock, flags); | 
|  |  | 
|  | return fn ? fn(regs, instr) : 1; | 
|  | } | 
|  |  | 
|  | asmlinkage void __exception do_undefinstr(struct pt_regs *regs) | 
|  | { | 
|  | unsigned int instr; | 
|  | siginfo_t info; | 
|  | void __user *pc; | 
|  |  | 
|  | pc = (void __user *)instruction_pointer(regs); | 
|  |  | 
|  | if (processor_mode(regs) == SVC_MODE) { | 
|  | #ifdef CONFIG_THUMB2_KERNEL | 
|  | if (thumb_mode(regs)) { | 
|  | instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]); | 
|  | if (is_wide_instruction(instr)) { | 
|  | u16 inst2; | 
|  | inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]); | 
|  | instr = __opcode_thumb32_compose(instr, inst2); | 
|  | } | 
|  | } else | 
|  | #endif | 
|  | instr = __mem_to_opcode_arm(*(u32 *) pc); | 
|  | } else if (thumb_mode(regs)) { | 
|  | if (get_user(instr, (u16 __user *)pc)) | 
|  | goto die_sig; | 
|  | instr = __mem_to_opcode_thumb16(instr); | 
|  | if (is_wide_instruction(instr)) { | 
|  | unsigned int instr2; | 
|  | if (get_user(instr2, (u16 __user *)pc+1)) | 
|  | goto die_sig; | 
|  | instr2 = __mem_to_opcode_thumb16(instr2); | 
|  | instr = __opcode_thumb32_compose(instr, instr2); | 
|  | } | 
|  | } else { | 
|  | if (get_user(instr, (u32 __user *)pc)) | 
|  | goto die_sig; | 
|  | instr = __mem_to_opcode_arm(instr); | 
|  | } | 
|  |  | 
|  | if (call_undef_hook(regs, instr) == 0) | 
|  | return; | 
|  |  | 
|  | die_sig: | 
|  | #ifdef CONFIG_DEBUG_USER | 
|  | if (user_debug & UDBG_UNDEFINED) { | 
|  | pr_info("%s (%d): undefined instruction: pc=%p\n", | 
|  | current->comm, task_pid_nr(current), pc); | 
|  | __show_regs(regs); | 
|  | dump_instr(KERN_INFO, regs); | 
|  | } | 
|  | #endif | 
|  |  | 
|  | info.si_signo = SIGILL; | 
|  | info.si_errno = 0; | 
|  | info.si_code  = ILL_ILLOPC; | 
|  | info.si_addr  = pc; | 
|  |  | 
|  | arm_notify_die("Oops - undefined instruction", regs, &info, 0, 6); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Handle FIQ similarly to NMI on x86 systems. | 
|  | * | 
|  | * The runtime environment for NMIs is extremely restrictive | 
|  | * (NMIs can pre-empt critical sections meaning almost all locking is | 
|  | * forbidden) meaning this default FIQ handling must only be used in | 
|  | * circumstances where non-maskability improves robustness, such as | 
|  | * watchdog or debug logic. | 
|  | * | 
|  | * This handler is not appropriate for general purpose use in drivers | 
|  | * platform code and can be overrideen using set_fiq_handler. | 
|  | */ | 
|  | asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs) | 
|  | { | 
|  | struct pt_regs *old_regs = set_irq_regs(regs); | 
|  |  | 
|  | nmi_enter(); | 
|  |  | 
|  | /* nop. FIQ handlers for special arch/arm features can be added here. */ | 
|  |  | 
|  | nmi_exit(); | 
|  |  | 
|  | set_irq_regs(old_regs); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * bad_mode handles the impossible case in the vectors.  If you see one of | 
|  | * these, then it's extremely serious, and could mean you have buggy hardware. | 
|  | * It never returns, and never tries to sync.  We hope that we can at least | 
|  | * dump out some state information... | 
|  | */ | 
|  | asmlinkage void bad_mode(struct pt_regs *regs, int reason) | 
|  | { | 
|  | console_verbose(); | 
|  |  | 
|  | pr_crit("Bad mode in %s handler detected\n", handler[reason]); | 
|  |  | 
|  | die("Oops - bad mode", regs, 0); | 
|  | local_irq_disable(); | 
|  | panic("bad mode"); | 
|  | } | 
|  |  | 
|  | static int bad_syscall(int n, struct pt_regs *regs) | 
|  | { | 
|  | siginfo_t info; | 
|  |  | 
|  | if ((current->personality & PER_MASK) != PER_LINUX) { | 
|  | send_sig(SIGSEGV, current, 1); | 
|  | return regs->ARM_r0; | 
|  | } | 
|  |  | 
|  | #ifdef CONFIG_DEBUG_USER | 
|  | if (user_debug & UDBG_SYSCALL) { | 
|  | pr_err("[%d] %s: obsolete system call %08x.\n", | 
|  | task_pid_nr(current), current->comm, n); | 
|  | dump_instr(KERN_ERR, regs); | 
|  | } | 
|  | #endif | 
|  |  | 
|  | info.si_signo = SIGILL; | 
|  | info.si_errno = 0; | 
|  | info.si_code  = ILL_ILLTRP; | 
|  | info.si_addr  = (void __user *)instruction_pointer(regs) - | 
|  | (thumb_mode(regs) ? 2 : 4); | 
|  |  | 
|  | arm_notify_die("Oops - bad syscall", regs, &info, n, 0); | 
|  |  | 
|  | return regs->ARM_r0; | 
|  | } | 
|  |  | 
|  | static inline int | 
|  | __do_cache_op(unsigned long start, unsigned long end) | 
|  | { | 
|  | int ret; | 
|  |  | 
|  | do { | 
|  | unsigned long chunk = min(PAGE_SIZE, end - start); | 
|  |  | 
|  | if (fatal_signal_pending(current)) | 
|  | return 0; | 
|  |  | 
|  | ret = flush_cache_user_range(start, start + chunk); | 
|  | if (ret) | 
|  | return ret; | 
|  |  | 
|  | cond_resched(); | 
|  | start += chunk; | 
|  | } while (start < end); | 
|  |  | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static inline int | 
|  | do_cache_op(unsigned long start, unsigned long end, int flags) | 
|  | { | 
|  | if (end < start || flags) | 
|  | return -EINVAL; | 
|  |  | 
|  | if (!access_ok(VERIFY_READ, start, end - start)) | 
|  | return -EFAULT; | 
|  |  | 
|  | return __do_cache_op(start, end); | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Handle all unrecognised system calls. | 
|  | *  0x9f0000 - 0x9fffff are some more esoteric system calls | 
|  | */ | 
|  | #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) | 
|  | asmlinkage int arm_syscall(int no, struct pt_regs *regs) | 
|  | { | 
|  | siginfo_t info; | 
|  |  | 
|  | if ((no >> 16) != (__ARM_NR_BASE>> 16)) | 
|  | return bad_syscall(no, regs); | 
|  |  | 
|  | switch (no & 0xffff) { | 
|  | case 0: /* branch through 0 */ | 
|  | info.si_signo = SIGSEGV; | 
|  | info.si_errno = 0; | 
|  | info.si_code  = SEGV_MAPERR; | 
|  | info.si_addr  = NULL; | 
|  |  | 
|  | arm_notify_die("branch through zero", regs, &info, 0, 0); | 
|  | return 0; | 
|  |  | 
|  | case NR(breakpoint): /* SWI BREAK_POINT */ | 
|  | regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; | 
|  | ptrace_break(current, regs); | 
|  | return regs->ARM_r0; | 
|  |  | 
|  | /* | 
|  | * Flush a region from virtual address 'r0' to virtual address 'r1' | 
|  | * _exclusive_.  There is no alignment requirement on either address; | 
|  | * user space does not need to know the hardware cache layout. | 
|  | * | 
|  | * r2 contains flags.  It should ALWAYS be passed as ZERO until it | 
|  | * is defined to be something else.  For now we ignore it, but may | 
|  | * the fires of hell burn in your belly if you break this rule. ;) | 
|  | * | 
|  | * (at a later date, we may want to allow this call to not flush | 
|  | * various aspects of the cache.  Passing '0' will guarantee that | 
|  | * everything necessary gets flushed to maintain consistency in | 
|  | * the specified region). | 
|  | */ | 
|  | case NR(cacheflush): | 
|  | return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); | 
|  |  | 
|  | case NR(usr26): | 
|  | if (!(elf_hwcap & HWCAP_26BIT)) | 
|  | break; | 
|  | regs->ARM_cpsr &= ~MODE32_BIT; | 
|  | return regs->ARM_r0; | 
|  |  | 
|  | case NR(usr32): | 
|  | if (!(elf_hwcap & HWCAP_26BIT)) | 
|  | break; | 
|  | regs->ARM_cpsr |= MODE32_BIT; | 
|  | return regs->ARM_r0; | 
|  |  | 
|  | case NR(set_tls): | 
|  | set_tls(regs->ARM_r0); | 
|  | return 0; | 
|  |  | 
|  | default: | 
|  | /* Calls 9f00xx..9f07ff are defined to return -ENOSYS | 
|  | if not implemented, rather than raising SIGILL.  This | 
|  | way the calling program can gracefully determine whether | 
|  | a feature is supported.  */ | 
|  | if ((no & 0xffff) <= 0x7ff) | 
|  | return -ENOSYS; | 
|  | break; | 
|  | } | 
|  | #ifdef CONFIG_DEBUG_USER | 
|  | /* | 
|  | * experience shows that these seem to indicate that | 
|  | * something catastrophic has happened | 
|  | */ | 
|  | if (user_debug & UDBG_SYSCALL) { | 
|  | pr_err("[%d] %s: arm syscall %d\n", | 
|  | task_pid_nr(current), current->comm, no); | 
|  | dump_instr("", regs); | 
|  | if (user_mode(regs)) { | 
|  | __show_regs(regs); | 
|  | c_backtrace(frame_pointer(regs), processor_mode(regs)); | 
|  | } | 
|  | } | 
|  | #endif | 
|  | info.si_signo = SIGILL; | 
|  | info.si_errno = 0; | 
|  | info.si_code  = ILL_ILLTRP; | 
|  | info.si_addr  = (void __user *)instruction_pointer(regs) - | 
|  | (thumb_mode(regs) ? 2 : 4); | 
|  |  | 
|  | arm_notify_die("Oops - bad syscall(2)", regs, &info, no, 0); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | #ifdef CONFIG_TLS_REG_EMUL | 
|  |  | 
|  | /* | 
|  | * We might be running on an ARMv6+ processor which should have the TLS | 
|  | * register but for some reason we can't use it, or maybe an SMP system | 
|  | * using a pre-ARMv6 processor (there are apparently a few prototypes like | 
|  | * that in existence) and therefore access to that register must be | 
|  | * emulated. | 
|  | */ | 
|  |  | 
|  | static int get_tp_trap(struct pt_regs *regs, unsigned int instr) | 
|  | { | 
|  | int reg = (instr >> 12) & 15; | 
|  | if (reg == 15) | 
|  | return 1; | 
|  | regs->uregs[reg] = current_thread_info()->tp_value[0]; | 
|  | regs->ARM_pc += 4; | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static struct undef_hook arm_mrc_hook = { | 
|  | .instr_mask	= 0x0fff0fff, | 
|  | .instr_val	= 0x0e1d0f70, | 
|  | .cpsr_mask	= PSR_T_BIT, | 
|  | .cpsr_val	= 0, | 
|  | .fn		= get_tp_trap, | 
|  | }; | 
|  |  | 
|  | static int __init arm_mrc_hook_init(void) | 
|  | { | 
|  | register_undef_hook(&arm_mrc_hook); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | late_initcall(arm_mrc_hook_init); | 
|  |  | 
|  | #endif | 
|  |  | 
|  | /* | 
|  | * A data abort trap was taken, but we did not handle the instruction. | 
|  | * Try to abort the user program, or panic if it was the kernel. | 
|  | */ | 
|  | asmlinkage void | 
|  | baddataabort(int code, unsigned long instr, struct pt_regs *regs) | 
|  | { | 
|  | unsigned long addr = instruction_pointer(regs); | 
|  | siginfo_t info; | 
|  |  | 
|  | #ifdef CONFIG_DEBUG_USER | 
|  | if (user_debug & UDBG_BADABORT) { | 
|  | pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n", | 
|  | task_pid_nr(current), current->comm, code, instr); | 
|  | dump_instr(KERN_ERR, regs); | 
|  | show_pte(current->mm, addr); | 
|  | } | 
|  | #endif | 
|  |  | 
|  | info.si_signo = SIGILL; | 
|  | info.si_errno = 0; | 
|  | info.si_code  = ILL_ILLOPC; | 
|  | info.si_addr  = (void __user *)addr; | 
|  |  | 
|  | arm_notify_die("unknown data abort code", regs, &info, instr, 0); | 
|  | } | 
|  |  | 
|  | void __readwrite_bug(const char *fn) | 
|  | { | 
|  | pr_err("%s called, but not implemented\n", fn); | 
|  | BUG(); | 
|  | } | 
|  | EXPORT_SYMBOL(__readwrite_bug); | 
|  |  | 
|  | void __pte_error(const char *file, int line, pte_t pte) | 
|  | { | 
|  | pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte)); | 
|  | } | 
|  |  | 
|  | void __pmd_error(const char *file, int line, pmd_t pmd) | 
|  | { | 
|  | pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd)); | 
|  | } | 
|  |  | 
|  | void __pgd_error(const char *file, int line, pgd_t pgd) | 
|  | { | 
|  | pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd)); | 
|  | } | 
|  |  | 
|  | asmlinkage void __div0(void) | 
|  | { | 
|  | pr_err("Division by zero in kernel.\n"); | 
|  | dump_stack(); | 
|  | } | 
|  | EXPORT_SYMBOL(__div0); | 
|  |  | 
|  | void abort(void) | 
|  | { | 
|  | BUG(); | 
|  |  | 
|  | /* if that doesn't kill us, halt */ | 
|  | panic("Oops failed to kill thread"); | 
|  | } | 
|  | EXPORT_SYMBOL(abort); | 
|  |  | 
|  | void __init trap_init(void) | 
|  | { | 
|  | return; | 
|  | } | 
|  |  | 
|  | #ifdef CONFIG_KUSER_HELPERS | 
|  | static void __init kuser_init(void *vectors) | 
|  | { | 
|  | extern char __kuser_helper_start[], __kuser_helper_end[]; | 
|  | int kuser_sz = __kuser_helper_end - __kuser_helper_start; | 
|  |  | 
|  | memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz); | 
|  |  | 
|  | /* | 
|  | * vectors + 0xfe0 = __kuser_get_tls | 
|  | * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8 | 
|  | */ | 
|  | if (tls_emu || has_tls_reg) | 
|  | memcpy(vectors + 0xfe0, vectors + 0xfe8, 4); | 
|  | } | 
|  | #else | 
|  | static inline void __init kuser_init(void *vectors) | 
|  | { | 
|  | } | 
|  | #endif | 
|  |  | 
|  | void __init early_trap_init(void *vectors_base) | 
|  | { | 
|  | #ifndef CONFIG_CPU_V7M | 
|  | unsigned long vectors = (unsigned long)vectors_base; | 
|  | extern char __stubs_start[], __stubs_end[]; | 
|  | extern char __vectors_start[], __vectors_end[]; | 
|  | unsigned i; | 
|  |  | 
|  | vectors_page = vectors_base; | 
|  |  | 
|  | /* | 
|  | * Poison the vectors page with an undefined instruction.  This | 
|  | * instruction is chosen to be undefined for both ARM and Thumb | 
|  | * ISAs.  The Thumb version is an undefined instruction with a | 
|  | * branch back to the undefined instruction. | 
|  | */ | 
|  | for (i = 0; i < PAGE_SIZE / sizeof(u32); i++) | 
|  | ((u32 *)vectors_base)[i] = 0xe7fddef1; | 
|  |  | 
|  | /* | 
|  | * Copy the vectors, stubs and kuser helpers (in entry-armv.S) | 
|  | * into the vector page, mapped at 0xffff0000, and ensure these | 
|  | * are visible to the instruction stream. | 
|  | */ | 
|  | memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start); | 
|  | memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start); | 
|  |  | 
|  | kuser_init(vectors_base); | 
|  |  | 
|  | flush_icache_range(vectors, vectors + PAGE_SIZE * 2); | 
|  | #else /* ifndef CONFIG_CPU_V7M */ | 
|  | /* | 
|  | * on V7-M there is no need to copy the vector table to a dedicated | 
|  | * memory area. The address is configurable and so a table in the kernel | 
|  | * image can be used. | 
|  | */ | 
|  | #endif | 
|  | } |