| /* |
| * linux/arch/arm/kernel/traps.c |
| * |
| * Copyright (C) 1995-2002 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/config.h> |
| #include <linux/module.h> |
| #include <linux/signal.h> |
| #include <linux/spinlock.h> |
| #include <linux/personality.h> |
| #include <linux/ptrace.h> |
| #include <linux/kallsyms.h> |
| #include <linux/delay.h> |
| #include <linux/init.h> |
| |
| #include <asm/atomic.h> |
| #include <asm/cacheflush.h> |
| #include <asm/system.h> |
| #include <asm/uaccess.h> |
| #include <asm/unistd.h> |
| #include <asm/traps.h> |
| |
| #include "ptrace.h" |
| #include "signal.h" |
| |
| const char *processor_modes[]= |
| { "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" , |
| "UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26", |
| "USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" , |
| "UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32" |
| }; |
| |
| static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" }; |
| |
| #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 |
| |
| void dump_backtrace_entry(unsigned long where, unsigned long from) |
| { |
| #ifdef CONFIG_KALLSYMS |
| printk("[<%08lx>] ", where); |
| print_symbol("(%s) ", where); |
| printk("from [<%08lx>] ", from); |
| print_symbol("(%s)\n", from); |
| #else |
| printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from); |
| #endif |
| } |
| |
| /* |
| * 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 != 0)) |
| return -EFAULT; |
| |
| return 0; |
| } |
| |
| /* |
| * Dump out the contents of some memory nicely... |
| */ |
| static void dump_mem(const char *str, unsigned long bottom, unsigned long top) |
| { |
| unsigned long p = bottom & ~31; |
| 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(0x%08lx to 0x%08lx)\n", str, bottom, top); |
| |
| for (p = bottom & ~31; p < top;) { |
| printk("%04lx: ", p & 0xffff); |
| |
| for (i = 0; i < 8; i++, p += 4) { |
| unsigned int val; |
| |
| if (p < bottom || p >= top) |
| printk(" "); |
| else { |
| __get_user(val, (unsigned long *)p); |
| printk("%08x ", val); |
| } |
| } |
| printk ("\n"); |
| } |
| |
| set_fs(fs); |
| } |
| |
| static void dump_instr(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; |
| 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("Code: "); |
| for (i = -4; i < 1; i++) { |
| unsigned int val, bad; |
| |
| if (thumb) |
| bad = __get_user(val, &((u16 *)addr)[i]); |
| else |
| bad = __get_user(val, &((u32 *)addr)[i]); |
| |
| if (!bad) |
| printk(i == 0 ? "(%0*x) " : "%0*x ", width, val); |
| else { |
| printk("bad PC value."); |
| break; |
| } |
| } |
| printk("\n"); |
| |
| set_fs(fs); |
| } |
| |
| static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) |
| { |
| unsigned int fp; |
| int ok = 1; |
| |
| printk("Backtrace: "); |
| fp = regs->ARM_fp; |
| if (!fp) { |
| printk("no frame pointer"); |
| ok = 0; |
| } else if (verify_stack(fp)) { |
| printk("invalid frame pointer 0x%08x", fp); |
| ok = 0; |
| } else if (fp < (unsigned long)end_of_stack(tsk)) |
| printk("frame pointer underflow"); |
| printk("\n"); |
| |
| if (ok) |
| c_backtrace(fp, processor_mode(regs)); |
| } |
| |
| void dump_stack(void) |
| { |
| #ifdef CONFIG_DEBUG_ERRORS |
| __backtrace(); |
| #endif |
| } |
| |
| EXPORT_SYMBOL(dump_stack); |
| |
| void show_stack(struct task_struct *tsk, unsigned long *sp) |
| { |
| unsigned long fp; |
| |
| if (!tsk) |
| tsk = current; |
| |
| if (tsk != current) |
| fp = thread_saved_fp(tsk); |
| else |
| asm("mov%? %0, fp" : "=r" (fp)); |
| |
| c_backtrace(fp, 0x10); |
| barrier(); |
| } |
| |
| static void __die(const char *str, int err, struct thread_info *thread, struct pt_regs *regs) |
| { |
| struct task_struct *tsk = thread->task; |
| static int die_counter; |
| |
| printk("Internal error: %s: %x [#%d]\n", str, err, ++die_counter); |
| print_modules(); |
| __show_regs(regs); |
| printk("Process %s (pid: %d, stack limit = 0x%p)\n", |
| tsk->comm, tsk->pid, thread + 1); |
| |
| if (!user_mode(regs) || in_interrupt()) { |
| dump_mem("Stack: ", regs->ARM_sp, |
| THREAD_SIZE + (unsigned long)task_stack_page(tsk)); |
| dump_backtrace(regs, tsk); |
| dump_instr(regs); |
| } |
| } |
| |
| DEFINE_SPINLOCK(die_lock); |
| |
| /* |
| * This function is protected against re-entrancy. |
| */ |
| NORET_TYPE void die(const char *str, struct pt_regs *regs, int err) |
| { |
| struct thread_info *thread = current_thread_info(); |
| |
| console_verbose(); |
| spin_lock_irq(&die_lock); |
| bust_spinlocks(1); |
| __die(str, err, thread, regs); |
| bust_spinlocks(0); |
| spin_unlock_irq(&die_lock); |
| |
| if (panic_on_oops) { |
| printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n"); |
| ssleep(5); |
| panic("Fatal exception"); |
| } |
| |
| do_exit(SIGSEGV); |
| } |
| |
| void 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); |
| } |
| } |
| |
| static LIST_HEAD(undef_hook); |
| static DEFINE_SPINLOCK(undef_lock); |
| |
| void register_undef_hook(struct undef_hook *hook) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&undef_lock, flags); |
| list_add(&hook->node, &undef_hook); |
| spin_unlock_irqrestore(&undef_lock, flags); |
| } |
| |
| void unregister_undef_hook(struct undef_hook *hook) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&undef_lock, flags); |
| list_del(&hook->node); |
| spin_unlock_irqrestore(&undef_lock, flags); |
| } |
| |
| asmlinkage void do_undefinstr(struct pt_regs *regs) |
| { |
| unsigned int correction = thumb_mode(regs) ? 2 : 4; |
| unsigned int instr; |
| struct undef_hook *hook; |
| siginfo_t info; |
| void __user *pc; |
| |
| /* |
| * According to the ARM ARM, PC is 2 or 4 bytes ahead, |
| * depending whether we're in Thumb mode or not. |
| * Correct this offset. |
| */ |
| regs->ARM_pc -= correction; |
| |
| pc = (void __user *)instruction_pointer(regs); |
| if (thumb_mode(regs)) { |
| get_user(instr, (u16 __user *)pc); |
| } else { |
| get_user(instr, (u32 __user *)pc); |
| } |
| |
| spin_lock_irq(&undef_lock); |
| 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) { |
| if (hook->fn(regs, instr) == 0) { |
| spin_unlock_irq(&undef_lock); |
| return; |
| } |
| } |
| } |
| spin_unlock_irq(&undef_lock); |
| |
| #ifdef CONFIG_DEBUG_USER |
| if (user_debug & UDBG_UNDEFINED) { |
| printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n", |
| current->comm, current->pid, pc); |
| dump_instr(regs); |
| } |
| #endif |
| |
| info.si_signo = SIGILL; |
| info.si_errno = 0; |
| info.si_code = ILL_ILLOPC; |
| info.si_addr = pc; |
| |
| notify_die("Oops - undefined instruction", regs, &info, 0, 6); |
| } |
| |
| asmlinkage void do_unexp_fiq (struct pt_regs *regs) |
| { |
| #ifndef CONFIG_IGNORE_FIQ |
| printk("Hmm. Unexpected FIQ received, but trying to continue\n"); |
| printk("You may have a hardware problem...\n"); |
| #endif |
| } |
| |
| /* |
| * 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, int proc_mode) |
| { |
| console_verbose(); |
| |
| printk(KERN_CRIT "Bad mode in %s handler detected: mode %s\n", |
| handler[reason], processor_modes[proc_mode]); |
| |
| die("Oops - bad mode", regs, 0); |
| local_irq_disable(); |
| panic("bad mode"); |
| } |
| |
| static int bad_syscall(int n, struct pt_regs *regs) |
| { |
| struct thread_info *thread = current_thread_info(); |
| siginfo_t info; |
| |
| if (current->personality != PER_LINUX && |
| current->personality != PER_LINUX_32BIT && |
| thread->exec_domain->handler) { |
| thread->exec_domain->handler(n, regs); |
| return regs->ARM_r0; |
| } |
| |
| #ifdef CONFIG_DEBUG_USER |
| if (user_debug & UDBG_SYSCALL) { |
| printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n", |
| current->pid, current->comm, n); |
| dump_instr(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); |
| |
| notify_die("Oops - bad syscall", regs, &info, n, 0); |
| |
| return regs->ARM_r0; |
| } |
| |
| static inline void |
| do_cache_op(unsigned long start, unsigned long end, int flags) |
| { |
| struct vm_area_struct *vma; |
| |
| if (end < start || flags) |
| return; |
| |
| vma = find_vma(current->active_mm, start); |
| if (vma && vma->vm_start < end) { |
| if (start < vma->vm_start) |
| start = vma->vm_start; |
| if (end > vma->vm_end) |
| end = vma->vm_end; |
| |
| flush_cache_user_range(vma, 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) |
| { |
| struct thread_info *thread = current_thread_info(); |
| 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; |
| |
| 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): |
| do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2); |
| return 0; |
| |
| 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): |
| thread->tp_value = regs->ARM_r0; |
| #if defined(CONFIG_HAS_TLS_REG) |
| asm ("mcr p15, 0, %0, c13, c0, 3" : : "r" (regs->ARM_r0) ); |
| #elif !defined(CONFIG_TLS_REG_EMUL) |
| /* |
| * User space must never try to access this directly. |
| * Expect your app to break eventually if you do so. |
| * The user helper at 0xffff0fe0 must be used instead. |
| * (see entry-armv.S for details) |
| */ |
| *((unsigned int *)0xffff0ff0) = regs->ARM_r0; |
| #endif |
| return 0; |
| |
| #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG |
| /* |
| * Atomically store r1 in *r2 if *r2 is equal to r0 for user space. |
| * Return zero in r0 if *MEM was changed or non-zero if no exchange |
| * happened. Also set the user C flag accordingly. |
| * If access permissions have to be fixed up then non-zero is |
| * returned and the operation has to be re-attempted. |
| * |
| * *NOTE*: This is a ghost syscall private to the kernel. Only the |
| * __kuser_cmpxchg code in entry-armv.S should be aware of its |
| * existence. Don't ever use this from user code. |
| */ |
| case 0xfff0: |
| { |
| extern void do_DataAbort(unsigned long addr, unsigned int fsr, |
| struct pt_regs *regs); |
| unsigned long val; |
| unsigned long addr = regs->ARM_r2; |
| struct mm_struct *mm = current->mm; |
| pgd_t *pgd; pmd_t *pmd; pte_t *pte; |
| spinlock_t *ptl; |
| |
| regs->ARM_cpsr &= ~PSR_C_BIT; |
| down_read(&mm->mmap_sem); |
| pgd = pgd_offset(mm, addr); |
| if (!pgd_present(*pgd)) |
| goto bad_access; |
| pmd = pmd_offset(pgd, addr); |
| if (!pmd_present(*pmd)) |
| goto bad_access; |
| pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
| if (!pte_present(*pte) || !pte_dirty(*pte)) { |
| pte_unmap_unlock(pte, ptl); |
| goto bad_access; |
| } |
| val = *(unsigned long *)addr; |
| val -= regs->ARM_r0; |
| if (val == 0) { |
| *(unsigned long *)addr = regs->ARM_r1; |
| regs->ARM_cpsr |= PSR_C_BIT; |
| } |
| pte_unmap_unlock(pte, ptl); |
| up_read(&mm->mmap_sem); |
| return val; |
| |
| bad_access: |
| up_read(&mm->mmap_sem); |
| /* simulate a write access fault */ |
| do_DataAbort(addr, 15 + (1 << 11), regs); |
| return -1; |
| } |
| #endif |
| |
| 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 <= 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) { |
| printk("[%d] %s: arm syscall %d\n", |
| current->pid, current->comm, no); |
| dump_instr(regs); |
| if (user_mode(regs)) { |
| __show_regs(regs); |
| c_backtrace(regs->ARM_fp, 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); |
| |
| 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; |
| 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 |
| |
| void __bad_xchg(volatile void *ptr, int size) |
| { |
| printk("xchg: bad data size: pc 0x%p, ptr 0x%p, size %d\n", |
| __builtin_return_address(0), ptr, size); |
| BUG(); |
| } |
| EXPORT_SYMBOL(__bad_xchg); |
| |
| /* |
| * 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) { |
| printk(KERN_ERR "[%d] %s: bad data abort: code %d instr 0x%08lx\n", |
| current->pid, current->comm, code, instr); |
| dump_instr(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; |
| |
| notify_die("unknown data abort code", regs, &info, instr, 0); |
| } |
| |
| void __attribute__((noreturn)) __bug(const char *file, int line, void *data) |
| { |
| printk(KERN_CRIT"kernel BUG at %s:%d!", file, line); |
| if (data) |
| printk(" - extra data = %p", data); |
| printk("\n"); |
| *(int *)0 = 0; |
| |
| /* Avoid "noreturn function does return" */ |
| for (;;); |
| } |
| EXPORT_SYMBOL(__bug); |
| |
| void __readwrite_bug(const char *fn) |
| { |
| printk("%s called, but not implemented\n", fn); |
| BUG(); |
| } |
| EXPORT_SYMBOL(__readwrite_bug); |
| |
| void __pte_error(const char *file, int line, unsigned long val) |
| { |
| printk("%s:%d: bad pte %08lx.\n", file, line, val); |
| } |
| |
| void __pmd_error(const char *file, int line, unsigned long val) |
| { |
| printk("%s:%d: bad pmd %08lx.\n", file, line, val); |
| } |
| |
| void __pgd_error(const char *file, int line, unsigned long val) |
| { |
| printk("%s:%d: bad pgd %08lx.\n", file, line, val); |
| } |
| |
| asmlinkage void __div0(void) |
| { |
| printk("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) |
| { |
| extern char __stubs_start[], __stubs_end[]; |
| extern char __vectors_start[], __vectors_end[]; |
| extern char __kuser_helper_start[], __kuser_helper_end[]; |
| int kuser_sz = __kuser_helper_end - __kuser_helper_start; |
| |
| /* |
| * 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 *)0xffff0000, __vectors_start, __vectors_end - __vectors_start); |
| memcpy((void *)0xffff0200, __stubs_start, __stubs_end - __stubs_start); |
| memcpy((void *)0xffff1000 - kuser_sz, __kuser_helper_start, kuser_sz); |
| |
| /* |
| * Copy signal return handlers into the vector page, and |
| * set sigreturn to be a pointer to these. |
| */ |
| memcpy((void *)KERN_SIGRETURN_CODE, sigreturn_codes, |
| sizeof(sigreturn_codes)); |
| |
| flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE); |
| modify_domain(DOMAIN_USER, DOMAIN_CLIENT); |
| } |