diff options
Diffstat (limited to 'arch/arm/kernel/traps.c')
| -rw-r--r-- | arch/arm/kernel/traps.c | 734 |
1 files changed, 734 insertions, 0 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c new file mode 100644 index 0000000..79abc4d --- /dev/null +++ b/arch/arm/kernel/traps.c @@ -0,0 +1,734 @@ +/* + * 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/module.h> +#include <linux/signal.h> +#include <linux/spinlock.h> +#include <linux/personality.h> +#include <linux/kallsyms.h> +#include <linux/delay.h> +#include <linux/hardirq.h> +#include <linux/init.h> +#include <linux/uaccess.h> + +#include <asm/atomic.h> +#include <asm/cacheflush.h> +#include <asm/system.h> +#include <asm/unistd.h> +#include <asm/traps.h> + +#include "ptrace.h" +#include "signal.h" + +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 + +static void dump_mem(const char *str, unsigned long bottom, unsigned long top); + +void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame) +{ +#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 + + if (in_exception_text(where)) + dump_mem("Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); +} + +/* + * 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; +} + +/* + * 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) +{ + __backtrace(); +} + +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) : : "cc"); + + c_backtrace(fp, 0x10); + 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 + +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]" S_PREEMPT S_SMP "\n", + str, err, ++die_counter); + print_modules(); + __show_regs(regs); + printk("Process %s (pid: %d, stack limit = 0x%p)\n", + tsk->comm, task_pid_nr(tsk), 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(); + + oops_enter(); + + console_verbose(); + spin_lock_irq(&die_lock); + bust_spinlocks(1); + __die(str, err, thread, regs); + bust_spinlocks(0); + add_taint(TAINT_DIE); + spin_unlock_irq(&die_lock); + + if (in_interrupt()) + panic("Fatal exception in interrupt"); + + if (panic_on_oops) + panic("Fatal exception"); + + oops_exit(); + do_exit(SIGSEGV); +} + +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); + } +} + +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); +} + +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; + + 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; + spin_unlock_irqrestore(&undef_lock, flags); + + return fn ? fn(regs, instr) : 1; +} + +asmlinkage void __exception do_undefinstr(struct pt_regs *regs) +{ + unsigned int correction = thumb_mode(regs) ? 2 : 4; + unsigned int instr; + 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 (processor_mode(regs) == SVC_MODE) { + instr = *(u32 *) pc; + } else if (thumb_mode(regs)) { + get_user(instr, (u16 __user *)pc); + } else { + get_user(instr, (u32 __user *)pc); + } + + if (call_undef_hook(regs, instr) == 0) + return; + +#ifdef CONFIG_DEBUG_USER + if (user_debug & UDBG_UNDEFINED) { + printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n", + current->comm, task_pid_nr(current), pc); + dump_instr(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); +} + +asmlinkage void do_unexp_fiq (struct pt_regs *regs) +{ + printk("Hmm. Unexpected FIQ received, but trying to continue\n"); + printk("You may have a hardware problem...\n"); +} + +/* + * 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(); + + printk(KERN_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) +{ + 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", + task_pid_nr(current), 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); + + arm_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; + + 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): + 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: + for (;;) { + 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); + } +#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", + task_pid_nr(current), 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); + + 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; + 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", + task_pid_nr(current), 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; + + arm_notify_die("unknown data abort code", regs, &info, instr, 0); +} + +void __attribute__((noreturn)) __bug(const char *file, int line) +{ + printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line); + *(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) +{ + return; +} + +void __init early_trap_init(void) +{ + unsigned long vectors = CONFIG_VECTORS_BASE; + 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 *)vectors, __vectors_start, __vectors_end - __vectors_start); + memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start); + memcpy((void *)vectors + 0x1000 - 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(vectors, vectors + PAGE_SIZE); + modify_domain(DOMAIN_USER, DOMAIN_CLIENT); +} |
