![Nicolas Pitre](/assets/img/avatar_default.png)
Patch from Nicolas Pitre This better express things, and should cover RMK's weird SMP toys. Signed-off-by: Nicolas Pitre Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
640 lines
15 KiB
C
640 lines
15 KiB
C
/*
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* linux/arch/arm/kernel/traps.c
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*
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* Copyright (C) 1995-2002 Russell King
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* Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* 'traps.c' handles hardware exceptions after we have saved some state in
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* 'linux/arch/arm/lib/traps.S'. Mostly a debugging aid, but will probably
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* kill the offending process.
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/signal.h>
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#include <linux/spinlock.h>
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#include <linux/personality.h>
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#include <linux/ptrace.h>
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#include <linux/kallsyms.h>
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#include <linux/init.h>
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#include <asm/atomic.h>
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#include <asm/cacheflush.h>
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#include <asm/io.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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#include <asm/unistd.h>
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#include <asm/traps.h>
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#include "ptrace.h"
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const char *processor_modes[]=
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{ "USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
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"UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
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"USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
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"UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
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};
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static const char *handler[]= { "prefetch abort", "data abort", "address exception", "interrupt" };
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#ifdef CONFIG_DEBUG_USER
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unsigned int user_debug;
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static int __init user_debug_setup(char *str)
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{
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get_option(&str, &user_debug);
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return 1;
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}
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__setup("user_debug=", user_debug_setup);
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#endif
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void dump_backtrace_entry(unsigned long where, unsigned long from)
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{
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#ifdef CONFIG_KALLSYMS
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printk("[<%08lx>] ", where);
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print_symbol("(%s) ", where);
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printk("from [<%08lx>] ", from);
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print_symbol("(%s)\n", from);
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#else
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printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
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#endif
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}
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/*
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* Stack pointers should always be within the kernels view of
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* physical memory. If it is not there, then we can't dump
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* out any information relating to the stack.
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*/
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static int verify_stack(unsigned long sp)
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{
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if (sp < PAGE_OFFSET || (sp > (unsigned long)high_memory && high_memory != 0))
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return -EFAULT;
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return 0;
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}
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/*
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* Dump out the contents of some memory nicely...
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*/
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static void dump_mem(const char *str, unsigned long bottom, unsigned long top)
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{
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unsigned long p = bottom & ~31;
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mm_segment_t fs;
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int i;
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/*
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* We need to switch to kernel mode so that we can use __get_user
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* to safely read from kernel space. Note that we now dump the
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* code first, just in case the backtrace kills us.
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*/
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fs = get_fs();
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set_fs(KERNEL_DS);
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printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
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for (p = bottom & ~31; p < top;) {
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printk("%04lx: ", p & 0xffff);
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for (i = 0; i < 8; i++, p += 4) {
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unsigned int val;
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if (p < bottom || p >= top)
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printk(" ");
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else {
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__get_user(val, (unsigned long *)p);
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printk("%08x ", val);
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}
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}
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printk ("\n");
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}
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set_fs(fs);
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}
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static void dump_instr(struct pt_regs *regs)
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{
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unsigned long addr = instruction_pointer(regs);
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const int thumb = thumb_mode(regs);
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const int width = thumb ? 4 : 8;
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mm_segment_t fs;
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int i;
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/*
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* We need to switch to kernel mode so that we can use __get_user
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* to safely read from kernel space. Note that we now dump the
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* code first, just in case the backtrace kills us.
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*/
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fs = get_fs();
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set_fs(KERNEL_DS);
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printk("Code: ");
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for (i = -4; i < 1; i++) {
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unsigned int val, bad;
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if (thumb)
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bad = __get_user(val, &((u16 *)addr)[i]);
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else
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bad = __get_user(val, &((u32 *)addr)[i]);
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if (!bad)
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printk(i == 0 ? "(%0*x) " : "%0*x ", width, val);
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else {
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printk("bad PC value.");
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break;
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}
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}
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printk("\n");
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set_fs(fs);
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}
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static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
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{
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unsigned int fp;
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int ok = 1;
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printk("Backtrace: ");
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fp = regs->ARM_fp;
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if (!fp) {
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printk("no frame pointer");
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ok = 0;
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} else if (verify_stack(fp)) {
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printk("invalid frame pointer 0x%08x", fp);
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ok = 0;
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} else if (fp < (unsigned long)(tsk->thread_info + 1))
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printk("frame pointer underflow");
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printk("\n");
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if (ok)
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c_backtrace(fp, processor_mode(regs));
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}
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void dump_stack(void)
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{
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#ifdef CONFIG_DEBUG_ERRORS
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__backtrace();
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#endif
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}
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EXPORT_SYMBOL(dump_stack);
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void show_stack(struct task_struct *tsk, unsigned long *sp)
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{
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unsigned long fp;
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if (!tsk)
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tsk = current;
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if (tsk != current)
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fp = thread_saved_fp(tsk);
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else
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asm("mov%? %0, fp" : "=r" (fp));
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c_backtrace(fp, 0x10);
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barrier();
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}
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DEFINE_SPINLOCK(die_lock);
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/*
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* This function is protected against re-entrancy.
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*/
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NORET_TYPE void die(const char *str, struct pt_regs *regs, int err)
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{
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struct task_struct *tsk = current;
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static int die_counter;
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console_verbose();
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spin_lock_irq(&die_lock);
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bust_spinlocks(1);
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printk("Internal error: %s: %x [#%d]\n", str, err, ++die_counter);
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print_modules();
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__show_regs(regs);
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printk("Process %s (pid: %d, stack limit = 0x%p)\n",
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tsk->comm, tsk->pid, tsk->thread_info + 1);
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if (!user_mode(regs) || in_interrupt()) {
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dump_mem("Stack: ", regs->ARM_sp,
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THREAD_SIZE + (unsigned long)tsk->thread_info);
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dump_backtrace(regs, tsk);
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dump_instr(regs);
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}
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bust_spinlocks(0);
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spin_unlock_irq(&die_lock);
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do_exit(SIGSEGV);
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}
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void die_if_kernel(const char *str, struct pt_regs *regs, int err)
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{
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if (user_mode(regs))
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return;
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die(str, regs, err);
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}
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static void notify_die(const char *str, struct pt_regs *regs, siginfo_t *info,
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unsigned long err, unsigned long trap)
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{
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if (user_mode(regs)) {
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current->thread.error_code = err;
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current->thread.trap_no = trap;
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force_sig_info(info->si_signo, info, current);
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} else {
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die(str, regs, err);
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}
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}
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static LIST_HEAD(undef_hook);
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static DEFINE_SPINLOCK(undef_lock);
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void register_undef_hook(struct undef_hook *hook)
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{
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spin_lock_irq(&undef_lock);
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list_add(&hook->node, &undef_hook);
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spin_unlock_irq(&undef_lock);
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}
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void unregister_undef_hook(struct undef_hook *hook)
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{
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spin_lock_irq(&undef_lock);
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list_del(&hook->node);
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spin_unlock_irq(&undef_lock);
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}
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asmlinkage void do_undefinstr(struct pt_regs *regs)
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{
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unsigned int correction = thumb_mode(regs) ? 2 : 4;
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unsigned int instr;
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struct undef_hook *hook;
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siginfo_t info;
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void __user *pc;
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/*
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* According to the ARM ARM, PC is 2 or 4 bytes ahead,
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* depending whether we're in Thumb mode or not.
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* Correct this offset.
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*/
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regs->ARM_pc -= correction;
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pc = (void __user *)instruction_pointer(regs);
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if (thumb_mode(regs)) {
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get_user(instr, (u16 __user *)pc);
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} else {
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get_user(instr, (u32 __user *)pc);
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}
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spin_lock_irq(&undef_lock);
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list_for_each_entry(hook, &undef_hook, node) {
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if ((instr & hook->instr_mask) == hook->instr_val &&
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(regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) {
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if (hook->fn(regs, instr) == 0) {
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spin_unlock_irq(&undef_lock);
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return;
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}
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}
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}
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spin_unlock_irq(&undef_lock);
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#ifdef CONFIG_DEBUG_USER
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if (user_debug & UDBG_UNDEFINED) {
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printk(KERN_INFO "%s (%d): undefined instruction: pc=%p\n",
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current->comm, current->pid, pc);
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dump_instr(regs);
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}
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#endif
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info.si_signo = SIGILL;
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info.si_errno = 0;
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info.si_code = ILL_ILLOPC;
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info.si_addr = pc;
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notify_die("Oops - undefined instruction", regs, &info, 0, 6);
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}
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asmlinkage void do_unexp_fiq (struct pt_regs *regs)
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{
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#ifndef CONFIG_IGNORE_FIQ
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printk("Hmm. Unexpected FIQ received, but trying to continue\n");
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printk("You may have a hardware problem...\n");
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#endif
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}
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/*
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* bad_mode handles the impossible case in the vectors. If you see one of
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* these, then it's extremely serious, and could mean you have buggy hardware.
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* It never returns, and never tries to sync. We hope that we can at least
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* dump out some state information...
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*/
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asmlinkage void bad_mode(struct pt_regs *regs, int reason, int proc_mode)
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{
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console_verbose();
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printk(KERN_CRIT "Bad mode in %s handler detected: mode %s\n",
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handler[reason], processor_modes[proc_mode]);
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die("Oops - bad mode", regs, 0);
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local_irq_disable();
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panic("bad mode");
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}
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static int bad_syscall(int n, struct pt_regs *regs)
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{
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struct thread_info *thread = current_thread_info();
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siginfo_t info;
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if (current->personality != PER_LINUX && thread->exec_domain->handler) {
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thread->exec_domain->handler(n, regs);
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return regs->ARM_r0;
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}
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#ifdef CONFIG_DEBUG_USER
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if (user_debug & UDBG_SYSCALL) {
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printk(KERN_ERR "[%d] %s: obsolete system call %08x.\n",
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current->pid, current->comm, n);
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dump_instr(regs);
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}
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#endif
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info.si_signo = SIGILL;
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info.si_errno = 0;
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info.si_code = ILL_ILLTRP;
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info.si_addr = (void __user *)instruction_pointer(regs) -
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(thumb_mode(regs) ? 2 : 4);
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notify_die("Oops - bad syscall", regs, &info, n, 0);
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return regs->ARM_r0;
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}
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static inline void
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do_cache_op(unsigned long start, unsigned long end, int flags)
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{
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struct vm_area_struct *vma;
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if (end < start || flags)
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return;
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vma = find_vma(current->active_mm, start);
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if (vma && vma->vm_start < end) {
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if (start < vma->vm_start)
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start = vma->vm_start;
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if (end > vma->vm_end)
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end = vma->vm_end;
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flush_cache_user_range(vma, start, end);
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}
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}
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/*
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* Handle all unrecognised system calls.
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* 0x9f0000 - 0x9fffff are some more esoteric system calls
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*/
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#define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
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asmlinkage int arm_syscall(int no, struct pt_regs *regs)
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{
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struct thread_info *thread = current_thread_info();
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siginfo_t info;
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if ((no >> 16) != 0x9f)
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return bad_syscall(no, regs);
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switch (no & 0xffff) {
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case 0: /* branch through 0 */
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info.si_signo = SIGSEGV;
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info.si_errno = 0;
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info.si_code = SEGV_MAPERR;
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info.si_addr = NULL;
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notify_die("branch through zero", regs, &info, 0, 0);
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return 0;
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case NR(breakpoint): /* SWI BREAK_POINT */
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regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
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ptrace_break(current, regs);
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return regs->ARM_r0;
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/*
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* Flush a region from virtual address 'r0' to virtual address 'r1'
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* _exclusive_. There is no alignment requirement on either address;
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* user space does not need to know the hardware cache layout.
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*
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* r2 contains flags. It should ALWAYS be passed as ZERO until it
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* is defined to be something else. For now we ignore it, but may
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* the fires of hell burn in your belly if you break this rule. ;)
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*
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* (at a later date, we may want to allow this call to not flush
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* various aspects of the cache. Passing '0' will guarantee that
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* everything necessary gets flushed to maintain consistency in
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* the specified region).
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*/
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case NR(cacheflush):
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do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
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return 0;
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case NR(usr26):
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if (!(elf_hwcap & HWCAP_26BIT))
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break;
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regs->ARM_cpsr &= ~MODE32_BIT;
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return regs->ARM_r0;
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case NR(usr32):
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if (!(elf_hwcap & HWCAP_26BIT))
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break;
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regs->ARM_cpsr |= MODE32_BIT;
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return regs->ARM_r0;
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case NR(set_tls):
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thread->tp_value = regs->ARM_r0;
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#if defined(CONFIG_HAS_TLS_REG)
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asm ("mcr p15, 0, %0, c13, c0, 3" : : "r" (regs->ARM_r0) );
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#elif !defined(CONFIG_TLS_REG_EMUL)
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/*
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* User space must never try to access this directly.
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* Expect your app to break eventually if you do so.
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* The user helper at 0xffff0fe0 must be used instead.
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* (see entry-armv.S for details)
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*/
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*((unsigned int *)0xffff0ff0) = regs->ARM_r0;
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#endif
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return 0;
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default:
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/* Calls 9f00xx..9f07ff are defined to return -ENOSYS
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if not implemented, rather than raising SIGILL. This
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way the calling program can gracefully determine whether
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a feature is supported. */
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if (no <= 0x7ff)
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return -ENOSYS;
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break;
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}
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#ifdef CONFIG_DEBUG_USER
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/*
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* experience shows that these seem to indicate that
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* something catastrophic has happened
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*/
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if (user_debug & UDBG_SYSCALL) {
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printk("[%d] %s: arm syscall %d\n",
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current->pid, current->comm, no);
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dump_instr(regs);
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if (user_mode(regs)) {
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__show_regs(regs);
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c_backtrace(regs->ARM_fp, processor_mode(regs));
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}
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}
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#endif
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info.si_signo = SIGILL;
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info.si_errno = 0;
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info.si_code = ILL_ILLTRP;
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info.si_addr = (void __user *)instruction_pointer(regs) -
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(thumb_mode(regs) ? 2 : 4);
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notify_die("Oops - bad syscall(2)", regs, &info, no, 0);
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return 0;
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}
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#ifdef CONFIG_TLS_REG_EMUL
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/*
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* We might be running on an ARMv6+ processor which should have the TLS
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* register but for some reason we can't use it, or maybe an SMP system
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* using a pre-ARMv6 processor (there are apparently a few prototypes like
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* that in existence) and therefore access to that register must be
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* emulated.
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*/
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static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
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{
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int reg = (instr >> 12) & 15;
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if (reg == 15)
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return 1;
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regs->uregs[reg] = current_thread_info()->tp_value;
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regs->ARM_pc += 4;
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return 0;
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}
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static struct undef_hook arm_mrc_hook = {
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.instr_mask = 0x0fff0fff,
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.instr_val = 0x0e1d0f70,
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.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);
|
|
}
|
|
|
|
volatile void __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;
|
|
}
|
|
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);
|
|
flush_icache_range(0xffff0000, 0xffff0000 + PAGE_SIZE);
|
|
modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
|
|
}
|