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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/kernel/traps.c
downloadlinux-stericsson-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/kernel/traps.c')
-rw-r--r--arch/i386/kernel/traps.c1084
1 files changed, 1084 insertions, 0 deletions
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
new file mode 100644
index 000000000000..6c0e383915b6
--- /dev/null
+++ b/arch/i386/kernel/traps.c
@@ -0,0 +1,1084 @@
+/*
+ * linux/arch/i386/traps.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * Pentium III FXSR, SSE support
+ * Gareth Hughes <gareth@valinux.com>, May 2000
+ */
+
+/*
+ * 'Traps.c' handles hardware traps and faults after we have saved some
+ * state in 'asm.s'.
+ */
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/highmem.h>
+#include <linux/kallsyms.h>
+#include <linux/ptrace.h>
+#include <linux/utsname.h>
+#include <linux/kprobes.h>
+
+#ifdef CONFIG_EISA
+#include <linux/ioport.h>
+#include <linux/eisa.h>
+#endif
+
+#ifdef CONFIG_MCA
+#include <linux/mca.h>
+#endif
+
+#include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/atomic.h>
+#include <asm/debugreg.h>
+#include <asm/desc.h>
+#include <asm/i387.h>
+#include <asm/nmi.h>
+
+#include <asm/smp.h>
+#include <asm/arch_hooks.h>
+#include <asm/kdebug.h>
+
+#include <linux/irq.h>
+#include <linux/module.h>
+
+#include "mach_traps.h"
+
+asmlinkage int system_call(void);
+
+struct desc_struct default_ldt[] = { { 0, 0 }, { 0, 0 }, { 0, 0 },
+ { 0, 0 }, { 0, 0 } };
+
+/* Do we ignore FPU interrupts ? */
+char ignore_fpu_irq = 0;
+
+/*
+ * The IDT has to be page-aligned to simplify the Pentium
+ * F0 0F bug workaround.. We have a special link segment
+ * for this.
+ */
+struct desc_struct idt_table[256] __attribute__((__section__(".data.idt"))) = { {0, 0}, };
+
+asmlinkage void divide_error(void);
+asmlinkage void debug(void);
+asmlinkage void nmi(void);
+asmlinkage void int3(void);
+asmlinkage void overflow(void);
+asmlinkage void bounds(void);
+asmlinkage void invalid_op(void);
+asmlinkage void device_not_available(void);
+asmlinkage void coprocessor_segment_overrun(void);
+asmlinkage void invalid_TSS(void);
+asmlinkage void segment_not_present(void);
+asmlinkage void stack_segment(void);
+asmlinkage void general_protection(void);
+asmlinkage void page_fault(void);
+asmlinkage void coprocessor_error(void);
+asmlinkage void simd_coprocessor_error(void);
+asmlinkage void alignment_check(void);
+asmlinkage void spurious_interrupt_bug(void);
+asmlinkage void machine_check(void);
+
+static int kstack_depth_to_print = 24;
+struct notifier_block *i386die_chain;
+static DEFINE_SPINLOCK(die_notifier_lock);
+
+int register_die_notifier(struct notifier_block *nb)
+{
+ int err = 0;
+ unsigned long flags;
+ spin_lock_irqsave(&die_notifier_lock, flags);
+ err = notifier_chain_register(&i386die_chain, nb);
+ spin_unlock_irqrestore(&die_notifier_lock, flags);
+ return err;
+}
+
+static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
+{
+ return p > (void *)tinfo &&
+ p < (void *)tinfo + THREAD_SIZE - 3;
+}
+
+static inline unsigned long print_context_stack(struct thread_info *tinfo,
+ unsigned long *stack, unsigned long ebp)
+{
+ unsigned long addr;
+
+#ifdef CONFIG_FRAME_POINTER
+ while (valid_stack_ptr(tinfo, (void *)ebp)) {
+ addr = *(unsigned long *)(ebp + 4);
+ printk(" [<%08lx>] ", addr);
+ print_symbol("%s", addr);
+ printk("\n");
+ ebp = *(unsigned long *)ebp;
+ }
+#else
+ while (valid_stack_ptr(tinfo, stack)) {
+ addr = *stack++;
+ if (__kernel_text_address(addr)) {
+ printk(" [<%08lx>]", addr);
+ print_symbol(" %s", addr);
+ printk("\n");
+ }
+ }
+#endif
+ return ebp;
+}
+
+void show_trace(struct task_struct *task, unsigned long * stack)
+{
+ unsigned long ebp;
+
+ if (!task)
+ task = current;
+
+ if (task == current) {
+ /* Grab ebp right from our regs */
+ asm ("movl %%ebp, %0" : "=r" (ebp) : );
+ } else {
+ /* ebp is the last reg pushed by switch_to */
+ ebp = *(unsigned long *) task->thread.esp;
+ }
+
+ while (1) {
+ struct thread_info *context;
+ context = (struct thread_info *)
+ ((unsigned long)stack & (~(THREAD_SIZE - 1)));
+ ebp = print_context_stack(context, stack, ebp);
+ stack = (unsigned long*)context->previous_esp;
+ if (!stack)
+ break;
+ printk(" =======================\n");
+ }
+}
+
+void show_stack(struct task_struct *task, unsigned long *esp)
+{
+ unsigned long *stack;
+ int i;
+
+ if (esp == NULL) {
+ if (task)
+ esp = (unsigned long*)task->thread.esp;
+ else
+ esp = (unsigned long *)&esp;
+ }
+
+ stack = esp;
+ for(i = 0; i < kstack_depth_to_print; i++) {
+ if (kstack_end(stack))
+ break;
+ if (i && ((i % 8) == 0))
+ printk("\n ");
+ printk("%08lx ", *stack++);
+ }
+ printk("\nCall Trace:\n");
+ show_trace(task, esp);
+}
+
+/*
+ * The architecture-independent dump_stack generator
+ */
+void dump_stack(void)
+{
+ unsigned long stack;
+
+ show_trace(current, &stack);
+}
+
+EXPORT_SYMBOL(dump_stack);
+
+void show_registers(struct pt_regs *regs)
+{
+ int i;
+ int in_kernel = 1;
+ unsigned long esp;
+ unsigned short ss;
+
+ esp = (unsigned long) (&regs->esp);
+ ss = __KERNEL_DS;
+ if (regs->xcs & 3) {
+ in_kernel = 0;
+ esp = regs->esp;
+ ss = regs->xss & 0xffff;
+ }
+ print_modules();
+ printk("CPU: %d\nEIP: %04x:[<%08lx>] %s VLI\nEFLAGS: %08lx"
+ " (%s) \n",
+ smp_processor_id(), 0xffff & regs->xcs, regs->eip,
+ print_tainted(), regs->eflags, system_utsname.release);
+ print_symbol("EIP is at %s\n", regs->eip);
+ printk("eax: %08lx ebx: %08lx ecx: %08lx edx: %08lx\n",
+ regs->eax, regs->ebx, regs->ecx, regs->edx);
+ printk("esi: %08lx edi: %08lx ebp: %08lx esp: %08lx\n",
+ regs->esi, regs->edi, regs->ebp, esp);
+ printk("ds: %04x es: %04x ss: %04x\n",
+ regs->xds & 0xffff, regs->xes & 0xffff, ss);
+ printk("Process %s (pid: %d, threadinfo=%p task=%p)",
+ current->comm, current->pid, current_thread_info(), current);
+ /*
+ * When in-kernel, we also print out the stack and code at the
+ * time of the fault..
+ */
+ if (in_kernel) {
+ u8 *eip;
+
+ printk("\nStack: ");
+ show_stack(NULL, (unsigned long*)esp);
+
+ printk("Code: ");
+
+ eip = (u8 *)regs->eip - 43;
+ for (i = 0; i < 64; i++, eip++) {
+ unsigned char c;
+
+ if (eip < (u8 *)PAGE_OFFSET || __get_user(c, eip)) {
+ printk(" Bad EIP value.");
+ break;
+ }
+ if (eip == (u8 *)regs->eip)
+ printk("<%02x> ", c);
+ else
+ printk("%02x ", c);
+ }
+ }
+ printk("\n");
+}
+
+static void handle_BUG(struct pt_regs *regs)
+{
+ unsigned short ud2;
+ unsigned short line;
+ char *file;
+ char c;
+ unsigned long eip;
+
+ if (regs->xcs & 3)
+ goto no_bug; /* Not in kernel */
+
+ eip = regs->eip;
+
+ if (eip < PAGE_OFFSET)
+ goto no_bug;
+ if (__get_user(ud2, (unsigned short *)eip))
+ goto no_bug;
+ if (ud2 != 0x0b0f)
+ goto no_bug;
+ if (__get_user(line, (unsigned short *)(eip + 2)))
+ goto bug;
+ if (__get_user(file, (char **)(eip + 4)) ||
+ (unsigned long)file < PAGE_OFFSET || __get_user(c, file))
+ file = "<bad filename>";
+
+ printk("------------[ cut here ]------------\n");
+ printk(KERN_ALERT "kernel BUG at %s:%d!\n", file, line);
+
+no_bug:
+ return;
+
+ /* Here we know it was a BUG but file-n-line is unavailable */
+bug:
+ printk("Kernel BUG\n");
+}
+
+void die(const char * str, struct pt_regs * regs, long err)
+{
+ static struct {
+ spinlock_t lock;
+ u32 lock_owner;
+ int lock_owner_depth;
+ } die = {
+ .lock = SPIN_LOCK_UNLOCKED,
+ .lock_owner = -1,
+ .lock_owner_depth = 0
+ };
+ static int die_counter;
+
+ if (die.lock_owner != _smp_processor_id()) {
+ console_verbose();
+ spin_lock_irq(&die.lock);
+ die.lock_owner = smp_processor_id();
+ die.lock_owner_depth = 0;
+ bust_spinlocks(1);
+ }
+
+ if (++die.lock_owner_depth < 3) {
+ int nl = 0;
+ handle_BUG(regs);
+ printk(KERN_ALERT "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter);
+#ifdef CONFIG_PREEMPT
+ printk("PREEMPT ");
+ nl = 1;
+#endif
+#ifdef CONFIG_SMP
+ printk("SMP ");
+ nl = 1;
+#endif
+#ifdef CONFIG_DEBUG_PAGEALLOC
+ printk("DEBUG_PAGEALLOC");
+ nl = 1;
+#endif
+ if (nl)
+ printk("\n");
+ notify_die(DIE_OOPS, (char *)str, regs, err, 255, SIGSEGV);
+ show_registers(regs);
+ } else
+ printk(KERN_ERR "Recursive die() failure, output suppressed\n");
+
+ bust_spinlocks(0);
+ die.lock_owner = -1;
+ spin_unlock_irq(&die.lock);
+ if (in_interrupt())
+ panic("Fatal exception in interrupt");
+
+ if (panic_on_oops) {
+ printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
+ ssleep(5);
+ panic("Fatal exception");
+ }
+ do_exit(SIGSEGV);
+}
+
+static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
+{
+ if (!(regs->eflags & VM_MASK) && !(3 & regs->xcs))
+ die(str, regs, err);
+}
+
+static void do_trap(int trapnr, int signr, char *str, int vm86,
+ struct pt_regs * regs, long error_code, siginfo_t *info)
+{
+ if (regs->eflags & VM_MASK) {
+ if (vm86)
+ goto vm86_trap;
+ goto trap_signal;
+ }
+
+ if (!(regs->xcs & 3))
+ goto kernel_trap;
+
+ trap_signal: {
+ struct task_struct *tsk = current;
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_no = trapnr;
+ if (info)
+ force_sig_info(signr, info, tsk);
+ else
+ force_sig(signr, tsk);
+ return;
+ }
+
+ kernel_trap: {
+ if (!fixup_exception(regs))
+ die(str, regs, error_code);
+ return;
+ }
+
+ vm86_trap: {
+ int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr);
+ if (ret) goto trap_signal;
+ return;
+ }
+}
+
+#define DO_ERROR(trapnr, signr, str, name) \
+fastcall void do_##name(struct pt_regs * regs, long error_code) \
+{ \
+ if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
+ == NOTIFY_STOP) \
+ return; \
+ do_trap(trapnr, signr, str, 0, regs, error_code, NULL); \
+}
+
+#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
+fastcall void do_##name(struct pt_regs * regs, long error_code) \
+{ \
+ siginfo_t info; \
+ info.si_signo = signr; \
+ info.si_errno = 0; \
+ info.si_code = sicode; \
+ info.si_addr = (void __user *)siaddr; \
+ if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
+ == NOTIFY_STOP) \
+ return; \
+ do_trap(trapnr, signr, str, 0, regs, error_code, &info); \
+}
+
+#define DO_VM86_ERROR(trapnr, signr, str, name) \
+fastcall void do_##name(struct pt_regs * regs, long error_code) \
+{ \
+ if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
+ == NOTIFY_STOP) \
+ return; \
+ do_trap(trapnr, signr, str, 1, regs, error_code, NULL); \
+}
+
+#define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
+fastcall void do_##name(struct pt_regs * regs, long error_code) \
+{ \
+ siginfo_t info; \
+ info.si_signo = signr; \
+ info.si_errno = 0; \
+ info.si_code = sicode; \
+ info.si_addr = (void __user *)siaddr; \
+ if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
+ == NOTIFY_STOP) \
+ return; \
+ do_trap(trapnr, signr, str, 1, regs, error_code, &info); \
+}
+
+DO_VM86_ERROR_INFO( 0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->eip)
+#ifndef CONFIG_KPROBES
+DO_VM86_ERROR( 3, SIGTRAP, "int3", int3)
+#endif
+DO_VM86_ERROR( 4, SIGSEGV, "overflow", overflow)
+DO_VM86_ERROR( 5, SIGSEGV, "bounds", bounds)
+DO_ERROR_INFO( 6, SIGILL, "invalid operand", invalid_op, ILL_ILLOPN, regs->eip)
+DO_ERROR( 9, SIGFPE, "coprocessor segment overrun", coprocessor_segment_overrun)
+DO_ERROR(10, SIGSEGV, "invalid TSS", invalid_TSS)
+DO_ERROR(11, SIGBUS, "segment not present", segment_not_present)
+DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
+DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
+
+fastcall void do_general_protection(struct pt_regs * regs, long error_code)
+{
+ int cpu = get_cpu();
+ struct tss_struct *tss = &per_cpu(init_tss, cpu);
+ struct thread_struct *thread = &current->thread;
+
+ /*
+ * Perform the lazy TSS's I/O bitmap copy. If the TSS has an
+ * invalid offset set (the LAZY one) and the faulting thread has
+ * a valid I/O bitmap pointer, we copy the I/O bitmap in the TSS
+ * and we set the offset field correctly. Then we let the CPU to
+ * restart the faulting instruction.
+ */
+ if (tss->io_bitmap_base == INVALID_IO_BITMAP_OFFSET_LAZY &&
+ thread->io_bitmap_ptr) {
+ memcpy(tss->io_bitmap, thread->io_bitmap_ptr,
+ thread->io_bitmap_max);
+ /*
+ * If the previously set map was extending to higher ports
+ * than the current one, pad extra space with 0xff (no access).
+ */
+ if (thread->io_bitmap_max < tss->io_bitmap_max)
+ memset((char *) tss->io_bitmap +
+ thread->io_bitmap_max, 0xff,
+ tss->io_bitmap_max - thread->io_bitmap_max);
+ tss->io_bitmap_max = thread->io_bitmap_max;
+ tss->io_bitmap_base = IO_BITMAP_OFFSET;
+ put_cpu();
+ return;
+ }
+ put_cpu();
+
+ if (regs->eflags & VM_MASK)
+ goto gp_in_vm86;
+
+ if (!(regs->xcs & 3))
+ goto gp_in_kernel;
+
+ current->thread.error_code = error_code;
+ current->thread.trap_no = 13;
+ force_sig(SIGSEGV, current);
+ return;
+
+gp_in_vm86:
+ local_irq_enable();
+ handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
+ return;
+
+gp_in_kernel:
+ if (!fixup_exception(regs)) {
+ if (notify_die(DIE_GPF, "general protection fault", regs,
+ error_code, 13, SIGSEGV) == NOTIFY_STOP)
+ return;
+ die("general protection fault", regs, error_code);
+ }
+}
+
+static void mem_parity_error(unsigned char reason, struct pt_regs * regs)
+{
+ printk("Uhhuh. NMI received. Dazed and confused, but trying to continue\n");
+ printk("You probably have a hardware problem with your RAM chips\n");
+
+ /* Clear and disable the memory parity error line. */
+ clear_mem_error(reason);
+}
+
+static void io_check_error(unsigned char reason, struct pt_regs * regs)
+{
+ unsigned long i;
+
+ printk("NMI: IOCK error (debug interrupt?)\n");
+ show_registers(regs);
+
+ /* Re-enable the IOCK line, wait for a few seconds */
+ reason = (reason & 0xf) | 8;
+ outb(reason, 0x61);
+ i = 2000;
+ while (--i) udelay(1000);
+ reason &= ~8;
+ outb(reason, 0x61);
+}
+
+static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
+{
+#ifdef CONFIG_MCA
+ /* Might actually be able to figure out what the guilty party
+ * is. */
+ if( MCA_bus ) {
+ mca_handle_nmi();
+ return;
+ }
+#endif
+ printk("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
+ reason, smp_processor_id());
+ printk("Dazed and confused, but trying to continue\n");
+ printk("Do you have a strange power saving mode enabled?\n");
+}
+
+static DEFINE_SPINLOCK(nmi_print_lock);
+
+void die_nmi (struct pt_regs *regs, const char *msg)
+{
+ spin_lock(&nmi_print_lock);
+ /*
+ * We are in trouble anyway, lets at least try
+ * to get a message out.
+ */
+ bust_spinlocks(1);
+ printk(msg);
+ printk(" on CPU%d, eip %08lx, registers:\n",
+ smp_processor_id(), regs->eip);
+ show_registers(regs);
+ printk("console shuts up ...\n");
+ console_silent();
+ spin_unlock(&nmi_print_lock);
+ bust_spinlocks(0);
+ do_exit(SIGSEGV);
+}
+
+static void default_do_nmi(struct pt_regs * regs)
+{
+ unsigned char reason = 0;
+
+ /* Only the BSP gets external NMIs from the system. */
+ if (!smp_processor_id())
+ reason = get_nmi_reason();
+
+ if (!(reason & 0xc0)) {
+ if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 0, SIGINT)
+ == NOTIFY_STOP)
+ return;
+#ifdef CONFIG_X86_LOCAL_APIC
+ /*
+ * Ok, so this is none of the documented NMI sources,
+ * so it must be the NMI watchdog.
+ */
+ if (nmi_watchdog) {
+ nmi_watchdog_tick(regs);
+ return;
+ }
+#endif
+ unknown_nmi_error(reason, regs);
+ return;
+ }
+ if (notify_die(DIE_NMI, "nmi", regs, reason, 0, SIGINT) == NOTIFY_STOP)
+ return;
+ if (reason & 0x80)
+ mem_parity_error(reason, regs);
+ if (reason & 0x40)
+ io_check_error(reason, regs);
+ /*
+ * Reassert NMI in case it became active meanwhile
+ * as it's edge-triggered.
+ */
+ reassert_nmi();
+}
+
+static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
+{
+ return 0;
+}
+
+static nmi_callback_t nmi_callback = dummy_nmi_callback;
+
+fastcall void do_nmi(struct pt_regs * regs, long error_code)
+{
+ int cpu;
+
+ nmi_enter();
+
+ cpu = smp_processor_id();
+ ++nmi_count(cpu);
+
+ if (!nmi_callback(regs, cpu))
+ default_do_nmi(regs);
+
+ nmi_exit();
+}
+
+void set_nmi_callback(nmi_callback_t callback)
+{
+ nmi_callback = callback;
+}
+
+void unset_nmi_callback(void)
+{
+ nmi_callback = dummy_nmi_callback;
+}
+
+#ifdef CONFIG_KPROBES
+fastcall int do_int3(struct pt_regs *regs, long error_code)
+{
+ if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
+ == NOTIFY_STOP)
+ return 1;
+ /* This is an interrupt gate, because kprobes wants interrupts
+ disabled. Normal trap handlers don't. */
+ restore_interrupts(regs);
+ do_trap(3, SIGTRAP, "int3", 1, regs, error_code, NULL);
+ return 0;
+}
+#endif
+
+/*
+ * Our handling of the processor debug registers is non-trivial.
+ * We do not clear them on entry and exit from the kernel. Therefore
+ * it is possible to get a watchpoint trap here from inside the kernel.
+ * However, the code in ./ptrace.c has ensured that the user can
+ * only set watchpoints on userspace addresses. Therefore the in-kernel
+ * watchpoint trap can only occur in code which is reading/writing
+ * from user space. Such code must not hold kernel locks (since it
+ * can equally take a page fault), therefore it is safe to call
+ * force_sig_info even though that claims and releases locks.
+ *
+ * Code in ./signal.c ensures that the debug control register
+ * is restored before we deliver any signal, and therefore that
+ * user code runs with the correct debug control register even though
+ * we clear it here.
+ *
+ * Being careful here means that we don't have to be as careful in a
+ * lot of more complicated places (task switching can be a bit lazy
+ * about restoring all the debug state, and ptrace doesn't have to
+ * find every occurrence of the TF bit that could be saved away even
+ * by user code)
+ */
+fastcall void do_debug(struct pt_regs * regs, long error_code)
+{
+ unsigned int condition;
+ struct task_struct *tsk = current;
+
+ __asm__ __volatile__("movl %%db6,%0" : "=r" (condition));
+
+ if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
+ SIGTRAP) == NOTIFY_STOP)
+ return;
+ /* It's safe to allow irq's after DR6 has been saved */
+ if (regs->eflags & X86_EFLAGS_IF)
+ local_irq_enable();
+
+ /* Mask out spurious debug traps due to lazy DR7 setting */
+ if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
+ if (!tsk->thread.debugreg[7])
+ goto clear_dr7;
+ }
+
+ if (regs->eflags & VM_MASK)
+ goto debug_vm86;
+
+ /* Save debug status register where ptrace can see it */
+ tsk->thread.debugreg[6] = condition;
+
+ /*
+ * Single-stepping through TF: make sure we ignore any events in
+ * kernel space (but re-enable TF when returning to user mode).
+ */
+ if (condition & DR_STEP) {
+ /*
+ * We already checked v86 mode above, so we can
+ * check for kernel mode by just checking the CPL
+ * of CS.
+ */
+ if ((regs->xcs & 3) == 0)
+ goto clear_TF_reenable;
+ }
+
+ /* Ok, finally something we can handle */
+ send_sigtrap(tsk, regs, error_code);
+
+ /* Disable additional traps. They'll be re-enabled when
+ * the signal is delivered.
+ */
+clear_dr7:
+ __asm__("movl %0,%%db7"
+ : /* no output */
+ : "r" (0));
+ return;
+
+debug_vm86:
+ handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
+ return;
+
+clear_TF_reenable:
+ set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+ regs->eflags &= ~TF_MASK;
+ return;
+}
+
+/*
+ * Note that we play around with the 'TS' bit in an attempt to get
+ * the correct behaviour even in the presence of the asynchronous
+ * IRQ13 behaviour
+ */
+void math_error(void __user *eip)
+{
+ struct task_struct * task;
+ siginfo_t info;
+ unsigned short cwd, swd;
+
+ /*
+ * Save the info for the exception handler and clear the error.
+ */
+ task = current;
+ save_init_fpu(task);
+ task->thread.trap_no = 16;
+ task->thread.error_code = 0;
+ info.si_signo = SIGFPE;
+ info.si_errno = 0;
+ info.si_code = __SI_FAULT;
+ info.si_addr = eip;
+ /*
+ * (~cwd & swd) will mask out exceptions that are not set to unmasked
+ * status. 0x3f is the exception bits in these regs, 0x200 is the
+ * C1 reg you need in case of a stack fault, 0x040 is the stack
+ * fault bit. We should only be taking one exception at a time,
+ * so if this combination doesn't produce any single exception,
+ * then we have a bad program that isn't syncronizing its FPU usage
+ * and it will suffer the consequences since we won't be able to
+ * fully reproduce the context of the exception
+ */
+ cwd = get_fpu_cwd(task);
+ swd = get_fpu_swd(task);
+ switch (((~cwd) & swd & 0x3f) | (swd & 0x240)) {
+ case 0x000:
+ default:
+ break;
+ case 0x001: /* Invalid Op */
+ case 0x041: /* Stack Fault */
+ case 0x241: /* Stack Fault | Direction */
+ info.si_code = FPE_FLTINV;
+ /* Should we clear the SF or let user space do it ???? */
+ break;
+ case 0x002: /* Denormalize */
+ case 0x010: /* Underflow */
+ info.si_code = FPE_FLTUND;
+ break;
+ case 0x004: /* Zero Divide */
+ info.si_code = FPE_FLTDIV;
+ break;
+ case 0x008: /* Overflow */
+ info.si_code = FPE_FLTOVF;
+ break;
+ case 0x020: /* Precision */
+ info.si_code = FPE_FLTRES;
+ break;
+ }
+ force_sig_info(SIGFPE, &info, task);
+}
+
+fastcall void do_coprocessor_error(struct pt_regs * regs, long error_code)
+{
+ ignore_fpu_irq = 1;
+ math_error((void __user *)regs->eip);
+}
+
+static void simd_math_error(void __user *eip)
+{
+ struct task_struct * task;
+ siginfo_t info;
+ unsigned short mxcsr;
+
+ /*
+ * Save the info for the exception handler and clear the error.
+ */
+ task = current;
+ save_init_fpu(task);
+ task->thread.trap_no = 19;
+ task->thread.error_code = 0;
+ info.si_signo = SIGFPE;
+ info.si_errno = 0;
+ info.si_code = __SI_FAULT;
+ info.si_addr = eip;
+ /*
+ * The SIMD FPU exceptions are handled a little differently, as there
+ * is only a single status/control register. Thus, to determine which
+ * unmasked exception was caught we must mask the exception mask bits
+ * at 0x1f80, and then use these to mask the exception bits at 0x3f.
+ */
+ mxcsr = get_fpu_mxcsr(task);
+ switch (~((mxcsr & 0x1f80) >> 7) & (mxcsr & 0x3f)) {
+ case 0x000:
+ default:
+ break;
+ case 0x001: /* Invalid Op */
+ info.si_code = FPE_FLTINV;
+ break;
+ case 0x002: /* Denormalize */
+ case 0x010: /* Underflow */
+ info.si_code = FPE_FLTUND;
+ break;
+ case 0x004: /* Zero Divide */
+ info.si_code = FPE_FLTDIV;
+ break;
+ case 0x008: /* Overflow */
+ info.si_code = FPE_FLTOVF;
+ break;
+ case 0x020: /* Precision */
+ info.si_code = FPE_FLTRES;
+ break;
+ }
+ force_sig_info(SIGFPE, &info, task);
+}
+
+fastcall void do_simd_coprocessor_error(struct pt_regs * regs,
+ long error_code)
+{
+ if (cpu_has_xmm) {
+ /* Handle SIMD FPU exceptions on PIII+ processors. */
+ ignore_fpu_irq = 1;
+ simd_math_error((void __user *)regs->eip);
+ } else {
+ /*
+ * Handle strange cache flush from user space exception
+ * in all other cases. This is undocumented behaviour.
+ */
+ if (regs->eflags & VM_MASK) {
+ handle_vm86_fault((struct kernel_vm86_regs *)regs,
+ error_code);
+ return;
+ }
+ die_if_kernel("cache flush denied", regs, error_code);
+ current->thread.trap_no = 19;
+ current->thread.error_code = error_code;
+ force_sig(SIGSEGV, current);
+ }
+}
+
+fastcall void do_spurious_interrupt_bug(struct pt_regs * regs,
+ long error_code)
+{
+#if 0
+ /* No need to warn about this any longer. */
+ printk("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
+#endif
+}
+
+fastcall void setup_x86_bogus_stack(unsigned char * stk)
+{
+ unsigned long *switch16_ptr, *switch32_ptr;
+ struct pt_regs *regs;
+ unsigned long stack_top, stack_bot;
+ unsigned short iret_frame16_off;
+ int cpu = smp_processor_id();
+ /* reserve the space on 32bit stack for the magic switch16 pointer */
+ memmove(stk, stk + 8, sizeof(struct pt_regs));
+ switch16_ptr = (unsigned long *)(stk + sizeof(struct pt_regs));
+ regs = (struct pt_regs *)stk;
+ /* now the switch32 on 16bit stack */
+ stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
+ stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
+ switch32_ptr = (unsigned long *)(stack_top - 8);
+ iret_frame16_off = CPU_16BIT_STACK_SIZE - 8 - 20;
+ /* copy iret frame on 16bit stack */
+ memcpy((void *)(stack_bot + iret_frame16_off), &regs->eip, 20);
+ /* fill in the switch pointers */
+ switch16_ptr[0] = (regs->esp & 0xffff0000) | iret_frame16_off;
+ switch16_ptr[1] = __ESPFIX_SS;
+ switch32_ptr[0] = (unsigned long)stk + sizeof(struct pt_regs) +
+ 8 - CPU_16BIT_STACK_SIZE;
+ switch32_ptr[1] = __KERNEL_DS;
+}
+
+fastcall unsigned char * fixup_x86_bogus_stack(unsigned short sp)
+{
+ unsigned long *switch32_ptr;
+ unsigned char *stack16, *stack32;
+ unsigned long stack_top, stack_bot;
+ int len;
+ int cpu = smp_processor_id();
+ stack_bot = (unsigned long)&per_cpu(cpu_16bit_stack, cpu);
+ stack_top = stack_bot + CPU_16BIT_STACK_SIZE;
+ switch32_ptr = (unsigned long *)(stack_top - 8);
+ /* copy the data from 16bit stack to 32bit stack */
+ len = CPU_16BIT_STACK_SIZE - 8 - sp;
+ stack16 = (unsigned char *)(stack_bot + sp);
+ stack32 = (unsigned char *)
+ (switch32_ptr[0] + CPU_16BIT_STACK_SIZE - 8 - len);
+ memcpy(stack32, stack16, len);
+ return stack32;
+}
+
+/*
+ * 'math_state_restore()' saves the current math information in the
+ * old math state array, and gets the new ones from the current task
+ *
+ * Careful.. There are problems with IBM-designed IRQ13 behaviour.
+ * Don't touch unless you *really* know how it works.
+ *
+ * Must be called with kernel preemption disabled (in this case,
+ * local interrupts are disabled at the call-site in entry.S).
+ */
+asmlinkage void math_state_restore(struct pt_regs regs)
+{
+ struct thread_info *thread = current_thread_info();
+ struct task_struct *tsk = thread->task;
+
+ clts(); /* Allow maths ops (or we recurse) */
+ if (!tsk_used_math(tsk))
+ init_fpu(tsk);
+ restore_fpu(tsk);
+ thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
+}
+
+#ifndef CONFIG_MATH_EMULATION
+
+asmlinkage void math_emulate(long arg)
+{
+ printk("math-emulation not enabled and no coprocessor found.\n");
+ printk("killing %s.\n",current->comm);
+ force_sig(SIGFPE,current);
+ schedule();
+}
+
+#endif /* CONFIG_MATH_EMULATION */
+
+#ifdef CONFIG_X86_F00F_BUG
+void __init trap_init_f00f_bug(void)
+{
+ __set_fixmap(FIX_F00F_IDT, __pa(&idt_table), PAGE_KERNEL_RO);
+
+ /*
+ * Update the IDT descriptor and reload the IDT so that
+ * it uses the read-only mapped virtual address.
+ */
+ idt_descr.address = fix_to_virt(FIX_F00F_IDT);
+ __asm__ __volatile__("lidt %0" : : "m" (idt_descr));
+}
+#endif
+
+#define _set_gate(gate_addr,type,dpl,addr,seg) \
+do { \
+ int __d0, __d1; \
+ __asm__ __volatile__ ("movw %%dx,%%ax\n\t" \
+ "movw %4,%%dx\n\t" \
+ "movl %%eax,%0\n\t" \
+ "movl %%edx,%1" \
+ :"=m" (*((long *) (gate_addr))), \
+ "=m" (*(1+(long *) (gate_addr))), "=&a" (__d0), "=&d" (__d1) \
+ :"i" ((short) (0x8000+(dpl<<13)+(type<<8))), \
+ "3" ((char *) (addr)),"2" ((seg) << 16)); \
+} while (0)
+
+
+/*
+ * This needs to use 'idt_table' rather than 'idt', and
+ * thus use the _nonmapped_ version of the IDT, as the
+ * Pentium F0 0F bugfix can have resulted in the mapped
+ * IDT being write-protected.
+ */
+void set_intr_gate(unsigned int n, void *addr)
+{
+ _set_gate(idt_table+n,14,0,addr,__KERNEL_CS);
+}
+
+/*
+ * This routine sets up an interrupt gate at directory privilege level 3.
+ */
+static inline void set_system_intr_gate(unsigned int n, void *addr)
+{
+ _set_gate(idt_table+n, 14, 3, addr, __KERNEL_CS);
+}
+
+static void __init set_trap_gate(unsigned int n, void *addr)
+{
+ _set_gate(idt_table+n,15,0,addr,__KERNEL_CS);
+}
+
+static void __init set_system_gate(unsigned int n, void *addr)
+{
+ _set_gate(idt_table+n,15,3,addr,__KERNEL_CS);
+}
+
+static void __init set_task_gate(unsigned int n, unsigned int gdt_entry)
+{
+ _set_gate(idt_table+n,5,0,0,(gdt_entry<<3));
+}
+
+
+void __init trap_init(void)
+{
+#ifdef CONFIG_EISA
+ void __iomem *p = ioremap(0x0FFFD9, 4);
+ if (readl(p) == 'E'+('I'<<8)+('S'<<16)+('A'<<24)) {
+ EISA_bus = 1;
+ }
+ iounmap(p);
+#endif
+
+#ifdef CONFIG_X86_LOCAL_APIC
+ init_apic_mappings();
+#endif
+
+ set_trap_gate(0,&divide_error);
+ set_intr_gate(1,&debug);
+ set_intr_gate(2,&nmi);
+ set_system_intr_gate(3, &int3); /* int3-5 can be called from all */
+ set_system_gate(4,&overflow);
+ set_system_gate(5,&bounds);
+ set_trap_gate(6,&invalid_op);
+ set_trap_gate(7,&device_not_available);
+ set_task_gate(8,GDT_ENTRY_DOUBLEFAULT_TSS);
+ set_trap_gate(9,&coprocessor_segment_overrun);
+ set_trap_gate(10,&invalid_TSS);
+ set_trap_gate(11,&segment_not_present);
+ set_trap_gate(12,&stack_segment);
+ set_trap_gate(13,&general_protection);
+ set_intr_gate(14,&page_fault);
+ set_trap_gate(15,&spurious_interrupt_bug);
+ set_trap_gate(16,&coprocessor_error);
+ set_trap_gate(17,&alignment_check);
+#ifdef CONFIG_X86_MCE
+ set_trap_gate(18,&machine_check);
+#endif
+ set_trap_gate(19,&simd_coprocessor_error);
+
+ set_system_gate(SYSCALL_VECTOR,&system_call);
+
+ /*
+ * Should be a barrier for any external CPU state.
+ */
+ cpu_init();
+
+ trap_init_hook();
+}
+
+static int __init kstack_setup(char *s)
+{
+ kstack_depth_to_print = simple_strtoul(s, NULL, 0);
+ return 0;
+}
+__setup("kstack=", kstack_setup);