/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
*
* 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 'entry.S'.
*/
#include <linux/moduleparam.h>
#include <linux/interrupt.h>
#include <linux/kallsyms.h>
#include <linux/spinlock.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/utsname.h>
#include <linux/kdebug.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/ptrace.h>
#include <linux/string.h>
#include <linux/unwind.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/kexec.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/init.h>
#include <linux/bug.h>
#include <linux/nmi.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/io.h>
#if defined(CONFIG_EDAC)
#include <linux/edac.h>
#endif
#include <asm/stacktrace.h>
#include <asm/processor.h>
#include <asm/debugreg.h>
#include <asm/atomic.h>
#include <asm/system.h>
#include <asm/unwind.h>
#include <asm/desc.h>
#include <asm/i387.h>
#include <asm/pgalloc.h>
#include <asm/proto.h>
#include <asm/pda.h>
#include <asm/traps.h>
#include <mach_traps.h>
static int ignore_nmis;
static inline void conditional_sti(struct pt_regs *regs)
{
if (regs->flags & X86_EFLAGS_IF)
local_irq_enable();
}
static inline void preempt_conditional_sti(struct pt_regs *regs)
{
inc_preempt_count();
if (regs->flags & X86_EFLAGS_IF)
local_irq_enable();
}
static inline void preempt_conditional_cli(struct pt_regs *regs)
{
if (regs->flags & X86_EFLAGS_IF)
local_irq_disable();
/* Make sure to not schedule here because we could be running
on an exception stack. */
dec_preempt_count();
}
static void __kprobes
do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
long error_code, siginfo_t *info)
{
struct task_struct *tsk = current;
if (!user_mode(regs))
goto kernel_trap;
/*
* We want error_code and trap_no set for userspace faults and
* kernelspace faults which result in die(), but not
* kernelspace faults which are fixed up. die() gives the
* process no chance to handle the signal and notice the
* kernel fault information, so that won't result in polluting
* the information about previously queued, but not yet
* delivered, faults. See also do_general_protection below.
*/
tsk->thread.error_code = error_code;
tsk->thread.trap_no = trapnr;
if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
printk_ratelimit()) {
printk(KERN_INFO
"%s[%d] trap %s ip:%lx sp:%lx error:%lx",
tsk->comm, tsk->pid, str,
regs->ip, regs->sp, error_code);
print_vma_addr(" in ", regs->ip);
printk("\n");
}
if (info)
force_sig_info(signr, info, tsk);
else
force_sig(signr, tsk);
return;
kernel_trap:
if (!fixup_exception(regs)) {
tsk->thread.error_code = error_code;
tsk->thread.trap_no = trapnr;
die(str, regs, error_code);
}
return;
}
#define DO_ERROR(trapnr, signr, str, name) \
dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
{ \
if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
== NOTIFY_STOP) \
return; \
conditional_sti(regs); \
do_trap(trapnr, signr, str, regs, error_code, NULL); \
}
#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
dotraplinkage 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; \
conditional_sti(regs); \
do_trap(trapnr, signr, str, regs, error_code, &info); \
}
DO_ERROR_INFO(0, SIGFPE, "divide error", divide_error, FPE_INTDIV, regs->ip)
DO_ERROR(4, SIGSEGV, "overflow", overflow)
DO_ERROR(5, SIGSEGV, "bounds", bounds)
DO_ERROR_INFO(6, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN, regs->ip)
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_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
/* Runs on IST stack */
dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
{
if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
12, SIGBUS) == NOTIFY_STOP)
return;
preempt_conditional_sti(regs);
do_trap(12, SIGBUS, "stack segment", regs, error_code, NULL);
preempt_conditional_cli(regs);
}
dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
{
static const char str[] = "double fault";
struct task_struct *tsk = current;
/* Return not checked because double check cannot be ignored */
notify_die(DIE_TRAP, str, regs, error_code, 8, SIGSEGV);
tsk->thread.error_code = error_code;
tsk->thread.trap_no = 8;
/* This is always a kernel trap and never fixable (and thus must
never return). */
for (;;)
die(str, regs, error_code);
}
dotraplinkage void __kprobes
do_general_protection(struct pt_regs *regs, long error_code)
{
struct task_struct *tsk;
conditional_sti(regs);
tsk = current;
if (!user_mode(regs))
goto gp_in_kernel;
tsk->thread.error_code = error_code;
tsk->thread.trap_no = 13;
if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
printk_ratelimit()) {
printk(KERN_INFO
"%s[%d] general protection ip:%lx sp:%lx error:%lx",
tsk->comm, tsk->pid,
regs->ip, regs->sp, error_code);
print_vma_addr(" in ", regs->ip);
printk("\n");
}
force_sig(SIGSEGV, tsk);
return;
gp_in_kernel:
if (fixup_exception(regs))
return;
tsk->thread.error_code = error_code;
tsk->thread.trap_no = 13;
if (notify_die(DIE_GPF, "general protection fault", regs,
error_code, 13, SIGSEGV) == NOTIFY_STOP)
return;
die("general protection fault", regs, error_code);
}
static notrace __kprobes void
mem_parity_error(unsigned char reason, struct pt_regs *regs)
{
printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n",
reason);
printk(KERN_EMERG "You have some hardware problem, likely on the PCI bus.\n");
#if defined(CONFIG_EDAC)
if (edac_handler_set()) {
edac_atomic_assert_error();
return;
}
#endif
if (panic_on_unrecovered_nmi)
panic("NMI: Not continuing");
printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
/* Clear and disable the memory parity error line. */
reason = (reason & 0xf) | 4;
outb(reason, 0x61);
}
static notrace __kprobes void
io_check_error(unsigned char reason, struct pt_regs *regs)
{
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);
mdelay(2000);
reason &= ~8;
outb(reason, 0x61);
}
static notrace __kprobes void
unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
{
if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) ==
NOTIFY_STOP)
return;
printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n",
reason);
printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
if (panic_on_unrecovered_nmi)
panic("NMI: Not continuing");
printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
}
/* Runs on IST stack. This code must keep interrupts off all the time.
Nested NMIs are prevented by the CPU. */
asmlinkage notrace __kprobes void default_do_nmi(struct pt_regs *regs)
{
unsigned char reason = 0;
int cpu;
cpu = smp_processor_id();
/* Only the BSP gets external NMIs from the system. */
if (!cpu)
reason = get_nmi_reason();
if (!(reason & 0xc0)) {
if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
== NOTIFY_STOP)
return;
/*
* Ok, so this is none of the documented NMI sources,
* so it must be the NMI watchdog.
*/
if (nmi_watchdog_tick(regs, reason))
return;
if (!do_nmi_callback(regs, cpu))
unknown_nmi_error(reason, regs);
return;
}
if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
return;
/* AK: following checks seem to be broken on modern chipsets. FIXME */
if (reason & 0x80)
mem_parity_error(reason, regs);
if (reason & 0x40)
io_check_error(reason, regs);
}
dotraplinkage notrace __kprobes void
do_nmi(struct pt_regs *regs, long error_code)
{
nmi_enter();
add_pda(__nmi_count, 1);
if (!ignore_nmis)
default_do_nmi(regs);
nmi_exit();
}
void stop_nmi(void)
{
acpi_nmi_disable();
ignore_nmis++;
}
void restart_nmi(void)
{
ignore_nmis--;
acpi_nmi_enable();
}
/* runs on IST stack. */
dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
{
if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
== NOTIFY_STOP)
return;
preempt_conditional_sti(regs);
do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
preempt_conditional_cli(regs);
}
/* Help handler running on IST stack to switch back to user stack
for scheduling or signal handling. The actual stack switch is done in
entry.S */
asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
{
struct pt_regs *regs = eregs;
/* Did already sync */
if (eregs == (struct pt_regs *)eregs->sp)
;
/* Exception from user space */
else if (user_mode(eregs))
regs = task_pt_regs(current);
/* Exception from kernel and interrupts are enabled. Move to
kernel process stack. */
else if (eregs->flags & X86_EFLAGS_IF)
regs = (struct pt_regs *)(eregs->sp -= sizeof(struct pt_regs));
if (eregs != regs)
*regs = *eregs;
return regs;
}
/* runs on IST stack. */
dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
{
struct task_struct *tsk = current;
unsigned long condition;
int si_code;
get_debugreg(condition, 6);
/*
* The processor cleared BTF, so don't mark that we need it set.
*/
clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR);
tsk->thread.debugctlmsr = 0;
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 */
preempt_conditional_sti(regs);
/* Mask out spurious debug traps due to lazy DR7 setting */
if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
if (!tsk->thread.debugreg7)
goto clear_dr7;
}
/* Save debug status register where ptrace can see it */
tsk->thread.debugreg6 = 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) {
if (!user_mode(regs))
goto clear_TF_reenable;
}
si_code = get_si_code(condition);
/* Ok, finally something we can handle */
send_sigtrap(tsk, regs, error_code, si_code);
/*
* Disable additional traps. They'll be re-enabled when
* the signal is delivered.
*/
clear_dr7:
set_debugreg(0, 7);
preempt_conditional_cli(regs);
return;
clear_TF_reenable:
set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
regs->flags &= ~X86_EFLAGS_TF;
preempt_conditional_cli(regs);
return;
}
static int kernel_math_error(struct pt_regs *regs, const char *str, int trapnr)
{
if (fixup_exception(regs))
return 1;
notify_die(DIE_GPF, str, regs, 0, trapnr, SIGFPE);
/* Illegal floating point operation in the kernel */
current->thread.trap_no = trapnr;
die(str, regs, 0);
return 0;
}
/*
* 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 *ip)
{
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 = ip;
/*
* (~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 synchronizing 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 (swd & ~cwd & 0x3f) {
case 0x000: /* No unmasked exception */
default: /* Multiple exceptions */
break;
case 0x001: /* Invalid Op */
/*
* swd & 0x240 == 0x040: Stack Underflow
* swd & 0x240 == 0x240: Stack Overflow
* User must clear the SF bit (0x40) if set
*/
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);
}
dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
{
conditional_sti(regs);
if (!user_mode(regs) &&
kernel_math_error(regs, "kernel x87 math error", 16))
return;
math_error((void __user *)regs->ip);
}
asmlinkage void bad_intr(void)
{
printk("bad interrupt");
}
static void simd_math_error(void __user *ip)
{
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 = ip;
/*
* 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);
}
dotraplinkage void
do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
{
conditional_sti(regs);
if (!user_mode(regs) &&
kernel_math_error(regs, "kernel simd math error", 19))
return;
simd_math_error((void __user *)regs->ip);
}
dotraplinkage void
do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
{
}
asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
{
}
asmlinkage void __attribute__((weak)) mce_threshold_interrupt(void)
{
}
/*
* '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.
*/
asmlinkage void math_state_restore(void)
{
struct task_struct *me = current;
if (!used_math()) {
local_irq_enable();
/*
* does a slab alloc which can sleep
*/
if (init_fpu(me)) {
/*
* ran out of memory!
*/
do_group_exit(SIGKILL);
return;
}
local_irq_disable();
}
clts(); /* Allow maths ops (or we recurse) */
/*
* Paranoid restore. send a SIGSEGV if we fail to restore the state.
*/
if (unlikely(restore_fpu_checking(me))) {
stts();
force_sig(SIGSEGV, me);
return;
}
task_thread_info(me)->status |= TS_USEDFPU;
me->fpu_counter++;
}
EXPORT_SYMBOL_GPL(math_state_restore);
dotraplinkage void __kprobes
do_device_not_available(struct pt_regs *regs, long error)
{
math_state_restore();
}
void __init trap_init(void)
{
set_intr_gate(0, ÷_error);
set_intr_gate_ist(1, &debug, DEBUG_STACK);
set_intr_gate_ist(2, &nmi, NMI_STACK);
/* int3 can be called from all */
set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
/* int4 can be called from all */
set_system_intr_gate(4, &overflow);
set_intr_gate(5, &bounds);
set_intr_gate(6, &invalid_op);
set_intr_gate(7, &device_not_available);
set_intr_gate_ist(8, &double_fault, DOUBLEFAULT_STACK);
set_intr_gate(9, &coprocessor_segment_overrun);
set_intr_gate(10, &invalid_TSS);
set_intr_gate(11, &segment_not_present);
set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);
set_intr_gate(13, &general_protection);
set_intr_gate(14, &page_fault);
set_intr_gate(15, &spurious_interrupt_bug);
set_intr_gate(16, &coprocessor_error);
set_intr_gate(17, &alignment_check);
#ifdef CONFIG_X86_MCE
set_intr_gate_ist(18, &machine_check, MCE_STACK);
#endif
set_intr_gate(19, &simd_coprocessor_error);
#ifdef CONFIG_IA32_EMULATION
set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
#endif
/*
* Should be a barrier for any external CPU state:
*/
cpu_init();
}
