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linux/arch/x86/kernel/traps.c
Jeremy Fitzhardinge db949bba3c x86-32: use non-lazy io bitmap context switching 
Impact: remove 32-bit optimization to prepare unification

x86-32 and -64 differ in the way they context-switch tasks
with io permission bitmaps.  x86-64 simply copies the next
tasks io bitmap into place (if any) on context switch.  x86-32
invalidates the bitmap on context switch, so that the next
IO instruction will fault; at that point it installs the
appropriate IO bitmap.

This makes context switching IO-bitmap-using tasks a bit more
less expensive, at the cost of making the next IO instruction
slower due to the extra fault.  This tradeoff only makes sense
if IO-bitmap-using processes are relatively common, but they
don't actually use IO instructions very often.

However, in a typical desktop system, the only process likely
to be using IO bitmaps is the X server, and nothing at all on
a server.  Therefore the lazy context switch doesn't really win
all that much, and its just a gratuitious difference from
64-bit code.

This patch removes the lazy context switch, with a view to
unifying this code in a later change.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-02 12:07:48 +01:00

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/*
* 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
*/
/*
* Handle hardware traps and faults.
*/
#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/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>
#ifdef CONFIG_EISA
#include <linux/ioport.h>
#include <linux/eisa.h>
#endif
#ifdef CONFIG_MCA
#include <linux/mca.h>
#endif
#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/traps.h>
#include <asm/desc.h>
#include <asm/i387.h>
#include <asm/mach_traps.h>
#ifdef CONFIG_X86_64
#include <asm/pgalloc.h>
#include <asm/proto.h>
#else
#include <asm/processor-flags.h>
#include <asm/setup.h>
#include <asm/traps.h>
#include "cpu/mcheck/mce.h"
asmlinkage int system_call(void);
/* Do we ignore FPU interrupts ? */
char ignore_fpu_irq;
/*
* The IDT has to be page-aligned to simplify the Pentium
* F0 0F bug workaround.. We have a special link segment
* for this.
*/
gate_desc idt_table[256]
__attribute__((__section__(".data.idt"))) = { { { { 0, 0 } } }, };
#endif
DECLARE_BITMAP(used_vectors, NR_VECTORS);
EXPORT_SYMBOL_GPL(used_vectors);
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 conditional_cli(struct pt_regs *regs)
{
if (regs->flags & X86_EFLAGS_IF)
local_irq_disable();
}
static inline void preempt_conditional_cli(struct pt_regs *regs)
{
if (regs->flags & X86_EFLAGS_IF)
local_irq_disable();
dec_preempt_count();
}
#ifdef CONFIG_X86_32
static inline void
die_if_kernel(const char *str, struct pt_regs *regs, long err)
{
if (!user_mode_vm(regs))
die(str, regs, err);
}
#endif
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;
#ifdef CONFIG_X86_32
if (regs->flags & X86_VM_MASK) {
/*
* traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
* On nmi (interrupt 2), do_trap should not be called.
*/
if (trapnr < 6)
goto vm86_trap;
goto trap_signal;
}
#endif
if (!user_mode(regs))
goto kernel_trap;
#ifdef CONFIG_X86_32
trap_signal:
#endif
/*
* 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;
#ifdef CONFIG_X86_64
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");
}
#endif
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;
#ifdef CONFIG_X86_32
vm86_trap:
if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
error_code, trapnr))
goto trap_signal;
return;
#endif
}
#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)
#ifdef CONFIG_X86_32
DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
#endif
DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
#ifdef CONFIG_X86_64
/* 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);
}
#endif
dotraplinkage void __kprobes
do_general_protection(struct pt_regs *regs, long error_code)
{
struct task_struct *tsk;
conditional_sti(regs);
#ifdef CONFIG_X86_32
if (regs->flags & X86_VM_MASK)
goto gp_in_vm86;
#endif
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, task_pid_nr(tsk),
regs->ip, regs->sp, error_code);
print_vma_addr(" in ", regs->ip);
printk("\n");
}
force_sig(SIGSEGV, tsk);
return;
#ifdef CONFIG_X86_32
gp_in_vm86:
local_irq_enable();
handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
return;
#endif
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 on CPU %d.\n",
reason, smp_processor_id());
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)
{
unsigned long i;
printk(KERN_EMERG "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 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;
#ifdef CONFIG_MCA
/*
* Might actually be able to figure out what the guilty party
* is:
*/
if (MCA_bus) {
mca_handle_nmi();
return;
}
#endif
printk(KERN_EMERG
"Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
reason, smp_processor_id());
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");
}
static 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;
#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_tick(regs, reason))
return;
if (!do_nmi_callback(regs, cpu))
unknown_nmi_error(reason, regs);
#else
unknown_nmi_error(reason, regs);
#endif
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);
#ifdef CONFIG_X86_32
/*
* Reassert NMI in case it became active meanwhile
* as it's edge-triggered:
*/
reassert_nmi();
#endif
}
dotraplinkage notrace __kprobes void
do_nmi(struct pt_regs *regs, long error_code)
{
nmi_enter();
inc_irq_stat(__nmi_count);
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();
}
/* May run on IST stack. */
dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
{
#ifdef CONFIG_KPROBES
if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
== NOTIFY_STOP)
return;
#else
if (notify_die(DIE_TRAP, "int3", regs, error_code, 3, SIGTRAP)
== NOTIFY_STOP)
return;
#endif
preempt_conditional_sti(regs);
do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
preempt_conditional_cli(regs);
}
#ifdef CONFIG_X86_64
/*
* 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;
}
#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)
*
* May run 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;
}
#ifdef CONFIG_X86_32
if (regs->flags & X86_VM_MASK)
goto debug_vm86;
#endif
/* 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;
#ifdef CONFIG_X86_32
debug_vm86:
/* reenable preemption: handle_vm86_trap() might sleep */
dec_preempt_count();
handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
conditional_cli(regs);
return;
#endif
clear_TF_reenable:
set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
regs->flags &= ~X86_EFLAGS_TF;
preempt_conditional_cli(regs);
return;
}
#ifdef CONFIG_X86_64
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;
}
#endif
/*
* 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, err;
/*
* 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_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);
err = swd & ~cwd;
if (err & 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;
} else if (err & 0x004) { /* Divide by Zero */
info.si_code = FPE_FLTDIV;
} else if (err & 0x008) { /* Overflow */
info.si_code = FPE_FLTOVF;
} else if (err & 0x012) { /* Denormal, Underflow */
info.si_code = FPE_FLTUND;
} else if (err & 0x020) { /* Precision */
info.si_code = FPE_FLTRES;
} else {
/*
* If we're using IRQ 13, or supposedly even some trap 16
* implementations, it's possible we get a spurious trap...
*/
return; /* Spurious trap, no error */
}
force_sig_info(SIGFPE, &info, task);
}
dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
{
conditional_sti(regs);
#ifdef CONFIG_X86_32
ignore_fpu_irq = 1;
#else
if (!user_mode(regs) &&
kernel_math_error(regs, "kernel x87 math error", 16))
return;
#endif
math_error((void __user *)regs->ip);
}
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);
#ifdef CONFIG_X86_32
if (cpu_has_xmm) {
/* Handle SIMD FPU exceptions on PIII+ processors. */
ignore_fpu_irq = 1;
simd_math_error((void __user *)regs->ip);
return;
}
/*
* Handle strange cache flush from user space exception
* in all other cases. This is undocumented behaviour.
*/
if (regs->flags & X86_VM_MASK) {
handle_vm86_fault((struct kernel_vm86_regs *)regs, error_code);
return;
}
current->thread.trap_no = 19;
current->thread.error_code = error_code;
die_if_kernel("cache flush denied", regs, error_code);
force_sig(SIGSEGV, current);
#else
if (!user_mode(regs) &&
kernel_math_error(regs, "kernel simd math error", 19))
return;
simd_math_error((void __user *)regs->ip);
#endif
}
dotraplinkage void
do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
{
conditional_sti(regs);
#if 0
/* No need to warn about this any longer. */
printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
#endif
}
#ifdef CONFIG_X86_32
unsigned long patch_espfix_desc(unsigned long uesp, unsigned long kesp)
{
struct desc_struct *gdt = get_cpu_gdt_table(smp_processor_id());
unsigned long base = (kesp - uesp) & -THREAD_SIZE;
unsigned long new_kesp = kesp - base;
unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT;
__u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS];
/* Set up base for espfix segment */
desc &= 0x00f0ff0000000000ULL;
desc |= ((((__u64)base) << 16) & 0x000000ffffff0000ULL) |
((((__u64)base) << 32) & 0xff00000000000000ULL) |
((((__u64)lim_pages) << 32) & 0x000f000000000000ULL) |
(lim_pages & 0xffff);
*(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc;
return new_kesp;
}
#else
asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
{
}
asmlinkage void __attribute__((weak)) mce_threshold_interrupt(void)
{
}
#endif
/*
* '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(void)
{
struct thread_info *thread = current_thread_info();
struct task_struct *tsk = thread->task;
if (!tsk_used_math(tsk)) {
local_irq_enable();
/*
* does a slab alloc which can sleep
*/
if (init_fpu(tsk)) {
/*
* ran out of memory!
*/
do_group_exit(SIGKILL);
return;
}
local_irq_disable();
}
clts(); /* Allow maths ops (or we recurse) */
#ifdef CONFIG_X86_32
restore_fpu(tsk);
#else
/*
* Paranoid restore. send a SIGSEGV if we fail to restore the state.
*/
if (unlikely(restore_fpu_checking(tsk))) {
stts();
force_sig(SIGSEGV, tsk);
return;
}
#endif
thread->status |= TS_USEDFPU; /* So we fnsave on switch_to() */
tsk->fpu_counter++;
}
EXPORT_SYMBOL_GPL(math_state_restore);
#ifndef CONFIG_MATH_EMULATION
void math_emulate(struct math_emu_info *info)
{
printk(KERN_EMERG
"math-emulation not enabled and no coprocessor found.\n");
printk(KERN_EMERG "killing %s.\n", current->comm);
force_sig(SIGFPE, current);
schedule();
}
#endif /* CONFIG_MATH_EMULATION */
dotraplinkage void __kprobes
do_device_not_available(struct pt_regs *regs, long error_code)
{
#ifdef CONFIG_X86_32
if (read_cr0() & X86_CR0_EM) {
struct math_emu_info info = { };
conditional_sti(regs);
info.regs = regs;
math_emulate(&info);
} else {
math_state_restore(); /* interrupts still off */
conditional_sti(regs);
}
#else
math_state_restore();
#endif
}
#ifdef CONFIG_X86_32
dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
{
siginfo_t info;
local_irq_enable();
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_BADSTK;
info.si_addr = NULL;
if (notify_die(DIE_TRAP, "iret exception",
regs, error_code, 32, SIGILL) == NOTIFY_STOP)
return;
do_trap(32, SIGILL, "iret exception", regs, error_code, &info);
}
#endif
void __init trap_init(void)
{
int i;
#ifdef CONFIG_EISA
void __iomem *p = early_ioremap(0x0FFFD9, 4);
if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
EISA_bus = 1;
early_iounmap(p, 4);
#endif
set_intr_gate(0, &divide_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);
#ifdef CONFIG_X86_32
set_task_gate(8, GDT_ENTRY_DOUBLEFAULT_TSS);
#else
set_intr_gate_ist(8, &double_fault, DOUBLEFAULT_STACK);
#endif
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
#ifdef CONFIG_X86_32
if (cpu_has_fxsr) {
printk(KERN_INFO "Enabling fast FPU save and restore... ");
set_in_cr4(X86_CR4_OSFXSR);
printk("done.\n");
}
if (cpu_has_xmm) {
printk(KERN_INFO
"Enabling unmasked SIMD FPU exception support... ");
set_in_cr4(X86_CR4_OSXMMEXCPT);
printk("done.\n");
}
set_system_trap_gate(SYSCALL_VECTOR, &system_call);
#endif
/* Reserve all the builtin and the syscall vector: */
for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
set_bit(i, used_vectors);
#ifdef CONFIG_X86_64
set_bit(IA32_SYSCALL_VECTOR, used_vectors);
#else
set_bit(SYSCALL_VECTOR, used_vectors);
#endif
/*
* Should be a barrier for any external CPU state:
*/
cpu_init();
#ifdef CONFIG_X86_32
x86_quirk_trap_init();
#endif
}
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