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#ifdef CONFIG_PREEMPT_NOTIFIERS_COMPAT
#include <linux/sched.h>
#include <linux/percpu.h>
static DEFINE_SPINLOCK(pn_lock);
static LIST_HEAD(pn_list);
#define dprintk(fmt) do { \
if (0) \
printk("%s (%d/%d): " fmt, __FUNCTION__, \
current->pid, raw_smp_processor_id()); \
} while (0)
static void preempt_enable_sched_out_notifiers(void)
{
asm volatile ("mov %0, %%db0" : : "r"(schedule));
asm volatile ("mov %0, %%db7" : : "r"(0x701ul));
current->thread.kvm_compat_debugreg(7) = 0ul;
#ifdef TIF_DEBUG
clear_tsk_thread_flag(current, TIF_DEBUG);
#endif
}
static void preempt_enable_sched_in_notifiers(void * addr)
{
asm volatile ("mov %0, %%db0" : : "r"(addr));
asm volatile ("mov %0, %%db7" : : "r"(0x701ul));
current->thread.kvm_compat_debugreg(0) = (unsigned long) addr;
current->thread.kvm_compat_debugreg(7) = 0x701ul;
#ifdef TIF_DEBUG
set_tsk_thread_flag(current, TIF_DEBUG);
#endif
}
static void __preempt_disable_notifiers(void)
{
asm volatile ("mov %0, %%db7" : : "r"(0ul));
}
static void preempt_disable_notifiers(void)
{
__preempt_disable_notifiers();
current->thread.kvm_compat_debugreg(7) = 0ul;
#ifdef TIF_DEBUG
clear_tsk_thread_flag(current, TIF_DEBUG);
#endif
}
static void fastcall __attribute__((used)) preempt_notifier_trigger(void *** ip)
{
struct preempt_notifier *pn;
int cpu = raw_smp_processor_id();
int found = 0;
dprintk(" - in\n");
//dump_stack();
spin_lock(&pn_lock);
list_for_each_entry(pn, &pn_list, link)
if (pn->tsk == current) {
found = 1;
break;
}
spin_unlock(&pn_lock);
if (found) {
if ((void *) *ip != schedule) {
dprintk("sched_in\n");
preempt_enable_sched_out_notifiers();
preempt_disable();
local_irq_enable();
pn->ops->sched_in(pn, cpu);
local_irq_disable();
preempt_enable_no_resched();
} else {
void * sched_in_addr;
dprintk("sched_out\n");
#ifdef CONFIG_X86_64
sched_in_addr = **(ip+3);
#else
/* no special debug stack switch on x86 */
sched_in_addr = (void *) *(ip+3);
#endif
preempt_enable_sched_in_notifiers(sched_in_addr);
preempt_disable();
local_irq_enable();
pn->ops->sched_out(pn, NULL);
local_irq_disable();
preempt_enable_no_resched();
}
} else
__preempt_disable_notifiers();
dprintk(" - out\n");
}
unsigned long orig_int1_handler;
#ifdef CONFIG_X86_64
#define SAVE_REGS \
"push %rax; push %rbx; push %rcx; push %rdx; " \
"push %rsi; push %rdi; push %rbp; " \
"push %r8; push %r9; push %r10; push %r11; " \
"push %r12; push %r13; push %r14; push %r15"
#define RESTORE_REGS \
"pop %r15; pop %r14; pop %r13; pop %r12; " \
"pop %r11; pop %r10; pop %r9; pop %r8; " \
"pop %rbp; pop %rdi; pop %rsi; " \
"pop %rdx; pop %rcx; pop %rbx; pop %rax "
#define TMP "%rax"
#else
#define SAVE_REGS "pusha"
#define RESTORE_REGS "popa"
#define TMP "%eax"
#endif
asm ("pn_int1_handler: \n\t"
"push " TMP " \n\t"
"mov %db7, " TMP " \n\t"
"cmp $0x701, " TMP " \n\t"
"pop " TMP " \n\t"
"jnz .Lnotme \n\t"
"push " TMP " \n\t"
"mov %db6, " TMP " \n\t"
"test $0x1, " TMP " \n\t"
"pop " TMP " \n\t"
"jz .Lnotme \n\t"
SAVE_REGS "\n\t"
#ifdef CONFIG_X86_64
"leaq 120(%rsp),%rdi\n\t"
#else
"leal 32(%esp),%eax\n\t"
#endif
"call preempt_notifier_trigger \n\t"
RESTORE_REGS "\n\t"
#ifdef CONFIG_X86_64
"orq $0x10000, 16(%rsp) \n\t"
"iretq \n\t"
#else
"orl $0x10000, 8(%esp) \n\t"
"iret \n\t"
#endif
".Lnotme: \n\t"
#ifdef CONFIG_X86_64
"jmpq *orig_int1_handler\n\t"
#else
"jmpl *orig_int1_handler\n\t"
#endif
);
void preempt_notifier_register(struct preempt_notifier *notifier)
{
unsigned long flags;
dprintk(" - in\n");
spin_lock_irqsave(&pn_lock, flags);
preempt_enable_sched_out_notifiers();
notifier->tsk = current;
list_add(¬ifier->link, &pn_list);
spin_unlock_irqrestore(&pn_lock, flags);
dprintk(" - out\n");
}
void preempt_notifier_unregister(struct preempt_notifier *notifier)
{
unsigned long flags;
dprintk(" - in\n");
spin_lock_irqsave(&pn_lock, flags);
list_del(¬ifier->link);
spin_unlock_irqrestore(&pn_lock, flags);
preempt_disable_notifiers();
dprintk(" - out\n");
}
struct intr_gate {
u16 offset0;
u16 segment;
u16 junk;
u16 offset1;
#ifdef CONFIG_X86_64
u32 offset2;
u32 blah;
#endif
} __attribute__((packed));
struct idt_desc {
u16 limit;
struct intr_gate *gates;
} __attribute__((packed));
static struct intr_gate orig_int1_gate;
void pn_int1_handler(void);
void preempt_notifier_sys_init(void)
{
struct idt_desc idt_desc;
struct intr_gate *int1_gate;
printk("kvm: emulating preempt notifiers;"
" do not benchmark on this machine\n");
dprintk("\n");
asm ("sidt %0" : "=m"(idt_desc));
int1_gate = &idt_desc.gates[1];
orig_int1_gate = *int1_gate;
orig_int1_handler = int1_gate->offset0
| ((u32)int1_gate->offset1 << 16);
#ifdef CONFIG_X86_64
orig_int1_handler |= (u64)int1_gate->offset2 << 32;
#endif
int1_gate->offset0 = (unsigned long)pn_int1_handler;
int1_gate->offset1 = (unsigned long)pn_int1_handler >> 16;
#ifdef CONFIG_X86_64
int1_gate->offset2 = (unsigned long)pn_int1_handler >> 32;
#endif
}
static void do_disable(void *blah)
{
#ifdef TIF_DEBUG
if (!test_tsk_thread_flag(current, TIF_DEBUG))
#else
if (!current->thread.kvm_compat_debugreg(7))
#endif
__preempt_disable_notifiers();
}
void preempt_notifier_sys_exit(void)
{
struct idt_desc idt_desc;
dprintk("\n");
kvm_on_each_cpu(do_disable, NULL, 1);
asm ("sidt %0" : "=m"(idt_desc));
idt_desc.gates[1] = orig_int1_gate;
}
#endif
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