blob: 1c113db9ed573c3d8723fccc177431861df2bd19 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
/*
* Code for supporting irq vector tracepoints.
*
* Copyright (C) 2013 Seiji Aguchi <seiji.aguchi@hds.com>
*
*/
#include <asm/hw_irq.h>
#include <asm/desc.h>
#include <linux/atomic.h>
atomic_t trace_idt_ctr = ATOMIC_INIT(0);
struct desc_ptr trace_idt_descr = { NR_VECTORS * 16 - 1,
(unsigned long) trace_idt_table };
/* No need to be aligned, but done to keep all IDTs defined the same way. */
gate_desc trace_idt_table[NR_VECTORS] __page_aligned_bss;
static int trace_irq_vector_refcount;
static DEFINE_MUTEX(irq_vector_mutex);
static void set_trace_idt_ctr(int val)
{
atomic_set(&trace_idt_ctr, val);
/* Ensure the trace_idt_ctr is set before sending IPI */
wmb();
}
static void switch_idt(void *arg)
{
unsigned long flags;
local_irq_save(flags);
load_current_idt();
local_irq_restore(flags);
}
void trace_irq_vector_regfunc(void)
{
mutex_lock(&irq_vector_mutex);
if (!trace_irq_vector_refcount) {
set_trace_idt_ctr(1);
smp_call_function(switch_idt, NULL, 0);
switch_idt(NULL);
}
trace_irq_vector_refcount++;
mutex_unlock(&irq_vector_mutex);
}
void trace_irq_vector_unregfunc(void)
{
mutex_lock(&irq_vector_mutex);
trace_irq_vector_refcount--;
if (!trace_irq_vector_refcount) {
set_trace_idt_ctr(0);
smp_call_function(switch_idt, NULL, 0);
switch_idt(NULL);
}
mutex_unlock(&irq_vector_mutex);
}
|
