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0d1edf46 JF |
1 | #include <linux/hardirq.h> |
2 | ||
3 | #include <xen/interface/xen.h> | |
4 | #include <xen/interface/sched.h> | |
5 | #include <xen/interface/vcpu.h> | |
6 | ||
7 | #include <asm/xen/hypercall.h> | |
8 | #include <asm/xen/hypervisor.h> | |
9 | ||
10 | #include "xen-ops.h" | |
11 | ||
12 | /* | |
13 | * Force a proper event-channel callback from Xen after clearing the | |
14 | * callback mask. We do this in a very simple manner, by making a call | |
15 | * down into Xen. The pending flag will be checked by Xen on return. | |
16 | */ | |
17 | void xen_force_evtchn_callback(void) | |
18 | { | |
19 | (void)HYPERVISOR_xen_version(0, NULL); | |
20 | } | |
21 | ||
22 | static void __init __xen_init_IRQ(void) | |
23 | { | |
0d1edf46 JF |
24 | int i; |
25 | ||
26 | /* Create identity vector->irq map */ | |
27 | for(i = 0; i < NR_VECTORS; i++) { | |
28 | int cpu; | |
29 | ||
30 | for_each_possible_cpu(cpu) | |
31 | per_cpu(vector_irq, cpu)[i] = i; | |
32 | } | |
0d1edf46 JF |
33 | |
34 | xen_init_IRQ(); | |
35 | } | |
36 | ||
37 | static unsigned long xen_save_fl(void) | |
38 | { | |
39 | struct vcpu_info *vcpu; | |
40 | unsigned long flags; | |
41 | ||
42 | vcpu = x86_read_percpu(xen_vcpu); | |
43 | ||
44 | /* flag has opposite sense of mask */ | |
45 | flags = !vcpu->evtchn_upcall_mask; | |
46 | ||
47 | /* convert to IF type flag | |
48 | -0 -> 0x00000000 | |
49 | -1 -> 0xffffffff | |
50 | */ | |
51 | return (-flags) & X86_EFLAGS_IF; | |
52 | } | |
53 | ||
54 | static void xen_restore_fl(unsigned long flags) | |
55 | { | |
56 | struct vcpu_info *vcpu; | |
57 | ||
58 | /* convert from IF type flag */ | |
59 | flags = !(flags & X86_EFLAGS_IF); | |
60 | ||
61 | /* There's a one instruction preempt window here. We need to | |
62 | make sure we're don't switch CPUs between getting the vcpu | |
63 | pointer and updating the mask. */ | |
64 | preempt_disable(); | |
65 | vcpu = x86_read_percpu(xen_vcpu); | |
66 | vcpu->evtchn_upcall_mask = flags; | |
67 | preempt_enable_no_resched(); | |
68 | ||
69 | /* Doesn't matter if we get preempted here, because any | |
70 | pending event will get dealt with anyway. */ | |
71 | ||
72 | if (flags == 0) { | |
73 | preempt_check_resched(); | |
74 | barrier(); /* unmask then check (avoid races) */ | |
75 | if (unlikely(vcpu->evtchn_upcall_pending)) | |
76 | xen_force_evtchn_callback(); | |
77 | } | |
78 | } | |
79 | ||
80 | static void xen_irq_disable(void) | |
81 | { | |
82 | /* There's a one instruction preempt window here. We need to | |
83 | make sure we're don't switch CPUs between getting the vcpu | |
84 | pointer and updating the mask. */ | |
85 | preempt_disable(); | |
86 | x86_read_percpu(xen_vcpu)->evtchn_upcall_mask = 1; | |
87 | preempt_enable_no_resched(); | |
88 | } | |
89 | ||
90 | static void xen_irq_enable(void) | |
91 | { | |
92 | struct vcpu_info *vcpu; | |
93 | ||
94 | /* We don't need to worry about being preempted here, since | |
95 | either a) interrupts are disabled, so no preemption, or b) | |
96 | the caller is confused and is trying to re-enable interrupts | |
97 | on an indeterminate processor. */ | |
98 | ||
99 | vcpu = x86_read_percpu(xen_vcpu); | |
100 | vcpu->evtchn_upcall_mask = 0; | |
101 | ||
102 | /* Doesn't matter if we get preempted here, because any | |
103 | pending event will get dealt with anyway. */ | |
104 | ||
105 | barrier(); /* unmask then check (avoid races) */ | |
106 | if (unlikely(vcpu->evtchn_upcall_pending)) | |
107 | xen_force_evtchn_callback(); | |
108 | } | |
109 | ||
110 | static void xen_safe_halt(void) | |
111 | { | |
112 | /* Blocking includes an implicit local_irq_enable(). */ | |
113 | if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0) | |
114 | BUG(); | |
115 | } | |
116 | ||
117 | static void xen_halt(void) | |
118 | { | |
119 | if (irqs_disabled()) | |
120 | HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL); | |
121 | else | |
122 | xen_safe_halt(); | |
123 | } | |
124 | ||
125 | static const struct pv_irq_ops xen_irq_ops __initdata = { | |
126 | .init_IRQ = __xen_init_IRQ, | |
127 | .save_fl = xen_save_fl, | |
128 | .restore_fl = xen_restore_fl, | |
129 | .irq_disable = xen_irq_disable, | |
130 | .irq_enable = xen_irq_enable, | |
131 | .safe_halt = xen_safe_halt, | |
132 | .halt = xen_halt, | |
133 | #ifdef CONFIG_X86_64 | |
134 | .adjust_exception_frame = xen_adjust_exception_frame, | |
135 | #endif | |
136 | }; | |
137 | ||
138 | void __init xen_init_irq_ops() | |
139 | { | |
140 | pv_irq_ops = xen_irq_ops; | |
141 | } |