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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
0d1edf46 JF |
2 | #include <linux/hardirq.h> |
3 | ||
66bcaf0b TG |
4 | #include <asm/x86_init.h> |
5 | ||
0d1edf46 JF |
6 | #include <xen/interface/xen.h> |
7 | #include <xen/interface/sched.h> | |
8 | #include <xen/interface/vcpu.h> | |
2771374d | 9 | #include <xen/features.h> |
0ec53ecf | 10 | #include <xen/events.h> |
0d1edf46 JF |
11 | |
12 | #include <asm/xen/hypercall.h> | |
13 | #include <asm/xen/hypervisor.h> | |
14 | ||
15 | #include "xen-ops.h" | |
16 | ||
17 | /* | |
18 | * Force a proper event-channel callback from Xen after clearing the | |
19 | * callback mask. We do this in a very simple manner, by making a call | |
20 | * down into Xen. The pending flag will be checked by Xen on return. | |
21 | */ | |
22 | void xen_force_evtchn_callback(void) | |
23 | { | |
24 | (void)HYPERVISOR_xen_version(0, NULL); | |
25 | } | |
26 | ||
2605fc21 | 27 | asmlinkage __visible unsigned long xen_save_fl(void) |
0d1edf46 JF |
28 | { |
29 | struct vcpu_info *vcpu; | |
30 | unsigned long flags; | |
31 | ||
2113f469 | 32 | vcpu = this_cpu_read(xen_vcpu); |
0d1edf46 JF |
33 | |
34 | /* flag has opposite sense of mask */ | |
35 | flags = !vcpu->evtchn_upcall_mask; | |
36 | ||
37 | /* convert to IF type flag | |
38 | -0 -> 0x00000000 | |
39 | -1 -> 0xffffffff | |
40 | */ | |
41 | return (-flags) & X86_EFLAGS_IF; | |
42 | } | |
ecb93d1c | 43 | PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl); |
0d1edf46 | 44 | |
a2e7f0e3 | 45 | __visible void xen_restore_fl(unsigned long flags) |
0d1edf46 JF |
46 | { |
47 | struct vcpu_info *vcpu; | |
48 | ||
49 | /* convert from IF type flag */ | |
50 | flags = !(flags & X86_EFLAGS_IF); | |
51 | ||
fb58e300 | 52 | /* See xen_irq_enable() for why preemption must be disabled. */ |
0d1edf46 | 53 | preempt_disable(); |
2113f469 | 54 | vcpu = this_cpu_read(xen_vcpu); |
0d1edf46 | 55 | vcpu->evtchn_upcall_mask = flags; |
0d1edf46 JF |
56 | |
57 | if (flags == 0) { | |
0d1edf46 JF |
58 | barrier(); /* unmask then check (avoid races) */ |
59 | if (unlikely(vcpu->evtchn_upcall_pending)) | |
60 | xen_force_evtchn_callback(); | |
fb58e300 DV |
61 | preempt_enable(); |
62 | } else | |
63 | preempt_enable_no_resched(); | |
0d1edf46 | 64 | } |
ecb93d1c | 65 | PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl); |
0d1edf46 | 66 | |
2605fc21 | 67 | asmlinkage __visible void xen_irq_disable(void) |
0d1edf46 JF |
68 | { |
69 | /* There's a one instruction preempt window here. We need to | |
70 | make sure we're don't switch CPUs between getting the vcpu | |
71 | pointer and updating the mask. */ | |
72 | preempt_disable(); | |
2113f469 | 73 | this_cpu_read(xen_vcpu)->evtchn_upcall_mask = 1; |
0d1edf46 JF |
74 | preempt_enable_no_resched(); |
75 | } | |
ecb93d1c | 76 | PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable); |
0d1edf46 | 77 | |
2605fc21 | 78 | asmlinkage __visible void xen_irq_enable(void) |
0d1edf46 JF |
79 | { |
80 | struct vcpu_info *vcpu; | |
81 | ||
fb58e300 DV |
82 | /* |
83 | * We may be preempted as soon as vcpu->evtchn_upcall_mask is | |
84 | * cleared, so disable preemption to ensure we check for | |
85 | * events on the VCPU we are still running on. | |
86 | */ | |
87 | preempt_disable(); | |
0d1edf46 | 88 | |
2113f469 | 89 | vcpu = this_cpu_read(xen_vcpu); |
0d1edf46 JF |
90 | vcpu->evtchn_upcall_mask = 0; |
91 | ||
92 | /* Doesn't matter if we get preempted here, because any | |
93 | pending event will get dealt with anyway. */ | |
94 | ||
95 | barrier(); /* unmask then check (avoid races) */ | |
96 | if (unlikely(vcpu->evtchn_upcall_pending)) | |
97 | xen_force_evtchn_callback(); | |
fb58e300 DV |
98 | |
99 | preempt_enable(); | |
0d1edf46 | 100 | } |
ecb93d1c | 101 | PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable); |
0d1edf46 JF |
102 | |
103 | static void xen_safe_halt(void) | |
104 | { | |
105 | /* Blocking includes an implicit local_irq_enable(). */ | |
106 | if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0) | |
107 | BUG(); | |
108 | } | |
109 | ||
110 | static void xen_halt(void) | |
111 | { | |
112 | if (irqs_disabled()) | |
ad5475f9 VK |
113 | HYPERVISOR_vcpu_op(VCPUOP_down, |
114 | xen_vcpu_nr(smp_processor_id()), NULL); | |
0d1edf46 JF |
115 | else |
116 | xen_safe_halt(); | |
117 | } | |
118 | ||
251511a1 | 119 | static const struct pv_irq_ops xen_irq_ops __initconst = { |
ecb93d1c JF |
120 | .save_fl = PV_CALLEE_SAVE(xen_save_fl), |
121 | .restore_fl = PV_CALLEE_SAVE(xen_restore_fl), | |
122 | .irq_disable = PV_CALLEE_SAVE(xen_irq_disable), | |
123 | .irq_enable = PV_CALLEE_SAVE(xen_irq_enable), | |
124 | ||
0d1edf46 JF |
125 | .safe_halt = xen_safe_halt, |
126 | .halt = xen_halt, | |
0d1edf46 JF |
127 | }; |
128 | ||
7d81c3b9 | 129 | void __init xen_init_irq_ops(void) |
0d1edf46 | 130 | { |
5c83511b | 131 | pv_ops.irq = xen_irq_ops; |
66bcaf0b | 132 | x86_init.irqs.intr_init = xen_init_IRQ; |
0d1edf46 | 133 | } |