1 | /* |
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3 | * |
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27 | */ |
28 | /* |
29 | * @OSF_COPYRIGHT@ |
30 | */ |
31 | /* |
32 | * Mach Operating System |
33 | * Copyright (c) 1991,1990,1989 Carnegie Mellon University |
34 | * All Rights Reserved. |
35 | * |
36 | * Permission to use, copy, modify and distribute this software and its |
37 | * documentation is hereby granted, provided that both the copyright |
38 | * notice and this permission notice appear in all copies of the |
39 | * software, derivative works or modified versions, and any portions |
40 | * thereof, and that both notices appear in supporting documentation. |
41 | * |
42 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" |
43 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR |
44 | * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. |
45 | * |
46 | * Carnegie Mellon requests users of this software to return to |
47 | * |
48 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU |
49 | * School of Computer Science |
50 | * Carnegie Mellon University |
51 | * Pittsburgh PA 15213-3890 |
52 | * |
53 | * any improvements or extensions that they make and grant Carnegie Mellon |
54 | * the rights to redistribute these changes. |
55 | */ |
56 | /* |
57 | */ |
58 | |
59 | /* |
60 | * kern/ast.h: Definitions for Asynchronous System Traps. |
61 | */ |
62 | |
63 | #ifndef _KERN_AST_H_ |
64 | #define _KERN_AST_H_ |
65 | |
66 | |
67 | #include <kern/assert.h> |
68 | #include <kern/macro_help.h> |
69 | #include <kern/spl.h> |
70 | |
71 | /* |
72 | * A processor detects an AST when it is about to return from an |
73 | * interrupt context, and calls ast_taken_kernel or ast_taken_user |
74 | * depending on whether it was returning from userspace or kernelspace. |
75 | * |
76 | * Machine-dependent code is responsible for maintaining |
77 | * a set of reasons for an AST. |
78 | */ |
79 | typedef uint32_t ast_t; |
80 | |
81 | /* |
82 | * When returning from interrupt/trap context to kernel mode, |
83 | * if AST_URGENT is set, then ast_taken_kernel is called, for |
84 | * instance to effect preemption of a kernel thread by a realtime |
85 | * thread. |
86 | * |
87 | * This is also done when re-enabling preemption or re-enabling |
88 | * interrupts, since an AST may have been set while preemption |
89 | * was disabled, and it should take effect as soon as possible. |
90 | * |
91 | * When returning from interrupt/trap/syscall context to user |
92 | * mode, any and all ASTs that are pending should be handled by |
93 | * calling ast_taken_user. |
94 | * |
95 | * If a thread context switches, only ASTs not in AST_PER_THREAD |
96 | * remain active. The per-thread ASTs are stored in the thread_t |
97 | * and re-enabled when the thread context switches back. |
98 | * |
99 | * Typically the preemption ASTs are set as a result of threads |
100 | * becoming runnable, threads changing priority, or quantum |
101 | * expiration. If a thread becomes runnable and is chosen |
102 | * to run on another processor, cause_ast_check() may be called |
103 | * to IPI that processor and request csw_check() be run there. |
104 | */ |
105 | |
106 | /* |
107 | * Bits for reasons |
108 | * TODO: Split the context switch and return-to-user AST namespaces |
109 | * NOTE: Some of these are exported as the 'reason' code in scheduler tracepoints |
110 | */ |
111 | #define AST_PREEMPT 0x01 |
112 | #define AST_QUANTUM 0x02 |
113 | #define AST_URGENT 0x04 |
114 | #define AST_HANDOFF 0x08 |
115 | #define AST_YIELD 0x10 |
116 | #define AST_APC 0x20 /* migration APC hook */ |
117 | #define AST_LEDGER 0x40 |
118 | #define AST_BSD 0x80 |
119 | #define AST_KPERF 0x100 /* kernel profiling */ |
120 | #define AST_MACF 0x200 /* MACF user ret pending */ |
121 | /* 0x400, 0x800 unused */ |
122 | #define AST_GUARD 0x1000 |
123 | #define AST_TELEMETRY_USER 0x2000 /* telemetry sample requested on interrupt from userspace */ |
124 | #define AST_TELEMETRY_KERNEL 0x4000 /* telemetry sample requested on interrupt from kernel */ |
125 | #define AST_TELEMETRY_PMI 0x8000 /* telemetry sample requested on PMI */ |
126 | #define AST_SFI 0x10000 /* Evaluate if SFI wait is needed before return to userspace */ |
127 | #define AST_DTRACE 0x20000 |
128 | #define AST_TELEMETRY_IO 0x40000 /* telemetry sample requested for I/O */ |
129 | #define AST_KEVENT 0x80000 |
130 | #define AST_REBALANCE 0x100000 /* thread context switched due to rebalancing */ |
131 | #define AST_UNQUIESCE 0x200000 /* catch unquiesced processor before returning to userspace */ |
132 | |
133 | #define AST_NONE 0x00 |
134 | #define AST_ALL (~AST_NONE) |
135 | |
136 | #define AST_SCHEDULING (AST_PREEMPTION | AST_YIELD | AST_HANDOFF) |
137 | #define AST_PREEMPTION (AST_PREEMPT | AST_QUANTUM | AST_URGENT) |
138 | |
139 | #define AST_TELEMETRY_ALL (AST_TELEMETRY_USER | AST_TELEMETRY_KERNEL | \ |
140 | AST_TELEMETRY_PMI | AST_TELEMETRY_IO) |
141 | |
142 | /* Per-thread ASTs follow the thread at context-switch time. */ |
143 | #define AST_PER_THREAD (AST_APC | AST_BSD | AST_MACF | AST_LEDGER | AST_GUARD | AST_TELEMETRY_ALL | AST_KEVENT) |
144 | |
145 | /* Handle AST_URGENT detected while in the kernel */ |
146 | extern void ast_taken_kernel(void); |
147 | |
148 | /* Handle an AST flag set while returning to user mode (may continue via thread_exception_return) */ |
149 | extern void ast_taken_user(void); |
150 | |
151 | /* Check for pending ASTs */ |
152 | extern void ast_check(processor_t processor); |
153 | |
154 | /* Pending ast mask for the current processor */ |
155 | extern ast_t *ast_pending(void); |
156 | |
157 | /* Set AST flags on current processor */ |
158 | extern void ast_on(ast_t reasons); |
159 | |
160 | /* Clear AST flags on current processor */ |
161 | extern void ast_off(ast_t reasons); |
162 | |
163 | /* Consume specified AST flags from current processor */ |
164 | extern ast_t ast_consume(ast_t reasons); |
165 | |
166 | /* Read specified AST flags from current processor */ |
167 | extern ast_t ast_peek(ast_t reasons); |
168 | |
169 | /* Re-set current processor's per-thread AST flags to those set on thread */ |
170 | extern void ast_context(thread_t thread); |
171 | |
172 | /* Propagate ASTs set on a thread to the current processor */ |
173 | extern void ast_propagate(thread_t thread); |
174 | |
175 | /* |
176 | * Set an AST on a thread with thread_ast_set. |
177 | * |
178 | * You can then propagate it to the current processor with ast_propagate(), |
179 | * or tell another processor to act on it with cause_ast_check(). |
180 | * |
181 | * See act_set_ast() for an example. |
182 | */ |
183 | #define thread_ast_set(act, reason) (hw_atomic_or_noret(&(act)->ast, (reason))) |
184 | #define thread_ast_clear(act, reason) (hw_atomic_and_noret(&(act)->ast, ~(reason))) |
185 | |
186 | #ifdef MACH_BSD |
187 | |
188 | extern void act_set_astbsd(thread_t); |
189 | extern void bsd_ast(thread_t); |
190 | |
191 | #endif /* MACH_BSD */ |
192 | |
193 | #ifdef CONFIG_DTRACE |
194 | extern void ast_dtrace_on(void); |
195 | extern void dtrace_ast(void); |
196 | #endif /* CONFIG_DTRACE */ |
197 | |
198 | extern void kevent_ast(thread_t thread, uint16_t bits); |
199 | extern void act_set_astkevent(thread_t thread, uint16_t bits); |
200 | |
201 | #endif /* _KERN_AST_H_ */ |
202 | |