1 | /* irq.c |
---|
2 | * |
---|
3 | * This file contains the implementation of the function described in irq.h |
---|
4 | * |
---|
5 | * CopyRight (C) 1998 valette@crf.canon.fr |
---|
6 | * |
---|
7 | * The license and distribution terms for this file may be |
---|
8 | * found in found in the file LICENSE in this distribution or at |
---|
9 | * http://www.rtems.com/license/LICENSE. |
---|
10 | * |
---|
11 | * $Id$ |
---|
12 | */ |
---|
13 | |
---|
14 | #include "asm.h" |
---|
15 | #include <irq_asm.h> |
---|
16 | |
---|
17 | BEGIN_CODE |
---|
18 | |
---|
19 | SYM (_ISR_Handler): |
---|
20 | /* |
---|
21 | * Before this was point is reached the vectors unique |
---|
22 | * entry point did the following: |
---|
23 | * |
---|
24 | * 1. saved scratch registers registers eax edx ecx" |
---|
25 | * 2. put the vector number in ecx. |
---|
26 | * |
---|
27 | * BEGINNING OF ESTABLISH SEGMENTS |
---|
28 | * |
---|
29 | * WARNING: If an interrupt can occur when the segments are |
---|
30 | * not correct, then this is where we should establish |
---|
31 | * the segments. In addition to establishing the |
---|
32 | * segments, it may be necessary to establish a stack |
---|
33 | * in the current data area on the outermost interrupt. |
---|
34 | * |
---|
35 | * NOTE: If the previous values of the segment registers are |
---|
36 | * pushed, do not forget to adjust SAVED_REGS. |
---|
37 | * |
---|
38 | * NOTE: Make sure the exit code which restores these |
---|
39 | * when this type of code is needed. |
---|
40 | */ |
---|
41 | |
---|
42 | /***** ESTABLISH SEGMENTS CODE GOES HERE ******/ |
---|
43 | |
---|
44 | /* |
---|
45 | * END OF ESTABLISH SEGMENTS |
---|
46 | */ |
---|
47 | |
---|
48 | /* |
---|
49 | * Now switch stacks if necessary |
---|
50 | */ |
---|
51 | |
---|
52 | movw SYM (i8259s_cache), ax /* move current i8259 interrupt mask in ax */ |
---|
53 | pushl eax /* push it on the stack */ |
---|
54 | /* |
---|
55 | * compute the new PIC mask: |
---|
56 | * |
---|
57 | * <new mask> = <old mask> | irq_mask_or_tbl[<intr number aka ecx>] |
---|
58 | */ |
---|
59 | movw SYM (irq_mask_or_tbl) (,ecx,2), dx |
---|
60 | orw dx, ax |
---|
61 | /* |
---|
62 | * Install new computed value on the i8259 and update cache |
---|
63 | * accordingly |
---|
64 | */ |
---|
65 | movw ax, SYM (i8259s_cache) |
---|
66 | outb $PIC_MASTER_IMR_IO_PORT |
---|
67 | movb ah, al |
---|
68 | outb $PIC_SLAVE_IMR_IO_PORT |
---|
69 | |
---|
70 | /* |
---|
71 | * acknowledge the interrupt |
---|
72 | * |
---|
73 | */ |
---|
74 | movb $PIC_EOI, al |
---|
75 | cmpl $7, ecx |
---|
76 | jbe .master |
---|
77 | outb $PIC_SLAVE_COMMAND_IO_PORT |
---|
78 | .master: |
---|
79 | outb $PIC_MASTER_COMMAND_IO_PORT |
---|
80 | |
---|
81 | .check_stack_switch: |
---|
82 | pushl ebp |
---|
83 | movl esp, ebp /* ebp = previous stack pointer */ |
---|
84 | cmpl $0, SYM (_ISR_Nest_level) /* is this the outermost interrupt? */ |
---|
85 | jne nested /* No, then continue */ |
---|
86 | movl SYM (_CPU_Interrupt_stack_high), esp |
---|
87 | |
---|
88 | /* |
---|
89 | * We want to insure that the old stack pointer is on the |
---|
90 | * stack we will be on at the end of the ISR when we restore it. |
---|
91 | * By saving it on every interrupt, all we have to do is pop it |
---|
92 | * near the end of every interrupt. |
---|
93 | */ |
---|
94 | |
---|
95 | nested: |
---|
96 | incl SYM (_ISR_Nest_level) /* one nest level deeper */ |
---|
97 | incl SYM (_Thread_Dispatch_disable_level) /* disable multitasking */ |
---|
98 | /* |
---|
99 | * re-enable interrupts at processor level as the current |
---|
100 | * interrupt source is now masked via i8259 |
---|
101 | */ |
---|
102 | sti |
---|
103 | |
---|
104 | /* |
---|
105 | * ECX is preloaded with the vector number but it is a scratch register |
---|
106 | * so we must save it again. |
---|
107 | */ |
---|
108 | |
---|
109 | pushl ecx /* push vector number */ |
---|
110 | mov SYM (current_irq) (,ecx,4),eax |
---|
111 | /* eax = Users handler */ |
---|
112 | call *eax /* invoke user ISR */ |
---|
113 | /* |
---|
114 | * disable interrupts_again |
---|
115 | */ |
---|
116 | cli |
---|
117 | popl ecx /* ecx = vector number */ |
---|
118 | /* |
---|
119 | * restore stack |
---|
120 | */ |
---|
121 | movl ebp, esp |
---|
122 | popl ebp |
---|
123 | |
---|
124 | /* |
---|
125 | * restore the original i8259 masks |
---|
126 | */ |
---|
127 | popl eax |
---|
128 | movw ax, SYM (i8259s_cache) |
---|
129 | outb $PIC_MASTER_IMR_IO_PORT |
---|
130 | movb ah, al |
---|
131 | outb $PIC_SLAVE_IMR_IO_PORT |
---|
132 | |
---|
133 | |
---|
134 | decl SYM (_ISR_Nest_level) /* one less ISR nest level */ |
---|
135 | /* If interrupts are nested, */ |
---|
136 | /* then dispatching is disabled */ |
---|
137 | |
---|
138 | decl SYM (_Thread_Dispatch_disable_level) |
---|
139 | /* unnest multitasking */ |
---|
140 | /* Is dispatch disabled */ |
---|
141 | jne .exit /* Yes, then exit */ |
---|
142 | |
---|
143 | cmpl $0, SYM (_Context_Switch_necessary) |
---|
144 | /* Is task switch necessary? */ |
---|
145 | jne .schedule /* Yes, then call the scheduler */ |
---|
146 | |
---|
147 | cmpl $0, SYM (_ISR_Signals_to_thread_executing) |
---|
148 | /* signals sent to Run_thread */ |
---|
149 | /* while in interrupt handler? */ |
---|
150 | je .exit /* No, exit */ |
---|
151 | |
---|
152 | |
---|
153 | .bframe: |
---|
154 | movl $0, SYM (_ISR_Signals_to_thread_executing) |
---|
155 | /* |
---|
156 | * This code is the less critical path. In order to have a single |
---|
157 | * Thread Context, we take the same frame than the one pushed on |
---|
158 | * exceptions. This makes sense because Signal is a software |
---|
159 | * exception. |
---|
160 | */ |
---|
161 | popl edx |
---|
162 | popl ecx |
---|
163 | popl eax |
---|
164 | |
---|
165 | pushl $0 # fake fault code |
---|
166 | pushl $0 # fake exception number |
---|
167 | |
---|
168 | pusha |
---|
169 | pushl esp |
---|
170 | call _ThreadProcessSignalsFromIrq |
---|
171 | addl $4, esp |
---|
172 | popa |
---|
173 | addl $8, esp |
---|
174 | iret |
---|
175 | |
---|
176 | .schedule: |
---|
177 | /* |
---|
178 | * the scratch registers have already been saved and we are already |
---|
179 | * back on the thread system stack. So we can call _Thread_Displatch |
---|
180 | * directly |
---|
181 | */ |
---|
182 | call _Thread_Dispatch |
---|
183 | /* |
---|
184 | * fall through exit to restore complete contex (scratch registers |
---|
185 | * eip, CS, Flags). |
---|
186 | */ |
---|
187 | .exit: |
---|
188 | /* |
---|
189 | * BEGINNING OF DE-ESTABLISH SEGMENTS |
---|
190 | * |
---|
191 | * NOTE: Make sure there is code here if code is added to |
---|
192 | * load the segment registers. |
---|
193 | * |
---|
194 | */ |
---|
195 | |
---|
196 | /******* DE-ESTABLISH SEGMENTS CODE GOES HERE ********/ |
---|
197 | |
---|
198 | /* |
---|
199 | * END OF DE-ESTABLISH SEGMENTS |
---|
200 | */ |
---|
201 | popl edx |
---|
202 | popl ecx |
---|
203 | popl eax |
---|
204 | iret |
---|
205 | |
---|
206 | |
---|
207 | #define DISTINCT_INTERRUPT_ENTRY(_vector) \ |
---|
208 | .p2align 4 ; \ |
---|
209 | PUBLIC (rtems_irq_prologue_ ## _vector ) ; \ |
---|
210 | SYM (rtems_irq_prologue_ ## _vector ): \ |
---|
211 | pushl eax ; \ |
---|
212 | pushl ecx ; \ |
---|
213 | pushl edx ; \ |
---|
214 | movl $ _vector, ecx ; \ |
---|
215 | jmp SYM (_ISR_Handler) ; |
---|
216 | |
---|
217 | DISTINCT_INTERRUPT_ENTRY(0) |
---|
218 | DISTINCT_INTERRUPT_ENTRY(1) |
---|
219 | DISTINCT_INTERRUPT_ENTRY(2) |
---|
220 | DISTINCT_INTERRUPT_ENTRY(3) |
---|
221 | DISTINCT_INTERRUPT_ENTRY(4) |
---|
222 | DISTINCT_INTERRUPT_ENTRY(5) |
---|
223 | DISTINCT_INTERRUPT_ENTRY(6) |
---|
224 | DISTINCT_INTERRUPT_ENTRY(7) |
---|
225 | DISTINCT_INTERRUPT_ENTRY(8) |
---|
226 | DISTINCT_INTERRUPT_ENTRY(9) |
---|
227 | DISTINCT_INTERRUPT_ENTRY(10) |
---|
228 | DISTINCT_INTERRUPT_ENTRY(11) |
---|
229 | DISTINCT_INTERRUPT_ENTRY(12) |
---|
230 | DISTINCT_INTERRUPT_ENTRY(13) |
---|
231 | DISTINCT_INTERRUPT_ENTRY(14) |
---|
232 | DISTINCT_INTERRUPT_ENTRY(15) |
---|
233 | |
---|
234 | /* |
---|
235 | * routine used to initialize the IDT by default |
---|
236 | */ |
---|
237 | |
---|
238 | PUBLIC (default_raw_idt_handler) |
---|
239 | PUBLIC (raw_idt_notify) |
---|
240 | |
---|
241 | SYM (default_raw_idt_handler): |
---|
242 | pusha |
---|
243 | cld |
---|
244 | call raw_idt_notify |
---|
245 | popa |
---|
246 | iret |
---|
247 | |
---|
248 | END_CODE |
---|
249 | |
---|
250 | END |
---|