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
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
|
/* irq.c
*
* This file contains the implementation of the function described in irq.h
*
* CopyRight (C) 1998 valette@crf.canon.fr
*
* The license and distribution terms for this file may be
* found in found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#include "asm.h"
#include <irq_asm.h>
.set SAVED_REGS , 32 # space consumed by saved regs
.set EIP_OFFSET , SAVED_REGS # offset of tasks eip
.set CS_OFFSET , EIP_OFFSET+4 # offset of tasks code segment
.set EFLAGS_OFFSET , CS_OFFSET+4 # offset of tasks eflags
/*PAGE
* void _new_ISR_Displatch()
*
* Entry point from the outermost interrupt service routine exit.
* The current stack is the supervisor mode stack.
*/
PUBLIC (_new_ISR_Displatch)
SYM (_New_ISR_Displatch):
call SYM (_Thread_Dispatch) # invoke Dispatcher
/*
* BEGINNING OF DE-ESTABLISH SEGMENTS
*
* NOTE: Make sure there is code here if code is added to
* load the segment registers.
*
*/
/***** DE-ESTABLISH SEGMENTS CODE GOES HERE ****/
/*
* END OF DE-ESTABLISH SEGMENTS
*/
popa # restore general registers
iret # return to interrupted thread
SYM (_New_ISR_Handler):
/*
* Before this was point is reached the vectors unique
* entry point did the following:
*
* 1. saved sctach registers registers eax edx ecx"
* 2. put the vector number in ecx.
*
* BEGINNING OF ESTABLISH SEGMENTS
*
* WARNING: If an interrupt can occur when the segments are
* not correct, then this is where we should establish
* the segments. In addition to establishing the
* segments, it may be necessary to establish a stack
* in the current data area on the outermost interrupt.
*
* NOTE: If the previous values of the segment registers are
* pushed, do not forget to adjust SAVED_REGS.
*
* NOTE: Make sure the exit code which restores these
* when this type of code is needed.
*/
/***** ESTABLISH SEGMENTS CODE GOES HERE ******/
/*
* END OF ESTABLISH SEGMENTS
*/
/*
* Now switch stacks if necessary
*/
movw SYM (i8259s_cache), ax # move current i8259 interrupt mask in ax
pushl eax # push it on the stack
/*
* compute the new PIC mask:
*
* <new mask> = <old mask> | irq_mask_or_tbl[<intr number aka ecx>]
*/
movw SYM (irq_mask_or_tbl) (,ecx,2), dx
orw dx, ax
/*
* Install new computed value on the i8259 and update cache
* accordingly
*/
movw ax, SYM (i8259s_cache)
outb $PIC_MASTER_IMR_IO_PORT
movb ah, al
outb $PIC_SLAVE_IMR_IO_PORT
/*
* acknowledge the interrupt
*
*/
movb $PIC_EOI, al
cmpl $7, ecx
jbe .master
outb $PIC_SLAVE_COMMAND_IO_PORT
.master:
outb $PIC_MASTER_COMMAND_IO_PORT
.check_stack_switch:
pushl ebp
movl esp, ebp # ebp = previous stack pointer
cmpl $0, SYM (_ISR_Nest_level) # is this the outermost interrupt?
jne nested # No, then continue
movl SYM (_CPU_Interrupt_stack_high), esp
/*
* We want to insure that the old stack pointer is on the
* stack we will be on at the end of the ISR when we restore it.
* By saving it on every interrupt, all we have to do is pop it
* near the end of every interrupt.
*/
nested:
incl SYM (_ISR_Nest_level) # one nest level deeper
incl SYM (_Thread_Dispatch_disable_level) # disable multitasking
/*
* re-enable interrupts at processor level as the current
* interrupt source is now masked via i8259
*/
sti
/*
* ECX is preloaded with the vector number but it is a scratch register
* so we must save it again.
*/
pushl ecx # push vector number
mov SYM (current_irq) (,ecx,4),eax
# eax = Users handler
call *eax # invoke user ISR
/*
* disable interrupts_again
*/
cli
popl ecx # ecx = vector number
/*
* restore stack
*/
movl ebp, esp
popl ebp
/*
* restore the original i8259 masks
*/
popl eax
movw ax, SYM (i8259s_cache)
outb $PIC_MASTER_IMR_IO_PORT
movb ah, al
outb $PIC_SLAVE_IMR_IO_PORT
decl SYM (_ISR_Nest_level) # one less ISR nest level
# If interrupts are nested,
# then dispatching is disabled
decl SYM (_Thread_Dispatch_disable_level)
# unnest multitasking
# Is dispatch disabled
jne .exit # Yes, then exit
cmpl $0, SYM (_Context_Switch_necessary)
# Is task switch necessary?
jne bframe # Yes, then build stack
cmpl $0, SYM (_ISR_Signals_to_thread_executing)
# signals sent to Run_thread
# while in interrupt handler?
je .exit # No, exit
bframe:
movl $0, SYM (_ISR_Signals_to_thread_executing)
/*
* complete code as if a pusha had been executed on entry
*/
pushl ebx
pushl esp
pushl ebp
pushl esi
pushl edi
# push the isf for Isr_dispatch
pushl EFLAGS_OFFSET(esp) # push tasks eflags
push cs # cs of Isr_dispatch
pushl $ SYM (_New_ISR_Displatch)# entry point
iret
.exit:
/*
* BEGINNING OF DE-ESTABLISH SEGMENTS
*
* NOTE: Make sure there is code here if code is added to
* load the segment registers.
*
*/
/******* DE-ESTABLISH SEGMENTS CODE GOES HERE ********/
/*
* END OF DE-ESTABLISH SEGMENTS
*/
popl edx
popl ecx
popl eax
iret
#define DISTINCT_INTERRUPT_ENTRY(_vector) \
.p2align 4 ; \
PUBLIC (rtems_irq_prologue_ ## _vector ) ; \
SYM (rtems_irq_prologue_ ## _vector ): \
pushl eax ; \
pushl ecx ; \
pushl edx ; \
movl $ _vector, ecx ; \
jmp SYM (_New_ISR_Handler) ;
DISTINCT_INTERRUPT_ENTRY(0)
DISTINCT_INTERRUPT_ENTRY(1)
DISTINCT_INTERRUPT_ENTRY(2)
DISTINCT_INTERRUPT_ENTRY(3)
DISTINCT_INTERRUPT_ENTRY(4)
DISTINCT_INTERRUPT_ENTRY(5)
DISTINCT_INTERRUPT_ENTRY(6)
DISTINCT_INTERRUPT_ENTRY(7)
DISTINCT_INTERRUPT_ENTRY(8)
DISTINCT_INTERRUPT_ENTRY(9)
DISTINCT_INTERRUPT_ENTRY(10)
DISTINCT_INTERRUPT_ENTRY(11)
DISTINCT_INTERRUPT_ENTRY(12)
DISTINCT_INTERRUPT_ENTRY(13)
DISTINCT_INTERRUPT_ENTRY(14)
DISTINCT_INTERRUPT_ENTRY(15)
/*
* routine used to initialize the IDT by default
*/
PUBLIC (default_raw_idt_handler)
PUBLIC (raw_idt_notify)
SYM (default_raw_idt_handler):
pusha
cld
call raw_idt_notify
popa
iret
|
