linux_0

Linux 内核源代码（V!1.0.9)

74                 if (new_value)
75                         *bitmap_base++ |= mask;
76                 else
77                         *bitmap_base++ &= ~mask;
78         }
79 }
80 
81 /* Check for set bits in BITMAP starting at BASE, going to EXTENT. */
82 asmlinkage int check_bitmap(unsigned long *bitmap, short base, short extent)
83 {
84         int mask;
85         unsigned long *bitmap_base = bitmap + (base >> 5);
86         unsigned short low_index = base & 0x1f;
87         int length = low_index + extent;
88 
89         if (low_index != 0) {
90                 mask = (~0 << low_index);
91                 if (length < 32)
92                                 mask &= ~(~0 << length);
93                 if (*bitmap_base++ & mask)
94                         return 1;
95                 length -= 32;
96         }
97         while (length >= 32) {
98                 if (*bitmap_base++ != 0)
99                         return 1;
100                 length -= 32;
101         }
102 
103         if (length > 0) {
104                 mask = ~(~0 << length);
105                 if (*bitmap_base++ & mask)
106                         return 1;
107         }
108         return 0;
109 }
110 
111 /*
112  * this changes the io permissions bitmap in the current task.
113  */
114 asmlinkage int sys_ioperm(unsigned long from, unsigned long num, int turn_on)
115 {
116         if (from + num <= from)
117                 return -EINVAL;
118         if (from + num > IO_BITMAP_SIZE*32)
119                 return -EINVAL;
120         if (!suser())
121                 return -EPERM;
122 
123 #ifdef IODEBUG
124         printk("io: from=%d num=%d %s\n", from, num, (turn_on ? "on" : "off"));
125 #endif
126         set_bitmap((unsigned long *)current->tss.io_bitmap, from, num, !turn_on);
127         return 0;
128 }
129 
130 unsigned int *stack;
131 
132 /*
133  * sys_iopl has to be used when you want to access the IO ports
134  * beyond the 0x3ff range: to get the full 65536 ports bitmapped
135  * you'd need 8kB of bitmaps/process, which is a bit excessive.
136  *
137  * Here we just change the eflags value on the stack: we allow
138  * only the super-user to do it. This depends on the stack-layout
139  * on system-call entry - see also fork() and the signal handling
140  * code.
141  */
142 asmlinkage int sys_iopl(long ebx,long ecx,long edx,
143              long esi, long edi, long ebp, long eax, long ds,
144              long es, long fs, long gs, long orig_eax,
145              long eip,long cs,long eflags,long esp,long ss)
146 {
147         unsigned int level = ebx;
148 
149         if (level > 3)
150                 return -EINVAL;
151         if (!suser())
152                 return -EPERM;
153         *(&eflags) = (eflags & 0xffffcfff) | (level << 12);
154         return 0;
155 }
156 
157 
158 void snarf_region(unsigned int from, unsigned int num)
159 {
160         if (from > IO_BITMAP_SIZE*32)
161                 return;
162         if (from + num > IO_BITMAP_SIZE*32)
163                 num = IO_BITMAP_SIZE*32 - from;
164         set_bitmap(ioport_registrar, from, num, 1);
165         return;
166 }
167 
168 int check_region(unsigned int from, unsigned int num)
169 {
170         if (from > IO_BITMAP_SIZE*32)
171                 return 0;
172         if (from + num > IO_BITMAP_SIZE*32)
173                 num = IO_BITMAP_SIZE*32 - from;
174         return check_bitmap(ioport_registrar, from, num);
175 }
176 
177 /* Called from init/main.c to reserve IO ports. */
178 void reserve_setup(char *str, int *ints)
179 {
180         int i;
181 
182         for (i = 1; i < ints[0]; i += 2)
183                 snarf_region(ints[i], ints[i+1]);
184 }
185 
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1 /*
2  *      linux/kernel/irq.c
3  *
4  *      Copyright (C) 1992 Linus Torvalds
5  *
6  * This file contains the code used by various IRQ handling routines:
7  * asking for different IRQ's should be done through these routines
8  * instead of just grabbing them. Thus setups with different IRQ numbers
9  * shouldn't result in any weird surprises, and installing new handlers
10  * should be easier.
11  */
12 
13 /*
14  * IRQ's are in fact implemented a bit like signal handlers for the kernel.
15  * The same sigaction struct is used, and with similar semantics (ie there
16  * is a SA_INTERRUPT flag etc). Naturally it's not a 1:1 relation, but there
17  * are similarities.
18  *
19  * sa_handler(int irq_NR) is the default function called.
20  * sa_mask is 0 if nothing uses this IRQ
21  * sa_flags contains various info: SA_INTERRUPT etc
22  * sa_restorer is the unused
23  */
24 
25 #include <linux/ptrace.h>
26 #include <linux/errno.h>
27 #include <linux/kernel_stat.h>
28 #include <linux/signal.h>
29 #include <linux/sched.h>
30 #include <linux/interrupt.h>
31 
32 #include <asm/system.h>
33 #include <asm/io.h>
34 #include <asm/irq.h>
35 
36 #define CR0_NE 32
37 
38 static unsigned char cache_21 = 0xff;
39 static unsigned char cache_A1 = 0xff;
40 
41 unsigned long intr_count = 0;
42 unsigned long bh_active = 0;
43 unsigned long bh_mask = 0xFFFFFFFF;
44 struct bh_struct bh_base[32]; 
45 
46 void disable_irq(unsigned int irq_nr)
47 {
48         unsigned long flags;
49         unsigned char mask;
50 
51         mask = 1 << (irq_nr & 7);
52         save_flags(flags);
53         if (irq_nr < 8) {
54                 cli();
55                 cache_21 |= mask;
56                 outb(cache_21,0x21);
57                 restore_flags(flags);
58                 return;
59         }
60         cli();
61         cache_A1 |= mask;
62         outb(cache_A1,0xA1);
63         restore_flags(flags);
64 }
65 
66 void enable_irq(unsigned int irq_nr)
67 {
68         unsigned long flags;
69         unsigned char mask;
70 
71         mask = ~(1 << (irq_nr & 7));
72         save_flags(flags);
73         if (irq_nr < 8) {
74                 cli();
75                 cache_21 &= mask;
76                 outb(cache_21,0x21);
77                 restore_flags(flags);
78                 return;
79         }
80         cli();
81         cache_A1 &= mask;
82         outb(cache_A1,0xA1);
83         restore_flags(flags);
84 }
85 
86 /*
87  * do_bottom_half() runs at normal kernel priority: all interrupts
88  * enabled.  do_bottom_half() is atomic with respect to itself: a
89  * bottom_half handler need not be re-entrant.
90  */
91 asmlinkage void do_bottom_half(void)
92 {
93         unsigned long active;
94         unsigned long mask, left;
95         struct bh_struct *bh;
96 
97         bh = bh_base;
98         active = bh_active & bh_mask;
99         for (mask = 1, left = ~0 ; left & active ; bh++,mask += mask,left += left) {
100                 if (mask & active) {
101                         void (*fn)(void *);
102                         bh_active &= ~mask;
103                         fn = bh->routine;
104                         if (!fn)
105                                 goto bad_bh;
106                         fn(bh->data);
107                 }
108         }
109         return;
110 bad_bh:
111         printk ("irq.c:bad bottom half entry\n");
112 }
113 
114 /*
115  * This builds up the IRQ handler stubs using some ugly macros in irq.h
116  *
117  * These macros create the low-level assembly IRQ routines that do all
118  * the operations that are needed to keep the AT interrupt-controller
119  * happy. They are also written to be fast - and to disable interrupts
120  * as little as humanly possible.
121  *
122  * NOTE! These macros expand to three different handlers for each line: one
123  * complete handler that does all the fancy stuff (including signal handling),
124  * and one fast handler that is meant for simple IRQ's that want to be
125  * atomic. The specific handler is chosen depending on the SA_INTERRUPT
126  * flag when installing a handler. Finally, one "bad interrupt" handler, that
127  * is used when no handler is present.
128  */
129 BUILD_IRQ(FIRST,0,0x01)
130 BUILD_IRQ(FIRST,1,0x02)
131 BUILD_IRQ(FIRST,2,0x04)
132 BUILD_IRQ(FIRST,3,0x08)
133 BUILD_IRQ(FIRST,4,0x10)
134 BUILD_IRQ(FIRST,5,0x20)
135 BUILD_IRQ(FIRST,6,0x40)
136 BUILD_IRQ(FIRST,7,0x80)
137 BUILD_IRQ(SECOND,8,0x01)
138 BUILD_IRQ(SECOND,9,0x02)
139 BUILD_IRQ(SECOND,10,0x04)
140 BUILD_IRQ(SECOND,11,0x08)
141 BUILD_IRQ(SECOND,12,0x10)
142 BUILD_IRQ(SECOND,13,0x20)
143 BUILD_IRQ(SECOND,14,0x40)
144 BUILD_IRQ(SECOND,15,0x80)
145 
146 /*
147  * Pointers to the low-level handlers: first the general ones, then the
148  * fast ones, then the bad ones.
149  */
150 static void (*interrupt[16])(void) = {
151         IRQ0_interrupt, IRQ1_interrupt, IRQ2_interrupt, IRQ3_interrupt,
152         IRQ4_interrupt, IRQ5_interrupt, IRQ6_interrupt, IRQ7_interrupt,
153         IRQ8_interrupt, IRQ9_interrupt, IRQ10_interrupt, IRQ11_interrupt,
154         IRQ12_interrupt, IRQ13_interrupt, IRQ14_interrupt, IRQ15_interrupt
155 };
156 
157 static void (*fast_interrupt[16])(void) = {
158         fast_IRQ0_interrupt, fast_IRQ1_interrupt,
159         fast_IRQ2_interrupt, fast_IRQ3_interrupt,
160         fast_IRQ4_interrupt, fast_IRQ5_interrupt,
161         fast_IRQ6_interrupt, fast_IRQ7_interrupt,
162         fast_IRQ8_interrupt, fast_IRQ9_interrupt,
163         fast_IRQ10_interrupt, fast_IRQ11_interrupt,
164         fast_IRQ12_interrupt, fast_IRQ13_interrupt,
165         fast_IRQ14_interrupt, fast_IRQ15_interrupt
166 };
167 
168 static void (*bad_interrupt[16])(void) = {
169         bad_IRQ0_interrupt, bad_IRQ1_interrupt,
170         bad_IRQ2_interrupt, bad_IRQ3_interrupt,
171         bad_IRQ4_interrupt, bad_IRQ5_interrupt,
172         bad_IRQ6_interrupt, bad_IRQ7_interrupt,
173         bad_IRQ8_interrupt, bad_IRQ9_interrupt,
174         bad_IRQ10_interrupt, bad_IRQ11_interrupt,
175         bad_IRQ12_interrupt, bad_IRQ13_interrupt,
176         bad_IRQ14_interrupt, bad_IRQ15_interrupt
177 };
178 
179 /*
180  * Initial irq handlers.
181  */
182 static struct sigaction irq_sigaction[16] = {
183         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
184         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
185         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
186         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
187         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
188         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
189         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
190         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }
191 };
192 
193 /*
194  * do_IRQ handles IRQ's that have been installed without the
195  * SA_INTERRUPT flag: it uses the full signal-handling return
196  * and runs with other interrupts enabled. All relatively slow
197  * IRQ's should use this format: notably the keyboard/timer
198  * routines.
199  */
200 asmlinkage void do_IRQ(int irq, struct pt_regs * regs)
201 {
202         struct sigaction * sa = irq + irq_sigaction;
203 
204         kstat.interrupts[irq]++;
205         sa->sa_handler((int) regs);
206 }
207 
208 /*
209  * do_fast_IRQ handles IRQ's that don't need the fancy interrupt return
210  * stuff - the handler is also running with interrupts disabled unless
211  * it explicitly enables them later.
212  */
213 asmlinkage void do_fast_IRQ(int irq)
214 {
215         struct sigaction * sa = irq + irq_sigaction;
216 
217         kstat.interrupts[irq]++;
218         sa->sa_handler(irq);
219 }
220 
221 int irqaction(unsigned int irq, struct sigaction * new_sa)
222 {
223         struct sigaction * sa;
224         unsigned long flags;
225 
226         if (irq > 15)
227                 return -EINVAL;
228         sa = irq + irq_sigaction;
229         if (sa->sa_mask)
230                 return -EBUSY;
231         if (!new_sa->sa_handler)
232                 return -EINVAL;
233         save_flags(flags);
234         cli();
235         *sa = *new_sa;
236         sa->sa_mask = 1;
237         if (sa->sa_flags & SA_INTERRUPT)
238                 set_intr_gate(0x20+irq,fast_interrupt[irq]);
239         else
240                 set_intr_gate(0x20+irq,interrupt[irq]);
241         if (irq < 8) {
242                 cache_21 &= ~(1<<irq);
243                 outb(cache_21,0x21);
244         } else {
245                 cache_21 &= ~(1<<2);
246                 cache_A1 &= ~(1<<(irq-8));
247                 outb(cache_21,0x21);
248                 outb(cache_A1,0xA1);
249         }