Documentation: add a guideline for hard_start_xmit method
[linux-2.6] / include / asm-x86 / irqflags_32.h
1 /*
2  * include/asm-i386/irqflags.h
3  *
4  * IRQ flags handling
5  *
6  * This file gets included from lowlevel asm headers too, to provide
7  * wrapped versions of the local_irq_*() APIs, based on the
8  * raw_local_irq_*() functions from the lowlevel headers.
9  */
10 #ifndef _ASM_IRQFLAGS_H
11 #define _ASM_IRQFLAGS_H
12 #include <asm/processor-flags.h>
13
14 #ifndef __ASSEMBLY__
15 static inline unsigned long native_save_fl(void)
16 {
17         unsigned long f;
18         asm volatile("pushfl ; popl %0":"=g" (f): /* no input */);
19         return f;
20 }
21
22 static inline void native_restore_fl(unsigned long f)
23 {
24         asm volatile("pushl %0 ; popfl": /* no output */
25                              :"g" (f)
26                              :"memory", "cc");
27 }
28
29 static inline void native_irq_disable(void)
30 {
31         asm volatile("cli": : :"memory");
32 }
33
34 static inline void native_irq_enable(void)
35 {
36         asm volatile("sti": : :"memory");
37 }
38
39 static inline void native_safe_halt(void)
40 {
41         asm volatile("sti; hlt": : :"memory");
42 }
43
44 static inline void native_halt(void)
45 {
46         asm volatile("hlt": : :"memory");
47 }
48 #endif  /* __ASSEMBLY__ */
49
50 #ifdef CONFIG_PARAVIRT
51 #include <asm/paravirt.h>
52 #else
53 #ifndef __ASSEMBLY__
54
55 static inline unsigned long __raw_local_save_flags(void)
56 {
57         return native_save_fl();
58 }
59
60 static inline void raw_local_irq_restore(unsigned long flags)
61 {
62         native_restore_fl(flags);
63 }
64
65 static inline void raw_local_irq_disable(void)
66 {
67         native_irq_disable();
68 }
69
70 static inline void raw_local_irq_enable(void)
71 {
72         native_irq_enable();
73 }
74
75 /*
76  * Used in the idle loop; sti takes one instruction cycle
77  * to complete:
78  */
79 static inline void raw_safe_halt(void)
80 {
81         native_safe_halt();
82 }
83
84 /*
85  * Used when interrupts are already enabled or to
86  * shutdown the processor:
87  */
88 static inline void halt(void)
89 {
90         native_halt();
91 }
92
93 /*
94  * For spinlocks, etc:
95  */
96 static inline unsigned long __raw_local_irq_save(void)
97 {
98         unsigned long flags = __raw_local_save_flags();
99
100         raw_local_irq_disable();
101
102         return flags;
103 }
104
105 #else
106 #define DISABLE_INTERRUPTS(clobbers)    cli
107 #define ENABLE_INTERRUPTS(clobbers)     sti
108 #define ENABLE_INTERRUPTS_SYSEXIT       sti; sysexit
109 #define INTERRUPT_RETURN                iret
110 #define GET_CR0_INTO_EAX                movl %cr0, %eax
111 #endif /* __ASSEMBLY__ */
112 #endif /* CONFIG_PARAVIRT */
113
114 #ifndef __ASSEMBLY__
115 #define raw_local_save_flags(flags) \
116                 do { (flags) = __raw_local_save_flags(); } while (0)
117
118 #define raw_local_irq_save(flags) \
119                 do { (flags) = __raw_local_irq_save(); } while (0)
120
121 static inline int raw_irqs_disabled_flags(unsigned long flags)
122 {
123         return !(flags & X86_EFLAGS_IF);
124 }
125
126 static inline int raw_irqs_disabled(void)
127 {
128         unsigned long flags = __raw_local_save_flags();
129
130         return raw_irqs_disabled_flags(flags);
131 }
132
133 /*
134  * makes the traced hardirq state match with the machine state
135  *
136  * should be a rarely used function, only in places where its
137  * otherwise impossible to know the irq state, like in traps.
138  */
139 static inline void trace_hardirqs_fixup_flags(unsigned long flags)
140 {
141         if (raw_irqs_disabled_flags(flags))
142                 trace_hardirqs_off();
143         else
144                 trace_hardirqs_on();
145 }
146
147 static inline void trace_hardirqs_fixup(void)
148 {
149         unsigned long flags = __raw_local_save_flags();
150
151         trace_hardirqs_fixup_flags(flags);
152 }
153 #endif /* __ASSEMBLY__ */
154
155 /*
156  * Do the CPU's IRQ-state tracing from assembly code. We call a
157  * C function, so save all the C-clobbered registers:
158  */
159 #ifdef CONFIG_TRACE_IRQFLAGS
160
161 # define TRACE_IRQS_ON                          \
162         pushl %eax;                             \
163         pushl %ecx;                             \
164         pushl %edx;                             \
165         call trace_hardirqs_on;                 \
166         popl %edx;                              \
167         popl %ecx;                              \
168         popl %eax;
169
170 # define TRACE_IRQS_OFF                         \
171         pushl %eax;                             \
172         pushl %ecx;                             \
173         pushl %edx;                             \
174         call trace_hardirqs_off;                \
175         popl %edx;                              \
176         popl %ecx;                              \
177         popl %eax;
178
179 #else
180 # define TRACE_IRQS_ON
181 # define TRACE_IRQS_OFF
182 #endif
183
184 #ifdef CONFIG_DEBUG_LOCK_ALLOC
185 # define LOCKDEP_SYS_EXIT                       \
186         pushl %eax;                             \
187         pushl %ecx;                             \
188         pushl %edx;                             \
189         call lockdep_sys_exit;                  \
190         popl %edx;                              \
191         popl %ecx;                              \
192         popl %eax;
193 #else
194 # define LOCKDEP_SYS_EXIT
195 #endif
196
197 #endif