L4Re Operating System Framework
Interface and Usage Documentation
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cpu.h
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1
7/*
8 * (c) 2004-2009 Author(s)
9 * economic rights: Technische Universität Dresden (Germany)
10 * This file is part of TUD:OS and distributed under the terms of the
11 * GNU Lesser General Public License 2.1.
12 * Please see the COPYING-LGPL-2.1 file for details.
13 */
14
15#ifndef __L4_UTIL_CPU_H
16#define __L4_UTIL_CPU_H
17
18#include <l4/sys/compiler.h>
19
21
34
41L4_INLINE unsigned int l4util_cpu_capabilities(void);
42
49
53L4_INLINE void
54l4util_cpu_cpuid(unsigned long mode,
55 unsigned long *eax, unsigned long *ebx,
56 unsigned long *ecx, unsigned long *edx);
57
59static inline void
60l4util_cpu_pause(void)
61{
62 __asm__ __volatile__ ("rep; nop");
63}
64
65L4_INLINE int
67{
68 unsigned long eax;
69
70 asm volatile("pushl %%ebx \t\n"
71 "pushfl \t\n"
72 "popl %%eax \t\n" /* get eflags */
73 "movl %%eax, %%ebx \t\n" /* save it */
74 "xorl $0x200000, %%eax \t\n" /* toggle ID bit */
75 "pushl %%eax \t\n"
76 "popfl \t\n" /* set again */
77 "pushfl \t\n"
78 "popl %%eax \t\n" /* get it again */
79 "xorl %%ebx, %%eax \t\n"
80 "pushl %%ebx \t\n"
81 "popfl \t\n" /* restore saved flags */
82 "popl %%ebx \t\n"
83 : "=a" (eax)
84 : /* no input */
85 );
86
87 return eax & 0x200000;
88}
89
90L4_INLINE void
91l4util_cpu_cpuid(unsigned long mode,
92 unsigned long *eax, unsigned long *ebx,
93 unsigned long *ecx, unsigned long *edx)
94{
95 asm volatile("pushl %%ebx \t\n"
96 "cpuid \t\n"
97 "mov %%ebx, %%esi \t\n"
98 "popl %%ebx \t\n"
99 : "=a" (*eax),
100 "=S" (*ebx),
101 "=c" (*ecx),
102 "=d" (*edx)
103 : "a" (mode));
104}
105
106L4_INLINE unsigned int
108{
109 unsigned long dummy, capability;
110
111 /* get CPU capabilities */
112 l4util_cpu_cpuid(1, &dummy, &dummy, &dummy, &capability);
113
114 return capability;
115}
116
117L4_INLINE unsigned int
119{
121 return 0; /* CPU has not cpuid instruction */
122
124}
125
127
128#endif
129
L4 compiler related defines.
#define L4_INLINE
L4 Inline function attribute.
Definition compiler.h:62
#define EXTERN_C_BEGIN
Start section with C types and functions.
Definition compiler.h:192
#define EXTERN_C_END
End section with C types and functions.
Definition compiler.h:193
void l4util_cpu_cpuid(unsigned long mode, unsigned long *eax, unsigned long *ebx, unsigned long *ecx, unsigned long *edx)
Generic CPUID access function.
Definition cpu.h:72
unsigned int l4util_cpu_capabilities_nocheck(void)
Returns the CPU capabilities.
Definition cpu.h:86
unsigned int l4util_cpu_capabilities(void)
Returns the CPU capabilities if the "cpuid" instruction is available.
Definition cpu.h:97
int l4util_cpu_has_cpuid(void)
Check whether the CPU supports the "cpuid" instruction.
Definition cpu.h:66