51c19b4f59
Improve performance of time system calls when using Linux pvclock, by reading time info from fixmap visible copy of pvclock data. Originally from Jeremy Fitzhardinge. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
59 lines
1.1 KiB
C
59 lines
1.1 KiB
C
#ifndef _ASM_X86_VSYSCALL_H
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#define _ASM_X86_VSYSCALL_H
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enum vsyscall_num {
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__NR_vgettimeofday,
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__NR_vtime,
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__NR_vgetcpu,
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};
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#define VSYSCALL_START (-10UL << 20)
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#define VSYSCALL_SIZE 1024
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#define VSYSCALL_END (-2UL << 20)
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#define VSYSCALL_MAPPED_PAGES 1
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#define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
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#ifdef __KERNEL__
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#include <linux/seqlock.h>
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#define VGETCPU_RDTSCP 1
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#define VGETCPU_LSL 2
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/* kernel space (writeable) */
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extern int vgetcpu_mode;
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extern struct timezone sys_tz;
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#include <asm/vvar.h>
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extern void map_vsyscall(void);
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/*
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* Called on instruction fetch fault in vsyscall page.
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* Returns true if handled.
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*/
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extern bool emulate_vsyscall(struct pt_regs *regs, unsigned long address);
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#ifdef CONFIG_X86_64
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#define VGETCPU_CPU_MASK 0xfff
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static inline unsigned int __getcpu(void)
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{
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unsigned int p;
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if (VVAR(vgetcpu_mode) == VGETCPU_RDTSCP) {
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/* Load per CPU data from RDTSCP */
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native_read_tscp(&p);
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} else {
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/* Load per CPU data from GDT */
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asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
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}
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return p;
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}
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#endif /* CONFIG_X86_64 */
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#endif /* __KERNEL__ */
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#endif /* _ASM_X86_VSYSCALL_H */
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