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312df5f1a1
There are unfortunately more and more multi processor Opteron systems which don't have HPET timer support in the southbridge. This covers in particular Nvidia and VIA chipsets. They also don't guarantee that the TSCs are synchronized between CPUs; and especially with MP powernow the systems are nearly unusable because the time gets very inconsistent between CPUs. The timer code for x86-64 was originally written under the assumption that we could fall back to the HPET timer on such systems. But this doesn't work there. Another alternative is to use the ACPI PM timer as primary time source. This patch does that. The kernel only uses PM timer when there is no other choice because it has some disadvantages. Ported over from i386. It should be faster than the i386 version because I dropped the "read three times" workaround, but is still considerable slower than HPET and also does not work together with vsyscalls which have to be disabled. Cc: <mark.langsdorf@amd.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
64 lines
1.9 KiB
C
64 lines
1.9 KiB
C
#ifndef _ASM_X86_64_VSYSCALL_H_
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#define _ASM_X86_64_VSYSCALL_H_
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#include <linux/seqlock.h>
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enum vsyscall_num {
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__NR_vgettimeofday,
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__NR_vtime,
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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_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))
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#ifdef __KERNEL__
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#define __section_vxtime __attribute__ ((unused, __section__ (".vxtime"), aligned(16)))
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#define __section_wall_jiffies __attribute__ ((unused, __section__ (".wall_jiffies"), aligned(16)))
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#define __section_jiffies __attribute__ ((unused, __section__ (".jiffies"), aligned(16)))
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#define __section_sys_tz __attribute__ ((unused, __section__ (".sys_tz"), aligned(16)))
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#define __section_sysctl_vsyscall __attribute__ ((unused, __section__ (".sysctl_vsyscall"), aligned(16)))
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#define __section_xtime __attribute__ ((unused, __section__ (".xtime"), aligned(16)))
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#define __section_xtime_lock __attribute__ ((unused, __section__ (".xtime_lock"), aligned(16)))
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#define VXTIME_TSC 1
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#define VXTIME_HPET 2
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#define VXTIME_PMTMR 3
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struct vxtime_data {
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long hpet_address; /* HPET base address */
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unsigned long hz; /* HPET clocks / sec */
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int last;
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unsigned long last_tsc;
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long quot;
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long tsc_quot;
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int mode;
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};
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#define hpet_readl(a) readl((void *)fix_to_virt(FIX_HPET_BASE) + a)
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#define hpet_writel(d,a) writel(d, (void *)fix_to_virt(FIX_HPET_BASE) + a)
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/* vsyscall space (readonly) */
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extern struct vxtime_data __vxtime;
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extern struct timespec __xtime;
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extern volatile unsigned long __jiffies;
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extern unsigned long __wall_jiffies;
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extern struct timezone __sys_tz;
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extern seqlock_t __xtime_lock;
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/* kernel space (writeable) */
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extern struct vxtime_data vxtime;
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extern unsigned long wall_jiffies;
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extern struct timezone sys_tz;
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extern int sysctl_vsyscall;
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extern seqlock_t xtime_lock;
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extern int sysctl_vsyscall;
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#define ARCH_HAVE_XTIME_LOCK 1
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#endif /* __KERNEL__ */
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#endif /* _ASM_X86_64_VSYSCALL_H_ */
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