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| author | Vojtech Pavlik <vojtech@suse.cz> | 2006-09-26 10:52:28 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-09-26 10:52:28 +0200 |
| commit | c08c820508233b424deab3302bc404bbecc6493a (patch) | |
| tree | d6ed79fb2d03513f6c71fc7e47705c4a19512f53 /arch/x86_64/kernel/head.S | |
| parent | a670fad0adb1cc6202a607d250f10bd380593905 (diff) | |
| download | lwn-c08c820508233b424deab3302bc404bbecc6493a.tar.gz lwn-c08c820508233b424deab3302bc404bbecc6493a.zip | |
[PATCH] Add the vgetcpu vsyscall
This patch adds a vgetcpu vsyscall, which depending on the CPU RDTSCP
capability uses either the RDTSCP or CPUID to obtain a CPU and node
numbers and pass them to the program.
AK: Lots of changes over Vojtech's original code:
Better prototype for vgetcpu()
It's better to pass the cpu / node numbers as separate arguments
to avoid mistakes when going from SMP to NUMA.
Also add a fast time stamp based cache using a user supplied
argument to speed things more up.
Use fast method from Chuck Ebbert to retrieve node/cpu from
GDT limit instead of CPUID
Made sure RDTSCP init is always executed after node is known.
Drop printk
Signed-off-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64/kernel/head.S')
| -rw-r--r-- | arch/x86_64/kernel/head.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S index c9739ca81d06..505ec4a57506 100644 --- a/arch/x86_64/kernel/head.S +++ b/arch/x86_64/kernel/head.S @@ -371,7 +371,7 @@ ENTRY(cpu_gdt_table) .quad 0,0 /* TSS */ .quad 0,0 /* LDT */ .quad 0,0,0 /* three TLS descriptors */ - .quad 0 /* unused */ + .quad 0x0000f40000000000 /* node/CPU stored in limit */ gdt_end: /* asm/segment.h:GDT_ENTRIES must match this */ /* This should be a multiple of the cache line size */ |