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authorJeremy Fitzhardinge <jeremy@goop.org>2007-05-02 13:27:16 -0400
committerAndi Kleen <andi@basil.nowhere.org>2007-05-02 13:27:16 -0400
commit7c3576d261ce046789a7db14f43303f8120910c7 (patch)
treead27a8459bbcdb183fe2411aec3b840942992ad5 /include/asm-i386/current.h
parent7a61d35d4b4056e7711031202da7605e052f4137 (diff)
[PATCH] i386: Convert PDA into the percpu section
Currently x86 (similar to x84-64) has a special per-cpu structure called "i386_pda" which can be easily and efficiently referenced via the %fs register. An ELF section is more flexible than a structure, allowing any piece of code to use this area. Indeed, such a section already exists: the per-cpu area. So this patch: (1) Removes the PDA and uses per-cpu variables for each current member. (2) Replaces the __KERNEL_PDA segment with __KERNEL_PERCPU. (3) Creates a per-cpu mirror of __per_cpu_offset called this_cpu_off, which can be used to calculate addresses for this CPU's variables. (4) Simplifies startup, because %fs doesn't need to be loaded with a special segment at early boot; it can be deferred until the first percpu area is allocated (or never for UP). The result is less code and one less x86-specific concept. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de>
Diffstat (limited to 'include/asm-i386/current.h')
-rw-r--r--include/asm-i386/current.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/include/asm-i386/current.h b/include/asm-i386/current.h
index 5252ee0f6d7a..d35248539912 100644
--- a/include/asm-i386/current.h
+++ b/include/asm-i386/current.h
@@ -1,14 +1,15 @@
1#ifndef _I386_CURRENT_H 1#ifndef _I386_CURRENT_H
2#define _I386_CURRENT_H 2#define _I386_CURRENT_H
3 3
4#include <asm/pda.h>
5#include <linux/compiler.h> 4#include <linux/compiler.h>
5#include <asm/percpu.h>
6 6
7struct task_struct; 7struct task_struct;
8 8
9DECLARE_PER_CPU(struct task_struct *, current_task);
9static __always_inline struct task_struct *get_current(void) 10static __always_inline struct task_struct *get_current(void)
10{ 11{
11 return read_pda(pcurrent); 12 return x86_read_percpu(current_task);
12} 13}
13 14
14#define current get_current() 15#define current get_current()