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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/smp.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/smp.h')
-rw-r--r--include/asm-i386/smp.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/asm-i386/smp.h b/include/asm-i386/smp.h
index 2d083cb4ca93..090abc1da32a 100644
--- a/include/asm-i386/smp.h
+++ b/include/asm-i386/smp.h
@@ -8,7 +8,6 @@
8#include <linux/kernel.h> 8#include <linux/kernel.h>
9#include <linux/threads.h> 9#include <linux/threads.h>
10#include <linux/cpumask.h> 10#include <linux/cpumask.h>
11#include <asm/pda.h>
12#endif 11#endif
13 12
14#if defined(CONFIG_X86_LOCAL_APIC) && !defined(__ASSEMBLY__) 13#if defined(CONFIG_X86_LOCAL_APIC) && !defined(__ASSEMBLY__)
@@ -112,7 +111,8 @@ do { } while (0)
112 * from the initial startup. We map APIC_BASE very early in page_setup(), 111 * from the initial startup. We map APIC_BASE very early in page_setup(),
113 * so this is correct in the x86 case. 112 * so this is correct in the x86 case.
114 */ 113 */
115#define raw_smp_processor_id() (read_pda(cpu_number)) 114DECLARE_PER_CPU(int, cpu_number);
115#define raw_smp_processor_id() (x86_read_percpu(cpu_number))
116 116
117extern cpumask_t cpu_callout_map; 117extern cpumask_t cpu_callout_map;
118extern cpumask_t cpu_callin_map; 118extern cpumask_t cpu_callin_map;