diff options
| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-05-02 19:27:16 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2007-05-02 19:27:16 +0200 |
| commit | 7c3576d261ce046789a7db14f43303f8120910c7 (patch) | |
| tree | ad27a8459bbcdb183fe2411aec3b840942992ad5 /arch/i386/kernel/cpu | |
| parent | 7a61d35d4b4056e7711031202da7605e052f4137 (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 'arch/i386/kernel/cpu')
| -rw-r--r-- | arch/i386/kernel/cpu/common.c | 17 |
1 files changed, 3 insertions, 14 deletions
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index 7a4c036d93c..27e00565f5e 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -18,7 +18,6 @@ #include <asm/apic.h> #include <mach_apic.h> #endif -#include <asm/pda.h> #include "cpu.h" @@ -47,13 +46,10 @@ DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = { [GDT_ENTRY_APMBIOS_BASE+2] = { 0x0000ffff, 0x00409200 }, /* data */ [GDT_ENTRY_ESPFIX_SS] = { 0x00000000, 0x00c09200 }, - [GDT_ENTRY_PDA] = { 0x00000000, 0x00c09200 }, /* set in setup_pda */ + [GDT_ENTRY_PERCPU] = { 0x00000000, 0x00000000 }, } }; EXPORT_PER_CPU_SYMBOL_GPL(gdt_page); -DEFINE_PER_CPU(struct i386_pda, _cpu_pda); -EXPORT_PER_CPU_SYMBOL(_cpu_pda); - static int cachesize_override __cpuinitdata = -1; static int disable_x86_fxsr __cpuinitdata; static int disable_x86_serial_nr __cpuinitdata = 1; @@ -634,21 +630,14 @@ void __init early_cpu_init(void) #endif } -/* Make sure %gs is initialized properly in idle threads */ +/* Make sure %fs is initialized properly in idle threads */ struct pt_regs * __devinit idle_regs(struct pt_regs *regs) { memset(regs, 0, sizeof(struct pt_regs)); - regs->xfs = __KERNEL_PDA; + regs->xfs = __KERNEL_PERCPU; return regs; } -/* Initial PDA used by boot CPU */ -struct i386_pda boot_pda = { - ._pda = &boot_pda, - .cpu_number = 0, - .pcurrent = &init_task, -}; - /* * cpu_init() initializes state that is per-CPU. Some data is already * initialized (naturally) in the bootstrap process, such as the GDT |