diff options
| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2006-12-07 02:14:03 +0100 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-12-07 02:14:03 +0100 |
| commit | ec7fcaabbfb3c5bd5189f857b6ac7bb9745ef291 (patch) | |
| tree | 9730e2849a9943e26f8d32f394296fd685b85e39 | |
| parent | b2938f880890ebfcccad356275e0000193153623 (diff) | |
[PATCH] i386: Implement "current" with the PDA
Use the pcurrent field in the PDA to implement the "current" macro. This ends
up compiling down to a single instruction to get the current task.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
| -rw-r--r-- | arch/i386/kernel/asm-offsets.c | 2 | ||||
| -rw-r--r-- | arch/i386/kernel/cpu/common.c | 2 | ||||
| -rw-r--r-- | arch/i386/kernel/process.c | 1 | ||||
| -rw-r--r-- | include/asm-i386/current.h | 7 | ||||
| -rw-r--r-- | include/asm-i386/pda.h | 2 |
5 files changed, 11 insertions, 3 deletions
diff --git a/arch/i386/kernel/asm-offsets.c b/arch/i386/kernel/asm-offsets.c index 85f1b038e9c3..0666eb0ed7bc 100644 --- a/arch/i386/kernel/asm-offsets.c +++ b/arch/i386/kernel/asm-offsets.c @@ -15,6 +15,7 @@ #include <asm/processor.h> #include <asm/thread_info.h> #include <asm/elf.h> +#include <asm/pda.h> #define DEFINE(sym, val) \ asm volatile("\n->" #sym " %0 " #val : : "i" (val)) @@ -99,4 +100,5 @@ void foo(void) BLANK(); OFFSET(PDA_cpu, i386_pda, cpu_number); + OFFSET(PDA_pcurrent, i386_pda, pcurrent); } diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c index e476202b887f..6958ae5e2fa5 100644 --- a/arch/i386/kernel/cpu/common.c +++ b/arch/i386/kernel/cpu/common.c @@ -651,6 +651,7 @@ __cpuinit int alloc_gdt(int cpu) struct i386_pda boot_pda = { ._pda = &boot_pda, .cpu_number = 0, + .pcurrent = &init_task, }; static inline void set_kernel_gs(void) @@ -696,6 +697,7 @@ __cpuinit int init_gdt(int cpu, struct task_struct *idle) memset(pda, 0, sizeof(*pda)); pda->_pda = pda; pda->cpu_number = cpu; + pda->pcurrent = idle; return 1; } diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index dc4272545179..8749b10d3805 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -684,6 +684,7 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas if (unlikely(prev->fs | next->fs)) loadsegment(fs, next->fs); + write_pda(pcurrent, next_p); /* * Restore IOPL if needed. diff --git a/include/asm-i386/current.h b/include/asm-i386/current.h index 3cbbecd79016..5252ee0f6d7a 100644 --- a/include/asm-i386/current.h +++ b/include/asm-i386/current.h @@ -1,13 +1,14 @@ #ifndef _I386_CURRENT_H #define _I386_CURRENT_H -#include <linux/thread_info.h> +#include <asm/pda.h> +#include <linux/compiler.h> struct task_struct; -static __always_inline struct task_struct * get_current(void) +static __always_inline struct task_struct *get_current(void) { - return current_thread_info()->task; + return read_pda(pcurrent); } #define current get_current() diff --git a/include/asm-i386/pda.h b/include/asm-i386/pda.h index f90fde22566d..08a35c478af2 100644 --- a/include/asm-i386/pda.h +++ b/include/asm-i386/pda.h @@ -7,12 +7,14 @@ #define _I386_PDA_H #include <linux/stddef.h> +#include <linux/types.h> struct i386_pda { struct i386_pda *_pda; /* pointer to self */ int cpu_number; + struct task_struct *pcurrent; /* current process */ }; extern struct i386_pda *_cpu_pda[]; |