The patch titled
i386-pda: Implement "current" with the PDA
has been added to the -mm tree. Its filename is
i386-pda-implement-current-with-the-pda.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: i386-pda: Implement "current" with the PDA
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
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@xxxxxxxxxxxxx>
Cc: Chuck Ebbert <76306.1226@xxxxxxxxxxxxxx>
Cc: Zachary Amsden <zach@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/i386/kernel/asm-offsets.c | 2 ++
arch/i386/kernel/cpu/common.c | 2 ++
arch/i386/kernel/process.c | 1 +
include/asm-i386/current.h | 7 ++++---
include/asm-i386/pda.h | 1 +
5 files changed, 10 insertions(+), 3 deletions(-)
diff -puN arch/i386/kernel/asm-offsets.c~i386-pda-implement-current-with-the-pda arch/i386/kernel/asm-offsets.c
--- a/arch/i386/kernel/asm-offsets.c~i386-pda-implement-current-with-the-pda
+++ a/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 -puN arch/i386/kernel/cpu/common.c~i386-pda-implement-current-with-the-pda arch/i386/kernel/cpu/common.c
--- a/arch/i386/kernel/cpu/common.c~i386-pda-implement-current-with-the-pda
+++ a/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 t
memset(pda, 0, sizeof(*pda));
pda->_pda = pda;
pda->cpu_number = cpu;
+ pda->pcurrent = idle;
return 1;
}
diff -puN arch/i386/kernel/process.c~i386-pda-implement-current-with-the-pda arch/i386/kernel/process.c
--- a/arch/i386/kernel/process.c~i386-pda-implement-current-with-the-pda
+++ a/arch/i386/kernel/process.c
@@ -688,6 +688,7 @@ struct task_struct fastcall * __switch_t
if (unlikely(prev->fs | next->fs))
loadsegment(fs, next->fs);
+ write_pda(pcurrent, next_p);
/*
* Restore IOPL if needed.
diff -puN include/asm-i386/current.h~i386-pda-implement-current-with-the-pda include/asm-i386/current.h
--- a/include/asm-i386/current.h~i386-pda-implement-current-with-the-pda
+++ a/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 -puN include/asm-i386/pda.h~i386-pda-implement-current-with-the-pda include/asm-i386/pda.h
--- a/include/asm-i386/pda.h~i386-pda-implement-current-with-the-pda
+++ a/include/asm-i386/pda.h
@@ -13,6 +13,7 @@ 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[];
_
Patches currently in -mm which might be from jeremy@xxxxxxxx are
x86-remove-default_ldt-and-simplify-ldt-setting.patch
i386-use-asm-offsets-for-the-offsets-of-registers-into-the-pt_regs-struct-rather-than-having-hard-coded-constants.patch
i386-pda-basic-definitions-for-i386-pda.patch
i386-pda-initialize-the-per-cpu-data-area.patch
i386-pda-use-%gs-as-the-pda-base-segment-in-the-kernel.patch
i386-pda-fix-places-where-using-%gs-changes-the-usermode-abi.patch
i386-pda-update-sys_vm86-to-cope-with-changed-pt_regs-and-%gs-usage.patch
i386-pda-implement-smp_processor_id-with-the-pda.patch
i386-pda-implement-current-with-the-pda.patch
i386-pda-store-the-interrupt-regs-pointer-in-the-pda.patch
generic-bug-implementation.patch
generic-bug-for-i386.patch
generic-bug-for-x86-64.patch
generic-bug-for-powerpc.patch
uml-add-generic-bug-support.patch
use-generic-bug-for-ppc.patch
bug-test-1.patch
-
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