x86-64: Move current task from PDA to per-cpu and consolidate with 32-bit.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

3 files changed, 7 insertions, 25 deletions

diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h
index 0728480f5c56..c68c361697e1 100644
--- a/arch/x86/include/asm/current.h
+++ b/arch/x86/include/asm/current.h
@@ -1,39 +1,21 @@
 #ifndef _ASM_X86_CURRENT_H
 #define _ASM_X86_CURRENT_H
 
-#ifdef CONFIG_X86_32
 #include <linux/compiler.h>
 #include <asm/percpu.h>
 
+#ifndef __ASSEMBLY__
 struct task_struct;
 
 DECLARE_PER_CPU(struct task_struct *, current_task);
-static __always_inline struct task_struct *get_current(void)
-{
-        return percpu_read(current_task);
-}
-
-#else /* X86_32 */
-
-#ifndef __ASSEMBLY__
-#include <asm/pda.h>
-
-struct task_struct;
 
 static __always_inline struct task_struct *get_current(void)
 {
-        return read_pda(pcurrent);
+        return percpu_read(current_task);
 }
 
-#else /* __ASSEMBLY__ */
-
-#include <asm/asm-offsets.h>
-#define GET_CURRENT(reg) movq %gs:(pda_pcurrent),reg
+#define current get_current()
 
 #endif /* __ASSEMBLY__ */
 
-#endif /* X86_32 */
-
-#define current get_current()
-
 #endif /* _ASM_X86_CURRENT_H */
diff --git a/arch/x86/include/asm/pda.h b/arch/x86/include/asm/pda.h
index 668d5a5b6f70..7209302d9227 100644
--- a/arch/x86/include/asm/pda.h
+++ b/arch/x86/include/asm/pda.h
@@ -11,8 +11,8 @@
 
 /* Per processor datastructure. %gs points to it while the kernel runs */
 struct x8664_pda {
-        struct task_struct *pcurrent;   /* 0  Current process */
-        unsigned long dummy;
+        unsigned long unused1;
+        unsigned long unused2;
         unsigned long kernelstack;      /* 16 top of kernel stack for current */
         unsigned long oldrsp;           /* 24 user rsp for system call */
         int irqcount;                   /* 32 Irq nesting counter. Starts -1 */
diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index 8e626ea33a1a..4399aac680e9 100644
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -94,7 +94,7 @@ do {									\
              "call __switch_to\n\t"                                       \
              ".globl thread_return\n"                                     \
              "thread_return:\n\t"                                         \
-             "movq %%gs:%P[pda_pcurrent],%%rsi\n\t"                       \
+             "movq "__percpu_seg_str"%P[current_task],%%rsi\n\t"          \
              "movq %P[thread_info](%%rsi),%%r8\n\t"                       \
              LOCK_PREFIX "btr  %[tif_fork],%P[ti_flags](%%r8)\n\t"        \
              "movq %%rax,%%rdi\n\t"                                       \
@@ -106,7 +106,7 @@ do {									\
                [ti_flags] "i" (offsetof(struct thread_info, flags)),      \
                [tif_fork] "i" (TIF_FORK),                                 \
                [thread_info] "i" (offsetof(struct task_struct, stack)),   \
-               [pda_pcurrent] "i" (offsetof(struct x8664_pda, pcurrent))  \
+               [current_task] "m" (per_cpu_var(current_task))             \
              : "memory", "cc" __EXTRA_CLOBBER)
 #endif