Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=7c3576d261ce046789a7db14f43303f8120910c7
Commit:     7c3576d261ce046789a7db14f43303f8120910c7
Parent:     7a61d35d4b4056e7711031202da7605e052f4137
Author:     Jeremy Fitzhardinge <[EMAIL PROTECTED]>
AuthorDate: Wed May 2 19:27:16 2007 +0200
Committer:  Andi Kleen <[EMAIL PROTECTED]>
CommitDate: Wed May 2 19:27:16 2007 +0200

    [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 <[EMAIL PROTECTED]>
    Signed-off-by: Jeremy Fitzhardinge <[EMAIL PROTECTED]>
    Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>
    Cc: Andi Kleen <[EMAIL PROTECTED]>
---
 arch/i386/kernel/asm-offsets.c |    5 --
 arch/i386/kernel/cpu/common.c  |   17 +----
 arch/i386/kernel/entry.S       |    5 +-
 arch/i386/kernel/head.S        |   31 ++--------
 arch/i386/kernel/i386_ksyms.c  |    2 -
 arch/i386/kernel/irq.c         |    3 +
 arch/i386/kernel/process.c     |   12 +++-
 arch/i386/kernel/smpboot.c     |   30 ++++-----
 arch/i386/kernel/vmi.c         |    6 +--
 arch/i386/kernel/vmlinux.lds.S |    1 -
 include/asm-i386/current.h     |    5 +-
 include/asm-i386/irq_regs.h    |   12 ++--
 include/asm-i386/pda.h         |   99 ------------------------------
 include/asm-i386/percpu.h      |  132 +++++++++++++++++++++++++++++++++++++---
 include/asm-i386/processor.h   |    2 +-
 include/asm-i386/segment.h     |    6 +-
 include/asm-i386/smp.h         |    4 +-
 17 files changed, 177 insertions(+), 195 deletions(-)

diff --git a/arch/i386/kernel/asm-offsets.c b/arch/i386/kernel/asm-offsets.c
index d558adf..b05e85f 100644
--- a/arch/i386/kernel/asm-offsets.c
+++ b/arch/i386/kernel/asm-offsets.c
@@ -15,7 +15,6 @@
 #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))
@@ -101,10 +100,6 @@ void foo(void)
 
        OFFSET(crypto_tfm_ctx_offset, crypto_tfm, __crt_ctx);
 
-       BLANK();
-       OFFSET(PDA_cpu, i386_pda, cpu_number);
-       OFFSET(PDA_pcurrent, i386_pda, pcurrent);
-
 #ifdef CONFIG_PARAVIRT
        BLANK();
        OFFSET(PARAVIRT_enabled, paravirt_ops, paravirt_enabled);
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index 7a4c036..27e0056 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
diff --git a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
index 3e4aa1f..7f92ceb 100644
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -132,7 +132,7 @@ VM_MASK             = 0x00020000
        movl $(__USER_DS), %edx; \
        movl %edx, %ds; \
        movl %edx, %es; \
-       movl $(__KERNEL_PDA), %edx; \
+       movl $(__KERNEL_PERCPU), %edx; \
        movl %edx, %fs
 
 #define RESTORE_INT_REGS \
@@ -556,7 +556,6 @@ END(syscall_badsys)
 
 #define FIXUP_ESPFIX_STACK \
        /* since we are on a wrong stack, we cant make it a C code :( */ \
-       movl %fs:PDA_cpu, %ebx; \
        PER_CPU(gdt_page, %ebx); \
        GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \
        addl %esp, %eax; \
@@ -681,7 +680,7 @@ error_code:
        pushl %fs
        CFI_ADJUST_CFA_OFFSET 4
        /*CFI_REL_OFFSET fs, 0*/
-       movl $(__KERNEL_PDA), %ecx
+       movl $(__KERNEL_PERCPU), %ecx
        movl %ecx, %fs
        UNWIND_ESPFIX_STACK
        popl %ecx
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S
index bb36c24..12277d8 100644
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -317,12 +317,12 @@ is386:    movl $2,%ecx            # set MP
        movl %eax,%cr0
 
        call check_x87
-       call setup_pda
        lgdt early_gdt_descr
        lidt idt_descr
        ljmp $(__KERNEL_CS),$1f
 1:     movl $(__KERNEL_DS),%eax        # reload all the segment registers
        movl %eax,%ss                   # after changing gdt.
+       movl %eax,%fs                   # gets reset once there's real percpu
 
        movl $(__USER_DS),%eax          # DS/ES contains default USER segment
        movl %eax,%ds
@@ -332,16 +332,17 @@ is386:    movl $2,%ecx            # set MP
        movl %eax,%gs
        lldt %ax
 
-       movl $(__KERNEL_PDA),%eax
-       mov  %eax,%fs
-
        cld                     # gcc2 wants the direction flag cleared at all 
times
        pushl $0                # fake return address for unwinder
 #ifdef CONFIG_SMP
        movb ready, %cl
        movb $1, ready
        cmpb $0,%cl             # the first CPU calls start_kernel
-       jne initialize_secondary # all other CPUs call initialize_secondary
+       je   1f
+       movl $(__KERNEL_PERCPU), %eax
+       movl %eax,%fs           # set this cpu's percpu
+       jmp initialize_secondary # all other CPUs call initialize_secondary
+1:
 #endif /* CONFIG_SMP */
        jmp start_kernel
 
@@ -365,23 +366,6 @@ check_x87:
        ret
 
 /*
- * Point the GDT at this CPU's PDA.  On boot this will be
- * cpu_gdt_table and boot_pda; for secondary CPUs, these will be
- * that CPU's GDT and PDA.
- */
-ENTRY(setup_pda)
-       /* get the PDA pointer */
-       movl start_pda, %eax
-
-       /* slot the PDA address into the GDT */
-       mov early_gdt_descr+2, %ecx
-       mov %ax, (__KERNEL_PDA+0+2)(%ecx)               /* base & 0x0000ffff */
-       shr $16, %eax
-       mov %al, (__KERNEL_PDA+4+0)(%ecx)               /* base & 0x00ff0000 */
-       mov %ah, (__KERNEL_PDA+4+3)(%ecx)               /* base & 0xff000000 */
-       ret
-
-/*
  *  setup_idt
  *
  *  sets up a idt with 256 entries pointing to
@@ -553,9 +537,6 @@ ENTRY(empty_zero_page)
  * This starts the data section.
  */
 .data
-ENTRY(start_pda)
-       .long boot_pda
-
 ENTRY(stack_start)
        .long init_thread_union+THREAD_SIZE
        .long __BOOT_DS
diff --git a/arch/i386/kernel/i386_ksyms.c b/arch/i386/kernel/i386_ksyms.c
index 4afe26e..e3d4b73 100644
--- a/arch/i386/kernel/i386_ksyms.c
+++ b/arch/i386/kernel/i386_ksyms.c
@@ -28,5 +28,3 @@ EXPORT_SYMBOL(__read_lock_failed);
 #endif
 
 EXPORT_SYMBOL(csum_partial);
-
-EXPORT_SYMBOL(_proxy_pda);
diff --git a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c
index 8db8d51..d2daf67 100644
--- a/arch/i386/kernel/irq.c
+++ b/arch/i386/kernel/irq.c
@@ -24,6 +24,9 @@
 DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_internodealigned_in_smp;
 EXPORT_PER_CPU_SYMBOL(irq_stat);
 
+DEFINE_PER_CPU(struct pt_regs *, irq_regs);
+EXPORT_PER_CPU_SYMBOL(irq_regs);
+
 /*
  * 'what should we do if we get a hw irq event on an illegal vector'.
  * each architecture has to answer this themselves.
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 5fb9524..6199947 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -39,6 +39,7 @@
 #include <linux/random.h>
 #include <linux/personality.h>
 #include <linux/tick.h>
+#include <linux/percpu.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -57,7 +58,6 @@
 
 #include <asm/tlbflush.h>
 #include <asm/cpu.h>
-#include <asm/pda.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
@@ -66,6 +66,12 @@ static int hlt_counter;
 unsigned long boot_option_idle_override = 0;
 EXPORT_SYMBOL(boot_option_idle_override);
 
+DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
+EXPORT_PER_CPU_SYMBOL(current_task);
+
+DEFINE_PER_CPU(int, cpu_number);
+EXPORT_PER_CPU_SYMBOL(cpu_number);
+
 /*
  * Return saved PC of a blocked thread.
  */
@@ -342,7 +348,7 @@ int kernel_thread(int (*fn)(void *), void * arg, unsigned 
long flags)
 
        regs.xds = __USER_DS;
        regs.xes = __USER_DS;
-       regs.xfs = __KERNEL_PDA;
+       regs.xfs = __KERNEL_PERCPU;
        regs.orig_eax = -1;
        regs.eip = (unsigned long) kernel_thread_helper;
        regs.xcs = __KERNEL_CS | get_kernel_rpl();
@@ -711,7 +717,7 @@ struct task_struct fastcall * __switch_to(struct 
task_struct *prev_p, struct tas
        if (prev->gs | next->gs)
                loadsegment(gs, next->gs);
 
-       write_pda(pcurrent, next_p);
+       x86_write_percpu(current_task, next_p);
 
        return prev_p;
 }
diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index 61e2842..f79b623 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -53,7 +53,6 @@
 #include <asm/desc.h>
 #include <asm/arch_hooks.h>
 #include <asm/nmi.h>
-#include <asm/pda.h>
 
 #include <mach_apic.h>
 #include <mach_wakecpu.h>
@@ -99,6 +98,9 @@ EXPORT_SYMBOL(x86_cpu_to_apicid);
 
 u8 apicid_2_node[MAX_APICID];
 
+DEFINE_PER_CPU(unsigned long, this_cpu_off);
+EXPORT_PER_CPU_SYMBOL(this_cpu_off);
+
 /*
  * Trampoline 80x86 program as an array.
  */
@@ -456,7 +458,6 @@ extern struct {
        void * esp;
        unsigned short ss;
 } stack_start;
-extern struct i386_pda *start_pda;
 
 #ifdef CONFIG_NUMA
 
@@ -784,20 +785,17 @@ static inline struct task_struct * alloc_idle_task(int 
cpu)
 /* Initialize the CPU's GDT.  This is either the boot CPU doing itself
    (still using the master per-cpu area), or a CPU doing it for a
    secondary which will soon come up. */
-static __cpuinit void init_gdt(int cpu, struct task_struct *idle)
+static __cpuinit void init_gdt(int cpu)
 {
        struct desc_struct *gdt = get_cpu_gdt_table(cpu);
-       struct i386_pda *pda = &per_cpu(_cpu_pda, cpu);
 
-       pack_descriptor((u32 *)&gdt[GDT_ENTRY_PDA].a,
-                       (u32 *)&gdt[GDT_ENTRY_PDA].b,
-                       (unsigned long)pda, sizeof(*pda) - 1,
-                       0x80 | DESCTYPE_S | 0x2, 0); /* present read-write data 
segment */
+       pack_descriptor((u32 *)&gdt[GDT_ENTRY_PERCPU].a,
+                       (u32 *)&gdt[GDT_ENTRY_PERCPU].b,
+                       __per_cpu_offset[cpu], 0xFFFFF,
+                       0x80 | DESCTYPE_S | 0x2, 0x8);
 
-       memset(pda, 0, sizeof(*pda));
-       pda->_pda = pda;
-       pda->cpu_number = cpu;
-       pda->pcurrent = idle;
+       per_cpu(this_cpu_off, cpu) = __per_cpu_offset[cpu];
+       per_cpu(cpu_number, cpu) = cpu;
 }
 
 /* Defined in head.S */
@@ -824,9 +822,9 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
        if (IS_ERR(idle))
                panic("failed fork for CPU %d", cpu);
 
-       init_gdt(cpu, idle);
+       init_gdt(cpu);
+       per_cpu(current_task, cpu) = idle;
        early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
-       start_pda = cpu_pda(cpu);
 
        idle->thread.eip = (unsigned long) start_secondary;
        /* start_eip had better be page-aligned! */
@@ -1188,14 +1186,14 @@ static inline void switch_to_new_gdt(void)
        gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());
        gdt_descr.size = GDT_SIZE - 1;
        load_gdt(&gdt_descr);
-       asm volatile ("mov %0, %%fs" : : "r" (__KERNEL_PDA) : "memory");
+       asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory");
 }
 
 void __init native_smp_prepare_boot_cpu(void)
 {
        unsigned int cpu = smp_processor_id();
 
-       init_gdt(cpu, current);
+       init_gdt(cpu);
        switch_to_new_gdt();
 
        cpu_set(cpu, cpu_online_map);
diff --git a/arch/i386/kernel/vmi.c b/arch/i386/kernel/vmi.c
index ccad7ee..1231298 100644
--- a/arch/i386/kernel/vmi.c
+++ b/arch/i386/kernel/vmi.c
@@ -504,8 +504,6 @@ static void vmi_pmd_clear(pmd_t *pmd)
 #endif
 
 #ifdef CONFIG_SMP
-extern void setup_pda(void);
-
 static void __devinit
 vmi_startup_ipi_hook(int phys_apicid, unsigned long start_eip,
                     unsigned long start_esp)
@@ -530,13 +528,11 @@ vmi_startup_ipi_hook(int phys_apicid, unsigned long 
start_eip,
 
        ap.ds = __USER_DS;
        ap.es = __USER_DS;
-       ap.fs = __KERNEL_PDA;
+       ap.fs = __KERNEL_PERCPU;
        ap.gs = 0;
 
        ap.eflags = 0;
 
-       setup_pda();
-
 #ifdef CONFIG_X86_PAE
        /* efer should match BSP efer. */
        if (cpu_has_nx) {
diff --git a/arch/i386/kernel/vmlinux.lds.S b/arch/i386/kernel/vmlinux.lds.S
index 2ce4aa1..d125784 100644
--- a/arch/i386/kernel/vmlinux.lds.S
+++ b/arch/i386/kernel/vmlinux.lds.S
@@ -26,7 +26,6 @@ OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
 OUTPUT_ARCH(i386)
 ENTRY(phys_startup_32)
 jiffies = jiffies_64;
-_proxy_pda = 1;
 
 PHDRS {
        text PT_LOAD FLAGS(5);  /* R_E */
diff --git a/include/asm-i386/current.h b/include/asm-i386/current.h
index 5252ee0..d352485 100644
--- a/include/asm-i386/current.h
+++ b/include/asm-i386/current.h
@@ -1,14 +1,15 @@
 #ifndef _I386_CURRENT_H
 #define _I386_CURRENT_H
 
-#include <asm/pda.h>
 #include <linux/compiler.h>
+#include <asm/percpu.h>
 
 struct task_struct;
 
+DECLARE_PER_CPU(struct task_struct *, current_task);
 static __always_inline struct task_struct *get_current(void)
 {
-       return read_pda(pcurrent);
+       return x86_read_percpu(current_task);
 }
  
 #define current get_current()
diff --git a/include/asm-i386/irq_regs.h b/include/asm-i386/irq_regs.h
index a1b3f7f..3368b20 100644
--- a/include/asm-i386/irq_regs.h
+++ b/include/asm-i386/irq_regs.h
@@ -1,25 +1,27 @@
 /*
  * Per-cpu current frame pointer - the location of the last exception frame on
- * the stack, stored in the PDA.
+ * the stack, stored in the per-cpu area.
  *
  * Jeremy Fitzhardinge <[EMAIL PROTECTED]>
  */
 #ifndef _ASM_I386_IRQ_REGS_H
 #define _ASM_I386_IRQ_REGS_H
 
-#include <asm/pda.h>
+#include <asm/percpu.h>
+
+DECLARE_PER_CPU(struct pt_regs *, irq_regs);
 
 static inline struct pt_regs *get_irq_regs(void)
 {
-       return read_pda(irq_regs);
+       return x86_read_percpu(irq_regs);
 }
 
 static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs)
 {
        struct pt_regs *old_regs;
 
-       old_regs = read_pda(irq_regs);
-       write_pda(irq_regs, new_regs);
+       old_regs = get_irq_regs();
+       x86_write_percpu(irq_regs, new_regs);
 
        return old_regs;
 }
diff --git a/include/asm-i386/pda.h b/include/asm-i386/pda.h
deleted file mode 100644
index aef7f73..0000000
--- a/include/asm-i386/pda.h
+++ /dev/null
@@ -1,99 +0,0 @@
-/*
-   Per-processor Data Areas
-   Jeremy Fitzhardinge <[EMAIL PROTECTED]> 2006
-   Based on asm-x86_64/pda.h by Andi Kleen.
- */
-#ifndef _I386_PDA_H
-#define _I386_PDA_H
-
-#include <linux/stddef.h>
-#include <linux/types.h>
-#include <asm/percpu.h>
-
-struct i386_pda
-{
-       struct i386_pda *_pda;          /* pointer to self */
-
-       int cpu_number;
-       struct task_struct *pcurrent;   /* current process */
-       struct pt_regs *irq_regs;
-};
-
-DECLARE_PER_CPU(struct i386_pda, _cpu_pda);
-#define cpu_pda(i)     (&per_cpu(_cpu_pda, (i)))
-#define pda_offset(field) offsetof(struct i386_pda, field)
-
-extern void __bad_pda_field(void);
-
-/* This variable is never instantiated.  It is only used as a stand-in
-   for the real per-cpu PDA memory, so that gcc can understand what
-   memory operations the inline asms() below are performing.  This
-   eliminates the need to make the asms volatile or have memory
-   clobbers, so gcc can readily analyse them. */
-extern struct i386_pda _proxy_pda;
-
-#define pda_to_op(op,field,val)                                                
\
-       do {                                                            \
-               typedef typeof(_proxy_pda.field) T__;                   \
-               if (0) { T__ tmp__; tmp__ = (val); }                    \
-               switch (sizeof(_proxy_pda.field)) {                     \
-               case 1:                                                 \
-                       asm(op "b %1,%%fs:%c2"                          \
-                           : "+m" (_proxy_pda.field)                   \
-                           :"ri" ((T__)val),                           \
-                            "i"(pda_offset(field)));                   \
-                       break;                                          \
-               case 2:                                                 \
-                       asm(op "w %1,%%fs:%c2"                          \
-                           : "+m" (_proxy_pda.field)                   \
-                           :"ri" ((T__)val),                           \
-                            "i"(pda_offset(field)));                   \
-                       break;                                          \
-               case 4:                                                 \
-                       asm(op "l %1,%%fs:%c2"                          \
-                           : "+m" (_proxy_pda.field)                   \
-                           :"ri" ((T__)val),                           \
-                            "i"(pda_offset(field)));                   \
-                       break;                                          \
-               default: __bad_pda_field();                             \
-               }                                                       \
-       } while (0)
-
-#define pda_from_op(op,field)                                          \
-       ({                                                              \
-               typeof(_proxy_pda.field) ret__;                         \
-               switch (sizeof(_proxy_pda.field)) {                     \
-               case 1:                                                 \
-                       asm(op "b %%fs:%c1,%0"                          \
-                           : "=r" (ret__)                              \
-                           : "i" (pda_offset(field)),                  \
-                             "m" (_proxy_pda.field));                  \
-                       break;                                          \
-               case 2:                                                 \
-                       asm(op "w %%fs:%c1,%0"                          \
-                           : "=r" (ret__)                              \
-                           : "i" (pda_offset(field)),                  \
-                             "m" (_proxy_pda.field));                  \
-                       break;                                          \
-               case 4:                                                 \
-                       asm(op "l %%fs:%c1,%0"                          \
-                           : "=r" (ret__)                              \
-                           : "i" (pda_offset(field)),                  \
-                             "m" (_proxy_pda.field));                  \
-                       break;                                          \
-               default: __bad_pda_field();                             \
-               }                                                       \
-               ret__; })
-
-/* Return a pointer to a pda field */
-#define pda_addr(field)                                                        
\
-       ((typeof(_proxy_pda.field) *)((unsigned char *)read_pda(_pda) + \
-                                     pda_offset(field)))
-
-#define read_pda(field) pda_from_op("mov",field)
-#define write_pda(field,val) pda_to_op("mov",field,val)
-#define add_pda(field,val) pda_to_op("add",field,val)
-#define sub_pda(field,val) pda_to_op("sub",field,val)
-#define or_pda(field,val) pda_to_op("or",field,val)
-
-#endif /* _I386_PDA_H */
diff --git a/include/asm-i386/percpu.h b/include/asm-i386/percpu.h
index a10e7c6..c5f12f0 100644
--- a/include/asm-i386/percpu.h
+++ b/include/asm-i386/percpu.h
@@ -1,9 +1,30 @@
 #ifndef __ARCH_I386_PERCPU__
 #define __ARCH_I386_PERCPU__
 
-#ifndef __ASSEMBLY__
-#include <asm-generic/percpu.h>
-#else
+#ifdef __ASSEMBLY__
+
+/*
+ * PER_CPU finds an address of a per-cpu variable.
+ *
+ * Args:
+ *    var - variable name
+ *    reg - 32bit register
+ *
+ * The resulting address is stored in the "reg" argument.
+ *
+ * Example:
+ *    PER_CPU(cpu_gdt_descr, %ebx)
+ */
+#ifdef CONFIG_SMP
+#define PER_CPU(var, reg)                      \
+       movl %fs:per_cpu__this_cpu_off, reg;            \
+       addl $per_cpu__##var, reg
+#else /* ! SMP */
+#define PER_CPU(var, reg) \
+       movl $per_cpu__##var, reg;
+#endif /* SMP */
+
+#else /* ...!ASSEMBLY */
 
 /*
  * PER_CPU finds an address of a per-cpu variable.
@@ -18,14 +39,107 @@
  *    PER_CPU(cpu_gdt_descr, %ebx)
  */
 #ifdef CONFIG_SMP
-#define PER_CPU(var, cpu) \
-       movl __per_cpu_offset(,cpu,4), cpu;     \
-       addl $per_cpu__##var, cpu;
-#else /* ! SMP */
-#define PER_CPU(var, cpu) \
-       movl $per_cpu__##var, cpu;
+/* Same as generic implementation except for optimized local access. */
+#define __GENERIC_PER_CPU
+
+/* This is used for other cpus to find our section. */
+extern unsigned long __per_cpu_offset[];
+
+/* Separate out the type, so (int[3], foo) works. */
+#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu__##name
+#define DEFINE_PER_CPU(type, name) \
+    __attribute__((__section__(".data.percpu"))) __typeof__(type) 
per_cpu__##name
+
+/* We can use this directly for local CPU (faster). */
+DECLARE_PER_CPU(unsigned long, this_cpu_off);
+
+/* var is in discarded region: offset to particular copy we want */
+#define per_cpu(var, cpu) (*({                         \
+       extern int simple_indentifier_##var(void);      \
+       RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]); }))
+
+#define __raw_get_cpu_var(var) (*({                                    \
+       extern int simple_indentifier_##var(void);                      \
+       RELOC_HIDE(&per_cpu__##var, x86_read_percpu(this_cpu_off));     \
+}))
+
+#define __get_cpu_var(var) __raw_get_cpu_var(var)
+
+/* A macro to avoid #include hell... */
+#define percpu_modcopy(pcpudst, src, size)                     \
+do {                                                           \
+       unsigned int __i;                                       \
+       for_each_possible_cpu(__i)                              \
+               memcpy((pcpudst)+__per_cpu_offset[__i],         \
+                      (src), (size));                          \
+} while (0)
+
+#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
+#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
+
+/* fs segment starts at (positive) offset == __per_cpu_offset[cpu] */
+#define __percpu_seg "%%fs:"
+#else  /* !SMP */
+#include <asm-generic/percpu.h>
+#define __percpu_seg ""
 #endif /* SMP */
 
+/* For arch-specific code, we can use direct single-insn ops (they
+ * don't give an lvalue though). */
+extern void __bad_percpu_size(void);
+
+#define percpu_to_op(op,var,val)                               \
+       do {                                                    \
+               typedef typeof(var) T__;                        \
+               if (0) { T__ tmp__; tmp__ = (val); }            \
+               switch (sizeof(var)) {                          \
+               case 1:                                         \
+                       asm(op "b %1,"__percpu_seg"%0"          \
+                           : "+m" (var)                        \
+                           :"ri" ((T__)val));                  \
+                       break;                                  \
+               case 2:                                         \
+                       asm(op "w %1,"__percpu_seg"%0"          \
+                           : "+m" (var)                        \
+                           :"ri" ((T__)val));                  \
+                       break;                                  \
+               case 4:                                         \
+                       asm(op "l %1,"__percpu_seg"%0"          \
+                           : "+m" (var)                        \
+                           :"ri" ((T__)val));                  \
+                       break;                                  \
+               default: __bad_percpu_size();                   \
+               }                                               \
+       } while (0)
+
+#define percpu_from_op(op,var)                                 \
+       ({                                                      \
+               typeof(var) ret__;                              \
+               switch (sizeof(var)) {                          \
+               case 1:                                         \
+                       asm(op "b "__percpu_seg"%1,%0"          \
+                           : "=r" (ret__)                      \
+                           : "m" (var));                       \
+                       break;                                  \
+               case 2:                                         \
+                       asm(op "w "__percpu_seg"%1,%0"          \
+                           : "=r" (ret__)                      \
+                           : "m" (var));                       \
+                       break;                                  \
+               case 4:                                         \
+                       asm(op "l "__percpu_seg"%1,%0"          \
+                           : "=r" (ret__)                      \
+                           : "m" (var));                       \
+                       break;                                  \
+               default: __bad_percpu_size();                   \
+               }                                               \
+               ret__; })
+
+#define x86_read_percpu(var) percpu_from_op("mov", per_cpu__##var)
+#define x86_write_percpu(var,val) percpu_to_op("mov", per_cpu__##var, val)
+#define x86_add_percpu(var,val) percpu_to_op("add", per_cpu__##var, val)
+#define x86_sub_percpu(var,val) percpu_to_op("sub", per_cpu__##var, val)
+#define x86_or_percpu(var,val) percpu_to_op("or", per_cpu__##var, val)
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ARCH_I386_PERCPU__ */
diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h
index 9222604..ced2da8 100644
--- a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -377,7 +377,7 @@ struct thread_struct {
        .vm86_info = NULL,                                              \
        .sysenter_cs = __KERNEL_CS,                                     \
        .io_bitmap_ptr = NULL,                                          \
-       .fs = __KERNEL_PDA,                                             \
+       .fs = __KERNEL_PERCPU,                                          \
 }
 
 /*
diff --git a/include/asm-i386/segment.h b/include/asm-i386/segment.h
index 065f10b..07e7062 100644
--- a/include/asm-i386/segment.h
+++ b/include/asm-i386/segment.h
@@ -39,7 +39,7 @@
  *  25 - APM BIOS support 
  *
  *  26 - ESPFIX small SS
- *  27 - PDA                           [ per-cpu private data area ]
+ *  27 - per-cpu                       [ offset to per-cpu data area ]
  *  28 - unused
  *  29 - unused
  *  30 - unused
@@ -74,8 +74,8 @@
 #define GDT_ENTRY_ESPFIX_SS            (GDT_ENTRY_KERNEL_BASE + 14)
 #define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8)
 
-#define GDT_ENTRY_PDA                  (GDT_ENTRY_KERNEL_BASE + 15)
-#define __KERNEL_PDA (GDT_ENTRY_PDA * 8)
+#define GDT_ENTRY_PERCPU                       (GDT_ENTRY_KERNEL_BASE + 15)
+#define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8)
 
 #define GDT_ENTRY_DOUBLEFAULT_TSS      31
 
diff --git a/include/asm-i386/smp.h b/include/asm-i386/smp.h
index 2d083cb..090abc1 100644
--- a/include/asm-i386/smp.h
+++ b/include/asm-i386/smp.h
@@ -8,7 +8,6 @@
 #include <linux/kernel.h>
 #include <linux/threads.h>
 #include <linux/cpumask.h>
-#include <asm/pda.h>
 #endif
 
 #if defined(CONFIG_X86_LOCAL_APIC) && !defined(__ASSEMBLY__)
@@ -112,7 +111,8 @@ do { } while (0)
  * from the initial startup. We map APIC_BASE very early in page_setup(),
  * so this is correct in the x86 case.
  */
-#define raw_smp_processor_id() (read_pda(cpu_number))
+DECLARE_PER_CPU(int, cpu_number);
+#define raw_smp_processor_id() (x86_read_percpu(cpu_number))
 
 extern cpumask_t cpu_callout_map;
 extern cpumask_t cpu_callin_map;
-
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