Merge branch 'tj-percpu' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/percpu

8 files changed, 29 insertions, 87 deletions

diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index 64c834a39aa..8793ab33e2c 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -11,7 +11,6 @@
 #include <linux/hardirq.h>
 #include <linux/suspend.h>
 #include <linux/kbuild.h>
-#include <asm/pda.h>
 #include <asm/processor.h>
 #include <asm/segment.h>
 #include <asm/thread_info.h>
@@ -48,10 +47,6 @@ int main(void)
 #endif
 	BLANK();
 #undef ENTRY
-#define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry))
-	DEFINE(pda_size, sizeof(struct x8664_pda));
-	BLANK();
-#undef ENTRY
 #ifdef CONFIG_PARAVIRT
 	BLANK();
 	OFFSET(PARAVIRT_enabled, pv_info, paravirt_enabled);
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 7976a6a0f65..3887fcf6e51 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -30,7 +30,6 @@
 #include <asm/genapic.h>
 #endif
 
-#include <asm/pda.h>
 #include <asm/pgtable.h>
 #include <asm/processor.h>
 #include <asm/desc.h>
@@ -881,12 +880,13 @@ __setup("clearcpuid=", setup_disablecpuid);
 #ifdef CONFIG_X86_64
 struct desc_ptr idt_descr = { 256 * 16 - 1, (unsigned long) idt_table };
 
-DEFINE_PER_CPU_PAGE_ALIGNED(char[IRQ_STACK_SIZE], irq_stack);
+DEFINE_PER_CPU_FIRST(union irq_stack_union,
+		     irq_stack_union) __aligned(PAGE_SIZE);
 #ifdef CONFIG_SMP
 DEFINE_PER_CPU(char *, irq_stack_ptr);	/* will be set during per cpu init */
 #else
 DEFINE_PER_CPU(char *, irq_stack_ptr) =
-	per_cpu_var(irq_stack) + IRQ_STACK_SIZE - 64;
+	per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64;
 #endif
 
 DEFINE_PER_CPU(unsigned long, kernel_stack) =
@@ -895,15 +895,6 @@ EXPORT_PER_CPU_SYMBOL(kernel_stack);
 
 DEFINE_PER_CPU(unsigned int, irq_count) = -1;
 
-void __cpuinit pda_init(int cpu)
-{
-	/* Setup up data that may be needed in __get_free_pages early */
-	loadsegment(fs, 0);
-	loadsegment(gs, 0);
-
-	load_pda_offset(cpu);
-}
-
 static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
 	[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ])
 	__aligned(PAGE_SIZE);
@@ -967,9 +958,9 @@ void __cpuinit cpu_init(void)
 	struct task_struct *me;
 	int i;
 
-	/* CPU 0 is initialised in head64.c */
-	if (cpu != 0)
-		pda_init(cpu);
+	loadsegment(fs, 0);
+	loadsegment(gs, 0);
+	load_gs_base(cpu);
 
 #ifdef CONFIG_NUMA
 	if (cpu != 0 && percpu_read(node_number) == 0 &&
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index af67d3227ea..f5b27224769 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -91,8 +91,6 @@ void __init x86_64_start_kernel(char * real_mode_data)
 	if (console_loglevel == 10)
 		early_printk("Kernel alive\n");
 
-	pda_init(0);
-
 	x86_64_start_reservations(real_mode_data);
 }
 
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index c8ace880661..a0a2b5ca9b7 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -207,19 +207,15 @@ ENTRY(secondary_startup_64)
 
 #ifdef CONFIG_SMP
 	/*
-	 * early_gdt_base should point to the gdt_page in static percpu init
-	 * data area.  Computing this requires two symbols - __per_cpu_load
-	 * and per_cpu__gdt_page.  As linker can't do no such relocation, do
-	 * it by hand.  As early_gdt_descr is manipulated by C code for
-	 * secondary CPUs, this should be done only once for the boot CPU
-	 * when early_gdt_descr_base contains zero.
+	 * Fix up static pointers that need __per_cpu_load added.  The assembler
+	 * is unable to do this directly.  This is only needed for the boot cpu.
+	 * These values are set up with the correct base addresses by C code for
+	 * secondary cpus.
 	 */
-	movq	early_gdt_descr_base(%rip), %rax
-	testq	%rax, %rax
-	jnz	1f
-	movq	$__per_cpu_load, %rax
-	addq	$per_cpu__gdt_page, %rax
-	movq	%rax, early_gdt_descr_base(%rip)
+	movq	initial_gs(%rip), %rax
+	cmpl	$0, per_cpu__cpu_number(%rax)
+	jne	1f
+	addq	%rax, early_gdt_descr_base(%rip)
 1:
 #endif
 	/*
@@ -246,13 +242,10 @@ ENTRY(secondary_startup_64)
 
 	/* Set up %gs.
 	 *
-	 * On SMP, %gs should point to the per-cpu area.  For initial
-	 * boot, make %gs point to the init data section.  For a
-	 * secondary CPU,initial_gs should be set to its pda address
-	 * before the CPU runs this code.
-	 *
-	 * On UP, initial_gs points to PER_CPU_VAR(__pda) and doesn't
-	 * change.
+	 * The base of %gs always points to the bottom of the irqstack
+	 * union.  If the stack protector canary is enabled, it is
+	 * located at %gs:40.  Note that, on SMP, the boot cpu uses
+	 * init data section till per cpu areas are set up.
 	 */
 	movl	$MSR_GS_BASE,%ecx
 	movq	initial_gs(%rip),%rax
@@ -285,7 +278,7 @@ ENTRY(secondary_startup_64)
 #ifdef CONFIG_SMP
 	.quad	__per_cpu_load
 #else
-	.quad	PER_CPU_VAR(__pda)
+	.quad	PER_CPU_VAR(irq_stack_union)
 #endif
 	__FINITDATA
 
@@ -431,12 +424,8 @@ NEXT_PAGE(level2_spare_pgt)
 	.globl early_gdt_descr
 early_gdt_descr:
 	.word	GDT_ENTRIES*8-1
-#ifdef CONFIG_SMP
 early_gdt_descr_base:
-	.quad   0x0000000000000000
-#else
 	.quad	per_cpu__gdt_page
-#endif
 
 ENTRY(phys_base)
 	/* This must match the first entry in level2_kernel_pgt */
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index aa89eabf09e..c422eebb0c5 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -47,7 +47,6 @@
 #include <asm/processor.h>
 #include <asm/i387.h>
 #include <asm/mmu_context.h>
-#include <asm/pda.h>
 #include <asm/prctl.h>
 #include <asm/desc.h>
 #include <asm/proto.h>
@@ -638,13 +637,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	percpu_write(kernel_stack,
 		  (unsigned long)task_stack_page(next_p) +
 		  THREAD_SIZE - KERNEL_STACK_OFFSET);
-#ifdef CONFIG_CC_STACKPROTECTOR
-	/*
-	 * Build time only check to make sure the stack_canary is at
-	 * offset 40 in the pda; this is a gcc ABI requirement
-	 */
-	BUILD_BUG_ON(offsetof(struct x8664_pda, stack_canary) != 40);
-#endif
 
 	/*
 	 * Now maybe reload the debug registers and handle I/O bitmaps
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index efbafbbff58..90b8e154bb5 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -77,30 +77,6 @@ static void __init setup_node_to_cpumask_map(void);
 static inline void setup_node_to_cpumask_map(void) { }
 #endif
 
-/*
- * Define load_pda_offset() and per-cpu __pda for x86_64.
- * load_pda_offset() is responsible for loading the offset of pda into
- * %gs.
- *
- * On SMP, pda offset also duals as percpu base address and thus it
- * should be at the start of per-cpu area.  To achieve this, it's
- * preallocated in vmlinux_64.lds.S directly instead of using
- * DEFINE_PER_CPU().
- */
-#ifdef CONFIG_X86_64
-void __cpuinit load_pda_offset(int cpu)
-{
-	/* Memory clobbers used to order pda/percpu accesses */
-	mb();
-	wrmsrl(MSR_GS_BASE, cpu_pda(cpu));
-	mb();
-}
-#ifndef CONFIG_SMP
-DEFINE_PER_CPU(struct x8664_pda, __pda);
-#endif
-EXPORT_PER_CPU_SYMBOL(__pda);
-#endif /* CONFIG_SMP && CONFIG_X86_64 */
-
 #ifdef CONFIG_X86_64
 
 /* correctly size the local cpu masks */
@@ -207,15 +183,13 @@ void __init setup_per_cpu_areas(void)
 		per_cpu(cpu_number, cpu) = cpu;
 #ifdef CONFIG_X86_64
 		per_cpu(irq_stack_ptr, cpu) =
-			(char *)per_cpu(irq_stack, cpu) + IRQ_STACK_SIZE - 64;
+			per_cpu(irq_stack_union.irq_stack, cpu) + IRQ_STACK_SIZE - 64;
 		/*
-		 * CPU0 modified pda in the init data area, reload pda
-		 * offset for CPU0 and clear the area for others.
+		 * Up to this point, CPU0 has been using .data.init
+		 * area.  Reload %gs offset for CPU0.
 		 */
 		if (cpu == 0)
-			load_pda_offset(0);
-		else
-			memset(cpu_pda(cpu), 0, sizeof(*cpu_pda(cpu)));
+			load_gs_base(cpu);
 #endif
 
 		DBG("PERCPU: cpu %4d %p\n", cpu, ptr);
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 98c2d055284..ed5aee5f3fc 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -59,7 +59,6 @@
 #ifdef CONFIG_X86_64
 #include <asm/pgalloc.h>
 #include <asm/proto.h>
-#include <asm/pda.h>
 #else
 #include <asm/processor-flags.h>
 #include <asm/arch_hooks.h>
diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S
index a09abb8fb97..c9740996430 100644
--- a/arch/x86/kernel/vmlinux_64.lds.S
+++ b/arch/x86/kernel/vmlinux_64.lds.S
@@ -220,8 +220,7 @@ SECTIONS
    * so that it can be accessed as a percpu variable.
    */
   . = ALIGN(PAGE_SIZE);
-  PERCPU_VADDR_PREALLOC(0, :percpu, pda_size)
-  per_cpu____pda = __per_cpu_start;
+  PERCPU_VADDR(0, :percpu)
 #else
   PERCPU(PAGE_SIZE)
 #endif
@@ -262,3 +261,8 @@ SECTIONS
  */
 ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
 	"kernel image bigger than KERNEL_IMAGE_SIZE")
+
+#ifdef CONFIG_SMP
+ASSERT((per_cpu__irq_stack_union == 0),
+        "irq_stack_union is not at start of per-cpu area");
+#endif