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Commit 2697fbd5 authored by Brian Gerst's avatar Brian Gerst Committed by Tejun Heo
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x86: load new GDT after setting up boot cpu per-cpu area 



Impact: sync 32 and 64-bit code

Merge load_gs_base() into switch_to_new_gdt().  Load the GDT and
per-cpu state for the boot cpu when its new area is set up.

Signed-off-by: default avatarBrian Gerst <brgerst@gmail.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 1825b8ed

arch/x86/include/asm/processor.h

+0 −5
Original line number Diff line number Diff line
@@ -394,11 +394,6 @@ union irq_stack_union { 


DECLARE_PER_CPU(union irq_stack_union, irq_stack_union);

DECLARE_PER_CPU(char *, irq_stack_ptr);



static inline void load_gs_base(int cpu)

{

	wrmsrl(MSR_GS_BASE, (unsigned long)per_cpu(irq_stack_union.gs_base, cpu));

}

#endif



extern void print_cpu_info(struct cpuinfo_x86 *);

arch/x86/kernel/cpu/common.c

+9 −6
Original line number Diff line number Diff line
@@ -258,12 +258,17 @@ __u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata; 
void switch_to_new_gdt(void)

{

	struct desc_ptr gdt_descr;

	int cpu = smp_processor_id();



	gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());

	gdt_descr.address = (long)get_cpu_gdt_table(cpu);

	gdt_descr.size = GDT_SIZE - 1;

	load_gdt(&gdt_descr);

	/* Reload the per-cpu base */

#ifdef CONFIG_X86_32

	asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory");

	loadsegment(fs, __KERNEL_PERCPU);

#else

	loadsegment(gs, 0);

	wrmsrl(MSR_GS_BASE, (unsigned long)per_cpu(irq_stack_union.gs_base, cpu));

#endif

}
@@ -968,10 +973,6 @@ void __cpuinit cpu_init(void) 
	struct task_struct *me;

	int i;



	loadsegment(fs, 0);

	loadsegment(gs, 0);

	load_gs_base(cpu);



#ifdef CONFIG_NUMA

	if (cpu != 0 && percpu_read(node_number) == 0 &&

	    cpu_to_node(cpu) != NUMA_NO_NODE)
@@ -993,6 +994,8 @@ void __cpuinit cpu_init(void) 
	 */



	switch_to_new_gdt();

	loadsegment(fs, 0);



	load_idt((const struct desc_ptr *)&idt_descr);



	memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);

arch/x86/kernel/setup_percpu.c

+3 −3
Original line number Diff line number Diff line
@@ -112,14 +112,14 @@ void __init setup_per_cpu_areas(void) 
#ifdef CONFIG_NUMA

		per_cpu(x86_cpu_to_node_map, cpu) =

				early_per_cpu_map(x86_cpu_to_node_map, cpu);

#endif

#endif

		/*

		 * Up to this point, the boot CPU has been using .data.init

		 * area.  Reload %gs offset for the boot CPU.

		 * area.  Reload any changed state for the boot CPU.

		 */

		if (cpu == boot_cpu_id)

			load_gs_base(cpu);

#endif

			switch_to_new_gdt();



		DBG("PERCPU: cpu %4d %p\n", cpu, ptr);

	}