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

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 794234e..befa20b 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -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 *);

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 67e30c8..0c766b8 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -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);

diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index bcca3a7..4caa78d 100644 (file)
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -113,13 +113,13 @@ void __init setup_per_cpu_areas(void)
                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);
        }