5 files changed, 15 insertions, 7 deletions

diff --git a/arch/x86/include/asm/trampoline.h b/arch/x86/include/asm/trampoline.h
index 780ba0ab94f9..90f06c25221d 100644
--- a/arch/x86/include/asm/trampoline.h
+++ b/arch/x86/include/asm/trampoline.h
@@ -13,6 +13,7 @@ extern unsigned char *trampoline_base;
 
 extern unsigned long init_rsp;
 extern unsigned long initial_code;
+extern unsigned long initial_gs;
 
 #define TRAMPOLINE_SIZE roundup(trampoline_end - trampoline_data, PAGE_SIZE)
 #define TRAMPOLINE_BASE 0x6000
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 707c1f6f95fa..9ff67f8dc2c0 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -101,6 +101,7 @@ int acpi_save_state_mem(void)
         stack_start.sp = temp_stack + sizeof(temp_stack);
         early_gdt_descr.address =
                         (unsigned long)get_cpu_gdt_table(smp_processor_id());
+        initial_gs = (unsigned long)cpu_pda(smp_processor_id());
 #endif
         initial_code = (unsigned long)wakeup_long64;
         saved_magic = 0x123456789abcdef0;
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index bc2900ca82c7..76ffba2aa66d 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -26,8 +26,8 @@
 #include <asm/bios_ebda.h>
 #include <asm/trampoline.h>
 
-/* boot cpu pda */
-static struct x8664_pda _boot_cpu_pda;
+/* boot cpu pda, referenced by head_64.S to initialize %gs for boot CPU */
+struct x8664_pda _boot_cpu_pda;
 
 #ifdef CONFIG_SMP
 /*
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 7ee0363871e8..2f0ab0089883 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -243,12 +243,15 @@ ENTRY(secondary_startup_64)
         movl %eax,%fs
         movl %eax,%gs
 
-        /* 
-         * Setup up a dummy PDA. this is just for some early bootup code
-         * that does in_interrupt() 
-         */ 
+        /* Set up %gs.
+         *
+         * %gs should point to the pda.  For initial boot, make %gs point
+         * to the _boot_cpu_pda in data section.  For a secondary CPU,
+         * initial_gs should be set to its pda address before the CPU runs
+         * this code.
+         */
         movl    $MSR_GS_BASE,%ecx
-        movq    $empty_zero_page,%rax
+        movq    initial_gs(%rip),%rax
         movq    %rax,%rdx
         shrq    $32,%rdx
         wrmsr   
@@ -274,6 +277,8 @@ ENTRY(secondary_startup_64)
         .align  8
         ENTRY(initial_code)
         .quad   x86_64_start_kernel
+        ENTRY(initial_gs)
+        .quad   _boot_cpu_pda
         __FINITDATA
 
         ENTRY(stack_start)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 1a712da1dfa0..70d846628bbf 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -854,6 +854,7 @@ do_rest:
 #else
         cpu_pda(cpu)->pcurrent = c_idle.idle;
         clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
+        initial_gs = (unsigned long)cpu_pda(cpu);
 #endif
         early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
         initial_code = (unsigned long)start_secondary;