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Diffstat (limited to 'arch/x86/kernel/head_64.S')
-rw-r--r--arch/x86/kernel/head_64.S36
1 files changed, 30 insertions, 6 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 0e275d4..a0a2b5c 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -19,6 +19,7 @@
#include <asm/msr.h>
#include <asm/cache.h>
#include <asm/processor-flags.h>
+#include <asm/percpu.h>
#ifdef CONFIG_PARAVIRT
#include <asm/asm-offsets.h>
@@ -204,6 +205,19 @@ ENTRY(secondary_startup_64)
pushq $0
popfq
+#ifdef CONFIG_SMP
+ /*
+ * 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 initial_gs(%rip), %rax
+ cmpl $0, per_cpu__cpu_number(%rax)
+ jne 1f
+ addq %rax, early_gdt_descr_base(%rip)
+1:
+#endif
/*
* We must switch to a new descriptor in kernel space for the GDT
* because soon the kernel won't have access anymore to the userspace
@@ -226,12 +240,15 @@ 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.
+ *
+ * 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 $empty_zero_page,%rax
+ movq initial_gs(%rip),%rax
movq %rax,%rdx
shrq $32,%rdx
wrmsr
@@ -257,6 +274,12 @@ ENTRY(secondary_startup_64)
.align 8
ENTRY(initial_code)
.quad x86_64_start_kernel
+ ENTRY(initial_gs)
+#ifdef CONFIG_SMP
+ .quad __per_cpu_load
+#else
+ .quad PER_CPU_VAR(irq_stack_union)
+#endif
__FINITDATA
ENTRY(stack_start)
@@ -401,7 +424,8 @@ NEXT_PAGE(level2_spare_pgt)
.globl early_gdt_descr
early_gdt_descr:
.word GDT_ENTRIES*8-1
- .quad per_cpu__gdt_page
+early_gdt_descr_base:
+ .quad per_cpu__gdt_page
ENTRY(phys_base)
/* This must match the first entry in level2_kernel_pgt */