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Subject[PATCH 3/5] x86-64: Rework __per_cpu_load adjustments
Date
Use cpu_number to determine if the adjustment is necessary.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
arch/x86/kernel/head_64.S | 24 ++++++++----------------
1 files changed, 8 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index c8ace88..98ea26a 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
/*
@@ -431,12 +427,8 @@ 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 */
--
1.6.1.rc1


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