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x86: use linker to offset symbols by __per_cpu_load

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Impact: cleanup and bug fix

Use the linker to create symbols for certain per-cpu variables
that are offset by __per_cpu_load.  This allows the removal of
the runtime fixup of the GDT pointer, which fixes a bug with
resume reported by Jiri Slaby.

Reported-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Brian Gerst
2009-02-08 09:58:39 -05:00
committed by Ingo Molnar
parent d3770449d3
commit 2add8e235c
5 changed files with 35 additions and 24 deletions
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21
arch/x86/kernel/head_64.S
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@@ -205,19 +205,6 @@ 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
@@ -275,11 +262,7 @@ ENTRY(secondary_startup_64)
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
.quad INIT_PER_CPU_VAR(irq_stack_union)
__FINITDATA
ENTRY(stack_start)
@@ -425,7 +408,7 @@ NEXT_PAGE(level2_spare_pgt)
early_gdt_descr:
.word GDT_ENTRIES*8-1
early_gdt_descr_base:
.quad per_cpu__gdt_page
.quad INIT_PER_CPU_VAR(gdt_page)
ENTRY(phys_base)
/* This must match the first entry in level2_kernel_pgt */