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authorTejun Heo <tj@kernel.org>2009-01-13 20:41:35 +0900
committerIngo Molnar <mingo@elte.hu>2009-01-16 14:19:14 +0100
commit3e5d8f978435bb9ba4dfe3f4514e65e7885db1a9 (patch)
tree1ce55b2ec16a0bd59a29857e05215960d463a1d8 /arch/x86/kernel/head64.c
parenta698c823e15149941b0f0281527d0c0d1daf2639 (diff)
x86: make percpu symbols zerobased on SMP
[ Based on original patch from Christoph Lameter and Mike Travis. ] This patch makes percpu symbols zerobased on x86_64 SMP by adding PERCPU_VADDR() to vmlinux.lds.h which helps setting explicit vaddr on the percpu output section and using it in vmlinux_64.lds.S. A new PHDR is added as existing ones cannot contain sections near address zero. PERCPU_VADDR() also adds a new symbol __per_cpu_load which always points to the vaddr of the loaded percpu data.init region. The following adjustments have been made to accomodate the address change. * code to locate percpu gdt_page in head_64.S is updated to add the load address to the gdt_page offset. * __per_cpu_load is used in places where access to the init data area is necessary. * pda->data_offset is initialized soon after C code is entered as zero value doesn't work anymore. This patch is mostly taken from Mike Travis' "x86_64: Base percpu variables at zero" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/head64.c')
-rw-r--r--arch/x86/kernel/head64.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index b9a4d8c4b935..bc2900ca82c7 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -44,6 +44,8 @@ void __init x86_64_init_pda(void)
{
_cpu_pda = __cpu_pda;
cpu_pda(0) = &_boot_cpu_pda;
+ cpu_pda(0)->data_offset =
+ (unsigned long)(__per_cpu_load - __per_cpu_start);
pda_init(0);
}