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| author | Tejun Heo <tj@kernel.org> | 2009-01-13 14:41:35 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-01-16 16:19:14 +0300 |
| commit | 3e5d8f978435bb9ba4dfe3f4514e65e7885db1a9 (patch) | |
| tree | 1ce55b2ec16a0bd59a29857e05215960d463a1d8 /include/asm-generic/vmlinux.lds.h | |
| parent | a698c823e15149941b0f0281527d0c0d1daf2639 (diff) | |
| download | linux-3e5d8f978435bb9ba4dfe3f4514e65e7885db1a9.tar.xz | |
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 'include/asm-generic/vmlinux.lds.h')
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 51 |
1 files changed, 45 insertions, 6 deletions
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index c61fab1dd2f8..fc2f55f2dcd6 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -430,12 +430,51 @@ *(.initcall7.init) \ *(.initcall7s.init) -#define PERCPU(align) \ - . = ALIGN(align); \ - VMLINUX_SYMBOL(__per_cpu_start) = .; \ - .data.percpu : AT(ADDR(.data.percpu) - LOAD_OFFSET) { \ +#define PERCPU_PROLOG(vaddr) \ + VMLINUX_SYMBOL(__per_cpu_load) = .; \ + .data.percpu vaddr : AT(__per_cpu_load - LOAD_OFFSET) { \ + VMLINUX_SYMBOL(__per_cpu_start) = .; + +#define PERCPU_EPILOG(phdr) \ + VMLINUX_SYMBOL(__per_cpu_end) = .; \ + } phdr \ + . = __per_cpu_load + SIZEOF(.data.percpu); + +/** + * PERCPU_VADDR - define output section for percpu area + * @vaddr: explicit base address (optional) + * @phdr: destination PHDR (optional) + * + * Macro which expands to output section for percpu area. If @vaddr + * is not blank, it specifies explicit base address and all percpu + * symbols will be offset from the given address. If blank, @vaddr + * always equals @laddr + LOAD_OFFSET. + * + * @phdr defines the output PHDR to use if not blank. Be warned that + * output PHDR is sticky. If @phdr is specified, the next output + * section in the linker script will go there too. @phdr should have + * a leading colon. + * + * This macro defines three symbols, __per_cpu_load, __per_cpu_start + * and __per_cpu_end. The first one is the vaddr of loaded percpu + * init data. __per_cpu_start equals @vaddr and __per_cpu_end is the + * end offset. + */ +#define PERCPU_VADDR(vaddr, phdr) \ + PERCPU_PROLOG(vaddr) \ *(.data.percpu.page_aligned) \ *(.data.percpu) \ *(.data.percpu.shared_aligned) \ - } \ - VMLINUX_SYMBOL(__per_cpu_end) = .; + PERCPU_EPILOG(phdr) + +/** + * PERCPU - define output section for percpu area, simple version + * @align: required alignment + * + * Align to @align and outputs output section for percpu area. This + * macro doesn't maniuplate @vaddr or @phdr and __per_cpu_load and + * __per_cpu_start will be identical. + */ +#define PERCPU(align) \ + . = ALIGN(align); \ + PERCPU_VADDR( , ) |