63cc8c7515
While examining holes in percpu section I found this : c05f5000 D per_cpu__current_task c05f5000 D __per_cpu_start c05f5004 D per_cpu__cpu_number c05f5008 D per_cpu__irq_regs c05f500c d per_cpu__cpu_devices c05f5040 D per_cpu__cyc2ns <Big Hole of about 4000 bytes> c05f6000 d per_cpu__cpuid4_info c05f6004 d per_cpu__cache_kobject c05f6008 d per_cpu__index_kobject <Big Hole of about 4000 bytes> c05f7000 D per_cpu__gdt_page This is because gdt_page is a percpu variable, defined with a page alignement, and linker is doing its job, two times because of .o nesting in the build process. I introduced a new macro DEFINE_PER_CPU_PAGE_ALIGNED() to avoid wasting this space. All page aligned variables (only one at this time) are put in a separate subsection .data.percpu.page_aligned, at the very begining of percpu zone. Before patch , on a x86_32 machine : .data.percpu 30232 3227471872 .data.percpu 22168 3227471872 Thats 8064 bytes saved for each CPU. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
355 lines
11 KiB
C
355 lines
11 KiB
C
#ifndef LOAD_OFFSET
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#define LOAD_OFFSET 0
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#endif
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#ifndef VMLINUX_SYMBOL
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#define VMLINUX_SYMBOL(_sym_) _sym_
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#endif
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/* Align . to a 8 byte boundary equals to maximum function alignment. */
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#define ALIGN_FUNCTION() . = ALIGN(8)
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/* The actual configuration determine if the init/exit sections
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* are handled as text/data or they can be discarded (which
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* often happens at runtime)
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*/
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#ifdef CONFIG_HOTPLUG
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#define DEV_KEEP(sec) *(.dev##sec)
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#define DEV_DISCARD(sec)
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#else
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#define DEV_KEEP(sec)
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#define DEV_DISCARD(sec) *(.dev##sec)
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#endif
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#ifdef CONFIG_HOTPLUG_CPU
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#define CPU_KEEP(sec) *(.cpu##sec)
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#define CPU_DISCARD(sec)
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#else
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#define CPU_KEEP(sec)
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#define CPU_DISCARD(sec) *(.cpu##sec)
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#endif
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#if defined(CONFIG_MEMORY_HOTPLUG)
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#define MEM_KEEP(sec) *(.mem##sec)
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#define MEM_DISCARD(sec)
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#else
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#define MEM_KEEP(sec)
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#define MEM_DISCARD(sec) *(.mem##sec)
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#endif
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/* .data section */
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#define DATA_DATA \
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*(.data) \
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*(.data.init.refok) \
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*(.ref.data) \
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DEV_KEEP(init.data) \
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DEV_KEEP(exit.data) \
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CPU_KEEP(init.data) \
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CPU_KEEP(exit.data) \
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MEM_KEEP(init.data) \
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MEM_KEEP(exit.data) \
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. = ALIGN(8); \
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VMLINUX_SYMBOL(__start___markers) = .; \
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*(__markers) \
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VMLINUX_SYMBOL(__stop___markers) = .;
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#define RO_DATA(align) \
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. = ALIGN((align)); \
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.rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start_rodata) = .; \
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*(.rodata) *(.rodata.*) \
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*(__vermagic) /* Kernel version magic */ \
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*(__markers_strings) /* Markers: strings */ \
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} \
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\
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.rodata1 : AT(ADDR(.rodata1) - LOAD_OFFSET) { \
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*(.rodata1) \
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} \
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\
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/* PCI quirks */ \
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.pci_fixup : AT(ADDR(.pci_fixup) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start_pci_fixups_early) = .; \
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*(.pci_fixup_early) \
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VMLINUX_SYMBOL(__end_pci_fixups_early) = .; \
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VMLINUX_SYMBOL(__start_pci_fixups_header) = .; \
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*(.pci_fixup_header) \
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VMLINUX_SYMBOL(__end_pci_fixups_header) = .; \
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VMLINUX_SYMBOL(__start_pci_fixups_final) = .; \
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*(.pci_fixup_final) \
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VMLINUX_SYMBOL(__end_pci_fixups_final) = .; \
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VMLINUX_SYMBOL(__start_pci_fixups_enable) = .; \
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*(.pci_fixup_enable) \
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VMLINUX_SYMBOL(__end_pci_fixups_enable) = .; \
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VMLINUX_SYMBOL(__start_pci_fixups_resume) = .; \
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*(.pci_fixup_resume) \
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VMLINUX_SYMBOL(__end_pci_fixups_resume) = .; \
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} \
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\
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/* RapidIO route ops */ \
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.rio_route : AT(ADDR(.rio_route) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start_rio_route_ops) = .; \
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*(.rio_route_ops) \
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VMLINUX_SYMBOL(__end_rio_route_ops) = .; \
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} \
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\
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/* Kernel symbol table: Normal symbols */ \
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__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___ksymtab) = .; \
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*(__ksymtab) \
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VMLINUX_SYMBOL(__stop___ksymtab) = .; \
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} \
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\
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/* Kernel symbol table: GPL-only symbols */ \
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__ksymtab_gpl : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___ksymtab_gpl) = .; \
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*(__ksymtab_gpl) \
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VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .; \
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} \
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\
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/* Kernel symbol table: Normal unused symbols */ \
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__ksymtab_unused : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___ksymtab_unused) = .; \
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*(__ksymtab_unused) \
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VMLINUX_SYMBOL(__stop___ksymtab_unused) = .; \
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} \
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\
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/* Kernel symbol table: GPL-only unused symbols */ \
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__ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___ksymtab_unused_gpl) = .; \
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*(__ksymtab_unused_gpl) \
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VMLINUX_SYMBOL(__stop___ksymtab_unused_gpl) = .; \
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} \
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\
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/* Kernel symbol table: GPL-future-only symbols */ \
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__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___ksymtab_gpl_future) = .; \
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*(__ksymtab_gpl_future) \
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VMLINUX_SYMBOL(__stop___ksymtab_gpl_future) = .; \
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} \
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\
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/* Kernel symbol table: Normal symbols */ \
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__kcrctab : AT(ADDR(__kcrctab) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___kcrctab) = .; \
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*(__kcrctab) \
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VMLINUX_SYMBOL(__stop___kcrctab) = .; \
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} \
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\
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/* Kernel symbol table: GPL-only symbols */ \
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__kcrctab_gpl : AT(ADDR(__kcrctab_gpl) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___kcrctab_gpl) = .; \
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*(__kcrctab_gpl) \
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VMLINUX_SYMBOL(__stop___kcrctab_gpl) = .; \
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} \
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\
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/* Kernel symbol table: Normal unused symbols */ \
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__kcrctab_unused : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___kcrctab_unused) = .; \
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*(__kcrctab_unused) \
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VMLINUX_SYMBOL(__stop___kcrctab_unused) = .; \
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} \
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\
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/* Kernel symbol table: GPL-only unused symbols */ \
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__kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___kcrctab_unused_gpl) = .; \
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*(__kcrctab_unused_gpl) \
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VMLINUX_SYMBOL(__stop___kcrctab_unused_gpl) = .; \
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} \
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\
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/* Kernel symbol table: GPL-future-only symbols */ \
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__kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___kcrctab_gpl_future) = .; \
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*(__kcrctab_gpl_future) \
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VMLINUX_SYMBOL(__stop___kcrctab_gpl_future) = .; \
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} \
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\
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/* Kernel symbol table: strings */ \
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__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
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*(__ksymtab_strings) \
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} \
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\
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/* __*init sections */ \
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__init_rodata : AT(ADDR(__init_rodata) - LOAD_OFFSET) { \
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*(.ref.rodata) \
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DEV_KEEP(init.rodata) \
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DEV_KEEP(exit.rodata) \
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CPU_KEEP(init.rodata) \
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CPU_KEEP(exit.rodata) \
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MEM_KEEP(init.rodata) \
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MEM_KEEP(exit.rodata) \
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} \
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\
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/* Built-in module parameters. */ \
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__param : AT(ADDR(__param) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start___param) = .; \
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*(__param) \
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VMLINUX_SYMBOL(__stop___param) = .; \
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. = ALIGN((align)); \
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VMLINUX_SYMBOL(__end_rodata) = .; \
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} \
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. = ALIGN((align));
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/* RODATA provided for backward compatibility.
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* All archs are supposed to use RO_DATA() */
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#define RODATA RO_DATA(4096)
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#define SECURITY_INIT \
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.security_initcall.init : AT(ADDR(.security_initcall.init) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__security_initcall_start) = .; \
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*(.security_initcall.init) \
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VMLINUX_SYMBOL(__security_initcall_end) = .; \
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}
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/* .text section. Map to function alignment to avoid address changes
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* during second ld run in second ld pass when generating System.map */
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#define TEXT_TEXT \
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ALIGN_FUNCTION(); \
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*(.text) \
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*(.ref.text) \
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*(.text.init.refok) \
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*(.exit.text.refok) \
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DEV_KEEP(init.text) \
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DEV_KEEP(exit.text) \
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CPU_KEEP(init.text) \
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CPU_KEEP(exit.text) \
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MEM_KEEP(init.text) \
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MEM_KEEP(exit.text)
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/* sched.text is aling to function alignment to secure we have same
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* address even at second ld pass when generating System.map */
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#define SCHED_TEXT \
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ALIGN_FUNCTION(); \
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VMLINUX_SYMBOL(__sched_text_start) = .; \
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*(.sched.text) \
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VMLINUX_SYMBOL(__sched_text_end) = .;
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/* spinlock.text is aling to function alignment to secure we have same
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* address even at second ld pass when generating System.map */
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#define LOCK_TEXT \
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ALIGN_FUNCTION(); \
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VMLINUX_SYMBOL(__lock_text_start) = .; \
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*(.spinlock.text) \
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VMLINUX_SYMBOL(__lock_text_end) = .;
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#define KPROBES_TEXT \
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ALIGN_FUNCTION(); \
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VMLINUX_SYMBOL(__kprobes_text_start) = .; \
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*(.kprobes.text) \
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VMLINUX_SYMBOL(__kprobes_text_end) = .;
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/* Section used for early init (in .S files) */
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#define HEAD_TEXT *(.head.text)
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/* init and exit section handling */
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#define INIT_DATA \
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*(.init.data) \
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DEV_DISCARD(init.data) \
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DEV_DISCARD(init.rodata) \
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CPU_DISCARD(init.data) \
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CPU_DISCARD(init.rodata) \
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MEM_DISCARD(init.data) \
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MEM_DISCARD(init.rodata)
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#define INIT_TEXT \
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*(.init.text) \
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DEV_DISCARD(init.text) \
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CPU_DISCARD(init.text) \
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MEM_DISCARD(init.text)
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#define EXIT_DATA \
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*(.exit.data) \
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DEV_DISCARD(exit.data) \
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DEV_DISCARD(exit.rodata) \
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CPU_DISCARD(exit.data) \
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CPU_DISCARD(exit.rodata) \
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MEM_DISCARD(exit.data) \
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MEM_DISCARD(exit.rodata)
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#define EXIT_TEXT \
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*(.exit.text) \
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DEV_DISCARD(exit.text) \
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CPU_DISCARD(exit.text) \
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MEM_DISCARD(exit.text)
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/* DWARF debug sections.
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Symbols in the DWARF debugging sections are relative to
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the beginning of the section so we begin them at 0. */
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#define DWARF_DEBUG \
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/* DWARF 1 */ \
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.debug 0 : { *(.debug) } \
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.line 0 : { *(.line) } \
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/* GNU DWARF 1 extensions */ \
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.debug_srcinfo 0 : { *(.debug_srcinfo) } \
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.debug_sfnames 0 : { *(.debug_sfnames) } \
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/* DWARF 1.1 and DWARF 2 */ \
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.debug_aranges 0 : { *(.debug_aranges) } \
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.debug_pubnames 0 : { *(.debug_pubnames) } \
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/* DWARF 2 */ \
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.debug_info 0 : { *(.debug_info \
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.gnu.linkonce.wi.*) } \
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.debug_abbrev 0 : { *(.debug_abbrev) } \
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.debug_line 0 : { *(.debug_line) } \
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.debug_frame 0 : { *(.debug_frame) } \
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.debug_str 0 : { *(.debug_str) } \
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.debug_loc 0 : { *(.debug_loc) } \
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.debug_macinfo 0 : { *(.debug_macinfo) } \
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/* SGI/MIPS DWARF 2 extensions */ \
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.debug_weaknames 0 : { *(.debug_weaknames) } \
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.debug_funcnames 0 : { *(.debug_funcnames) } \
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.debug_typenames 0 : { *(.debug_typenames) } \
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.debug_varnames 0 : { *(.debug_varnames) } \
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/* Stabs debugging sections. */
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#define STABS_DEBUG \
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.stab 0 : { *(.stab) } \
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.stabstr 0 : { *(.stabstr) } \
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.stab.excl 0 : { *(.stab.excl) } \
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.stab.exclstr 0 : { *(.stab.exclstr) } \
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.stab.index 0 : { *(.stab.index) } \
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.stab.indexstr 0 : { *(.stab.indexstr) } \
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.comment 0 : { *(.comment) }
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#define BUG_TABLE \
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. = ALIGN(8); \
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__bug_table : AT(ADDR(__bug_table) - LOAD_OFFSET) { \
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__start___bug_table = .; \
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*(__bug_table) \
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__stop___bug_table = .; \
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}
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#define NOTES \
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.notes : AT(ADDR(.notes) - LOAD_OFFSET) { \
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VMLINUX_SYMBOL(__start_notes) = .; \
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*(.note.*) \
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VMLINUX_SYMBOL(__stop_notes) = .; \
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}
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#define INITCALLS \
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*(.initcall0.init) \
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*(.initcall0s.init) \
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*(.initcall1.init) \
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*(.initcall1s.init) \
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*(.initcall2.init) \
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*(.initcall2s.init) \
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*(.initcall3.init) \
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*(.initcall3s.init) \
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*(.initcall4.init) \
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*(.initcall4s.init) \
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*(.initcall5.init) \
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*(.initcall5s.init) \
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*(.initcallrootfs.init) \
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*(.initcall6.init) \
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*(.initcall6s.init) \
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*(.initcall7.init) \
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*(.initcall7s.init)
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#define PERCPU(align) \
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. = ALIGN(align); \
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__per_cpu_start = .; \
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.data.percpu : AT(ADDR(.data.percpu) - LOAD_OFFSET) { \
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*(.data.percpu.page_aligned) \
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*(.data.percpu) \
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*(.data.percpu.shared_aligned) \
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} \
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__per_cpu_end = .;
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