mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
0e0ed6406e
Module CRCs are implemented as absolute symbols that get resolved by
a linker script. We build an intermediate .o that contains an
unresolved symbol for each CRC. genksysms parses this .o, calculates
the CRCs and writes a linker script that "resolves" the symbols to
the calculated CRC.
Unfortunately the ppc64 relocatable kernel sees these CRCs as symbols
that need relocating and relocates them at boot. Commit d4703aef
(module: handle ppc64 relocating kcrctabs when CONFIG_RELOCATABLE=y)
added a hook to reverse the bogus relocations. Part of this patch
created a symbol at 0x0:
# head -2 /proc/kallsyms
0000000000000000 T reloc_start
c000000000000000 T .__start
This reloc_start symbol is causing lots of confusion to perf. It
thinks reloc_start is a massive function that stretches from 0x0 to
0xc000000000000000 and we get various cryptic errors out of perf,
including:
problem incrementing symbol count, skipping event
This patch removes the reloc_start linker script label and instead
defines it as PHYSICAL_START. We also need to wrap it with
CONFIG_PPC64 because the ppc32 kernel can set a non zero
PHYSICAL_START at compile time and we wouldn't want to subtract
it from the CRCs in that case.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
264 lines
5.4 KiB
ArmAsm
264 lines
5.4 KiB
ArmAsm
#ifdef CONFIG_PPC64
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#define PROVIDE32(x) PROVIDE(__unused__##x)
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#else
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#define PROVIDE32(x) PROVIDE(x)
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#endif
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#include <asm/page.h>
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#include <asm-generic/vmlinux.lds.h>
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#include <asm/cache.h>
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#include <asm/thread_info.h>
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ENTRY(_stext)
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PHDRS {
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kernel PT_LOAD FLAGS(7); /* RWX */
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notes PT_NOTE FLAGS(0);
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dummy PT_NOTE FLAGS(0);
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/* binutils < 2.18 has a bug that makes it misbehave when taking an
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ELF file with all segments at load address 0 as input. This
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happens when running "strip" on vmlinux, because of the AT() magic
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in this linker script. People using GCC >= 4.2 won't run into
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this problem, because the "build-id" support will put some data
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into the "notes" segment (at a non-zero load address).
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To work around this, we force some data into both the "dummy"
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segment and the kernel segment, so the dummy segment will get a
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non-zero load address. It's not enough to always create the
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"notes" segment, since if nothing gets assigned to it, its load
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address will be zero. */
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}
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#ifdef CONFIG_PPC64
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OUTPUT_ARCH(powerpc:common64)
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jiffies = jiffies_64;
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#else
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OUTPUT_ARCH(powerpc:common)
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jiffies = jiffies_64 + 4;
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#endif
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SECTIONS
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{
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. = KERNELBASE;
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/*
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* Text, read only data and other permanent read-only sections
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*/
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/* Text and gots */
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.text : AT(ADDR(.text) - LOAD_OFFSET) {
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ALIGN_FUNCTION();
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HEAD_TEXT
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_text = .;
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/* careful! __ftr_alt_* sections need to be close to .text */
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*(.text .fixup __ftr_alt_* .ref.text)
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SCHED_TEXT
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LOCK_TEXT
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KPROBES_TEXT
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IRQENTRY_TEXT
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#ifdef CONFIG_PPC32
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*(.got1)
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__got2_start = .;
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*(.got2)
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__got2_end = .;
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#endif /* CONFIG_PPC32 */
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} :kernel
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. = ALIGN(PAGE_SIZE);
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_etext = .;
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PROVIDE32 (etext = .);
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/* Read-only data */
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RODATA
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EXCEPTION_TABLE(0)
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NOTES :kernel :notes
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/* The dummy segment contents for the bug workaround mentioned above
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near PHDRS. */
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.dummy : AT(ADDR(.dummy) - LOAD_OFFSET) {
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LONG(0)
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LONG(0)
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LONG(0)
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} :kernel :dummy
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/*
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* Init sections discarded at runtime
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*/
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. = ALIGN(PAGE_SIZE);
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__init_begin = .;
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INIT_TEXT_SECTION(PAGE_SIZE) :kernel
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/* .exit.text is discarded at runtime, not link time,
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* to deal with references from __bug_table
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*/
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.exit.text : AT(ADDR(.exit.text) - LOAD_OFFSET) {
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EXIT_TEXT
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}
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.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
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INIT_DATA
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__vtop_table_begin = .;
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*(.vtop_fixup);
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__vtop_table_end = .;
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__ptov_table_begin = .;
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*(.ptov_fixup);
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__ptov_table_end = .;
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}
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.init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
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INIT_SETUP(16)
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}
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.initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
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INIT_CALLS
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}
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.con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
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CON_INITCALL
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}
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SECURITY_INIT
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. = ALIGN(8);
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__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
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__start___ftr_fixup = .;
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*(__ftr_fixup)
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__stop___ftr_fixup = .;
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}
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. = ALIGN(8);
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__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
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__start___mmu_ftr_fixup = .;
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*(__mmu_ftr_fixup)
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__stop___mmu_ftr_fixup = .;
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}
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. = ALIGN(8);
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__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
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__start___lwsync_fixup = .;
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*(__lwsync_fixup)
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__stop___lwsync_fixup = .;
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}
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#ifdef CONFIG_PPC64
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. = ALIGN(8);
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__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
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__start___fw_ftr_fixup = .;
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*(__fw_ftr_fixup)
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__stop___fw_ftr_fixup = .;
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}
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#endif
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.init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
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INIT_RAM_FS
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}
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PERCPU_SECTION(L1_CACHE_BYTES)
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. = ALIGN(8);
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.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
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__machine_desc_start = . ;
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*(.machine.desc)
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__machine_desc_end = . ;
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}
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#ifdef CONFIG_RELOCATABLE
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. = ALIGN(8);
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.dynsym : AT(ADDR(.dynsym) - LOAD_OFFSET)
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{
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#ifdef CONFIG_RELOCATABLE_PPC32
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__dynamic_symtab = .;
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#endif
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*(.dynsym)
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}
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.dynstr : AT(ADDR(.dynstr) - LOAD_OFFSET) { *(.dynstr) }
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.dynamic : AT(ADDR(.dynamic) - LOAD_OFFSET)
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{
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__dynamic_start = .;
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*(.dynamic)
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}
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.hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
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.interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
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.rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
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{
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__rela_dyn_start = .;
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*(.rela*)
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}
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#endif
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/* freed after init ends here */
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. = ALIGN(PAGE_SIZE);
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__init_end = .;
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/*
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* And now the various read/write data
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*/
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. = ALIGN(PAGE_SIZE);
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_sdata = .;
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#ifdef CONFIG_PPC32
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.data : AT(ADDR(.data) - LOAD_OFFSET) {
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DATA_DATA
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*(.sdata)
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*(.got.plt) *(.got)
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}
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#else
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.data : AT(ADDR(.data) - LOAD_OFFSET) {
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DATA_DATA
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*(.data.rel*)
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*(.toc1)
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*(.branch_lt)
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}
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.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
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*(.opd)
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}
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.got : AT(ADDR(.got) - LOAD_OFFSET) {
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__toc_start = .;
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#ifndef CONFIG_RELOCATABLE
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__prom_init_toc_start = .;
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arch/powerpc/kernel/prom_init.o*(.toc .got)
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__prom_init_toc_end = .;
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#endif
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*(.got)
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*(.toc)
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}
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#endif
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/* The initial task and kernel stack */
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INIT_TASK_DATA_SECTION(THREAD_SIZE)
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.data..page_aligned : AT(ADDR(.data..page_aligned) - LOAD_OFFSET) {
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PAGE_ALIGNED_DATA(PAGE_SIZE)
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}
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.data..cacheline_aligned : AT(ADDR(.data..cacheline_aligned) - LOAD_OFFSET) {
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CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES)
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}
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.data..read_mostly : AT(ADDR(.data..read_mostly) - LOAD_OFFSET) {
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READ_MOSTLY_DATA(L1_CACHE_BYTES)
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}
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. = ALIGN(PAGE_SIZE);
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.data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
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NOSAVE_DATA
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}
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. = ALIGN(PAGE_SIZE);
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_edata = .;
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PROVIDE32 (edata = .);
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/*
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* And finally the bss
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*/
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BSS_SECTION(0, 0, 0)
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. = ALIGN(PAGE_SIZE);
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_end = . ;
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PROVIDE32 (end = .);
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/* Sections to be discarded. */
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DISCARDS
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}
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