8903826d0c
When disabling and re-enabling the MMU, it is necessary to take out an identity mapping for the code that manipulates the SCTLR in order to avoid it disappearing from under our feet. This is useful when soft rebooting and returning from CPU suspend. This patch allocates a set of page tables during boot and populates them with an identity mapping for the .idmap.text section. This means that users of the identity map do not need to manage their own pgd and can instead annotate their functions with __idmap or, in the case of assembly code, place them in the correct section. Acked-by: Dave Martin <dave.martin@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
310 lines
6 KiB
ArmAsm
310 lines
6 KiB
ArmAsm
/* ld script to make ARM Linux kernel
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* taken from the i386 version by Russell King
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* Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
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*/
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#include <asm-generic/vmlinux.lds.h>
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#include <asm/thread_info.h>
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#include <asm/memory.h>
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#include <asm/page.h>
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#define PROC_INFO \
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VMLINUX_SYMBOL(__proc_info_begin) = .; \
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*(.proc.info.init) \
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VMLINUX_SYMBOL(__proc_info_end) = .;
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#define IDMAP_TEXT \
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ALIGN_FUNCTION(); \
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VMLINUX_SYMBOL(__idmap_text_start) = .; \
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*(.idmap.text) \
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VMLINUX_SYMBOL(__idmap_text_end) = .;
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#ifdef CONFIG_HOTPLUG_CPU
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#define ARM_CPU_DISCARD(x)
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#define ARM_CPU_KEEP(x) x
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#else
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#define ARM_CPU_DISCARD(x) x
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#define ARM_CPU_KEEP(x)
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#endif
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#if (defined(CONFIG_SMP_ON_UP) && !defined(CONFIG_DEBUG_SPINLOCK)) || \
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defined(CONFIG_GENERIC_BUG)
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#define ARM_EXIT_KEEP(x) x
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#define ARM_EXIT_DISCARD(x)
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#else
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#define ARM_EXIT_KEEP(x)
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#define ARM_EXIT_DISCARD(x) x
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#endif
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OUTPUT_ARCH(arm)
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ENTRY(stext)
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#ifndef __ARMEB__
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jiffies = jiffies_64;
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#else
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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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/*
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* XXX: The linker does not define how output sections are
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* assigned to input sections when there are multiple statements
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* matching the same input section name. There is no documented
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* order of matching.
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*
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* unwind exit sections must be discarded before the rest of the
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* unwind sections get included.
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*/
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/DISCARD/ : {
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*(.ARM.exidx.exit.text)
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*(.ARM.extab.exit.text)
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ARM_CPU_DISCARD(*(.ARM.exidx.cpuexit.text))
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ARM_CPU_DISCARD(*(.ARM.extab.cpuexit.text))
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ARM_EXIT_DISCARD(EXIT_TEXT)
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ARM_EXIT_DISCARD(EXIT_DATA)
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EXIT_CALL
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#ifndef CONFIG_HOTPLUG
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*(.ARM.exidx.devexit.text)
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*(.ARM.extab.devexit.text)
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#endif
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#ifndef CONFIG_MMU
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*(.fixup)
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*(__ex_table)
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#endif
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#ifndef CONFIG_SMP_ON_UP
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*(.alt.smp.init)
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#endif
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*(.discard)
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*(.discard.*)
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}
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#ifdef CONFIG_XIP_KERNEL
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. = XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR);
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#else
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. = PAGE_OFFSET + TEXT_OFFSET;
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#endif
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.head.text : {
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_text = .;
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HEAD_TEXT
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}
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.text : { /* Real text segment */
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_stext = .; /* Text and read-only data */
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__exception_text_start = .;
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*(.exception.text)
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__exception_text_end = .;
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IRQENTRY_TEXT
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TEXT_TEXT
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SCHED_TEXT
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LOCK_TEXT
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KPROBES_TEXT
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IDMAP_TEXT
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#ifdef CONFIG_MMU
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*(.fixup)
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#endif
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*(.gnu.warning)
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*(.glue_7)
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*(.glue_7t)
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. = ALIGN(4);
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*(.got) /* Global offset table */
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ARM_CPU_KEEP(PROC_INFO)
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}
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RO_DATA(PAGE_SIZE)
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#ifdef CONFIG_ARM_UNWIND
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/*
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* Stack unwinding tables
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*/
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. = ALIGN(8);
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.ARM.unwind_idx : {
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__start_unwind_idx = .;
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*(.ARM.exidx*)
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__stop_unwind_idx = .;
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}
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.ARM.unwind_tab : {
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__start_unwind_tab = .;
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*(.ARM.extab*)
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__stop_unwind_tab = .;
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}
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#endif
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_etext = .; /* End of text and rodata section */
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#ifndef CONFIG_XIP_KERNEL
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. = ALIGN(PAGE_SIZE);
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__init_begin = .;
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#endif
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INIT_TEXT_SECTION(8)
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.exit.text : {
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ARM_EXIT_KEEP(EXIT_TEXT)
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}
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.init.proc.info : {
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ARM_CPU_DISCARD(PROC_INFO)
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}
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.init.arch.info : {
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__arch_info_begin = .;
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*(.arch.info.init)
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__arch_info_end = .;
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}
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.init.tagtable : {
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__tagtable_begin = .;
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*(.taglist.init)
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__tagtable_end = .;
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}
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#ifdef CONFIG_SMP_ON_UP
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.init.smpalt : {
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__smpalt_begin = .;
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*(.alt.smp.init)
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__smpalt_end = .;
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}
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#endif
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.init.pv_table : {
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__pv_table_begin = .;
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*(.pv_table)
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__pv_table_end = .;
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}
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.init.data : {
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#ifndef CONFIG_XIP_KERNEL
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INIT_DATA
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#endif
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INIT_SETUP(16)
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INIT_CALLS
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CON_INITCALL
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SECURITY_INITCALL
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INIT_RAM_FS
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}
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#ifndef CONFIG_XIP_KERNEL
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.exit.data : {
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ARM_EXIT_KEEP(EXIT_DATA)
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}
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#endif
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PERCPU_SECTION(32)
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#ifdef CONFIG_XIP_KERNEL
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__data_loc = ALIGN(4); /* location in binary */
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. = PAGE_OFFSET + TEXT_OFFSET;
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#else
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__init_end = .;
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. = ALIGN(THREAD_SIZE);
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__data_loc = .;
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#endif
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.data : AT(__data_loc) {
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_data = .; /* address in memory */
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_sdata = .;
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/*
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* first, the init task union, aligned
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* to an 8192 byte boundary.
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*/
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INIT_TASK_DATA(THREAD_SIZE)
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#ifdef CONFIG_XIP_KERNEL
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. = ALIGN(PAGE_SIZE);
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__init_begin = .;
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INIT_DATA
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ARM_EXIT_KEEP(EXIT_DATA)
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. = ALIGN(PAGE_SIZE);
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__init_end = .;
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#endif
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NOSAVE_DATA
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CACHELINE_ALIGNED_DATA(32)
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READ_MOSTLY_DATA(32)
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/*
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* The exception fixup table (might need resorting at runtime)
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*/
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. = ALIGN(32);
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__start___ex_table = .;
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#ifdef CONFIG_MMU
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*(__ex_table)
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#endif
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__stop___ex_table = .;
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/*
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* and the usual data section
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*/
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DATA_DATA
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CONSTRUCTORS
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_edata = .;
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}
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_edata_loc = __data_loc + SIZEOF(.data);
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#ifdef CONFIG_HAVE_TCM
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/*
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* We align everything to a page boundary so we can
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* free it after init has commenced and TCM contents have
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* been copied to its destination.
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*/
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.tcm_start : {
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. = ALIGN(PAGE_SIZE);
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__tcm_start = .;
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__itcm_start = .;
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}
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/*
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* Link these to the ITCM RAM
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* Put VMA to the TCM address and LMA to the common RAM
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* and we'll upload the contents from RAM to TCM and free
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* the used RAM after that.
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*/
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.text_itcm ITCM_OFFSET : AT(__itcm_start)
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{
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__sitcm_text = .;
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*(.tcm.text)
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*(.tcm.rodata)
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. = ALIGN(4);
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__eitcm_text = .;
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}
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/*
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* Reset the dot pointer, this is needed to create the
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* relative __dtcm_start below (to be used as extern in code).
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*/
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. = ADDR(.tcm_start) + SIZEOF(.tcm_start) + SIZEOF(.text_itcm);
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.dtcm_start : {
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__dtcm_start = .;
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}
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/* TODO: add remainder of ITCM as well, that can be used for data! */
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.data_dtcm DTCM_OFFSET : AT(__dtcm_start)
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{
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. = ALIGN(4);
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__sdtcm_data = .;
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*(.tcm.data)
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. = ALIGN(4);
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__edtcm_data = .;
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}
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/* Reset the dot pointer or the linker gets confused */
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. = ADDR(.dtcm_start) + SIZEOF(.data_dtcm);
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/* End marker for freeing TCM copy in linked object */
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.tcm_end : AT(ADDR(.dtcm_start) + SIZEOF(.data_dtcm)){
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. = ALIGN(PAGE_SIZE);
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__tcm_end = .;
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}
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#endif
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NOTES
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BSS_SECTION(0, 0, 0)
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_end = .;
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STABS_DEBUG
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.comment 0 : { *(.comment) }
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}
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/*
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* These must never be empty
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* If you have to comment these two assert statements out, your
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* binutils is too old (for other reasons as well)
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*/
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ASSERT((__proc_info_end - __proc_info_begin), "missing CPU support")
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ASSERT((__arch_info_end - __arch_info_begin), "no machine record defined")
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