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https://github.com/CTCaer/switch-l4t-atf.git
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ebd6efae67
Currently, sections within .text/.rodata/.data/.bss are emitted in the order they are seen by the linker. This leads to wasted space, when a section with a larger alignment follows one with a smaller alignment. We can avoid this wasted space by sorting the sections. To take full advantage of this, we must disable generation of common symbols, so "common" data can be sorted along with the rest of .bss. An example of the improvement, from `make DEBUG=1 PLAT=sun50i_a64 bl31`: .text => no change .rodata => 16 bytes saved .data => 11 bytes saved .bss => 576 bytes saved As a side effect, the addition of `-fno-common` in TF_CFLAGS makes it easier to spot bugs in header files. Signed-off-by: Samuel Holland <samuel@sholland.org> Change-Id: I073630a9b0b84e7302a7a500d4bb4b547be01d51
165 lines
4.4 KiB
ArmAsm
165 lines
4.4 KiB
ArmAsm
/*
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* Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <platform_def.h>
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#include <lib/xlat_tables/xlat_tables_defs.h>
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OUTPUT_FORMAT(PLATFORM_LINKER_FORMAT)
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OUTPUT_ARCH(PLATFORM_LINKER_ARCH)
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ENTRY(bl2_entrypoint)
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MEMORY {
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RAM (rwx): ORIGIN = BL2_BASE, LENGTH = BL2_LIMIT - BL2_BASE
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}
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SECTIONS
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{
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. = BL2_BASE;
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ASSERT(. == ALIGN(PAGE_SIZE),
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"BL2_BASE address is not aligned on a page boundary.")
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#if SEPARATE_CODE_AND_RODATA
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.text . : {
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__TEXT_START__ = .;
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*bl2_entrypoint.o(.text*)
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*(SORT_BY_ALIGNMENT(.text*))
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*(.vectors)
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. = ALIGN(PAGE_SIZE);
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__TEXT_END__ = .;
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} >RAM
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/* .ARM.extab and .ARM.exidx are only added because Clang need them */
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.ARM.extab . : {
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*(.ARM.extab* .gnu.linkonce.armextab.*)
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} >RAM
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.ARM.exidx . : {
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*(.ARM.exidx* .gnu.linkonce.armexidx.*)
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} >RAM
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.rodata . : {
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__RODATA_START__ = .;
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*(SORT_BY_ALIGNMENT(.rodata*))
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/* Ensure 8-byte alignment for descriptors and ensure inclusion */
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. = ALIGN(8);
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__PARSER_LIB_DESCS_START__ = .;
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KEEP(*(.img_parser_lib_descs))
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__PARSER_LIB_DESCS_END__ = .;
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. = ALIGN(PAGE_SIZE);
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__RODATA_END__ = .;
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} >RAM
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#else
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ro . : {
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__RO_START__ = .;
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*bl2_entrypoint.o(.text*)
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*(SORT_BY_ALIGNMENT(.text*))
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*(SORT_BY_ALIGNMENT(.rodata*))
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/* Ensure 8-byte alignment for descriptors and ensure inclusion */
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. = ALIGN(8);
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__PARSER_LIB_DESCS_START__ = .;
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KEEP(*(.img_parser_lib_descs))
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__PARSER_LIB_DESCS_END__ = .;
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*(.vectors)
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__RO_END_UNALIGNED__ = .;
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/*
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* Memory page(s) mapped to this section will be marked as
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* read-only, executable. No RW data from the next section must
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* creep in. Ensure the rest of the current memory page is unused.
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*/
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. = ALIGN(PAGE_SIZE);
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__RO_END__ = .;
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} >RAM
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#endif
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/*
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* Define a linker symbol to mark start of the RW memory area for this
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* image.
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*/
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__RW_START__ = . ;
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/*
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* .data must be placed at a lower address than the stacks if the stack
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* protector is enabled. Alternatively, the .data.stack_protector_canary
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* section can be placed independently of the main .data section.
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*/
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.data . : {
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__DATA_START__ = .;
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*(SORT_BY_ALIGNMENT(.data*))
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__DATA_END__ = .;
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} >RAM
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stacks (NOLOAD) : {
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__STACKS_START__ = .;
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*(tzfw_normal_stacks)
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__STACKS_END__ = .;
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} >RAM
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/*
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* The .bss section gets initialised to 0 at runtime.
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* Its base address should be 16-byte aligned for better performance of the
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* zero-initialization code.
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*/
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.bss : ALIGN(16) {
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__BSS_START__ = .;
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*(SORT_BY_ALIGNMENT(.bss*))
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*(COMMON)
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__BSS_END__ = .;
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} >RAM
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/*
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* The xlat_table section is for full, aligned page tables (4K).
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* Removing them from .bss avoids forcing 4K alignment on
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* the .bss section. The tables are initialized to zero by the translation
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* tables library.
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*/
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xlat_table (NOLOAD) : {
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*(xlat_table)
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} >RAM
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#if USE_COHERENT_MEM
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/*
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* The base address of the coherent memory section must be page-aligned (4K)
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* to guarantee that the coherent data are stored on their own pages and
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* are not mixed with normal data. This is required to set up the correct
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* memory attributes for the coherent data page tables.
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*/
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coherent_ram (NOLOAD) : ALIGN(PAGE_SIZE) {
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__COHERENT_RAM_START__ = .;
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*(tzfw_coherent_mem)
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__COHERENT_RAM_END_UNALIGNED__ = .;
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/*
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* Memory page(s) mapped to this section will be marked
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* as device memory. No other unexpected data must creep in.
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* Ensure the rest of the current memory page is unused.
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*/
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. = ALIGN(PAGE_SIZE);
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__COHERENT_RAM_END__ = .;
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} >RAM
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#endif
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/*
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* Define a linker symbol to mark end of the RW memory area for this
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* image.
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*/
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__RW_END__ = .;
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__BL2_END__ = .;
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__BSS_SIZE__ = SIZEOF(.bss);
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#if USE_COHERENT_MEM
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__COHERENT_RAM_UNALIGNED_SIZE__ =
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__COHERENT_RAM_END_UNALIGNED__ - __COHERENT_RAM_START__;
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#endif
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ASSERT(. <= BL2_LIMIT, "BL2 image has exceeded its limit.")
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}
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