4ca59c9237
Refactor the two linker scripts to put .sdata at the end of the data segment and .sbss at the start of the bss segment to try to maximize the reach of the global pointer. Also generally tries to clean up and align the two linker scripts as a new golden standard for other architectures.
106 lines
2.7 KiB
Plaintext
106 lines
2.7 KiB
Plaintext
/*
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* LK linker script for multi segment binaries.
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* In this case the read only portion of the binary lives in read only
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* memory, usually in ROM at a lower address.
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* Data and BSS live in a higher memory address and initial data is
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* copied from rom during initialization.
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*/
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PHDRS
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{
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code PT_LOAD FLAGS(5); /* PF_R|PF_X */
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rodata PT_LOAD FLAGS(4); /* PF_R */
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data PT_LOAD FLAGS(6); /* PF_R|PF_W */
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}
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ENTRY(_start)
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SECTIONS
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{
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. = %ROMBASE%;
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_start = .;
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__rom_start = .;
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/* text/read-only data */
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/* set the load address to physical MEMBASE */
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.text : {
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KEEP(*(.text.boot))
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*(.text .text*)
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*(.gnu.linkonce.t.*)
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} :code
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. = ALIGN(CONSTANT(MAXPAGESIZE));
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.rodata : {
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__rodata_start = .;
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*(.rodata .rodata.* .gnu.linkonce.r.*)
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} :rodata
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. = .;
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__rodata_end = .;
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__rom_end = . ;
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. = ALIGN(CONSTANT(MAXPAGESIZE));
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__data_start_rom = .;
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/* insert a dummy section that is used to anchor the following data segment */
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.dummy_post_rodata : { }
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/* in two segment binaries, the data starts at the bottom of ram (MEMBASE)
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* bump us forward to the start of ram
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*/
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. = %MEMBASE%;
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.data : AT ( ADDR (.dummy_post_rodata) + SIZEOF (.dummy_post_rodata) ) {
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__data_start = .;
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*(.data .data.* .gnu.linkonce.d.*)
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__ctor_list = .;
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KEEP(*(.ctors .init_array))
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__ctor_end = .;
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__dtor_list = .;
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KEEP(*(.dtors .fini_array))
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__dtor_end = .;
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*(.got*)
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*(.dynamic)
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} :data
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/* Try to put sdata and sbss near each other by putting sdata at the end of the data segment
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* and sbss at the start of the bss segment. This maximizes reach of things referenced off of
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* the global pointer. */
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.sdata : {
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__global_pointer$ = . + (4K / 2);
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/* Question: should we put srodata here on multi seg binaries? */
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*(.srodata.cst16) *(.srodata.cst8) *(.srodata.cst4) *(.srodata.cst2) *(.srodata .srodata.*)
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*(.sdata .sdata.* .gnu.linkonce.s.*)
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}
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. = ALIGN(%BITS% / 8);
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__data_end = .;
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__bss_start = .;
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.sbss : {
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*(.dynsbss)
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*(.sbss .sbss.* .gnu.linkonce.sb.*)
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*(.scommon)
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}
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/* uninitialized data (in same segment as writable data) */
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.bss : {
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/* regular bss */
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*(.bss .bss.*)
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*(.gnu.linkonce.b.*)
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}
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. = ALIGN(%BITS% / 8);
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__bss_end = .;
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/* Align the end to ensure anything after the kernel ends up on its own pages */
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. = ALIGN(CONSTANT(MAXPAGESIZE));
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_end = .;
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. = %MEMBASE% + %MEMSIZE%;
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_end_of_ram = .;
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/* Strip unnecessary stuff */
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/DISCARD/ : { *(.comment .note .eh_frame) }
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}
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