RISC-V: Align the .init.text section
In order to improve kernel text protection, we need separate .init.text/ .init.data/.text in separate sections. However, RISC-V linker relaxation code is not aware of any alignment between sections. As a result, it may relax any RISCV_CALL relocations between sections to JAL without realizing that an inter section alignment may move the address farther. That may lead to a relocation truncated fit error. However, linker relaxation code is aware of the individual section alignments. The detailed discussion on this issue can be found here. https://github.com/riscv/riscv-gnu-toolchain/issues/738 Keep the .init.text section aligned so that linker relaxation will take that as a hint while relaxing inter section calls. Here are the code size changes for each section because of this change. section change in size (in bytes) .head.text +4 .text +40 .init.text +6530 .exit.text +84 The only significant increase in size happened for .init.text because all intra relocations also use 2MB alignment. Suggested-by: Jim Wilson <jimw@sifive.com> Signed-off-by: Atish Patra <atish.patra@wdc.com> Tested-by: Greentime Hu <greentime.hu@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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@ -30,7 +30,13 @@ SECTIONS
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. = ALIGN(PAGE_SIZE);
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__init_begin = .;
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INIT_TEXT_SECTION(PAGE_SIZE)
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__init_text_begin = .;
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.init.text : AT(ADDR(.init.text) - LOAD_OFFSET) ALIGN(SECTION_ALIGN) { \
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_sinittext = .; \
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INIT_TEXT \
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_einittext = .; \
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}
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. = ALIGN(8);
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__soc_early_init_table : {
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__soc_early_init_table_start = .;
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