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| author |   Atish Patra <atish.patra@wdc.com> | 2020-11-04 16:04:37 -0800 |
|---|---|---|
| committer |   Palmer Dabbelt <palmerdabbelt@google.com> | 2020-11-25 16:05:27 -0800 |
| commit | b6566dc1acca38ce6ed845ce8a270fb181ff6d41 (patch) | |
| tree | 409d381e5841771953f6d9626204026ce8e16557 | |
| parent | RISC-V: Initialize SBI early (diff) | |
| download | linux-dev-b6566dc1acca38ce6ed845ce8a270fb181ff6d41.tar.xz linux-dev-b6566dc1acca38ce6ed845ce8a270fb181ff6d41.zip | |
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>
| -rw-r--r-- | arch/riscv/kernel/vmlinux.lds.S | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index 3ffbd6cbdb86..cacd7898ba7f 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -30,7 +30,13 @@ SECTIONS . = ALIGN(PAGE_SIZE); __init_begin = .; - INIT_TEXT_SECTION(PAGE_SIZE) + __init_text_begin = .; + .init.text : AT(ADDR(.init.text) - LOAD_OFFSET) ALIGN(SECTION_ALIGN) { \ + _sinittext = .; \ + INIT_TEXT \ + _einittext = .; \ + } + . = ALIGN(8); __soc_early_init_table : { __soc_early_init_table_start = .; |