linux/arch/riscv
Atish Patra b6566dc1ac
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>
2020-11-25 16:05:27 -08:00
..
boot riscv: Ignore Image.* and loader.bin 2020-11-09 11:54:46 -08:00
configs RISC-V: Add EFI stub support. 2020-10-02 14:31:21 -07:00
include riscv: Make stack walk callback consistent with generic code 2020-11-20 18:53:38 -08:00
kernel RISC-V: Align the .init.text section 2020-11-25 16:05:27 -08:00
lib riscv: use memcpy based uaccess for nommu again 2020-10-04 10:27:07 -07:00
mm riscv: Enable CMA support 2020-11-20 17:58:18 -08:00
net treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
Kbuild riscv: Allow device trees to be built into the kernel 2020-05-18 11:38:05 -07:00
Kconfig riscv: Enable ARCH_STACKWALK 2020-11-25 16:03:59 -08:00
Kconfig.debug RISC-V: Remove EARLY_PRINTK support 2018-12-17 10:23:46 -08:00
Kconfig.socs RISC-V: Remove CLINT related code from timer and arch 2020-08-20 10:58:13 -07:00
Makefile riscv: Clean up boot dir 2020-11-09 11:54:45 -08:00