| Message ID | 20230214150959.49088-1-falcon@tinylab.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Palmer Dabbelt |
| Headers | show |
| Series | [v2] RISC-V: Enable dead code elimination | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/cover_letter | success | Single patches do not need cover letters |
| conchuod/tree_selection | success | Guessed tree name to be for-next |
| conchuod/fixes_present | success | Fixes tag not required for -next series |
| conchuod/maintainers_pattern | success | MAINTAINERS pattern errors before the patch: 13 and now 13 |
| conchuod/verify_signedoff | success | Signed-off-by tag matches author and committer |
| conchuod/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| conchuod/build_rv64_clang_allmodconfig | success | Errors and warnings before: 914 this patch: 0 |
| conchuod/module_param | success | Was 0 now: 0 |
| conchuod/build_rv64_gcc_allmodconfig | success | Errors and warnings before: 2744 this patch: 0 |
| conchuod/alphanumeric_selects | warning | Out of order selects before the patch: 754 and now 755 |
| conchuod/build_rv32_defconfig | success | Build OK |
| conchuod/dtb_warn_rv64 | success | Errors and warnings before: 2 this patch: 2 |
| conchuod/header_inline | success | No static functions without inline keyword in header files |
| conchuod/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 15 lines checked |
| conchuod/source_inline | success | Was 0 now: 0 |
| conchuod/build_rv64_nommu_k210_defconfig | success | Build OK |
| conchuod/verify_fixes | success | No Fixes tag |
| conchuod/build_rv64_nommu_virt_defconfig | success | Build OK |
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index e2b656043abf..8a73d7180cb8 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -103,6 +103,7 @@ config RISCV select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL select HAVE_KRETPROBES if !XIP_KERNEL select HAVE_RETHOOK if !XIP_KERNEL + select HAVE_LD_DEAD_CODE_DATA_ELIMINATION select HAVE_MOVE_PMD select HAVE_MOVE_PUD select HAVE_PCI diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index 4e6c88aa4d87..51218cfe1ee4 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -101,7 +101,7 @@ SECTIONS . = ALIGN(8); .alternative : { __alt_start = .; - *(.alternative) + KEEP(*(.alternative)) __alt_end = .; } __init_end = .;
Select CONFIG_HAVE_LD_DEAD_CODE_DATA_ELIMINATION for RISC-V, allowing the user to enable dead code elimination. In order for this to work, ensure that we keep the alternative table by annotating them with KEEP. This boots well on qemu with both rv32_defconfig & rv64 defconfig, but it only shrinks their builds by ~1%, a smaller config is thereforce customized to test this feature: | rv32 | rv64 --------|------------------------|--------------------- No DCE | 4460684 | 4893488 DCE | 3986716 | 4376400 Shrink | 473968 (~10.6%) | 517088 (~10.5%) The config used above only reserves necessary options to boot on qemu with serial console, more like the size-critical embedded scenes: - rv64 config: https://pastebin.com/crz82T0s - rv32 config: rv64 config + 32-bit.config Signed-off-by: Zhangjin Wu <falcon@tinylab.org> --- arch/riscv/Kconfig | 1 + arch/riscv/kernel/vmlinux.lds.S | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-)