From: Jisheng Zhang <jszhang@kernel.org>
To: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>, Arnd Bergmann <arnd@arndb.de>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org
Subject: [PATCH 0/4] riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
Date: Thu, 11 May 2023 22:12:07 +0800 [thread overview]
Message-ID: <20230511141211.2418-1-jszhang@kernel.org> (raw)
When trying to run linux with various opensource riscv core on
resource limited FPGA platforms, for example, those FPGAs with less
than 16MB SDRAM, I want to save mem as much as possible. One of the
major technologies is kernel size optimizations, I found that riscv
does not currently support HAVE_LD_DEAD_CODE_DATA_ELIMINATION, which
passes -fdata-sections, -ffunction-sections to CFLAGS and passes the
--gc-sections flag to the linker.
This not only benefits my case on FPGA but also benefits defconfigs.
Here are some notable improvements from enabling this with defconfigs:
nommu_k210_defconfig:
text data bss dec hex
1112009 410288 59837 1582134 182436 before
962838 376656 51285 1390779 1538bb after
rv32_defconfig:
text data bss dec hex
8804455 2816544 290577 11911576 b5c198 before
8692295 2779872 288977 11761144 b375f8 after
defconfig:
text data bss dec hex
9438267 3391332 485333 13314932 cb2b74 before
9285914 3350052 483349 13119315 c82f53 after
patch1 and patch2 are clean ups.
patch3 fixes a typo.
patch4 finally enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION for riscv.
Jisheng Zhang (4):
riscv: vmlinux-xip.lds.S: remove .alternative section
riscv: move HAVE_RETHOOK to keep entries sorted
riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
vmlinux.lds.h: use correct .init.data.* section name
arch/riscv/Kconfig | 3 ++-
arch/riscv/kernel/vmlinux-xip.lds.S | 6 ------
arch/riscv/kernel/vmlinux.lds.S | 6 +++---
include/asm-generic/vmlinux.lds.h | 2 +-
4 files changed, 6 insertions(+), 11 deletions(-)
--
2.40.1
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next reply other threads:[~2023-05-11 14:40 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-11 14:12 Jisheng Zhang [this message]
2023-05-11 14:12 ` [PATCH 1/4] riscv: vmlinux-xip.lds.S: remove .alternative section Jisheng Zhang
2023-05-12 13:51 ` Conor Dooley
2023-05-12 15:36 ` Jisheng Zhang
2023-05-11 14:12 ` [PATCH 2/4] riscv: move HAVE_RETHOOK to keep entries sorted Jisheng Zhang
2023-05-12 13:54 ` Conor Dooley
2023-05-11 14:12 ` [PATCH 3/4] vmlinux.lds.h: use correct .init.data.* section name Jisheng Zhang
2023-06-01 4:58 ` Guo Ren
2023-05-11 14:12 ` [PATCH 4/4] riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION Jisheng Zhang
2023-05-12 13:58 ` Conor Dooley
2023-05-12 15:16 ` Conor Dooley
2023-05-12 15:39 ` Jisheng Zhang
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