From patchwork Mon Sep 25 22:33:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhangjin Wu X-Patchwork-Id: 13398518 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF41CCE79A7 for ; Mon, 25 Sep 2023 22:34:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232024AbjIYWeG (ORCPT ); Mon, 25 Sep 2023 18:34:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229509AbjIYWeG (ORCPT ); Mon, 25 Sep 2023 18:34:06 -0400 Received: from bg4.exmail.qq.com (bg4.exmail.qq.com [43.155.65.254]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94C2B120; Mon, 25 Sep 2023 15:33:57 -0700 (PDT) X-QQ-mid: bizesmtp81t1695681226tcihg9u5 Received: from linux-lab-host.localdomain ( [116.30.124.152]) by bizesmtp.qq.com (ESMTP) with id ; Tue, 26 Sep 2023 06:33:44 +0800 (CST) X-QQ-SSF: 01200000000000E0Y000B00A0000000 X-QQ-FEAT: mRz6/7wsmIhEdtJxEM3+86IjQT+Q2BIK68FoSWVkt5uacFvPZnMVGdTic5nTs yFZ0ibzgKsflWJT5L40MNO8tEShlHRSZXfPwo1fDK1vqatDKo41I1IcSCrqiVhPV3R730IR pGGbPSYS+zsSxMPHTdxpa5tYEQ5bid0+GVFXPgKxc958NIK+3X2yS09DZdjKtvv+ZgGgu7o TjD9ZGoNdbjLgdkWbeFwPWuG3Ix9bFnm9YzgcMo2/xX+um7cPVbTgxCUiYcCO1ji2JSBSDg W1QAoXySxRkRiichVOSgMt1ehzqHAV2HQiK/pIpW8o7df+gBQPQwGFGwlddP3v0GSA2kNcT V2gskPCLhmWYivb0+S/GRjN4K3Tpg== X-QQ-GoodBg: 0 X-BIZMAIL-ID: 1329585511254707149 From: Zhangjin Wu To: linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, Arnd Bergmann Cc: falcon@tinylab.org, palmer@rivosinc.com, paul.walmsley@sifive.com, paulburton@kernel.org, paulmck@kernel.org, tsbogend@alpha.franken.de, w@1wt.eu, =?utf-8?q?Thomas_Wei=C3=9Fschuh?= , Tim Bird Subject: [PATCH v1 0/7] DCE/DSE: Add Dead Syscalls Elimination support, part1 Date: Tue, 26 Sep 2023 06:33:44 +0800 Message-Id: X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:tinylab.org:qybglogicsvrgz:qybglogicsvrgz5a-1 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Hi, all This series aims to add DCE based DSE support, here is the first revision of the RFC patchset [1], the whole series includes three parts, here is the Part1. This Part1 adds basic DCE based DSE support. Part2 will further eliminate the unused syscalls forcely kept by the exception tables. Part3 will add DSE test support with nolibc-test.c. Changes from RFC patchset [1]: - The DCE support [2] for RISC-V has been merged [3] - The "nolibc: Record used syscalls in their own sections" [4] will be delayed to Part3 - Add debug support for DCE - Further allows CONFIG_USED_SYSCALLS accept a file stores used syscalls - Now, only accepts symbolic syscalls, not support integral number again - Works with newly added riscv syscalls suffix: __riscv_ - Further trims the syscall tables by removing the tailing invalid parts The nolibc-test based initrd run well on riscv64 kernel image with dead syscalls eliminated: $ nm build/riscv64/virt/linux/v6.6-rc2/vmlinux | grep "T __riscv_sys" | grep -v sys_ni_syscall | wc -l 48 These options should be enabled: CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y CONFIG_LD_DEAD_CODE_DATA_ELIMINATION_DEBUG=y CONFIG_TRIM_UNUSED_SYSCALLS=y CONFIG_USED_SYSCALLS="sys_dup sys_dup3 sys_ioctl sys_mknodat sys_mkdirat sys_unlinkat sys_symlinkat sys_linkat sys_mount sys_chdir sys_chroot sys_fchmodat sys_fchownat sys_openat sys_close sys_pipe2 sys_getdents64 sys_lseek sys_read sys_write sys_pselect6 sys_ppoll sys_exit sys_sched_yield sys_kill sys_reboot sys_getpgid sys_prctl sys_gettimeofday sys_getpid sys_getppid sys_getuid sys_geteuid sys_brk sys_munmap sys_clone sys_execve sys_mmap sys_wait4 sys_statx" The really used syscalls: $ echo "sys_dup sys_dup3 sys_ioctl sys_mknodat sys_mkdirat sys_unlinkat sys_symlinkat sys_linkat sys_mount sys_chdir sys_chroot sys_fchmodat sys_fchownat sys_openat sys_close sys_pipe2 sys_getdents64 sys_lseek sys_read sys_write sys_pselect6 sys_ppoll sys_exit sys_sched_yield sys_kill sys_reboot sys_getpgid sys_prctl sys_gettimeofday sys_getpid sys_getppid sys_getuid sys_geteuid sys_brk sys_munmap sys_clone sys_execve sys_mmap sys_wait4 sys_statx" | tr ' ' '\n' | wc -l 40 Thanks to Yuan Tan, he has researched and verified the elimination of the unused syscalls forcely kept by the exception tables, both section group and section link order attributes of ld work. part2 will be sent out soon to further remove another 8 unused syscalls and eventually we are able to run a dead loop application on a kernel image without syscalls. Best Regards, Zhangjin Wu --- [1]: https://lore.kernel.org/lkml/cover.1676594211.git.falcon@tinylab.org/ [2]: https://lore.kernel.org/lkml/234017be6d06ef84844583230542e31068fa3685.1676594211.git.falcon@tinylab.org/ [3]: https://lore.kernel.org/lkml/CAFP8O3+41QFVyNTVJ2iZYkB0tqnvdLTAoGShgGy-qPP1PHjBEw@mail.gmail.com/ [4]: https://lore.kernel.org/lkml/cbcbfbb37cabfd9aed6088c75515e4ea86006cff.1676594211.git.falcon@tinylab.org/ Zhangjin Wu (7): DCE: add debug support DCE/DSE: add unused syscalls elimination configure support DCE/DSE: Add a new scripts/Makefile.syscalls DCE/DSE: mips: add HAVE_TRIM_UNUSED_SYSCALLS support DCE/DSE: riscv: move syscall tables to syscalls/ DCE/DSE: riscv: add HAVE_TRIM_UNUSED_SYSCALLS support DCE/DSE: riscv: trim syscall tables Makefile | 3 + arch/mips/Kconfig | 1 + arch/mips/kernel/syscalls/Makefile | 23 ++++++- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/unistd.h | 2 + arch/riscv/kernel/Makefile | 7 +- arch/riscv/kernel/syscalls/Makefile | 69 +++++++++++++++++++ .../{ => syscalls}/compat_syscall_table.c | 4 +- .../kernel/{ => syscalls}/syscall_table.c | 4 +- init/Kconfig | 49 +++++++++++++ scripts/Makefile.syscalls | 29 ++++++++ 11 files changed, 182 insertions(+), 10 deletions(-) create mode 100644 arch/riscv/kernel/syscalls/Makefile rename arch/riscv/kernel/{ => syscalls}/compat_syscall_table.c (82%) rename arch/riscv/kernel/{ => syscalls}/syscall_table.c (83%) create mode 100644 scripts/Makefile.syscalls