From nobody Mon Apr 27 08:44:48 2026 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 A8F36C43334 for ; Wed, 15 Jun 2022 06:38:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354294AbiFOGiH (ORCPT ); Wed, 15 Jun 2022 02:38:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243437AbiFOGiF (ORCPT ); Wed, 15 Jun 2022 02:38:05 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B14483A5FC for ; Tue, 14 Jun 2022 23:38:02 -0700 (PDT) Received: from linux.localdomain (unknown [113.200.148.30]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dxr99HfqliljRDAA--.20432S3; Wed, 15 Jun 2022 14:38:00 +0800 (CST) From: Tiezhu Yang To: Huacai Chen , WANG Xuerui Cc: Xuefeng Li , Jianmin Lv , Jun Yi , Rui Wang , linux-kernel@vger.kernel.org Subject: [RFC PATCH v2 1/2] LoongArch: Only clone and clone3 need to call SAVE_STATIC Date: Wed, 15 Jun 2022 14:37:58 +0800 Message-Id: <1655275079-17651-2-git-send-email-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1655275079-17651-1-git-send-email-yangtiezhu@loongson.cn> References: <1655275079-17651-1-git-send-email-yangtiezhu@loongson.cn> X-CM-TRANSID: AQAAf9Dxr99HfqliljRDAA--.20432S3 X-Coremail-Antispam: 1UD129KBjvdXoWrZr1ktw17tr1kWr4UGryrCrg_yoWkuFX_A3 ZrG3yUWrWrAa92vF9rXF4fXasrAw48GF1FkFn2grWjka4UtrWDJwsIvw1UZFn8Kr4kXrs5 ZrWUWF92vr1FkjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbSkFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUGwA2048vs2IY02 0Ec7CjxVAFwI0_JFI_Gr1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVW5JVW7JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwA2z4 x0Y4vEx4A2jsIE14v26F4UJVW0owA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I2 62IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcV AFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r4j6F4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG 0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc2xSY4AK67AK6r47MxAIw28Icx kI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2Iq xVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42 IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY 6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aV CY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUU-J5DUUUUU== X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" In handle_syscall, it is unnecessary to call SAVE_STATIC for all syscalls, only clone and clone3 need to do this operation, so it is better to check the syscall number before call SAVE_STATIC. With this patch, it can reduce many store instructions. Signed-off-by: Tiezhu Yang --- arch/loongarch/kernel/entry.S | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S index d5b3dbc..53ce2cb 100644 --- a/arch/loongarch/kernel/entry.S +++ b/arch/loongarch/kernel/entry.S @@ -14,6 +14,7 @@ #include #include #include +#include =20 .text .cfi_sections .debug_frame @@ -56,8 +57,21 @@ SYM_FUNC_START(handle_syscall) cfi_st u0, PT_R21 cfi_st fp, PT_R22 =20 + /* + * Syscall number held in a7 which is stored in PT_R11. + * Only if syscall number is __NR_clone and __NR_clone3, call SAVE_STATIC. + */ + cfi_ld t3, PT_R11 + li.w t4, __NR_clone + beq t3, t4, 1f + li.w t4, __NR_clone3 + beq t3, t4, 1f + b 2f + +1: SAVE_STATIC =20 +2: move u0, t0 li.d tp, ~_THREAD_MASK and tp, tp, sp --=20 2.1.0 From nobody Mon Apr 27 08:44:48 2026 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 935B0C433EF for ; Wed, 15 Jun 2022 06:38:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351228AbiFOGiL (ORCPT ); Wed, 15 Jun 2022 02:38:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53584 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352380AbiFOGiF (ORCPT ); Wed, 15 Jun 2022 02:38:05 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id CA32B41615 for ; Tue, 14 Jun 2022 23:38:02 -0700 (PDT) Received: from linux.localdomain (unknown [113.200.148.30]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dxr99HfqliljRDAA--.20432S4; Wed, 15 Jun 2022 14:38:01 +0800 (CST) From: Tiezhu Yang To: Huacai Chen , WANG Xuerui Cc: Xuefeng Li , Jianmin Lv , Jun Yi , Rui Wang , linux-kernel@vger.kernel.org Subject: [RFC PATCH v2 2/2] LoongArch: No need to call RESTORE_ALL_AND_RET for all syscalls Date: Wed, 15 Jun 2022 14:37:59 +0800 Message-Id: <1655275079-17651-3-git-send-email-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1655275079-17651-1-git-send-email-yangtiezhu@loongson.cn> References: <1655275079-17651-1-git-send-email-yangtiezhu@loongson.cn> X-CM-TRANSID: AQAAf9Dxr99HfqliljRDAA--.20432S4 X-Coremail-Antispam: 1UD129KBjvJXoWxJr4fur1DXw1ruryrXrWUurg_yoW8KFW8p3 WqvFnakF4jgF97Cry3XryxurWay3Z7GF4UuFsFk395uw1kX345Xryvya4Dtr12kw48KrW8 Xa48GwsIgFyjqwUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBS14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_Jryl82xGYIkIc2 x26xkF7I0E14v26r4j6ryUM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UM2 8EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY02Avz4vE14v_GF1l42xK82 IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC2 0s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAKI48JMI IF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF 0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87 Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjTRKKZAUUUUU X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" In handle_syscall, it is unnecessary to call RESTORE_ALL_AND_RET for all syscalls. (1) If syscall number is __NR_clone and __NR_clone3, call RESTORE_STATIC_SOME_SP_AND_RET. (2) If syscall number is __NR_rt_sigreturn and __NR_rt_sigsuspend, call RESTORE_TEMP_SOME_SP_AND_RET. (3) The other syscalls call RESTORE_SOME_SP_AND_RET. With this patch, it can reduce many load instructions. Signed-off-by: Tiezhu Yang --- arch/loongarch/include/asm/stackframe.h | 17 +++++++++++++++++ arch/loongarch/kernel/entry.S | 24 +++++++++++++++++++++++- 2 files changed, 40 insertions(+), 1 deletion(-) diff --git a/arch/loongarch/include/asm/stackframe.h b/arch/loongarch/inclu= de/asm/stackframe.h index 4ca9530..52649a5f 100644 --- a/arch/loongarch/include/asm/stackframe.h +++ b/arch/loongarch/include/asm/stackframe.h @@ -216,4 +216,21 @@ RESTORE_SP_AND_RET \docfi .endm =20 + .macro RESTORE_SOME_SP_AND_RET docfi=3D0 + RESTORE_SOME \docfi + RESTORE_SP_AND_RET \docfi + .endm + + .macro RESTORE_STATIC_SOME_SP_AND_RET docfi=3D0 + RESTORE_STATIC \docfi + RESTORE_SOME \docfi + RESTORE_SP_AND_RET \docfi + .endm + + .macro RESTORE_TEMP_SOME_SP_AND_RET docfi=3D0 + RESTORE_TEMP \docfi + RESTORE_SOME \docfi + RESTORE_SP_AND_RET \docfi + .endm + #endif /* _ASM_STACKFRAME_H */ diff --git a/arch/loongarch/kernel/entry.S b/arch/loongarch/kernel/entry.S index 53ce2cb..58fe507 100644 --- a/arch/loongarch/kernel/entry.S +++ b/arch/loongarch/kernel/entry.S @@ -79,7 +79,29 @@ SYM_FUNC_START(handle_syscall) move a0, sp bl do_syscall =20 - RESTORE_ALL_AND_RET + /* + * Syscall number held in a7 which is stored in PT_R11. + * If syscall number is __NR_clone and __NR_clone3, + * call RESTORE_STATIC_SOME_SP_AND_RET. + * If syscall number is __NR_rt_sigreturn and __NR_rt_sigsuspend, + * call RESTORE_TEMP_SOME_SP_AND_RET. + * The other syscalls call RESTORE_SOME_SP_AND_RET. + */ + cfi_ld t3, PT_R11 + li.w t4, __NR_clone + beq t3, t4, 3f + li.w t4, __NR_clone3 + beq t3, t4, 3f + li.w t4, __NR_rt_sigreturn + beq t3, t4, 4f + li.w t4, __NR_rt_sigsuspend + beq t3, t4, 4f + + RESTORE_SOME_SP_AND_RET +3: + RESTORE_STATIC_SOME_SP_AND_RET +4: + RESTORE_TEMP_SOME_SP_AND_RET SYM_FUNC_END(handle_syscall) =20 SYM_CODE_START(ret_from_fork) --=20 2.1.0