From nobody Wed Apr 8 12:14:02 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 D58D1C433FE for ; Wed, 26 Oct 2022 03:55:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232289AbiJZDzZ (ORCPT ); Tue, 25 Oct 2022 23:55:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231597AbiJZDzV (ORCPT ); Tue, 25 Oct 2022 23:55:21 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0D0A717E16 for ; Tue, 25 Oct 2022 20:55:17 -0700 (PDT) Received: from loongson.cn (unknown [111.9.175.10]) by gateway (Coremail) with SMTP id _____8Dxndqkr1hjbYcCAA--.9980S3; Wed, 26 Oct 2022 11:55:16 +0800 (CST) Received: from localhost.localdomain (unknown [111.9.175.10]) by localhost.localdomain (Coremail) with SMTP id AQAAf8Axf+Cir1hj2yMFAA--.19823S2; Wed, 26 Oct 2022 11:55:15 +0800 (CST) From: Jinyang He To: Huacai Chen , WANG Xuerui , Oleg Nesterov Cc: Xi Ruoyao , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH v2 RESEND] LoongArch: Remove unused kernel stack padding Date: Wed, 26 Oct 2022 11:55:01 +0800 Message-Id: <20221026035501.11986-1-hejinyang@loongson.cn> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: AQAAf8Axf+Cir1hj2yMFAA--.19823S2 X-CM-SenderInfo: pkhmx0p1dqwqxorr0wxvrqhubq/ X-Coremail-Antispam: 1Uk129KBjvJXoWxZF4DKw4DuF4Uur4UKF1ftFb_yoWrXrWrpF 9rAwnrGr4jkF1vyryDtrs8uryDJwn7Kw1aga17ta4rCrnFqF1rXry8AryDXFyaqa95K3y0 gFyfKwsxtay5J3JanT9S1TB71UUUUUDqnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU b7AYFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s 1l1IIY67AEw4v_Jrv_JF1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVWUCVW8JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwA2z4 x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv6xkF7I0E14v26r4UJVWxJr1l e2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2xF0cIa020Ex4CE44I27wAqx4xG64xvF2 IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jrv_JF1lYx0Ex4A2jsIE14v26r1j6r4U McvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwCF04k20xvY0x0EwIxGrwCFx2 IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v2 6r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67 AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr1lIxAIcVCF04k26cxKx2IY s7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Jr 0_GrUvcSsGvfC2KfnxnUUI43ZEXa7IU8zwZ7UUUUU== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Kernel stack padding looks like obey MIPS o32 Calling Convention, as LoongArch is inspired by MIPS and keep it. Remove it avoid not clear code. Link: https://lore.kernel.org/loongarch/1662130897-13156-1-git-send-email-h= ejinyang@loongson.cn/ Signed-off-by: Jinyang He Reviewed-by: WANG Xuerui --- v2: Remove TOP_OF_KERNEL_STACK_PADDING Remove 'init stack pointer' in head.S arch/loongarch/include/asm/processor.h | 2 +- arch/loongarch/include/asm/ptrace.h | 2 +- arch/loongarch/kernel/head.S | 3 +-- arch/loongarch/kernel/process.c | 4 ++-- arch/loongarch/kernel/switch.S | 2 +- 5 files changed, 6 insertions(+), 7 deletions(-) diff --git a/arch/loongarch/include/asm/processor.h b/arch/loongarch/includ= e/asm/processor.h index 6954dc5d24e9..7184f1dc61f2 100644 --- a/arch/loongarch/include/asm/processor.h +++ b/arch/loongarch/include/asm/processor.h @@ -191,7 +191,7 @@ static inline void flush_thread(void) unsigned long __get_wchan(struct task_struct *p); =20 #define __KSTK_TOS(tsk) ((unsigned long)task_stack_page(tsk) + \ - THREAD_SIZE - 32 - sizeof(struct pt_regs)) + THREAD_SIZE - sizeof(struct pt_regs)) #define task_pt_regs(tsk) ((struct pt_regs *)__KSTK_TOS(tsk)) #define KSTK_EIP(tsk) (task_pt_regs(tsk)->csr_era) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->regs[3]) diff --git a/arch/loongarch/include/asm/ptrace.h b/arch/loongarch/include/a= sm/ptrace.h index 7437b9366c3b..59c4608de91d 100644 --- a/arch/loongarch/include/asm/ptrace.h +++ b/arch/loongarch/include/asm/ptrace.h @@ -133,7 +133,7 @@ static inline void die_if_kernel(const char *str, struc= t pt_regs *regs) #define current_pt_regs() \ ({ \ unsigned long sp =3D (unsigned long)__builtin_frame_address(0); \ - (struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1 - 32) - 1; \ + (struct pt_regs *)((sp | (THREAD_SIZE - 1)) + 1) - 1; \ }) =20 /* Helpers for working with the user stack pointer */ diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S index 97425779ce9f..84970e266658 100644 --- a/arch/loongarch/kernel/head.S +++ b/arch/loongarch/kernel/head.S @@ -84,10 +84,9 @@ SYM_CODE_START(kernel_entry) # kernel entry point =20 la.pcrel tp, init_thread_union /* Set the SP after an empty pt_regs. */ - PTR_LI sp, (_THREAD_SIZE - 32 - PT_SIZE) + PTR_LI sp, (_THREAD_SIZE - PT_SIZE) PTR_ADD sp, sp, tp set_saved_sp sp, t0, t1 - PTR_ADDI sp, sp, -4 * SZREG # init stack pointer =20 bl start_kernel ASM_BUG() diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/proces= s.c index 1256e3582475..2526b68f1c0f 100644 --- a/arch/loongarch/kernel/process.c +++ b/arch/loongarch/kernel/process.c @@ -129,7 +129,7 @@ int copy_thread(struct task_struct *p, const struct ker= nel_clone_args *args) unsigned long clone_flags =3D args->flags; struct pt_regs *childregs, *regs =3D current_pt_regs(); =20 - childksp =3D (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; + childksp =3D (unsigned long)task_stack_page(p) + THREAD_SIZE; =20 /* set up new TSS. */ childregs =3D (struct pt_regs *) childksp - 1; @@ -236,7 +236,7 @@ bool in_task_stack(unsigned long stack, struct task_str= uct *task, struct stack_info *info) { unsigned long begin =3D (unsigned long)task_stack_page(task); - unsigned long end =3D begin + THREAD_SIZE - 32; + unsigned long end =3D begin + THREAD_SIZE; =20 if (stack < begin || stack >=3D end) return false; diff --git a/arch/loongarch/kernel/switch.S b/arch/loongarch/kernel/switch.S index 43ebbc3990f7..202a163cb32f 100644 --- a/arch/loongarch/kernel/switch.S +++ b/arch/loongarch/kernel/switch.S @@ -26,7 +26,7 @@ SYM_FUNC_START(__switch_to) move tp, a2 cpu_restore_nonscratch a1 =20 - li.w t0, _THREAD_SIZE - 32 + li.w t0, _THREAD_SIZE PTR_ADD t0, t0, tp set_saved_sp t0, t1, t2 =20 --=20 2.34.3