From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f172.google.com (mail-yw1-f172.google.com [209.85.128.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB521466B1F for ; Sun, 11 Oct 2026 20:16:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791749816; cv=none; b=bQGXlFBOHu7E5k+a3+Xxu8u4SD3eSrhyQFDBV3MxCqd5Ygf9inYZ+Hy6yolBxclxE41QJi+mgjcn2mPvHyB9wEgOBn06vojD5+QnosinmkIO5Y0Ye13MN7S8AtjQFPo/q23s6dbiL8wQbeHaQ0Tvy8poRCf4h+0vXn7Pj9RS0lw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791749816; c=relaxed/simple; bh=1Lydj388n5XJbUniv4M5YY8iR7+Rzly+NPlrwZecqFg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=RnLUrlcJ/pxXc+5DHV8s8qFqfLnu8u2IHDuAkNIlZ/1fboCI/qnvdNR5GcfYRfZ8tjALcPT+xiXwHOxQmdv9feI2cJ8ea765WqD2vKvKzuK7qVMxN1vVwac7yKDYBUTtIjgY2P4t+CeAWDEiIC98tgiDml/xJspME9HJjpS3Dhw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=iXkxy83I; arc=none smtp.client-ip=209.85.128.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="iXkxy83I" Received: by mail-yw1-f172.google.com with SMTP id 00721157ae682-8ad98c3fb15so7914637b3.2 for ; Sun, 11 Oct 2026 13:16:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1791749810; x=1792354610; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=DuWRZ9OkHcwAnsa3x0jt7TLuHUCTDQyxo4PE4uuz/V4=; b=iXkxy83IEtVeQzvVu8gj98gIB1Rr9MlyRGotjhXR96QgnrKVfhLiSBtQmEJIwKN1OW qrd/5CBTgYGctiZxWWfRIuzJYZ74GHLl04EORtdGVNG47rPOMU6VxWwzec5OOOjkANjN AD2ibGTKCuSrl19uSj0gmoeoJhVXySIVM+6waFGhlnilMDqf9qPMoZQPJEfiB9ha8ULF c36e6LzERD97tFsCUPFC6yWRmaN3X/Zp4jY0MMgN/f2U3rBVF2zQdmHmTX2cehqjfdcK m59fPTTD70qOlJg4M7y2NQCsLbYisPMQc6fmgrwKBgHMo7Jc9VMOnDkfR2kfbJDh6jYV V2Ww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791749810; x=1792354610; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=DuWRZ9OkHcwAnsa3x0jt7TLuHUCTDQyxo4PE4uuz/V4=; b=nXhcUN9aFhmZjqSNPpTAe1Cvfa1L2N4V76ve/97903MBM624wS6DL5Cvr+BDOqdPKY 2nfHqXYEd7yuTxzrZHN715F1TklsDZBWubTmB3MgWfDcL0JEc8qj5isQQHvsJZLvmspq Wt9Emx81+V/CJG/GbFZpcb0p0Bna0lMECvK6ldRJYKlNMPz0U1/ppeQqSkZ+30l5kWib zOa91Zc/nY37veIP2ITSbseKwY1v/Hzz8u5/EhGbSKl/flE2pS/g6S8rapwcUgeHYV4Y B+1B4BRuXaIphUcqbf0v6bIXtbHzF7M1ibPj/0tjZplHNhFj7S6uKBzB8EhkM4Jn/qVW FeEg== X-Forwarded-Encrypted: i=1; AKwUvBwarklUl8219SgjPlYQjprna/9piZ+/qBijSS5jPJSNdCPFg7FmxYW9YSMgsbd0uVvSD16YXYiL81LfZNo=@vger.kernel.org X-Gm-Message-State: AFq9FYLjmvmOT3zHC2dheeLKdPQTbTftQmAiqwiL5aa0DieyvoGUsJ5K OcrLgcv5AOpCGVSfPH5QI+a71TWCaQCIH9kFVxo1y0X592EuRvqHjHEd X-Gm-Gg: AYBFou1SwpTYtezEDzt4wta25AI508U9KTkvIZnqXE+o/sZp4ixxJq9kvvq9/hYHI+N tk52xtS5Js7My+ohjoM0DcxS+xN6sB2sTvSWb+IkXq57ZiCh1dAIOJO/QOadb1DRFduyE3Iy4kU jVWdPKJLqTYMpUFSCvCxdpbjnNEtbafKwlUnXPGpZjBQOOlWM+EQGYhZNal3Nq4K2OpvJiMPtsU yx9CQK4k+tsERGiVvw68D++PlPR5SfJ9LA5TmBrc44oLvTaeSPfZ+Xa2SXQL5mMxvlBBbvIpBPm D8ad2i4zAZ1e3FX3embnJh/uCVaoTOb+SGdVQLxlCepwqX/kixLwF3K9RJvBBvsP6oX5+0xi0vo QxLtCkBS/g1YB/v11JZxauoY2QiC8gtAmKvkM78cXPAYNSqlzLiBXIKEwFykq9EHlpBBdfhh5eQ w+1hS5x6qZ6yrhqoooDjcbAK/Z8SfthC/NwKQPh8ZpgwyCxyfkyKGOszJbISBFK/1l9Z6Br81kU WAQB7Qih3v5UuK0k9HbDcbWiVlS7XajKGlT8YIAnhJHW7jKCoQDSG0h X-Received: by 2002:a05:690e:4802:b0:676:858d:35c5 with SMTP id 956f58d0204a3-679369f24b8mr1607590d50.55.1791749810536; Sun, 11 Oct 2026 13:16:50 -0700 (PDT) Received: from localhost ([2600:1702:7a90:6f9f:8bc4:8aec:108d:7a04]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-679356d5a8esm2948947d50.18.2026.10.11.13.16.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 11 Oct 2026 13:16:49 -0700 (PDT) From: Matt Turner Date: Sun, 11 Oct 2026 16:16:42 -0400 Subject: [PATCH 2/4] alpha: stop storing the user stack pointer in pt_regs Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261011-alpha-perf-regs-v3-v1-2-eaa625a39712@gmail.com> References: <20261011-alpha-perf-regs-v3-v1-0-eaa625a39712@gmail.com> In-Reply-To: <20261011-alpha-perf-regs-v3-v1-0-eaa625a39712@gmail.com> To: Richard Henderson , Magnus Lindholm Cc: linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-perf-users@vger.kernel.org, Matt Turner X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=3034; i=mattst88@gmail.com; h=from:subject:message-id; bh=1Lydj388n5XJbUniv4M5YY8iR7+Rzly+NPlrwZecqFg=; b=owGbwMvMwCW25rVmCc8sv+mMp9WSGLJOv1tlc755ccz9+oJW1ebH3/5eZmy6XHVgw/JjFdYqF 96GBnYs6/jIwiDGxTBTTJElbr0iy6y2HUt9Tkv/gpnDygQyRFqkgQEIWBj4chPzSo10jPRMtQ31 DIEMHaN4iJweg0ZmcXFpapFuWkGRQ15+SWJJZn5esV5+QWpeQXqBXlpmWklGRn5RcSrQCL281BJ TV0c3I0MDE0tHCzMnC0dTE2dnJ0MnN0dHZ1cnI0tzEwNnS0cTV0tzBi5OAZhrzm9iZJi6dMdci8 U6RRYygc/1K73uPN3mbbKXaeoRge73qz/ZmpQzMjzJlDJgnvXasKQj5HHGlkftd5bdPdK3Ob75v sPm5zsTtVkA X-Developer-Key: i=mattst88@gmail.com; a=openpgp; fpr=3BB639E56F861FA2E86505690FDD682D974CA72A Nothing reads pt_regs->usp now that user_stack_pointer() uses the PCB. Drop the stores, which saves a PAL_rdusp call on every syscall, and give the field back its old name. Assisted-by: Claude:claude-opus-5-5 Signed-off-by: Matt Turner --- arch/alpha/include/uapi/asm/ptrace.h | 2 +- arch/alpha/kernel/asm-offsets.c | 1 - arch/alpha/kernel/entry.S | 5 ----- arch/alpha/kernel/traps.c | 8 -------- 4 files changed, 1 insertion(+), 15 deletions(-) diff --git a/arch/alpha/include/uapi/asm/ptrace.h b/arch/alpha/include/uapi/asm/ptrace.h index 9d86b2a1526e..72ed913a910f 100644 --- a/arch/alpha/include/uapi/asm/ptrace.h +++ b/arch/alpha/include/uapi/asm/ptrace.h @@ -43,7 +43,7 @@ struct pt_regs { unsigned long trap_a1; unsigned long trap_a2; /* This makes the stack 16-byte aligned as GCC expects */ - unsigned long usp; + unsigned long __pad0; /* These are saved by PAL-code: */ unsigned long ps; unsigned long pc; diff --git a/arch/alpha/kernel/asm-offsets.c b/arch/alpha/kernel/asm-offsets.c index c89792c86044..22ed3c975b1c 100644 --- a/arch/alpha/kernel/asm-offsets.c +++ b/arch/alpha/kernel/asm-offsets.c @@ -30,7 +30,6 @@ static void __used foo(void) DEFINE(HAE_CACHE, offsetof(struct alpha_machine_vector, hae_cache)); DEFINE(HAE_REG, offsetof(struct alpha_machine_vector, hae_register)); - DEFINE(PT_REGS_USP, offsetof(struct pt_regs, usp)); DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); DEFINE(TI_SYSCALL_WORK, offsetof(struct thread_info, syscall_work)); diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S index bfa116d455fb..790389a15c3c 100644 --- a/arch/alpha/kernel/entry.S +++ b/arch/alpha/kernel/entry.S @@ -476,11 +476,6 @@ entSys: ldq $1, 0($sp) /* syscall nr from saved r0 */ stq $1, 8($sp) /* regs->r1 = shadow syscall nr */ - mov $0, $8 - call_pal PAL_rdusp - stq $0, PT_REGS_USP($sp) - mov $8, $0 - lda $8, 0x3fff bic $sp, $8, $8 diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c index cfaef96c4ce8..5882c65b7ef1 100644 --- a/arch/alpha/kernel/traps.c +++ b/arch/alpha/kernel/traps.c @@ -30,12 +30,6 @@ #include "proto.h" -static __always_inline void alpha_snapshot_usp(struct pt_regs *regs) -{ - if (user_mode(regs)) - regs->usp = rdusp(); -} - void dik_show_regs(struct pt_regs *regs, unsigned long *r9_15) { @@ -186,7 +180,6 @@ do_entArith(unsigned long summary, unsigned long write_mask, { long si_code = FPE_FLTINV; - alpha_snapshot_usp(regs); if (summary & 1) { /* Software-completion summary bit is set, so try to emulate the instruction. If the processor supports @@ -208,7 +201,6 @@ do_entIF(unsigned long type, struct pt_regs *regs) { int signo, code; - alpha_snapshot_usp(regs); if (type == 3) { /* FEN fault */ /* Irritating users can call PAL_clrfen to disable the FPU for the process. The kernel will then trap in -- 2.55.0