From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD8E819DF75; Thu, 5 Sep 2024 16:13:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725552820; cv=none; b=uVU+r3Qyh6dj3kR8lc8Ip/pGfJVgxR2UlcizdXWmT9SKZMZLETVycDzMFJDmx4X7v7OJP8oBVm5LblwtlyzcCIoep4For/HpFYguvFPr0jzuid+YoDPbGXguAZcYlUELvyJ8aNU+Q5hg+Ymi5ktoLaax7F6ROgDAGrd/o6EhdXo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725552820; c=relaxed/simple; bh=Ujb5yHl8obhHTgrsI+TQzp2K6D+LmQ7g6VfbyKGco00=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Kqs/0v/jqGQG11+Te/oZWPXK6BpFoQywl4/DVt2VxFGlVrKJSz+/h9hHjfhQ4A/yPk0Ct3nZ73tI7SaupUx1VUSTjFQi7a0LltjEwbJrK2lNIkj5G1Eq0NDtjb9GPmrYAjq0e+3UZDECCkrhPwVBsthaGE5FVLWfdMMupGM7XHo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=HegSE7me; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="HegSE7me" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5C3EC4CEC3; Thu, 5 Sep 2024 16:13:36 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="HegSE7me" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1725552814; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=55bJknDRImEIEh83mNWUbwqRYAr8coQT4CUKKDd4gNA=; b=HegSE7mehyaj6SAp/VnhlvGaaf85fyzlVkfWcnn7sUGLHgxLA3R706+39iH7IugfbGGag4 p5FlY4bhYQq8YynPTQwVluyERdi6BU1onSw+v7PJ1EWAFn80DQmJzY/8vYGa8CRoj7fR1k Bvw94kDNyDv1iVrUc3RWVgEGHcyil8w= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 9ecc21b4 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 5 Sep 2024 16:13:33 +0000 (UTC) Date: Thu, 5 Sep 2024 18:13:29 +0200 From: "Jason A. Donenfeld" To: Christophe Leroy Cc: Andrew Morton , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Michael Ellerman , Nicholas Piggin , Naveen N Rao , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Shuah Khan , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kselftest@vger.kernel.org, llvm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, Adhemerval Zanella , Xi Ruoyao Subject: Re: [PATCH v5 4/5] powerpc/vdso: Wire up getrandom() vDSO implementation on VDSO32 Message-ID: References: <1f49c2ce009f8b007ab0676fb41187b2d54f28b2.1725304404.git.christophe.leroy@csgroup.eu> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1f49c2ce009f8b007ab0676fb41187b2d54f28b2.1725304404.git.christophe.leroy@csgroup.eu> > +/* > + * The macro sets two stack frames, one for the caller and one for the callee > + * because there are no requirement for the caller to set a stack frame when > + * calling VDSO so it may have omitted to set one, especially on PPC64 > + */ > + > +.macro cvdso_call funct > + .cfi_startproc > + PPC_STLU r1, -PPC_MIN_STKFRM(r1) > + .cfi_adjust_cfa_offset PPC_MIN_STKFRM > + mflr r0 > + PPC_STLU r1, -PPC_MIN_STKFRM(r1) > + .cfi_adjust_cfa_offset PPC_MIN_STKFRM > + PPC_STL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) > + .cfi_rel_offset lr, PPC_MIN_STKFRM + PPC_LR_STKOFF > + get_datapage r8 > + addi r8, r8, VDSO_RNG_DATA_OFFSET > + bl CFUNC(DOTSYM(\funct)) > + PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) > + cmpwi r3, 0 > + mtlr r0 > + addi r1, r1, 2 * PPC_MIN_STKFRM > + .cfi_restore lr > + .cfi_def_cfa_offset 0 > + crclr so > + bgelr+ > + crset so > + neg r3, r3 > + blr > + .cfi_endproc > +.endm You wrote in an earlier email that this worked with time namespaces, but in my testing that doesn't seem to be the case. >From my test harness [1]: Normal single thread vdso: 25000000 times in 12.494133131 seconds libc: 25000000 times in 69.594625188 seconds syscall: 25000000 times in 67.349243972 seconds Time namespace single thread vdso: 25000000 times in 71.673057436 seconds libc: 25000000 times in 71.712774121 seconds syscall: 25000000 times in 66.902318080 seconds I'm seeing this on ppc, ppc64, and ppc64le. Can you figure out what's going on and send a fix, which I'll squash into this commit? Jason [1] https://git.zx2c4.com/linux-rng/commit/?h=jd/vdso-test-harness