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 B8B5E1DCB09; Fri, 4 Jul 2025 02:56:54 +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=1751597814; cv=none; b=S5wTE+hoCBLjjGLHbrfw1l7NsWSHHbCXwymydzJzz6YBJ9ngtO6PAzXZSPi7VJPiBuy59fn5pWXFWj24oo9n5O8ni7+9c3nUpg9P6/pyTRGISucK3rIThbutV7K4gnSpos91CLHOLvc+u69MoP04CG1JZOYrpHst3unfGTxzbxk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751597814; c=relaxed/simple; bh=dpKVhbg7scykD3su9SjXQjOIqalbcvI5GMk6pb9f330=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZhgLqZ3+lCquK1moEXB3NdQrjOP7Ck3KzOcZhOSnABFIYsIKRl1YOgDJ5J2KNnSfAk8HpAyBKcOG83DWTqcbXz1EFP1FPo4Z5WRVproSD+DhpQxzeIxG/jmT+NZGs9rJPXpsxbmLbLOWlCXtkITD0uUqkGFtnClFJWQZTvJWEgQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OzbvUBJV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OzbvUBJV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 04B0BC4CEF0; Fri, 4 Jul 2025 02:56:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751597814; bh=dpKVhbg7scykD3su9SjXQjOIqalbcvI5GMk6pb9f330=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OzbvUBJVeecszUyXLvImzILJGBClLv+O5DjY1gGAgL+hzspJC9pfCzoAYJXVjEwVe rk/yN6nvuaI6jcQrKTDvqJv6QYJZySe+YZm+9H/GOaurArFaOQC0jFoJSri6ejeSF/ sfF9mOQGBbTOx5aQC93NyXABMRjmwv68EXpQqdbSQw9pQi3dtPVvGmTYFx+k8d5qbe mVWY0Kbib4Z4KaykDVElREWOhuWTYm51s6na7rDax5TX3AVuSSaIY8woqOjtZq9W8h UmO2eNvpJ7pZrATUd8o0pWqRaeujROLjIZSC9qzaFjPa6NcA3r+3LNqJUR1WX6xdar z+YgYOIrB4q4Q== Date: Fri, 4 Jul 2025 05:56:50 +0300 From: Jarkko Sakkinen To: Prachotan Bathi Cc: Peter Huewe , Jason Gunthorpe , Stuart Yoder , linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 2/3] tpm_crb_ffa:Introduce memzero macro to replace memset Message-ID: References: <20250626184521.1079507-1-prachotan.bathi@arm.com> <20250626184521.1079507-3-prachotan.bathi@arm.com> <151a612b-198a-4f7e-94e7-10426831ab94@arm.com> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Jul 04, 2025 at 05:45:11AM +0300, Jarkko Sakkinen wrote: > On Wed, Jul 02, 2025 at 10:58:56PM -0500, Prachotan Bathi wrote: > > On 7/2/25 5:16 PM, Jarkko Sakkinen wrote: > > > > > On Thu, Jun 26, 2025 at 01:45:20PM -0500, Prachotan Bathi wrote: > > > > Add a memzero macro to simplify and standardize zeroing > > > > FF-A data args, replacing direct uses of memset for > > > > improved readability and maintainability. > > > > > > > > Signed-off-by: Prachotan Bathi > > > > --- > > > > drivers/char/tpm/tpm_crb_ffa.c | 6 ++++-- > > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c > > > > index 089d1e54bb46..397cc3b0a478 100644 > > > > --- a/drivers/char/tpm/tpm_crb_ffa.c > > > > +++ b/drivers/char/tpm/tpm_crb_ffa.c > > > > @@ -12,6 +12,8 @@ > > > > #include > > > > #include "tpm_crb_ffa.h" > > > > +#define memzero(s, n) memset((s), 0, (n)) > > > > + > > > > /* TPM service function status codes */ > > > > #define CRB_FFA_OK 0x05000001 > > > > #define CRB_FFA_OK_RESULTS_RETURNED 0x05000002 > > > > @@ -192,7 +194,7 @@ static int __tpm_crb_ffa_send_receive(unsigned long func_id, > > > > msg_ops = tpm_crb_ffa->ffa_dev->ops->msg_ops; > > > > if (ffa_partition_supports_direct_req2_recv(tpm_crb_ffa->ffa_dev)) { > > > > - memset(&tpm_crb_ffa->direct_msg_data2, 0x00, > > > > + memzero(&tpm_crb_ffa->direct_msg_data2, > > > > sizeof(struct ffa_send_direct_data2)); > > > > tpm_crb_ffa->direct_msg_data2.data[0] = func_id; > > > > @@ -205,7 +207,7 @@ static int __tpm_crb_ffa_send_receive(unsigned long func_id, > > > > if (!ret) > > > > ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data2.data[0]); > > > > } else { > > > > - memset(&tpm_crb_ffa->direct_msg_data, 0x00, > > > > + memzero(&tpm_crb_ffa->direct_msg_data, > > > > sizeof(struct ffa_send_direct_data)); > > > > tpm_crb_ffa->direct_msg_data.data1 = func_id; > > > > -- > > > > 2.43.0 > > > > > > > It adds a ross-reference to the source code, meaning that you have to > > > jump back and forth in the source code just to see that there is a > > > function that wraps up a single memset() call. > > > > > > How does that map to "readability"? > > > > > > BR, Jarkko > > > > Hi Jarkko > > > > I've implemented this change post your feedback on v4 of the initial patch > > series, maybe this should've been a question at that point, but what was the > > reasoning for recommending that I use memzero instead? I'll use the same > > reasoning to rephrase the commit message. > > OK I found what you were referring to: > > https://lore.kernel.org/linux-integrity/aFF-WNSolTdV9PZG@kernel.org/ > > Well, that was some truly misguided advice from my side so all the shame > here is on me :-) There's no global memzero() and neither explicit > version makes much sense here. Sorry about that. > > I gave it now (actual) thought, and here's what I'd propose: > > diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c > index 96746d5b03e3..e769f6143a7c 100644 > --- a/drivers/char/tpm/tpm_crb_ffa.c > +++ b/drivers/char/tpm/tpm_crb_ffa.c > @@ -203,26 +203,20 @@ static int __tpm_crb_ffa_try_send_receive(unsigned long func_id, > msg_ops = tpm_crb_ffa->ffa_dev->ops->msg_ops; > > if (ffa_partition_supports_direct_req2_recv(tpm_crb_ffa->ffa_dev)) { > - memzero(&tpm_crb_ffa->direct_msg_data2, > - sizeof(struct ffa_send_direct_data2)); > - > - tpm_crb_ffa->direct_msg_data2.data[0] = func_id; > - tpm_crb_ffa->direct_msg_data2.data[1] = a0; > - tpm_crb_ffa->direct_msg_data2.data[2] = a1; > - tpm_crb_ffa->direct_msg_data2.data[3] = a2; > + tpm_crb_ffa->direct_msg_data2 = (struct ffa_send_direct_data2){ > + .data = { func_id, a0, a1, a2 }, > + }; > > ret = msg_ops->sync_send_receive2(tpm_crb_ffa->ffa_dev, > &tpm_crb_ffa->direct_msg_data2); > if (!ret) > ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data2.data[0]); > } else { > - memzero(&tpm_crb_ffa->direct_msg_data, > - sizeof(struct ffa_send_direct_data)); > - > - tpm_crb_ffa->direct_msg_data.data1 = func_id; > - tpm_crb_ffa->direct_msg_data.data2 = a0; > - tpm_crb_ffa->direct_msg_data.data3 = a1; > - tpm_crb_ffa->direct_msg_data.data4 = a2; > + tpm_crb_ffa->direct_msg_data = (struct ffa_send_direct_data){ > + .data1 = func_id, > + .data2 = a0, > + .data3 = a1, Oops, lacks a2 but you probably get the idea :-) BR, Jarkko