From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 79F5622CBE6; Fri, 3 Jul 2026 08:38:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783067912; cv=none; b=XjDt5w66hTJjQ3MWFBSBwIY+MFjyH6jjvW/FauyG7Kqc6sGBl3GeGlGljHzkqgV2s94w4sl8ynP1bo5+QeO7OFXopiP211Xt98l+qFxvilVnICnyXwriXd6L51uYD/O+rTs0mcDz1D+YpTeSCde7+BZ99rMJy3hn2WpEd4Vz4Hw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783067912; c=relaxed/simple; bh=KcfAyjvfIggeRPUgM5kQPKdIyZKtYOy5nlDTfsdQLwM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=SFimwZd26z9/YFbhF6prb2bwYsp3nqX9VVWQHaSZw2t8JGD22wHmrsTNNiF0uWsSZs3t4ouGpf5NM7FL8Q/BQGoro8I+wYQdYAuCr2pWCTEDiE7xVq7QcY7/XzVFX0tnjevvd5HxIXw1/C3ZrmdiwtVx45eErUhEo5qtFYy2ffg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=GVNmKlA2; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="GVNmKlA2" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E09051476; Fri, 3 Jul 2026 01:38:24 -0700 (PDT) Received: from [10.211.55.3] (unknown [10.57.73.238]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 796F73F905; Fri, 3 Jul 2026 01:38:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1783067909; bh=KcfAyjvfIggeRPUgM5kQPKdIyZKtYOy5nlDTfsdQLwM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=GVNmKlA2lu3JViMT/eyKZ0Fyi70W3QFFyZVhNf0Jiw+O7ybwekm2eWKH7waeumEgv WOvthIC+BYMk3E/wuZ/vqkdx+65WWp7KhMHvYo0nL652grpVgQ9lay7FkmEy3JhZbc FvNwCqN4CcZ4ae2nRYYOH9w3NHp4RfF19M9jqbdw= Message-ID: <029910c3-e90f-4a35-8b01-4d3ff548deea@arm.com> Date: Wed, 1 Jul 2026 20:56:53 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Thunderbird Daily Subject: Re: [PATCH v2 02/15] arm_mpam: propagate MSC read errors for wrapper functions To: Andre Przywara , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , "Rafael J . Wysocki" , Len Brown , James Morse , Reinette Chatre , Fenghua Yu Cc: Jonathan Cameron , Srivathsa L Rao , Ganapatrao Kulkarni , Trilok Soni , Srinivas Ramana , Niyas Sait , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260702162229.4008659-1-andre.przywara@arm.com> <20260702162229.4008659-3-andre.przywara@arm.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <20260702162229.4008659-3-andre.przywara@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Andre, On 7/2/26 17:22, Andre Przywara wrote: > Allow the wrapper functions for IDR and ESR accesses to return an > error, and propagate read errors from the lower level up. > > Signed-off-by: Andre Przywara > --- > drivers/resctrl/mpam_devices.c | 51 +++++++++++++++++++++++----------- > 1 file changed, 35 insertions(+), 16 deletions(-) > > diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c > index df14b4513382..ce8738adb6ff 100644 > --- a/drivers/resctrl/mpam_devices.c > +++ b/drivers/resctrl/mpam_devices.c > @@ -247,27 +247,34 @@ static bool mpam_msc_check_aidr(struct mpam_msc *msc) > return true; > } > > -static u64 mpam_msc_read_idr(struct mpam_msc *msc) > +static int mpam_msc_read_idr(struct mpam_msc *msc, u64 *res) > { > u32 idr_high = 0, idr_low; > + int ret; > > lockdep_assert_held(&msc->part_sel_lock); > > - mpam_read_partsel_reg(msc, IDR, &idr_low); > - if (FIELD_GET(MPAMF_IDR_EXT, idr_low)) > - mpam_read_partsel_reg(msc, IDR + 4, &idr_high); > + ret = mpam_read_partsel_reg(msc, IDR, &idr_low); > + if (!ret && FIELD_GET(MPAMF_IDR_EXT, idr_low)) > + ret = mpam_read_partsel_reg(msc, IDR + 4, &idr_high); > > - return ((u64)idr_high << 32) | idr_low; > + if (!ret) > + *res = ((u64)idr_high << 32) | idr_low; > + > + return ret; > } Why does the pattern here, use of !ret rather than early return, differ from the one you've used in mpam_msc_read_esr()? Thanks, Ben > > -static void mpam_msc_clear_esr(struct mpam_msc *msc) > +static int mpam_msc_clear_esr(struct mpam_msc *msc) > { > u32 esr_low; > + int ret; > > - __mpam_read_reg(msc, MPAMF_ESR, &esr_low); > + ret = __mpam_read_reg(msc, MPAMF_ESR, &esr_low); > + if (ret) > + return ret; > > if (!esr_low) > - return; > + return 0; > > /* > * Clearing the high/low bits of MPAMF_ESR can not be atomic. > @@ -277,18 +284,30 @@ static void mpam_msc_clear_esr(struct mpam_msc *msc) > */ > if (msc->has_extd_esr) > __mpam_write_reg(msc, MPAMF_ESR + 4, 0); > + > __mpam_write_reg(msc, MPAMF_ESR, 0); > + > + return 0; > } > > -static u64 mpam_msc_read_esr(struct mpam_msc *msc) > +static int mpam_msc_read_esr(struct mpam_msc *msc, u64 *res) > { > u32 esr_high = 0, esr_low; > + int ret; > > - __mpam_read_reg(msc, MPAMF_ESR, &esr_low); > - if (msc->has_extd_esr) > - __mpam_read_reg(msc, MPAMF_ESR + 4, &esr_high); > + ret = __mpam_read_reg(msc, MPAMF_ESR, &esr_low); > + if (ret) > + return ret; > + > + if (msc->has_extd_esr) { > + ret = __mpam_read_reg(msc, MPAMF_ESR + 4, &esr_high); > + if (ret) > + return ret; > + } > > - return ((u64)esr_high << 32) | esr_low; > + *res = ((u64)esr_high << 32) | esr_low; > + > + return 0; > } > > static void __mpam_part_sel_raw(u32 partsel, struct mpam_msc *msc) > @@ -993,7 +1012,7 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc) > > /* Grab an IDR value to find out how many RIS there are */ > mutex_lock(&msc->part_sel_lock); > - idr = mpam_msc_read_idr(msc); > + mpam_msc_read_idr(msc, &idr); > mpam_read_partsel_reg(msc, IIDR, &msc->iidr); > > mutex_unlock(&msc->part_sel_lock); > @@ -1009,7 +1028,7 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc) > for (ris_idx = 0; ris_idx <= msc->ris_max; ris_idx++) { > mutex_lock(&msc->part_sel_lock); > __mpam_part_sel(ris_idx, 0, msc); > - idr = mpam_msc_read_idr(msc); > + mpam_msc_read_idr(msc, &idr); > mutex_unlock(&msc->part_sel_lock); > > partid_max = FIELD_GET(MPAMF_IDR_PARTID_MAX, idr); > @@ -2492,7 +2511,7 @@ static irqreturn_t __mpam_irq_handler(int irq, struct mpam_msc *msc) > &msc->accessibility))) > return IRQ_NONE; > > - reg = mpam_msc_read_esr(msc); > + mpam_msc_read_esr(msc, ®); > > errcode = FIELD_GET(MPAMF_ESR_ERRCODE, reg); > if (!errcode)