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 0FC8342E8F6; Fri, 10 Jul 2026 14:46:35 +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=1783694797; cv=none; b=PLAfNcm0+QW8lgWFsUenoVcd8Ki6BQBJLpGbIotHS0QKEyo/WUuY3xR1qUNlQN9YseCajZXV2ebrOfLhmB79om4yABaXNXaXjTDE5J7WBIXm5qDSPmTorKTqWLVQDYPy3MSDJxrArYnSSoUfvcgblY9XRiJcm8OikuanaTqESQQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783694797; c=relaxed/simple; bh=A8TmNSPeqpJAzvmZdC54I6h8zsSYk3uyCmo9kr9ZQkM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YJR96S+yW3fgKkBy2cbsUXJIO36OZMsJH0vAEyBAUDwODvZPdAlhGSvuK49BgL1QqIcXVyYmJWrefCYlS7Xv/2YIJ8IimnL1UdGDxmQFtcLYR/aBOYfy8zIsvGVr0EKZV2RVSM2Lc+TFaVqGEPRCtj7WCKLw61maS7+9yAg9BJA= 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=a82dhB/a; 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="a82dhB/a" 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 174A51F60; Fri, 10 Jul 2026 07:46:31 -0700 (PDT) Received: from e142021.munich.arm.com (e142021.arm.com [10.41.150.148]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6FB3E3F7B4; Fri, 10 Jul 2026 07:46:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1783694795; bh=A8TmNSPeqpJAzvmZdC54I6h8zsSYk3uyCmo9kr9ZQkM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a82dhB/a/qeziQ3agCtQsrAjwozE/bKvHdrRP3o8l8BUZwSSZ5534I/CpC/Bsgd/C BEtADS/zsvovWgKfPy62BrMb1W6fydvZClYVaAx/VBKy0ZnbBttukUnbLQKe75oA1D n7NU8akewFjaDleFHT2aDwJZpR38BWBgdJkPai8U= From: Andre Przywara To: Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , "Rafael J . Wysocki" , Len Brown , James Morse , Ben Horgan , 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 Subject: [PATCH v3 15/16] arm_mpam: prevent MPAM-Fb accesses inside IRQ handler Date: Fri, 10 Jul 2026 16:45:19 +0200 Message-ID: <20260710144520.917375-16-andre.przywara@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260710144520.917375-1-andre.przywara@arm.com> References: <20260710144520.917375-1-andre.przywara@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When an MPAM MSC gets into an error condition, it can trigger an error IRQ. We cannot really do much about those errors, but we at least query and log the error, then disable MPAM functionality. This error report relies on reading the MSC's error status register (ESR) in the IRQ handler, which is not possible for MPAM-Fb based MSC accesses, since they involve mailbox routines that might sleep. The same is true for clearing the interrupt at the source, which requires MSC access. For simplicity just skip the ESR read when the MSC is not using direct MMIO accesses, and just ignore the pending interrupts. We will wrap up MPAM functionality regardless, knowing the exact error value will not change that. Signed-off-by: Andre Przywara --- drivers/resctrl/mpam_devices.c | 38 ++++++++++++++++++++-------------- 1 file changed, 23 insertions(+), 15 deletions(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 4d3e642486d4..220b4a06e739 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -2645,7 +2645,7 @@ static int mpam_disable_msc_ecr(void *_msc) static irqreturn_t __mpam_irq_handler(int irq, struct mpam_msc *msc) { - u64 reg; + u64 reg = 0; u16 partid; u8 errcode, pmg, ris; @@ -2654,25 +2654,33 @@ static irqreturn_t __mpam_irq_handler(int irq, struct mpam_msc *msc) &msc->accessibility))) return IRQ_NONE; - mpam_msc_read_esr(msc, ®); + /* MPAM-Fb MSC accesses cannot be done in atomic context. */ + if (msc->iface == MPAM_IFACE_MMIO) { + mpam_msc_read_esr(msc, ®); - errcode = FIELD_GET(MPAMF_ESR_ERRCODE, reg); - if (!errcode) - return IRQ_NONE; + errcode = FIELD_GET(MPAMF_ESR_ERRCODE, reg); + if (!errcode) + return IRQ_NONE; - /* Clear level triggered irq */ - mpam_msc_clear_esr(msc); + /* Clear level triggered irq */ + mpam_msc_clear_esr(msc); - partid = FIELD_GET(MPAMF_ESR_PARTID_MON, reg); - pmg = FIELD_GET(MPAMF_ESR_PMG, reg); - ris = FIELD_GET(MPAMF_ESR_RIS, reg); + partid = FIELD_GET(MPAMF_ESR_PARTID_MON, reg); + pmg = FIELD_GET(MPAMF_ESR_PMG, reg); + ris = FIELD_GET(MPAMF_ESR_RIS, reg); - pr_err_ratelimited("error irq from msc:%u '%s', partid:%u, pmg: %u, ris: %u\n", - msc->id, mpam_errcode_names[errcode], partid, pmg, - ris); + pr_err_ratelimited("error irq from msc:%u '%s', partid:%u, pmg: %u, ris: %u\n", + msc->id, mpam_errcode_names[errcode], partid, + pmg, ris); - /* Disable this interrupt. */ - mpam_disable_msc_ecr(msc); + /* Disable this interrupt. */ + mpam_disable_msc_ecr(msc); + } else { + struct irq_data *d = irq_get_irq_data(irq); + + pr_err_ratelimited("unknown error irq %d/%ld from msc:%u\n", + irq, d ? irqd_to_hwirq(d) : -1, msc->id); + } /* Are we racing with the thread disabling MPAM? */ if (!mpam_is_enabled()) -- 2.43.0