From nobody Thu Apr 2 20:18:02 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 AF94335B15A for ; Thu, 12 Feb 2026 12:50:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770900610; cv=none; b=ca2j1awzV36viNh6MITRzvPZLSaaLU5qCxdYDG8jNGhDynp2JFTrMsvrpwJzRxPkAnXRZMgtQEvAFb7Le66lcma2ZnKQJKcGARBotynqrMEcw9Bx1lVOGjXA2wIRdI0bq2shy0iJeIaIyteWqfHTyQB5x8ASbiE09ufj5YyaFbc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770900610; c=relaxed/simple; bh=p6RXvl63SnjGqsNUIm9C1xnI/K8jfZRq3K9vUMKjQRo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gqyg3J/vkD3MHhvva1741zuiIcDDK5O2rEfQ5XfdQF/tB9fmmWHaEzn6j2y4m0Y/2Z/HHhJ1t8aHiU3Wv+/rnsuTQ2lIFEWIK8E9neKcTRksrZQB11om4tTK7e/OE5trvZMQ6V0R9dkoPVdeIslru2z4kK2GbylglP6Hl+S+SQ8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=KyMH74qq; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KyMH74qq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1770900606; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Nit8m3oaYzPkr/DHNj61xP6u3VIDPL4n4HKttTvb6ow=; b=KyMH74qqSTb5FIrV8/kT3I+mDceK46T1f0i80R+eFaSh5HsHb3iFNtRQ+f6LzPjN6xI4i3 i1UTByfSo28izPHR5DwUn5+SAa3w3YtQ1fZlJdA3VkevPTTmiFFzLi/9UKjC1GmKxhrrf8 FaWxmClT8j5/46t7OcH2ahIGj8RJGBY= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-385-jdHh-XruOWCeD0ao3BwDRQ-1; Thu, 12 Feb 2026 07:50:03 -0500 X-MC-Unique: jdHh-XruOWCeD0ao3BwDRQ-1 X-Mimecast-MFC-AGG-ID: jdHh-XruOWCeD0ao3BwDRQ_1770900601 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8A624195605B; Thu, 12 Feb 2026 12:50:01 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.44.22.11]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E0EA130001B9; Thu, 12 Feb 2026 12:49:55 +0000 (UTC) From: Gabriele Paoloni To: corbet@lwn.net, skhan@linuxfoundation.org, arnd@arndb.de, gregkh@linuxfoundation.org, brendan.higgins@linux.dev, raemoar63@gmail.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com Cc: acarminati@nvidia.com, linux-mm@kvack.org, safety-architecture@lists.elisa.tech, kstewart@linuxfoundation.org, chuckwolber@gmail.com, gpaoloni@redhat.com, Alessandro Carminati Subject: [RFC PATCH v3 4/6] char: mem: expose devmem helpers for KUnit testing Date: Thu, 12 Feb 2026 13:49:21 +0100 Message-ID: <20260212124923.222484-5-gpaoloni@redhat.com> In-Reply-To: <20260212124923.222484-1-gpaoloni@redhat.com> References: <20260212124923.222484-1-gpaoloni@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" From: Alessandro Carminati Refactor selected /dev/mem helpers to allow access from KUnit tests. This change: - makes page_is_allowed(), read_mem(), and write_mem() visible when KUnit is enabled - moves shared declarations into a new internal header - preserves existing behavior for non-KUnit builds Signed-off-by: Alessandro Carminati --- drivers/char/mem.c | 15 +++++++++++---- drivers/char/mem.h | 17 +++++++++++++++++ 2 files changed, 28 insertions(+), 4 deletions(-) create mode 100644 drivers/char/mem.h diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 9aa589ea2ef5..f1d0a2c11819 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -31,6 +31,10 @@ #include #include =20 +#include + +#include "mem.h" + #define DEVMEM_MINOR 1 #define DEVPORT_MINOR 4 =20 @@ -57,16 +61,17 @@ static inline int valid_mmap_phys_addr_range(unsigned l= ong pfn, size_t size) #endif =20 #ifdef CONFIG_STRICT_DEVMEM -static inline int page_is_allowed(unsigned long pfn) +INLINE_VISIBLE_IF_KUNIT int page_is_allowed(unsigned long pfn) { return devmem_is_allowed(pfn); } #else -static inline int page_is_allowed(unsigned long pfn) +INLINE_VISIBLE_IF_KUNIT int page_is_allowed(unsigned long pfn) { return 1; } #endif +EXPORT_SYMBOL_IF_KUNIT(page_is_allowed); =20 static inline bool should_stop_iteration(void) { @@ -104,7 +109,7 @@ static inline bool should_stop_iteration(void) * * %-ENOMEM - out of memory error for auxiliary kernel buffers supporting * the operation of copying content from the physical pages */ -static ssize_t read_mem(struct file *file, char __user *buf, +VISIBLE_IF_KUNIT ssize_t read_mem(struct file *file, char __user *buf, size_t count, loff_t *ppos) { phys_addr_t p =3D *ppos; @@ -190,6 +195,7 @@ static ssize_t read_mem(struct file *file, char __user = *buf, kfree(bounce); return err; } +EXPORT_SYMBOL_IF_KUNIT(read_mem); =20 /** * write_mem - write to physical memory (/dev/mem). @@ -234,7 +240,7 @@ static ssize_t read_mem(struct file *file, char __user = *buf, * be copied from user-space * * %-EPERM - access to any of the required pages is not allowed */ -static ssize_t write_mem(struct file *file, const char __user *buf, +VISIBLE_IF_KUNIT ssize_t write_mem(struct file *file, const char __user *b= uf, size_t count, loff_t *ppos) { phys_addr_t p =3D *ppos; @@ -306,6 +312,7 @@ static ssize_t write_mem(struct file *file, const char = __user *buf, *ppos +=3D written; return written; } +EXPORT_SYMBOL_IF_KUNIT(write_mem); =20 int __weak phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, unsigned long size, pgprot_t *vma_prot) diff --git a/drivers/char/mem.h b/drivers/char/mem.h new file mode 100644 index 000000000000..dfeb5f1d5ec8 --- /dev/null +++ b/drivers/char/mem.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2025 Red Hat inc Alessandro Carminati + */ + +#ifndef _LINUX_CHAR_MEM_H +#define _LINUX_CHAR_MEM_H + +#if IS_ENABLED(CONFIG_KUNIT) +ssize_t read_mem(struct file *file, char __user *buf, + size_t count, loff_t *ppos); +ssize_t write_mem(struct file *file, const char __user *buf, + size_t count, loff_t *ppos); +int page_is_allowed(unsigned long pfn); +#endif + +#endif /* _LINUX_CHAR_MEM_H */ --=20 2.48.1