[PATCH v2] lib: Use PFN_PHYS() in devmem_is_allowed()

From: Liang Wang <wangliang101@huawei.com>
To: <palmerdabbelt@google.com>, <mcgrof@kernel.org>,
	<linux-kernel@vger.kernel.org>, <gregkh@linuxfoundation.org>,
	<linux@armlinux.org.uk>, <linux-arm-kernel@lists.infradead.org>
Cc: <stable@vger.kernel.org>, <wangliang101@huawei.com>,
	<wangle6@huawei.com>, <kepler.chenxin@huawei.com>,
	<nixiaoming@huawei.com>, <wangkefeng.wang@huawei.com>
Subject: [PATCH v2] lib: Use PFN_PHYS() in devmem_is_allowed()
Date: Fri, 30 Jul 2021 15:43:15 +0800	[thread overview]
Message-ID: <20210730074315.63232-1-wangliang101@huawei.com> (raw)

The physical address may exceed 32 bits on ARM(when ARM_LPAE enabled),
use PFN_PHYS() in devmem_is_allowed(), or the physical address may
overflow and be truncated.

This bug was initially introduced from v2.6.37, and the function was moved
to lib when v5.11.

Fixes: 087aaffcdf9c ("ARM: implement CONFIG_STRICT_DEVMEM by disabling access to RAM via /dev/mem")
Fixes: 527701eda5f1 ("lib: Add a generic version of devmem_is_allowed()")
Cc: stable@vger.kernel.org # v2.6.37
Signed-off-by: Liang Wang <wangliang101@huawei.com>
---
v2: update subject and changelog
 lib/devmem_is_allowed.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/devmem_is_allowed.c b/lib/devmem_is_allowed.c
index c0d67c541849..60be9e24bd57 100644
--- a/lib/devmem_is_allowed.c
+++ b/lib/devmem_is_allowed.c
@@ -19,7 +19,7 @@
  */
 int devmem_is_allowed(unsigned long pfn)
 {
-	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
+	if (iomem_is_exclusive(PFN_PHYS(pfn)))
 		return 0;
 	if (!page_is_ram(pfn))
 		return 1;
-- 
2.32.0

