linux-kernel - [PATCH v2] lib: Use PFN_PHYS() in devmem_is

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Date:   Fri, 30 Jul 2021 15:43:15 +0800
From:   Liang Wang <wangliang101@...wei.com>
To:     <palmerdabbelt@...gle.com>, <mcgrof@...nel.org>,
        <linux-kernel@...r.kernel.org>, <gregkh@...uxfoundation.org>,
        <linux@...linux.org.uk>, <linux-arm-kernel@...ts.infradead.org>
CC:     <stable@...r.kernel.org>, <wangliang101@...wei.com>,
        <wangle6@...wei.com>, <kepler.chenxin@...wei.com>,
        <nixiaoming@...wei.com>, <wangkefeng.wang@...wei.com>
Subject: [PATCH v2] lib: Use PFN_PHYS() in devmem_is_allowed()

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@...r.kernel.org # v2.6.37
Signed-off-by: Liang Wang <wangliang101@...wei.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