+ lib-use-pfn_phys-in-devmem_is_allowed.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: lib: use PFN_PHYS() in devmem_is_allowed()
has been added to the -mm tree.  Its filename is
     lib-use-pfn_phys-in-devmem_is_allowed.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/lib-use-pfn_phys-in-devmem_is_allowed.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/lib-use-pfn_phys-in-devmem_is_allowed.patch

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------------------------------------------------------
From: Liang Wang <wangliang101@huawei.com>
Subject: lib: use PFN_PHYS() in devmem_is_allowed()

The physical address may exceed 32 bits on 32-bit systems with more than
32 bits of physcial address,use PFN_PHYS() in devmem_is_allowed(), or the
physical address may overflow and be truncated.

We found this bug when mapping a high addresses through devmem tool, when
CONFIG_STRICT_DEVMEM is enabled on the ARM with ARM_LPAE and devmem is
used to map a high address that is not in the iomem address range, an
unexpected error indicating no permission is returned.

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

Link: https://lkml.kernel.org/r/20210731025057.78825-1-wangliang101@huawei.com
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()")
Signed-off-by: Liang Wang <wangliang101@huawei.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Liang Wang <wangliang101@huawei.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: <stable@vger.kernel.org>	[2.6.37+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/devmem_is_allowed.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/lib/devmem_is_allowed.c~lib-use-pfn_phys-in-devmem_is_allowed
+++ a/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;
_

Patches currently in -mm which might be from wangliang101@huawei.com are

lib-use-pfn_phys-in-devmem_is_allowed.patch