diff mbox series

[merged] lib-use-pfn_phys-in-devmem_is_allowed.patch removed from -mm tree

Message ID 20210816203511.K2fX9guWK%akpm@linux-foundation.org
State New
Headers show
Series [merged] lib-use-pfn_phys-in-devmem_is_allowed.patch removed from -mm tree | expand

Commit Message

Andrew Morton Aug. 16, 2021, 8:35 p.m. UTC
The patch titled
     Subject: lib: use PFN_PHYS() in devmem_is_allowed()
has been removed from the -mm tree.  Its filename was
     lib-use-pfn_phys-in-devmem_is_allowed.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
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>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
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(-)
diff mbox series

Patch

--- 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;