[PATCH v3] lib: Use PFN_PHYS() in devmem_is_allowed()

[Palmer Dabbelt]

On Tue, 03 Aug 2021 22:01:46 PDT (-0700), wangkefeng.wang at huawei.com wrote:
>
> On 2021/7/31 10:50, Liang Wang wrote:
>> 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.
>>
>> Cc: Luis Chamberlain <mcgrof at kernel.org>
>> 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 at vger.kernel.org # v2.6.37
>> Signed-off-by: Liang Wang <wangliang101 at huawei.com>
> Reviewed-by: Kefeng Wang <wangkefeng.wang at huawei.com>

Weird, it's still only your replies that are coming through.  Given that 
this only manifests on 32-bit Arm systems, I'm going to leave this up to 
them for now.

Acked-by: Palmer Dabbelt <palmerdabbelt at google.com>