[PATCH] of: Fix comparison of reserved memory regions

[Michael Ellerman]

On 5 December 2015 04:07:39 GMT+11:00, Mitchel Humpherys <mitchelh at codeaurora.org> wrote:
>On Wed, Nov 18 2015 at 09:46:38 PM, Michael Ellerman
><mpe at ellerman.id.au> wrote:
>> In order to check for overlapping reserved memory regions, we first
>need
>> to sort the array of memory regions. This is implemented using
>sort(),
>> and a custom comparison function __rmem_cmp().
>>
>> Unfortunatley __rmem_cmp() doesn't work in all cases. Because the two
>> base values are phys_addr_t, they may be u64 on some platforms, in
>which
>> case subtracting one from the other and then (implicitly) casting to
>int
>> does not give us the -ve/0/+ve value we need.
>>
>> This leads to incorrect reports about overlaps, eg:
>>
>>   ibm,slw-image at 1ffe600000 (0x0000001ffe600000--0x0000001ffe700000)
>overlaps with
>>   ibm,firmware-allocs-memory at 1000000000
>(0x0000001000000000--0x0000001000dc0200)
>>
>> Fix it by just doing the standard double if and return 0 logic.
>>
>> Fixes: ae1add247bf8 ("of: Check for overlap in reserved memory
>regions")
>> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
>> ---
>>  drivers/of/of_reserved_mem.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>
>Woops, thanks.
>
>Tested-by: Mitchel Humpherys <mitchelh at codeaurora.org>

Thanks for testing.

Rob, can we get this merged for 4.4 please?

cheers 

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