[PATCH] of: Fix comparison of reserved memory regions

[Rob Herring]

On Sat, Dec 5, 2015 at 5:43 AM, Michael Ellerman <michael at ellerman.id.au> wrote:
>
>
> 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?

Yes. I meant to last week, but was waiting on getting another issue
sorted out. I should get it to Linus in the next couple of days.

Rob