Re: [Xen-devel] ARM32 - build-issues with xen/arm: vpl011: Add a new vuart node in the xenstore

[Bhupinder Thakur <bhupinder.thakur@xxxxxxxxxx>]

On 13 October 2017 at 00:34, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
> On 12/10/17 19:54, Bhupinder Thakur wrote:
>> On 5 October 2017 at 15:07, Wei Liu <wei.liu2@xxxxxxxxxx> wrote:
>>> On Wed, Oct 04, 2017 at 09:58:32PM -0400, Konrad Rzeszutek Wilk wrote:
>>>> I get this when compiling under ARM32 (Ubuntu 15.04,
>>>> gcc (Ubuntu/Linaro 4.9.2-10ubuntu13) 4.9.2):
>>>>
>>>> libxl_console.c: In function ‘libxl__device_vuart_add’:
>>>> libxl_console.c:379:5: error: format ‘%lu’ expects argument of type ‘long 
>>>> unsigned int’, but argument 3 has type ‘xen_pfn_t’ [-Werror=format=]
>>>>      flexarray_append(ro_front, GCSPRINTF("%lu", state->vuart_gfn));
>>>>      ^
>>>> ;
>>> My Wheezy 32bit chroot didn't catch this, sigh.
>>>
>>> Does the following patch work?
>>>
>>> From ae531197382bf0bc003606a9712075bdd22cfc24 Mon Sep 17 00:00:00 2001
>>> From: Wei Liu <wei.liu2@xxxxxxxxxx>
>>> Date: Thu, 5 Oct 2017 10:35:28 +0100
>>> Subject: [PATCH] libxl: use correct type modifier for vuart_gfn
>>> MIME-Version: 1.0
>>> Content-Type: text/plain; charset=UTF-8
>>> Content-Transfer-Encoding: 8bit
>>>
>>> Fixes compilation error like:
>>>
>>> libxl_console.c: In function ‘libxl__device_vuart_add’:
>>> libxl_console.c:379:5: error: format ‘%lu’ expects argument of type ‘long 
>>> unsigned int’, but argument 3 has type ‘xen_pfn_t’ [-Werror=format=]
>>>       flexarray_append(ro_front, GCSPRINTF("%lu", state->vuart_gfn));
>>>
>>> Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>>> Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
>>> ---
>>>  tools/libxl/libxl_console.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/tools/libxl/libxl_console.c b/tools/libxl/libxl_console.c
>>> index 13ecf128e2..c05dc28b99 100644
>>> --- a/tools/libxl/libxl_console.c
>>> +++ b/tools/libxl/libxl_console.c
>>> @@ -376,7 +376,7 @@ int libxl__device_vuart_add(libxl__gc *gc, uint32_t 
>>> domid,
>>>      flexarray_append(ro_front, "port");
>>>      flexarray_append(ro_front, GCSPRINTF("%"PRIu32, state->vuart_port));
>>>      flexarray_append(ro_front, "ring-ref");
>>> -    flexarray_append(ro_front, GCSPRINTF("%lu", state->vuart_gfn));
>>> +    flexarray_append(ro_front, GCSPRINTF("%"PRI_xen_pfn, 
>>> state->vuart_gfn));
>> Unfortunately, this is causing an issue as PRI_xen_pfn formats the
>> value as a hexadecimal value but xenconsole later reads it as a
>> decimal value and tries to map it, which fails and therefore vuart
>> console initialization fails.
>>
>> Earlier, I verified only 32-bit compilation but did not test the
>> change. It was a miss from my side. I have tested now with the format
>> string changed to PRIu64 and the vuart console is working fine.
>
> That however, would break x86.
>
> andrewcoop@andrewcoop:/local/xen.git/xen$ git grep 'define PRI_xen_pfn' -- :/
> include/public/arch-arm.h:276:#define PRI_xen_pfn PRIx64
> include/public/arch-x86/xen.h:77:#define PRI_xen_pfn "lx"
>
> The best way to fix this is to introduce a new define for both
> architectures which is PRIu64 and "lu" as appropriate.
>
> Suggestions:
>
> PRI_xen_pfn_dec
> PRIu_xen_pfn
>
> Neither are great, but the latter does follow the PRI nomenclature.
Thanks. I will introduce this new format specifier.

Regards,
Bhupinder

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