[Mesa-dev] [PATCH 03/39] llvmpipe: Fix overflow for 32 bits available memory computation

[Axel Davy]

On 17/05/2016 20:16, Rob Herring wrote:
> On Tue, May 17, 2016 at 11:35 AM, Axel Davy <axel.davy at ens.fr> wrote:
>> On 16/05/2016 23:28, Rob Herring wrote:
>>> On Sun, May 15, 2016 at 5:45 AM, Axel Davy <axel.davy at ens.fr> wrote:
>>>> And cap to 2 GB on 32 bits.
>>>>
>>>> Fixes https://bugs.freedesktop.org/show_bug.cgi?id=94561
>>>>
>>>> Signed-off-by: Axel Davy <axel.davy at ens.fr>
>>>> ---
>>>>    src/gallium/auxiliary/os/os_misc.c       | 2 +-
>>>>    src/gallium/drivers/llvmpipe/lp_screen.c | 5 +++++
>>>>    2 files changed, 6 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/src/gallium/auxiliary/os/os_misc.c
>>>> b/src/gallium/auxiliary/os/os_misc.c
>>>> index d6b83e9..cf2ef95 100644
>>>> --- a/src/gallium/auxiliary/os/os_misc.c
>>>> +++ b/src/gallium/auxiliary/os/os_misc.c
>>>> @@ -117,7 +117,7 @@ os_get_total_physical_memory(uint64_t *size)
>>>>       const long phys_pages = sysconf(_SC_PHYS_PAGES);
>>>>       const long page_size = sysconf(_SC_PAGE_SIZE);
>>>>
>>>> -   *size = phys_pages * page_size;
>>>> +   *size = (int64_t)phys_pages * (int64_t)page_size;
>>>>       return (phys_pages > 0 && page_size > 0);
>>>>    #elif defined(PIPE_OS_APPLE) || defined(PIPE_OS_BSD)
>>>>       size_t len = sizeof(*size);
>>>> diff --git a/src/gallium/drivers/llvmpipe/lp_screen.c
>>>> b/src/gallium/drivers/llvmpipe/lp_screen.c
>>>> index 4f61de8..2f84b75 100644
>>>> --- a/src/gallium/drivers/llvmpipe/lp_screen.c
>>>> +++ b/src/gallium/drivers/llvmpipe/lp_screen.c
>>>> @@ -279,6 +279,11 @@ llvmpipe_get_param(struct pipe_screen *screen, enum
>>>> pipe_cap param)
>>>>          if (!os_get_total_physical_memory(&system_memory))
>>>>             return 0;
>>>>
>>>> +#ifdef PIPE_ARCH_X86
>>>> +      /* cap to 2 GB on 32 bits system */
>>> What about non-x86 32-bit systems?
>>>
>>> Rob
>>>
>> Do you have a suggestion for a better check ?
> if (sizeof(void *) == 4)
>      /* cap to 2 GB on 32 bits system */
>      system_memory = MIN2(system_memory, 2048);
so obvious that it didn't come into my mind... thanks
>>
>> I could add in p_config.h a PIPE_ARCH_32 (and PIPE_ARCH_64), but I'm not
>> sure what to put in there,
>>
>> since it is possible to have a 32 bits processor with 64 bits memory
>> addressing.
> Yes, but userspace can still only see 32-bits worth in that case. I
> don't see how that matters here.
>
> Rob
>