[Patch 2/3] ARM 64 bit atomic operations
David Gilbert
david.gilbert@linaro.org
Fri Jul 1 17:08:00 GMT 2011
On 1 July 2011 17:03, Richard Henderson <rth@redhat.com> wrote:
> On 07/01/2011 08:55 AM, Dr. David Alan Gilbert wrote:
>> +/* Check that the kernel has a new enough version at load */
>> +void __check_for_sync8_kernelhelper (void)
>> +{
>> + if (__kernel_helper_version < 5)
>> + {
>> + const char err[] = "A newer kernel is required to run this binary. (__kernel_cmpxchg64 helper)\n";
>> + /* At this point we need a way to crash with some information
>> + for the user - I'm not sure I can rely on much else being
>> + available at this point, so do the same as generic-morestack.c
>> + write() and abort(). */
>> + write (2 /* stderr */, err, sizeof(err));
>> + abort ();
>> + }
>> +};
>
> Wouldn't it be better to convert the arm kernel to use a proper VDSO,
> so that this error actually comes from the dynamic linker? That's
> the beauty of a true VDSO -- proper symbol resolution.
Well I can't say I like the need for this check/exit - so yes if something else
could do it for me that would be great. Having said that, I don't know
the history of the ARM commpage/lack of VDSO , neither do I know how
big a change that would be.
Let me have a chat to some of the kernel guys who might know the history.
Dave
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