[PATCH v7 1/2] x86-64: Save APX registers in ld.so trampoline

[Florian Weimer]

* Noah Goldstein:

>> +/* Save SSE, AVX, AVX512, mask, bound and APX registers.  Bound and APX
>> +   registers are mutually exclusive.  */
>> +# define STATE_SAVE_MASK               \
>> +  ((1 << X86_XSTATE_SSE_ID)            \
>> +   | (1 << X86_XSTATE_AVX_ID)          \
>> +   | (1 << X86_XSTATE_BNDREGS_ID)      \
>> +   | (1 << X86_XSTATE_K_ID)            \
>> +   | (1 << X86_XSTATE_ZMM_H_ID)        \
>> +   | (1 << X86_XSTATE_ZMM_ID)          \
>> +   | (1 << X86_XSTATE_APX_F_ID))

> Need tile here?

We can't save the AMX state because it's too big and will overflow
existing stacks.  This change is immediately active on systems with AMX,
even for old applications which do not know about AMX at all.

Thanks,
Florian