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Paul Mackerras authored
This provides a facility which is intended for use by KVM, where the contents of the FP/VSX and VMX (Altivec) registers can be saved away to somewhere other than the thread_struct when kernel code wants to use floating point or VMX instructions. This is done by providing a pointer in the thread_struct to indicate where the state should be saved to. The giveup_fpu() and giveup_altivec() functions test these pointers and save state to the indicated location if they are non-NULL. Note that the MSR_FP/VEC bits in task->thread.regs->msr are still used to indicate whether the CPU register state is live, even when an alternate save location is being used. This also provides load_fp_state() and load_vr_state() functions, which load up FP/VSX and VMX state from memory into the CPU registers, and corresponding store_fp_state() and store_vr_state() functions, which store FP/VSX and VMX state into memory from the CPU registers. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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