Saving FPU registers during IRQ Handler

[Surysingh]

Hi All,
For Aarch64, in file arch\arm64\exceptions.s, for arm64_irq_current_el_SPx, why floating point state and registers are not saved?

Is there not a chance that interrupt service routine / handler will use and hence corrupt the floating point registers

[travisg]

This is correct. Nothing in the IRQ or scheduler path should use the FPU, so the context is not saved. This speeds things up greatly, since it takes quite a bit of time and space to save the full fpu/vector state.