From 4f83634710a1a7024b8acaa3b589dc5d8ca03ab0 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 27 Apr 2015 02:53:16 +0200 Subject: [PATCH] x86/fpu: Rename fpu_save_init() to copy_fpregs_to_fpstate() So fpu_save_init() is a historic name that got its name when the only way the FPU state was FNSAVE, which cleared (well, destroyed) the FPU state after saving it. Nowadays the name is misleading, because ever since the introduction of FXSAVE (and more modern FPU saving instructions) the 'we need to reload the FPU state' part is only true if there's a pending FPU exception [*], which is almost never the case. So rename it to copy_fpregs_to_fpstate() to make it clear what's happening. Also add a few comments about why we cannot keep registers in certain cases. Also clean up the control flow a bit, to make it more apparent when we are dropping/keeping FP registers, and to optimize the common case (of keeping fpregs) some more. [*] Probably not true anymore, modern instructions always leave the FPU state intact, even if exceptions are pending: because pending FP exceptions are posted on the next FP instruction, not asynchronously. They were truly asynchronous back in the IRQ13 case, and we had to synchronize with them, but that code is not working anymore: we don't have IRQ13 mapped in the IDT anymore. But a cleanup patch is obviously not the place to change subtle behavior. Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar --- Reading git-format-patch failed