> .. which *does* actually bring up something that might work, and might > be a good idea: remove the "restore math state or set TS" from the > normal kernel paths *entirely*, and move it to the "return to user > space" phase.
This definitely seems much more sensible. For processors without optimized context save/restore, the decision whether to restore eagerly is best made once the kernel has decided what it's returning *to*. >From an interrupt handler, there are now three cases: 1) FPU not in use, available for immediate use. 2) FPU in use by user-space; save to <location> before using. 3) FPU in use by kernel code; may not be used (unless we want to add nested FPU state save hair). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
