Common ARM context save/restore code
nicolas.pitre at linaro.org
Thu Oct 7 19:25:10 UTC 2010
On Thu, 7 Oct 2010, Vishwanath Sripathy wrote:
> Hi All,
> Purpose of this email is to debate on the pros and cons of having a common
> ARM context save/restore code.
> Currently each SOC has its own way of saving/restoring ARM registers and
> there has been a proposal to have a common code for the same instead of
> duplicating the same in different places.
Could you elaborate? I'm afraid I'm not following you.
The kernel as I know it has a common code path to save/restore registers
on context switch simply because all SOCs that I'm aware of all have the
same general registers to save/restore on context switch.
There are exceptions for some specialized registers, such as the XScale
WMMX registers, the Cirrus MaverickCrunch registers, the VFP registers
or the emulated FPA registers, etc. But those are nicely abstracted
away from the common code through runtime registered thread notifier
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