[PATCH v4.4 backport 06/16] powerpc/64: Add macros for annotating the destination of rfid/hrfid

Greg KH greg at kroah.com
Sun Feb 4 21:53:55 AEDT 2018


On Sun, Feb 04, 2018 at 04:00:00PM +1100, Michael Ellerman wrote:
> From: Nicholas Piggin <npiggin at gmail.com>
> 
> commit 50e51c13b3822d14ff6df4279423e4b7b2269bc3 upstream.
> 
> The rfid/hrfid ((Hypervisor) Return From Interrupt) instruction is
> used for switching from the kernel to userspace, and from the
> hypervisor to the guest kernel. However it can and is also used for
> other transitions, eg. from real mode kernel code to virtual mode
> kernel code, and it's not always clear from the code what the
> destination context is.
> 
> To make it clearer when reading the code, add macros which encode the
> expected destination context.
> 
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>

Also applied to 4.9.y, thanks.

greg k-h


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