[1/2] powerpc/tm: Fix FP and VMX register corruption

[Michael Ellerman]

On Mon, 2017-05-08 at 07:16:26 UTC, Michael Neuling wrote:
> In this commit:
>   commit dc3106690b20305c3df06b42456fe386dd632ac9
>   Author: Cyril Bur <cyrilbur at gmail.com>
>   powerpc: tm: Always use fp_state and vr_state to store live registers
> 
> A section of code was removed that copied the current state to
> checkpointed state.  This should not have been removed.
> 
> When an FP unavailable is taken inside a transaction, we need to abort
> the transaction. This is because at the time of the tbegin, the FP
> state is bogus so the state stored in the checkpointed registers is
> incorrect. To fix this, we treclaim (to get the checkpointed GPRs) and
> then copy the thread_struct FP live state into the checkpointed
> state. We then trecheckpoint so that the FP state is correctly
> restored into the CPU.
> 
> The coping of the FP registers from live to checkpointed is what was
> missing.
> 
> This simplifies the logic slightly from the original patch.
> tm_reclaim_thread() will now always write the checkpointed FP
> state. Either the checkpointed FP statte will be written as part of
> the actual treclaim (in tm.S), or it'll be a copy of the live
> state. Which one we use is based on MSR[FP] from userspace.
> 
> Similarly for VMX.
> 
> CC: <stable at vger.kernel.org> # 4.9+
> Signed-off-by: Michael Neuling <mikey at neuling.org>
> Reviewed-by: cyrilbur at gmail.com

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/f48e91e87e67b56bef63393d1a02c6

cheers