Subject: Re: [PATCH v2 2/6] powerpc/pkeys: Save the pkey registers before fork

From: Michael Ellerman <[email-masked]>
Date: Tue, 19 Jun 2018 22:39:56 +1000

Ram Pai <[email-masked]> writes:

> When a thread forks the contents of AMR, IAMR, UAMOR registers in the
> newly forked thread are not inherited.
>
> Save the registers before forking, for content of those
> registers to be automatically copied into the new thread.
>
> CC: Michael Ellerman <[email-masked]>
> CC: Florian Weimer <[email-masked]>
> CC: Andy Lutomirski <[email-masked]>
> CC: Thiago Jung Bauermann <[email-masked]>
> Signed-off-by: Ram Pai <[email-masked]>

Again this is an ABI change but we'll call it a bug fix I guess.

I'll add:

  Fixes: cf43d3b26452 ("powerpc: Enable pkey subsystem")
  Cc: [email-masked] # v4.16+

cheers

> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index 9ef4aea..991d097 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -583,6 +583,7 @@ static void save_all(struct task_struct *tsk)
>  		__giveup_spe(tsk);
>  
>  	msr_check_and_clear(msr_all_available);
> +	thread_pkey_regs_save(&tsk->thread);
>  }
>  
>  void flush_all_to_thread(struct task_struct *tsk)
> -- 
> 1.7.1