Subject: Re: [PATCH] powerpc/pseries: Handle UE event for memcpy_mcsafe

From: Mahesh J Salgaonkar <[email-masked]>
Date: Fri, 20 Mar 2020 10:53:18 +0530

On 2020-03-13 19:36:12 Fri, Ganesh Goudar wrote:
> If we hit UE at an instruction with a fixup entry, flag to
> ignore the event and set nip to continue execution at the
> fixup entry.
> For powernv this changes are already made by commit
> 895e3dceeb97 ("powerpc/mce: Handle UE event for memcpy_mcsafe")
> 
> Signed-off-by: Ganesh Goudar <[email-masked]>

Thanks for working on this. Looks good.

Reviewed-by: Mahesh Salgaonkar <[email-masked]>

Thanks,
-Mahesh.

> ---
>  arch/powerpc/platforms/pseries/ras.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
> index 5d49d9d711da..6dc3074a34c5 100644
> --- a/arch/powerpc/platforms/pseries/ras.c
> +++ b/arch/powerpc/platforms/pseries/ras.c
> @@ -10,6 +10,7 @@
>  #include <linux/fs.h>
>  #include <linux/reboot.h>
>  #include <linux/irq_work.h>
> +#include <linux/extable.h>
> 
>  #include <asm/machdep.h>
>  #include <asm/rtas.h>
> @@ -505,6 +506,7 @@ static int mce_handle_error(struct pt_regs *regs, struct rtas_error_log *errp)
>  	int initiator = rtas_error_initiator(errp);
>  	int severity = rtas_error_severity(errp);
>  	u8 error_type, err_sub_type;
> +	const struct exception_table_entry *entry;
> 
>  	if (initiator == RTAS_INITIATOR_UNKNOWN)
>  		mce_err.initiator = MCE_INITIATOR_UNKNOWN;
> @@ -558,6 +560,12 @@ static int mce_handle_error(struct pt_regs *regs, struct rtas_error_log *errp)
>  	switch (mce_log->error_type) {
>  	case MC_ERROR_TYPE_UE:
>  		mce_err.error_type = MCE_ERROR_TYPE_UE;
> +		entry = search_kernel_exception_table(regs->nip);
> +		if (entry) {
> +			mce_err.ignore_event = true;
> +			regs->nip = extable_fixup(entry);
> +			disposition = RTAS_DISP_FULLY_RECOVERED;
> +		}
>  		switch (err_sub_type) {
>  		case MC_ERROR_UE_IFETCH:
>  			mce_err.u.ue_error_type = MCE_UE_ERROR_IFETCH;
> -- 
> 2.17.2
> 

-- 
Mahesh J Salgaonkar