On 2020-03-25 20:34:06 Wed, Nicholas Piggin wrote:
> This allows rtas_args to be put on the machine check stack, which
> avoids a lot of complications with re-entrancy deadlocks.
>
> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
> ---
> arch/powerpc/kernel/setup_64.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 3bf03666ee09..ca1041f8a578 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -695,6 +695,9 @@ void __init exc_lvl_early_init(void)
> void __init emergency_stack_init(void)
> {
> u64 limit;
> +#ifdef CONFIG_PPC_BOOK3S_64
> + u64 mce_limit;
> +#endif
> unsigned int i;
>
> /*
> @@ -713,6 +716,16 @@ void __init emergency_stack_init(void)
> */
> limit = min(ppc64_bolted_size(), ppc64_rma_size);
>
> + /*
> + * Machine check on pseries calls rtas, but can't use the static
> + * rtas_args due to a machine check hitting while the lock is held.
> + * rtas args have to be under 4GB, so the machine check stack is
> + * limited to 4GB so args can be put on stack.
> + */
> + mce_limit = limit;
> + if (firmware_has_feature(FW_FEATURE_LPAR) && mce_limit >
> 4UL*1024*1024*1024)
> + mce_limit = 4UL*1024*1024*1024;
> +
Don't you need this as well under CONFIG_PPC_BOOK3S_64 #ifdef ??
Rest looks good.
Reviewed-by: Mahesh Salgaonkar <mah...@linux.ibm.com>
Thanks,
-Mahesh.
