Mahesh J Salgaonkar's on March 27, 2020 3:24 pm:
> 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 ??
Good catch.
Thanks,
Nick
