Re: [PATCH 3/3] MIPS: OCTEON: disable SMP if the bootloader version is incorrect

[David Daney <ddaney.cavm@gmail.com>]

On 06/16/2014 01:06 PM, Aaro Koskinen wrote:
> Disable SMP if the bootloader version is incorrect for HOTPLUG_CPU.
>
> Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>

NAK to this one.


> ---
>   arch/mips/cavium-octeon/smp.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c
> index ea96930..71f5505 100644
> --- a/arch/mips/cavium-octeon/smp.c
> +++ b/arch/mips/cavium-octeon/smp.c
> @@ -88,8 +88,10 @@ static void octeon_smp_hotplug_setup(void)
>   		return;
>
>   	labi = (struct linux_app_boot_info *)PHYS_TO_XKSEG_CACHED(LABI_ADDR_IN_BOOTLOADER);
> -	if (labi->labi_signature != LABI_SIGNATURE)
> -		panic("The bootloader version on this board is incorrect.");
> +	if (labi->labi_signature != LABI_SIGNATURE) {
> +		setup_max_cpus = 0;
> +		WARN(1, "Disabling SMP - the bootloader version on this board does not support HOTPLUG_CPU.");
> +	}

We really want to allow SMP, but just disable hot-plugging in the case 
that the bootloader magic is missing.  This is not what setup_max_cpus 
is for.

I would prefer to see a separate variable that indicated ability to 
hot-plug, and have that be used to gate both the watchdog things as well 
as octeon_cpu_disable().


>
>   	octeon_bootloader_entry_addr = labi->InitTLBStart_addr;
>   #endif
>