[PATCH] powerpc/configs: Disable /dev/port in skiroot defconfig

[Daniel Axtens]

Michael Ellerman <mpe at ellerman.id.au> writes:

> Daniel Axtens <dja at axtens.net> writes:
>> While reviewing lockdown patches, I discovered that we still enable
>> /dev/port (CONFIG_DEVPORT) in skiroot.
>>
>> We don't need it. Deselect CONFIG_DEVPORT for skiroot.
>
> Why don't we need it? :)

I should have explained this better :)

/dev/port is used for old x86 style IO accesses.

It's set up in drivers/char/mem.c, and is only created if
arch_has_dev_port() returns true. Per arch/powerpc/include/asm/io.h, on
PPC64 with PCI, this is only true if there's a legacy ISA bridge.

Even if a system has a legacy ISA bridge installed, we have no business
accessing it in skiroot.

Regards,
Daniel
>
> cheers
>
>> diff --git a/arch/powerpc/configs/skiroot_defconfig b/arch/powerpc/configs/skiroot_defconfig
>> index 5ba131c30f6b..b2e8f37156eb 100644
>> --- a/arch/powerpc/configs/skiroot_defconfig
>> +++ b/arch/powerpc/configs/skiroot_defconfig
>> @@ -212,6 +212,7 @@ CONFIG_IPMI_WATCHDOG=y
>>  CONFIG_HW_RANDOM=y
>>  CONFIG_TCG_TPM=y
>>  CONFIG_TCG_TIS_I2C_NUVOTON=y
>> +# CONFIG_DEVPORT is not set
>>  CONFIG_I2C=y
>>  # CONFIG_I2C_COMPAT is not set
>>  CONFIG_I2C_CHARDEV=y
>> -- 
>> 2.20.1