From: Daniel Axtens <dja@axtens.net>
To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc/configs: Disable /dev/port in skiroot defconfig
Date: Tue, 02 Jul 2019 16:41:51 +1000 [thread overview]
Message-ID: <87y31h0wgg.fsf@dja-thinkpad.axtens.net> (raw)
In-Reply-To: <87r27escsi.fsf@concordia.ellerman.id.au>
Michael Ellerman <mpe@ellerman.id.au> writes:
> Daniel Axtens <dja@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
next prev parent reply other threads:[~2019-07-02 6:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-27 5:30 [PATCH] powerpc/configs: Disable /dev/port in skiroot defconfig Daniel Axtens
2019-06-28 1:45 ` Michael Ellerman
2019-07-02 6:41 ` Daniel Axtens [this message]
2019-08-28 4:24 ` Michael Ellerman
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