linux-kernel - Re: [PATCH 3/5] MIPS: Loongson64: Enlarge IO_SPACE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <d927b5b6-e33e-4a94-c997-b1794dbde411@flygoat.com>
Date:   Mon, 20 Jul 2020 20:04:22 +0800
From:   Jiaxun Yang <jiaxun.yang@...goat.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     "open list:BROADCOM NVRAM DRIVER" <linux-mips@...r.kernel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Huacai Chen <chenhc@...ote.com>,
        Frank Rowand <frowand.list@...il.com>,
        Paul Burton <paulburton@...nel.org>,
        Nathan Chancellor <natechancellor@...il.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        DTML <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/5] MIPS: Loongson64: Enlarge IO_SPACE_LIMIT



在 2020/7/20 下午6:45, Arnd Bergmann 写道:
> On Mon, Jul 20, 2020 at 9:44 AM Jiaxun Yang <jiaxun.yang@...goat.com> wrote:
>> It can be very big on LS7A PCH systems.
>>
>> Signed-off-by: Jiaxun Yang <jiaxun.yang@...goat.com>
>> ---
>>    * On MIPS I/O ports are memory mapped, so we access them using normal
>> diff --git a/arch/mips/include/asm/mach-loongson64/spaces.h b/arch/mips/include/asm/mach-loongson64/spaces.h
>> index 3de0ac9d8829..b99b43854929 100644
>> --- a/arch/mips/include/asm/mach-loongson64/spaces.h
>> +++ b/arch/mips/include/asm/mach-loongson64/spaces.h
>> @@ -11,8 +11,7 @@
>>   #define PCI_IOSIZE     SZ_16M
>>   #define MAP_BASE       (PCI_IOBASE + PCI_IOSIZE)
>>
>> -/* Reserved at the start of PCI_IOBASE for legacy drivers */
>> -#define MMIO_LOWER_RESERVED    0x10000
>> +#define IO_SPACE_LIMIT 0x00ffffff
> Does this mean that firmware may already have assigned "high" I/O space
> numbers for devices? I'm not sure how well device drivers can generally
> deal with port numbers that don't fit into a 16-bit integer.
Limited test shows most drivers can deal with that. But We'll aware the 
problem,
thanks for the remind.
>
> Is it possible to run a 32-bit kernel on these machines? If yes, than
> taking up 16MB of virtual addresses may also become a problem.

We've killed the ability of running 32-bit kernel on MACH_LOONGSON64.

> In practice, one should rarely need more than a few kb worth of
> port numbers, unless you expect to see hundreds of legacy PCI
> devices.
I must blame stupid hardware design here. The LPC Controller (for ISA 
device) can eat
up to 0x20000 IO BAR, and we can't resize it. Thus we have to enlarge 
the I/O Space.

Thanks!

- Jiaxun
>
>         Arnd