From: James Morse <james.morse@arm.com>
To: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>, Guenter Roeck <linux@roeck-us.net>,
Hoan Tran <hotran@apm.com>, Jean Delvare <jdelvare@suse.com>,
Jonathan Corbet <corbet@lwn.net>,
Rob Herring <robh+dt@kernel.org>,
Jassi Brar <jassisinghbrar@gmail.com>,
Ashwin Chaugule <ashwin.chaugule@linaro.org>,
Duc Dang <dhdang@apm.com>,
lho@apm.com, linux-hwmon@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH v3 2/3] hwmon: xgene: Add hwmon driver
Date: Fri, 09 Sep 2016 10:31:39 +0100 [thread overview]
Message-ID: <57D2817B.8030007@arm.com> (raw)
In-Reply-To: <20160909031809.GG16712@linaro.org>
Hi,
On 09/09/16 04:18, AKASHI Takahiro wrote:
> On Thu, Sep 08, 2016 at 11:47:59AM +0100, James Morse wrote:
>> On 08/09/16 09:14, Arnd Bergmann wrote:
>>> On Wednesday, September 7, 2016 3:37:05 PM CEST Guenter Roeck wrote:
>>>> On Wed, Sep 07, 2016 at 11:41:44PM +0200, Arnd Bergmann wrote:
>>>>> On Thursday, July 21, 2016 1:55:56 PM CEST Hoan Tran wrote:
>>>>>> + ctx->comm_base_addr = cppc_ss->base_address;
>>>>>> + if (ctx->comm_base_addr) {
>>>>>> + ctx->pcc_comm_addr =
>>>>>> + acpi_os_ioremap(ctx->comm_base_addr,
>>>>>> + cppc_ss->length);
>>>>>>
>>>>>
>>>>> This causes the arm64 allmodconfig build to fail now, according to
>>>>> kernelci:
>>>>>
>>>>> 1 ERROR: "memblock_is_memory" [drivers/hwmon/xgene-hwmon.ko] undefined!
>>>>>
>>>>> Should this perhaps call ioremap() or memremap() instead?
>>>>>
>>>> Hmmm ... almost sounds to me like blaming the messenger. e7cd190385d1 ("arm64:
>>>> mark reserved memblock regions explicitly in iomem") starts using a function
>>>> in acpi_os_ioremap() which is not exported. On top of that, memblock_is_memory()
>>>> is declared as __init_memblock, which makes me really uncomfortable.
>>>> If acpi_os_ioremap() must not be used by modules, and possibly only during
>>>> early (?) initialization, maybe its declaration should state those limitations ?
>>>
>>> Ah, I didn't notice that. I guess both patches were correct individually and
>>> got added to linux-next around the same time but caused allmodconfig to blow up
>>> when used together.
>>>
>>> Adding everyone who was involved in the memblock patch to Cc here, maybe one
>>> of them has an idea what the correct fix is. There are only two other drivers
>>> using acpi_os_ioremap() and one of them is x86-specific, so it's still likely
>>> that drivers are not actually supposed to use this symbol. Making
>>> acpi_os_ioremap() an exported function in arm64 would also work.
>>
>> You could use acpi_os_map_iomem()/acpi_os_unmap_iomem() from acpi/acpi_io.h.
>> If there isn't an existing mapping these end up in acpi_os_ioremap(), and are
>> already EXPORT_SYMBOL_GPL().
>
> acpi_os_ioremap() is re-defined in arm64/include/asm/acpi.h.
>
> The problem is that, as memblock_is_memory() is declared as __init,
__init_memblock ...
... as is memblock_is_map_memory(), which we call from pfn_valid() which is
EXPORT_SYMBOL()'d
and used from modules, (e.g. mac80211.ko). So something fishy is going on...
>From include/linux/memblock.h:
> #ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
> #define __init_memblock __meminit
> #define __initdata_memblock __meminitdata
> #else
> #define __init_memblock
> #define __initdata_memblock
> #endif
arm64 doesn't define ARCH_DISCARD_MEMBLOCK, so we always keep these symbols.
If we didn't, pfn_valid() would break too.
Thanks,
James
next prev parent reply other threads:[~2016-09-09 9:32 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-21 20:55 [PATCH v3 0/3] hwmon: xgene: Add support for X-Gene hwmon driver Hoan Tran
2016-07-21 20:55 ` [PATCH v3 1/3] Documentation: dtb: xgene: Add hwmon dts binding documentation Hoan Tran
2016-07-21 22:02 ` Guenter Roeck
2016-07-21 20:55 ` [PATCH v3 2/3] hwmon: xgene: Add hwmon driver Hoan Tran
2016-07-21 22:09 ` Guenter Roeck
2016-07-21 22:21 ` Hoan Tran
2016-08-01 13:21 ` kbuild test robot
2016-08-01 16:39 ` Hoan Tran
2016-09-07 21:41 ` Arnd Bergmann
2016-09-07 22:27 ` Guenter Roeck
2016-09-08 8:15 ` Arnd Bergmann
2016-09-08 14:55 ` Guenter Roeck
2016-09-08 14:59 ` Arnd Bergmann
2016-09-07 22:37 ` Guenter Roeck
2016-09-08 8:14 ` Arnd Bergmann
2016-09-08 10:47 ` James Morse
2016-09-09 3:18 ` AKASHI Takahiro
2016-09-09 9:31 ` James Morse [this message]
2016-09-09 15:38 ` Arnd Bergmann
2016-09-09 15:38 ` [PATCH] hwmon: xgene: access mailbox as RAM Arnd Bergmann
2016-09-09 16:58 ` Guenter Roeck
2016-09-09 17:05 ` Hoan Tran
2016-09-09 19:24 ` Hoan Tran
2016-09-09 19:58 ` Arnd Bergmann
2016-09-09 20:10 ` [PATCH v2] " Arnd Bergmann
2016-09-09 20:47 ` Hoan Tran
2016-09-09 21:56 ` Guenter Roeck
2016-09-09 20:43 ` [PATCH] " Hoan Tran
2016-09-09 20:50 ` Arnd Bergmann
2016-09-09 20:51 ` Hoan Tran
2016-07-21 20:55 ` [PATCH v3 3/3] arm64: dts: apm: Add X-Gene SoC hwmon to device tree Hoan Tran
2016-07-21 22:09 ` Guenter Roeck
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