From: Hari Bathini <hbathini@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
linuxppc-dev <linuxppc-dev@ozlabs.org>
Cc: Paul Mackerras <paulus@samba.org>,
ben@codiert.org, sjitindarsingh@gmail.com
Subject: Re: [PATCH 1/4] powerpc/prom: avoid endian conversions for linux, memory-limit node
Date: Fri, 4 Aug 2017 11:02:11 +0530 [thread overview]
Message-ID: <7929ae2c-1b34-18b4-127a-ed0e438c751d@linux.vnet.ibm.com> (raw)
In-Reply-To: <8760e4q9bd.fsf@concordia.ellerman.id.au>
On Friday 04 August 2017 09:21 AM, Michael Ellerman wrote:
> Hari Bathini <hbathini@linux.vnet.ibm.com> writes:
>
>> As linux,memory-limit node is set and also later used by the kernel,
>> avoid endian conversions for this property.
>>
>> Fixes: 493adffcb43f ("powerpc: Make prom_init.c endian safe")
>> Cc: stable@vger.kernel.org # 3.12+
>> Cc: Anton Blanchard <anton@ozlabs.org>
>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
>> ---
>> arch/powerpc/kernel/prom_init.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
> As Ben said, this is not OK. The flat device tree is a data
> structure with a specified format[1], we don't violate the spec just to
> avoid an endian swap.
>
> Is there an actual bug you're trying to solve?
Yep. While retrieving this property in prom.c, no endian conversion is
being done.
It was broken for a while. Let me do the endian swap in prom.c while
retrieving..
Thanks
Hari
> [1]: https://www.devicetree.org/
>
>> diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
>> index 613f79f..723df83 100644
>> --- a/arch/powerpc/kernel/prom_init.c
>> +++ b/arch/powerpc/kernel/prom_init.c
>> @@ -3180,9 +3180,8 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
>> * Fill in some infos for use by the kernel later on
>> */
>> if (prom_memory_limit) {
>> - __be64 val = cpu_to_be64(prom_memory_limit);
>> prom_setprop(prom.chosen, "/chosen", "linux,memory-limit",
>> - &val, sizeof(val));
>> + &prom_memory_limit, sizeof(prom_memory_limit));
>> }
>> #ifdef CONFIG_PPC64
>> if (prom_iommu_off)
next prev parent reply other threads:[~2017-08-04 5:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-03 9:24 [PATCH 1/4] powerpc/prom: avoid endian conversions for linux, memory-limit node Hari Bathini
2017-08-03 9:24 ` [PATCH 2/4] powerpc/prom: fix early parsing of parameters Hari Bathini
2017-08-06 8:36 ` kbuild test robot
2017-08-03 9:25 ` [PATCH 3/4] powerpc/prom: fix early parsing of 'mem=' parameter Hari Bathini
2017-08-03 9:25 ` [PATCH 4/4] powerpc/prom: fix early parsing of 'disable_radix' parameter Hari Bathini
2017-08-04 1:37 ` [PATCH 1/4] powerpc/prom: avoid endian conversions for linux, memory-limit node Benjamin Herrenschmidt
2017-08-04 1:47 ` Benjamin Herrenschmidt
2017-08-04 5:35 ` Hari Bathini
2017-08-04 3:51 ` Michael Ellerman
2017-08-04 5:32 ` Hari Bathini [this message]
2017-08-04 10:14 ` Michael Ellerman
2017-08-04 18:38 ` Hari Bathini
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