From: Masayoshi Mizuma <msys.mizuma@gmail.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-arm-kernel@lists.infradead.org
Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>,
Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
Masayoshi Mizuma <msys.mizuma@gmail.com>,
linux-kernel@vger.kernel.org,
Zhang Lei <zhang.lei@jp.fujitsu.com>
Subject: [PATCH 0/2] Correct the cache line size warning
Date: Tue, 11 Jun 2019 11:17:29 -0400 [thread overview]
Message-ID: <20190611151731.6135-1-msys.mizuma@gmail.com> (raw)
From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
If the cache line size is greater than ARCH_DMA_MINALIGN (128),
the warning shows and it's tainted as TAINT_CPU_OUT_OF_SPEC.
However, it's not good about two points.
First, as discussed in the thread [1], the cpu cache line size will be
problem only on non-coherent devices.
Then, it should not be tainted as TAINT_CPU_OUT_OF_SPEC because
according to the specification of CTR_EL0.CWG, the maximum cache
writeback granule is 2048 byte (CWG == 0b1001).
This patch series try to:
- Show the warning only if the device is non-coherent device and
ARCH_DMA_MINALIGN is smaller than the cpu cache size.
- Show the warning and taints as TAINT_CPU_OUT_OF_SPEC if the cache line
size is greater than the maximum.
[1] https://lore.kernel.org/linux-arm-kernel/20180514145703.celnlobzn3uh5tc2@localhost/
Masayoshi Mizuma (2):
arm64/mm: check cpu cache line size with non-coherent device
arm64/mm: show TAINT_CPU_OUT_OF_SPEC warning if the cache size is over
the spec.
arch/arm64/include/asm/cache.h | 2 ++
arch/arm64/mm/dma-mapping.c | 9 +++++----
arch/arm64/mm/init.c | 5 +++++
3 files changed, 12 insertions(+), 4 deletions(-)
--
2.20.1
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next reply other threads:[~2019-06-11 15:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-11 15:17 Masayoshi Mizuma [this message]
2019-06-11 15:17 ` [PATCH 1/2] arm64/mm: check cpu cache line size with non-coherent device Masayoshi Mizuma
2019-06-11 18:00 ` Catalin Marinas
2019-06-11 22:02 ` Masayoshi Mizuma
2019-06-13 15:54 ` Catalin Marinas
2019-06-13 17:10 ` Robin Murphy
2019-06-11 15:17 ` [PATCH 2/2] arm64/mm: show TAINT_CPU_OUT_OF_SPEC warning if the cache size is over the spec Masayoshi Mizuma
2019-06-11 15:41 ` Catalin Marinas
2019-06-11 16:18 ` Masayoshi Mizuma
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