linux-kernel - Re: [PATCH v3 03/13] spi: atmel-quadspi: drop wrappers for iomem accesses

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]

Date:   Sat, 2 Feb 2019 08:44:27 +0000
From:   <Tudor.Ambarus@...rochip.com>
To:     <bbrezillon@...nel.org>
CC:     <mark.rutland@....com>, <devicetree@...r.kernel.org>,
        <alexandre.belloni@...tlin.com>, <linux-kernel@...r.kernel.org>,
        <Cyrille.Pitchen@...rochip.com>, <Nicolas.Ferre@...rochip.com>,
        <robh+dt@...nel.org>, <linux-spi@...r.kernel.org>,
        <Ludovic.Desroches@...rochip.com>, <broonie@...nel.org>,
        <linux-mtd@...ts.infradead.org>, <bugalski.piotr@...il.com>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v3 03/13] spi: atmel-quadspi: drop wrappers for iomem
 accesses



On 02/02/2019 09:11 AM, Boris Brezillon wrote:
> On Sat, 2 Feb 2019 04:07:19 +0000
> <Tudor.Ambarus@...rochip.com> wrote:
> 
>> From: Tudor Ambarus <tudor.ambarus@...rochip.com>
>>
>> The wrappers hid that the accesses are relaxed. Drop them.
>>
>> Suggested-by: Boris Brezillon <bbrezillon@...nel.org>
>> Signed-off-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
>> ---
>> v3: no change
>> v2: new patch
>>
>>  drivers/spi/atmel-quadspi.c | 47 +++++++++++++++++++--------------------------
>>  1 file changed, 20 insertions(+), 27 deletions(-)
>>
>> diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
>> index feeddcb25e1f..131374db0db4 100644
>> --- a/drivers/spi/atmel-quadspi.c
>> +++ b/drivers/spi/atmel-quadspi.c
>> @@ -175,17 +175,6 @@ static const struct qspi_mode sama5d2_qspi_modes[] = {
>>  	{ 4, 4, 4, QSPI_IFR_WIDTH_QUAD_CMD },
>>  };
>>  
>> -/* Register access functions */
>> -static inline u32 qspi_readl(struct atmel_qspi *aq, u32 reg)
>> -{
>> -	return readl_relaxed(aq->regs + reg);
>> -}
>> -
>> -static inline void qspi_writel(struct atmel_qspi *aq, u32 reg, u32 value)
>> -{
>> -	writel_relaxed(value, aq->regs + reg);
>> -}
>> -
>>  static inline bool is_compatible(const struct spi_mem_op *op,
>>  				 const struct qspi_mode *mode)
>>  {
>> @@ -229,6 +218,7 @@ static bool atmel_qspi_supports_op(struct spi_mem *mem,
>>  static int atmel_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
>>  {
>>  	struct atmel_qspi *aq = spi_controller_get_devdata(mem->spi->master);
>> +	void __iomem *base = aq->regs;
> 
> Can we name this variable regs instead of base or even get rid of it
> and dereference aq->regs in the xxx_relaxed() calls (doesn't look like
> the lines would be over 80 chars even when doing that). With this
> addressed, you can add:
> 
> Reviewed-by: Boris Brezillon <bbrezillon@...nel.org>

I chose to introduce the "base" variable when I have at least 2 dereferences in
a function, as an optimization. In exec_op() for example, there are 6
dereferences of aq->reqs. Why do you prefer keeping aq->regs?