Re: [PATCH v2 04/13] drivers/ata: Stop using 32-bit MSR interfaces

["Jürgen Groß" <jgross@suse.com>]

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On 19.08.26 15:40, David Laight wrote:
> On Wed, 19 Aug 2026 12:23:05 +0200
> Juergen Gross <jgross@suse.com> wrote:
> 
>> The 32-bit MSR interfaces rdmsr() and wrmsr() are planned to be
>> removed. Use the related 64-bit variants instead.
>>
>> In drivers/ata/pata_cs5536.c don't redefine rdmsr() and wrmsr() as
>> empty macros for avoiding misuse, but guard the affected code via
>> a simple #ifdef.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> ---
>> V2:
>> - avoid sign extension when using wrmsrq() (Sashiko bot)
>> ---
>>   drivers/ata/pata_cs5535.c | 20 ++++++++++----------
>>   drivers/ata/pata_cs5536.c | 17 ++++++++---------
>>   2 files changed, 18 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/ata/pata_cs5535.c b/drivers/ata/pata_cs5535.c
>> index d793fc441b46..e16c7f4c7c27 100644
>> --- a/drivers/ata/pata_cs5535.c
>> +++ b/drivers/ata/pata_cs5535.c
>> @@ -90,7 +90,7 @@ static void cs5535_set_piomode(struct ata_port *ap, struct ata_device *adev)
>>   	static const u16 pio_cmd_timings[5] = {
>>   		0xF7F4, 0x53F3, 0x13F1, 0x5131, 0x1131
>>   	};
>> -	u32 reg, __maybe_unused dummy;
>> +	u32 reg;
>>   	struct ata_device *pair = ata_dev_pair(adev);
>>   
>>   	int mode = adev->pio_mode - XFER_PIO_0;
>> @@ -102,16 +102,16 @@ static void cs5535_set_piomode(struct ata_port *ap, struct ata_device *adev)
>>   		cmdmode = min(mode, pairmode);
>>   		/* Write the other drive timing register if it changed */
>>   		if (cmdmode < pairmode)
>> -			wrmsr(ATAC_CH0D0_PIO + 2 * pair->devno,
>> -				pio_cmd_timings[cmdmode] << 16 | pio_timings[pairmode], 0);
>> +			wrmsrq(ATAC_CH0D0_PIO + 2 * pair->devno,
>> +				(u32)pio_cmd_timings[cmdmode] << 16 | pio_timings[pairmode]);
> 
> That cast is horribly subtle.
> Perhaps change the array to be u32 and shift the values in the array initialiser?

I like this idea.

I'll send V3 for this patch only as a reply to V2 of this patch.


Juergen

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