Re: [PATCH] wifi: ath11k: fix remapped ce accessing issue on 64bit OS

[Kalle Valo <kvalo@kernel.org>]

Larry Finger <Larry.Finger@lwfinger.net> writes:

> On 5/1/24 11:14 AM, Ziyang Huang wrote:
>
>> On 64bit OS, when ab->mem_ce is lower than or 4G far away from ab->mem,
>> u32 is not enough to store the offsets, which makes ath11k_ahb_read32()
>> and ath11k_ahb_write32() access incorrect address and causes Data Abort
>> Exception.
>> Let's use the high bits of offsets to decide where to access, which
>> is
>> similar as ath11k_pci_get_window_start() done. In the future, we can merge
>> these functions for unified regs accessing.
>> Signed-off-by: Ziyang Huang <hzyitc@outlook.com>
>> ---
>>   drivers/net/wireless/ath/ath11k/ahb.c | 34 ++++++++++++++++++++-------
>>   drivers/net/wireless/ath/ath11k/hal.c | 17 +++++---------
>>   drivers/net/wireless/ath/ath11k/hw.c  | 14 +++++------
>>   drivers/net/wireless/ath/ath11k/hw.h  |  7 +++++-
>>   4 files changed, 45 insertions(+), 27 deletions(-)
>> diff --git a/drivers/net/wireless/ath/ath11k/ahb.c
>> b/drivers/net/wireless/ath/ath11k/ahb.c
>> index 7c0a23517949..9e59b4de93a9 100644
>> --- a/drivers/net/wireless/ath/ath11k/ahb.c
>> +++ b/drivers/net/wireless/ath/ath11k/ahb.c
>> @@ -198,12 +198,30 @@ static const struct ath11k_pci_ops ath11k_ahb_pci_ops_wcn6750 = {
>>     static inline u32 ath11k_ahb_read32(struct ath11k_base *ab, u32
>> offset)
>>   {
>> -	return ioread32(ab->mem + offset);
>> +	switch (offset & ATH11K_REG_TYPE_MASK) {
>> +	case ATH11K_REG_TYPE_NORMAL:
>> +		return ioread32(ab->mem + FIELD_GET(ATH11K_REG_OFFSET_MASK, offset));
>> +	case ATH11K_REG_TYPE_CE:
>> +		return ioread32(ab->mem_ce + FIELD_GET(ATH11K_REG_OFFSET_MASK, offset));
>> +	default:
>> +		BUG();
>
> Do you really want to crash the system here? A dev_warn() or something
> similar would log the situation. I suspect this case is never taken,
> but a system crash is not a good response if it is.

Correct, BUG() is more or less banned from all wireless code.

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches