RE: [PATCH] rtw89: Fix crash by loading compressed firmware file

[Pkshih <pkshih@realtek.com>]

> -----Original Message-----
> From: Takashi Iwai <tiwai@suse.de>
> Sent: Friday, November 5, 2021 11:07 PM
> To: Pkshih <pkshih@realtek.com>
> Cc: kvalo@codeaurora.org; linux-wireless@vger.kernel.org; Larry.Finger@gmail.com;
> linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] rtw89: Fix crash by loading compressed firmware file
> 
> 
> You should put const in the cast in le32_get_bits() invocations, at
> least.
> 
> For the le32_replace_bits(), ideally it should be rewritten in some
> better way the compiler can catch.  e.g. use an inline function to
> take a void * argument without const,
> 
> static inline void RTW89_SET_FWCMD_CXRFK_TYPE(void *cmd, unsigned int val)
> {
> 	le32p_replace_bits((__le32 *)((u8 *)(cmd) + 2), val, GENMASK(17, 10));
> }
> 
> Then the compiler will warn when you pass a const pointer there.
> 

I have sent a patchset [1] to do these two things by patch 2 and 3.

> 
> BTW, while reading your reply, I noticed that it's an unaligned access
> to a 32bit value, which is another potential breakage on some
> architectures.  So the whole stuff has to be rewritten in anyway...
> 

We use these macros/inline function on skb->data mostly, and I 
suppose skb->data is a 32bit aligned address. Since I don't have
this kind of machine on hand, I would like to defer this work until
I have one.

> 
> > The macro SET_FW_HDR_PART_SIZE() is used to set the firmware
> > partition size we are going to download, and it is only used
> > by rtw89_fw_download_hdr(). So, I will set the partition size
> > after copying constant firmware header into skb->data.
> 
> Sounds good.
> 

Please check if my patch works on your platform.
Thanks you.

[1] https://lore.kernel.org/linux-wireless/20211111021457.13776-1-pkshih@realtek.com/T/#t

--
Ping-Ke