On Fri, 05 Nov 2021 15:28:39 +0100, Pkshih wrote: > > On Fri, 2021-11-05 at 11:03 +0200, Kalle Valo wrote: > > Takashi Iwai <tiwai@xxxxxxx> writes: > > > > > On Fri, 05 Nov 2021 09:25:13 +0100, > > > Kalle Valo wrote: > > > > Takashi Iwai <tiwai@xxxxxxx> writes: > > > > > > > > > On Fri, 05 Nov 2021 08:17:25 +0100, > > > > > Takashi Iwai wrote: > > > > > > When a firmware is loaded in the compressed format or via user-mode > > > > > > helper, it's mapped in read-only, and the rtw89 driver crashes at > > > > > > rtw89_fw_download() when it tries to modify some data. > > > > > > > > > > > > This patch is an attemp to avoid the crash by re-allocating the data > > > > > > via vmalloc() for the data modification. > > > > > > > > > > Alternatively, we may drop the code that modifies the loaded firmware > > > > > data? At least SET_FW_HDR_PART_SIZE() in rtw89_fw_hdr_parser() looks > > > > > writing it, and I have no idea why this overwrite is needed. > > > > > > > > Strange, isn't the firmware data marked as const just to avoid this kind > > > > of problem? Does rtw89 have wrong casts somewhere which removes the > > > > const? > > > > > > Yes. SET_FW_HDR_PART_SIZE() does the cast, dropping the const. > > > > Oh man, all of GET and SET macros in fw.h have those casts: > > > > #define GET_FW_HDR_MAJOR_VERSION(fwhdr) \ > > le32_get_bits(*((__le32 *)(fwhdr) + 1), GENMASK(7, 0)) > > #define GET_FW_HDR_MINOR_VERSION(fwhdr) \ > > le32_get_bits(*((__le32 *)(fwhdr) + 1), GENMASK(15, 8)) > > #define GET_FW_HDR_SUBVERSION(fwhdr) \ > > le32_get_bits(*((__le32 *)(fwhdr) + 1), GENMASK(23, 16)) > > > > I don't know how I missed those during my review :( But this is exactly > > why I prefer having a proper struct for commands and events, instead of > > u8 buf used with these macros. > > > > > I can use a struct to access firmware header, becuase their fields > are multiple of 8 bits. > > But, the "firmware section header" that is additional header followed > by firmware header, and it contains bit fields, likes: > > #define GET_FWSECTION_HDR_SEC_SIZE(fwhdr) \ > le32_get_bits(*((__le32 *)(fwhdr) + 1), GENMASK(23, 0)) > #define GET_FWSECTION_HDR_CHECKSUM(fwhdr) \ > le32_get_bits(*((__le32 *)(fwhdr) + 1), BIT(28)) > #define GET_FWSECTION_HDR_REDL(fwhdr) \ > le32_get_bits(*((__le32 *)(fwhdr) + 1), BIT(29)) > #define GET_FWSECTION_HDR_DL_ADDR(fwhdr) \ > le32_get_bits(*((__le32 *)(fwhdr)), GENMASK(31, 0)) > > If we use a struct, it needs big-/little- endians parts. > > Then, we will access firmware header with two methods; is > it reasonable? 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. 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... > 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. thanks, Takashi