> -----Original Message-----
> From: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
> Sent: Tuesday, November 8, 2022 9:39 AM
> To: kvalo@xxxxxxxxxx
> Cc: linux-wireless@xxxxxxxxxxxxxxx
> Subject: [PATCH v2] wifi: rtw89: use u32_encode_bits() to fill MAC quota value
>
> Coverity reported shift 16 bits could cause sign extension and might get
> an unexpected value. Since the input values are predefined and no this
> kind of case, original code is safe so far. But, still changing them to
> use u32_encode_bits() will be more clear and prevent mistakes in the
> future.
>
> The original message of Coverity is:
> Suspicious implicit sign extension: "max_cfg->cma0_dma" with type "u16"
> (16 bits, unsigned) is promoted in "max_cfg->cma0_dma << 16" to type
> "int" (32 bits, signed), then sign-extended to type "unsigned long"
> (64 bits, unsigned). If "max_cfg->cma0_dma << 16" is greater than
> 0x7FFFFFFF, the upper bits of the result will all be 1."
>
> Reported-by: coverity-bot <keescook+coverity-bot@xxxxxxxxxxxx>
> Addresses-Coverity-ID: 1527095 ("Integer handling issues")
> Fixes: e3ec7017f6a2 ("rtw89: add Realtek 802.11ax driver")
> Signed-off-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
Sorry, I forget to add changelog of v2.
v2: use u32_encode_bits() instead of FIELD_PREP() to set field value.
> ---
> drivers/net/wireless/realtek/rtw89/mac.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/wireless/realtek/rtw89/mac.c b/drivers/net/wireless/realtek/rtw89/mac.c
> index bb49033b587d2..814ca4bc22587 100644
> --- a/drivers/net/wireless/realtek/rtw89/mac.c
> +++ b/drivers/net/wireless/realtek/rtw89/mac.c
> @@ -1487,10 +1487,8 @@ static int dle_mix_cfg(struct rtw89_dev *rtwdev, const struct rtw89_dle_mem *cfg
> #define INVALID_QT_WCPU U16_MAX
> #define SET_QUOTA_VAL(_min_x, _max_x, _module, _idx) \
> do { \
> - val = ((_min_x) & \
> - B_AX_ ## _module ## _MIN_SIZE_MASK) | \
> - (((_max_x) << 16) & \
> - B_AX_ ## _module ## _MAX_SIZE_MASK); \
> + val = u32_encode_bits(_min_x, B_AX_ ## _module ## _MIN_SIZE_MASK) | \
> + u32_encode_bits(_max_x, B_AX_ ## _module ## _MAX_SIZE_MASK); \
> rtw89_write32(rtwdev, \
> R_AX_ ## _module ## _QTA ## _idx ## _CFG, \
> val); \
> --
> 2.25.1
>
>
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