RE: [PATCH net] net: wangxun: use BIT_ULL() to prevent shift overflow on 32-bit archs

> -----Original Message-----
> From: Jiawen Wu <[email protected]>
> Sent: Monday, August 24, 2026 9:21 AM
> To: [email protected]
> Cc: Mengyuan Lou <[email protected]>; Andrew Lunn
> <[email protected]>; David S. Miller <[email protected]>; Eric
> Dumazet <[email protected]>; Jakub Kicinski <[email protected]>; Paolo
> Abeni <[email protected]>; Keller, Jacob E <[email protected]>;
> Simon Horman <[email protected]>; Loktionov, Aleksandr
> <[email protected]>; Fabio Baltieri
> <[email protected]>; Zaremba, Larysa
> <[email protected]>; Jiawen Wu <[email protected]>
> Subject: [PATCH net] net: wangxun: use BIT_ULL() to prevent shift
> overflow on 32-bit archs
> 
> The macros TXGBE_INTR_MISC() and WX_INTR_Q() rely on the standard
> BIT() macro to generate interrupt masks based on the queue vector
> index.
> 
> On 32-bit architectures, BIT() evaluates to a 32-bit `unsigned long`.
> Since the number of queue vectors can be up to 63 on txgbe devices,
> performing a left shift of 32 or more results in an integer overflow
> and undefined behavior. This causes incorrect interrupt masking and
> unmasking logic for both the queue and miscellaneous interrupts on 32-
> bit systems.
> 
> Fix this by replacing BIT() with BIT_ULL() in these macros. This
> ensures that the bitwise shift is always performed safely on a 64-bit
> `unsigned long long` type, regardless of the underlying architecture.
> 
> Fixes: e37546ad1f9b ("net: wangxun: revert the adjustment of the IRQ
> vector sequence")
> Signed-off-by: Jiawen Wu <[email protected]>
> ---
>  drivers/net/ethernet/wangxun/libwx/wx_type.h    | 2 +-
>  drivers/net/ethernet/wangxun/txgbe/txgbe_type.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/wangxun/libwx/wx_type.h
> b/drivers/net/ethernet/wangxun/libwx/wx_type.h
> index 65e3e55db1cf..0520288d18ab 100644
> --- a/drivers/net/ethernet/wangxun/libwx/wx_type.h
> +++ b/drivers/net/ethernet/wangxun/libwx/wx_type.h
> @@ -1427,7 +1427,7 @@ struct wx {
>  };
> 
>  #define WX_INTR_ALL (~0ULL)
> -#define WX_INTR_Q(i) BIT((i))
> +#define WX_INTR_Q(i) BIT_ULL((i))
> 
>  /* register operations */
>  #define wr32(a, reg, value)	writel((value), ((a)->hw_addr +
> (reg)))
> diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
> b/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
> index 877234e3fdc2..fddcb011fa2f 100644
> --- a/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
> +++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
> @@ -303,7 +303,7 @@ struct txgbe_fdir_filter {
>  #define TXGBE_DEFAULT_RX_WORK           128
>  #endif
> 
> -#define TXGBE_INTR_MISC(A)    BIT((A)->num_q_vectors)
> +#define TXGBE_INTR_MISC(A)    BIT_ULL((A)->num_q_vectors)
>  #define TXGBE_INTR_QALL(A)    (TXGBE_INTR_MISC(A) - 1)
> 
>  #define TXGBE_MAX_EITR        GENMASK(11, 3)
> --
> 2.51.0

Reviewed-by: Aleksandr Loktionov <[email protected]>