[U-Boot] [PATCH v4] arm: socfpga: mailbox: Fix off-by-one error on command length checking

[Simon Goldschmidt]

Ley Foon Tan <ley.foon.tan at intel.com> schrieb am Mi., 24. Apr. 2019, 07:21:

> A mailbox command contains 1-u32 header + arguments. The "len" variable
> only contains the length of the arguments, but not the 1-u32 header.
> Include the length of header when checking the ring buffer space to
> prevent off-by-one error.
>
> Signed-off-by: Ley Foon Tan <ley.foon.tan at intel.com>
> Signed-off-by: Chee Hong Ang <chee.hong.ang at intel.com>
>

Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>

---
> v3->v4:
> - Change DWORD to u32 in commit message
> - Add note len is in u32 unit in code
>
> v2->v3:
> - Update commit description.
> ---
>  arch/arm/mach-socfpga/mailbox_s10.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-socfpga/mailbox_s10.c
> b/arch/arm/mach-socfpga/mailbox_s10.c
> index 3c33223936..4498ab55df 100644
> --- a/arch/arm/mach-socfpga/mailbox_s10.c
> +++ b/arch/arm/mach-socfpga/mailbox_s10.c
> @@ -55,11 +55,11 @@ static __always_inline int
> mbox_fill_cmd_circular_buff(u32 header, u32 len,
>         cout = MBOX_READL(MBOX_COUT) % MBOX_CMD_BUFFER_SIZE;
>
>         /* if command buffer is full or not enough free space
> -        * to fit the data
> +        * to fit the data. Note, len is in u32 unit.
>          */
>         if (((cin + 1) % MBOX_CMD_BUFFER_SIZE) == cout ||
>             ((MBOX_CMD_BUFFER_SIZE - cin + cout - 1) %
> -            MBOX_CMD_BUFFER_SIZE) < len)
> +            MBOX_CMD_BUFFER_SIZE) < (len + 1))
>                 return -ENOMEM;
>
>         /* write header to circular buffer */
> --
> 2.19.0
>
>