[PATCH] arm64: zynqmp: Fix set_fdtfile() not to break u-boots DTB

[Michal Simek]

st 24. 6. 2020 v 14:44 odesílatel Michal Simek <michal.simek at xilinx.com> napsal:
>
> Origin function was calling strsep which replaced delimiter ',' by a null
> byte ('\0'). Operation was done directly on FDT which ends up with the
> following behavior:
>
> ZynqMP>  printenv fdtfile
> fdtfile=xilinx/zynqmp.dtb
> ZynqMP> fdt addr $fdtcontroladdr
> ZynqMP> fdt print / compatible
> compatible = "xlnx", "zynqmp"
>
> As is visible fdtfile was correctly composed but a null byte caused that
> xlnx was separated from zynqmp.
> This hasn't been spotted because in all Xilinx DTs there are at least 3
> compatible string and only the first one was affected by this issue.
> But for systems which only had one compatible string "xlnx,zynqmp" it was
> causing an issue when U-Boot's DT was used by Linux kernel.
>
> The patch removes strsep calling and strchr is called instead which just
> locate the first char after deliminator ',' (variable called "name").
> And using this pointer in fdtfile composing.
>
> Fixes: 91d7e0c47f51 ("arm64: zynqmp: Create fdtfile from compatible string")
> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
> ---
>
>  board/xilinx/zynqmp/zynqmp.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/board/xilinx/zynqmp/zynqmp.c b/board/xilinx/zynqmp/zynqmp.c
> index ebb71729081d..8a4df6fc1ab6 100644
> --- a/board/xilinx/zynqmp/zynqmp.c
> +++ b/board/xilinx/zynqmp/zynqmp.c
> @@ -541,23 +541,30 @@ static int set_fdtfile(void)
>         char *compatible, *fdtfile;
>         const char *suffix = ".dtb";
>         const char *vendor = "xilinx/";
> +       int fdt_compat_len;
>
>         if (env_get("fdtfile"))
>                 return 0;
>
> -       compatible = (char *)fdt_getprop(gd->fdt_blob, 0, "compatible", NULL);
> -       if (compatible) {
> +       compatible = (char *)fdt_getprop(gd->fdt_blob, 0, "compatible",
> +                                        &fdt_compat_len);
> +       if (compatible && fdt_compat_len) {
> +               char *name;
> +
>                 debug("Compatible: %s\n", compatible);
>
> -               /* Discard vendor prefix */
> -               strsep(&compatible, ",");
> +               name = strchr(compatible, ',');
> +               if (!name)
> +                       return -EINVAL;
> +
> +               name++;
>
> -               fdtfile = calloc(1, strlen(vendor) + strlen(compatible) +
> +               fdtfile = calloc(1, strlen(vendor) + strlen(name) +
>                                  strlen(suffix) + 1);
>                 if (!fdtfile)
>                         return -ENOMEM;
>
> -               sprintf(fdtfile, "%s%s%s", vendor, compatible, suffix);
> +               sprintf(fdtfile, "%s%s%s", vendor, name, suffix);
>
>                 env_set("fdtfile", fdtfile);
>                 free(fdtfile);
> --
> 2.27.0
>

Applied.
M

-- 
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Xilinx Microblaze
Maintainer of Linux kernel - Xilinx Zynq ARM and ZynqMP ARM64 SoCs
U-Boot custodian - Xilinx Microblaze/Zynq/ZynqMP/Versal SoCs