Re: [PATCH 04/17] remoteproc/omap: Add a sanity check for DSP boot address alignment

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Mon 28 Oct 05:42 PDT 2019, Tero Kristo wrote:

> From: Suman Anna <s-anna@ti.com>
> 
> The DSP remote processors on OMAP SoCs require a boot register to
> be programmed with a boot address, and this boot address needs to
> be on a 1KB boundary. The current code is simply masking the boot
> address appropriately without performing any sanity checks before
> releasing the resets. An unaligned boot address results in an
> undefined execution behavior and can result in various bus errors
> like MMU Faults or L3 NoC errors. Such errors are hard to debug and
> can be easily avoided by adding a sanity check for the alignment
> before booting a DSP remote processor.
> 
> Signed-off-by: Suman Anna <s-anna@ti.com>
> Signed-off-by: Tero Kristo <t-kristo@ti.com>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

> ---
>  drivers/remoteproc/omap_remoteproc.c | 18 +++++++++++++++---
>  1 file changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/remoteproc/omap_remoteproc.c b/drivers/remoteproc/omap_remoteproc.c
> index cd776189d20b..a10377547533 100644
> --- a/drivers/remoteproc/omap_remoteproc.c
> +++ b/drivers/remoteproc/omap_remoteproc.c
> @@ -124,13 +124,22 @@ static void omap_rproc_kick(struct rproc *rproc, int vqid)
>   *
>   * Set boot address for a supported DSP remote processor.
>   */
> -static void omap_rproc_write_dsp_boot_addr(struct rproc *rproc)
> +static int omap_rproc_write_dsp_boot_addr(struct rproc *rproc)
>  {
> +	struct device *dev = rproc->dev.parent;
>  	struct omap_rproc *oproc = rproc->priv;
>  	struct omap_rproc_boot_data *bdata = oproc->boot_data;
>  	u32 offset = bdata->boot_reg;
>  
> +	if (rproc->bootaddr & (SZ_1K - 1)) {
> +		dev_err(dev, "invalid boot address 0x%x, must be aligned on a 1KB boundary\n",
> +			rproc->bootaddr);
> +		return -EINVAL;
> +	}
> +
>  	regmap_write(bdata->syscon, offset, rproc->bootaddr);
> +
> +	return 0;
>  }
>  
>  /*
> @@ -147,8 +156,11 @@ static int omap_rproc_start(struct rproc *rproc)
>  	int ret;
>  	struct mbox_client *client = &oproc->client;
>  
> -	if (oproc->boot_data)
> -		omap_rproc_write_dsp_boot_addr(rproc);
> +	if (oproc->boot_data) {
> +		ret = omap_rproc_write_dsp_boot_addr(rproc);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	client->dev = dev;
>  	client->tx_done = NULL;
> -- 
> 2.17.1
> 
> --
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