Re: [PATCHv7 03/15] remoteproc/omap: Add a sanity check for DSP boot address alignment

Mathieu Poirier
2020-03-03T22:56:44Z

On Fri, Feb 21, 2020 at 12:19:24PM +0200, 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>

Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> ---
> v7:
> - minor kerneldoc update (added return value details for
> omap_rproc_write_dsp_boot_addr)
>
> drivers/remoteproc/omap_remoteproc.c | 20 +++++++++++++++++---
> 1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/remoteproc/omap_remoteproc.c b/drivers/remoteproc/omap_remoteproc.c
> index d47d5ded651a..64b559caadff 100644
> --- a/drivers/remoteproc/omap_remoteproc.c
> +++ b/drivers/remoteproc/omap_remoteproc.c
> @@ -121,14 +121,25 @@ static void omap_rproc_kick(struct rproc *rproc, int vqid)
> * @rproc: handle of a remote processor
> *
> * Set boot address for a supported DSP remote processor.
> + *
> + * Return: 0 on success, or -EINVAL if boot address is not aligned properly
> */
> -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;
> }
>
> /*
> @@ -145,8 +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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