[Intel-gfx] [PATCH 4/9] drm/i915/dmc: extract function to parse css header

[Srivatsa, Anusha]

>-----Original Message-----
>From: De Marchi, Lucas
>Sent: Friday, June 7, 2019 2:12 AM
>To: intel-gfx at lists.freedesktop.org
>Cc: Vivi, Rodrigo <rodrigo.vivi at intel.com>; Srivatsa, Anusha
><anusha.srivatsa at intel.com>; De Marchi, Lucas <lucas.demarchi at intel.com>
>Subject: [PATCH 4/9] drm/i915/dmc: extract function to parse css header
>
>Let's start splitting the parse function, making all of them return the number of
>bytes parsed - different versions of the firmware header may require different
>sizes for the structures.
>
>v2: rework remaining bytes calculation on new protection for amount of
>    bytes read

Looks good.
Reviewed-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
>Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
>---
> drivers/gpu/drm/i915/intel_csr.c | 66 ++++++++++++++++++++------------
> 1 file changed, 41 insertions(+), 25 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c
>index ba72c29acbcc..79732075f008 100644
>--- a/drivers/gpu/drm/i915/intel_csr.c
>+++ b/drivers/gpu/drm/i915/intel_csr.c
>@@ -332,36 +332,22 @@ static u32 find_dmc_fw_offset(const struct
>intel_fw_info *fw_info,
> 	return dmc_offset;
> }
>
>-static u32 *parse_csr_fw(struct drm_i915_private *dev_priv,
>-			 const struct firmware *fw)
>+/* Return number of bytes parsed or 0 on error */ static u32
>+parse_csr_fw_css(struct intel_csr *csr,
>+			    struct intel_css_header *css_header,
>+			    size_t rem_size)
> {
>-	struct intel_css_header *css_header;
>-	struct intel_package_header *package_header;
>-	struct intel_dmc_header *dmc_header;
>-	struct intel_csr *csr = &dev_priv->csr;
>-	const struct stepping_info *si = intel_get_stepping_info(dev_priv);
>-	u32 dmc_offset, num_entries, max_entries, readcount = 0, nbytes;
>-	u32 i;
>-	u32 *dmc_payload;
>-	size_t fsize;
>-
>-	if (!fw)
>-		return NULL;
>-
>-	fsize = sizeof(struct intel_css_header) +
>-		sizeof(struct intel_package_header) +
>-		sizeof(struct intel_dmc_header);
>-	if (fsize > fw->size)
>-		goto error_truncated;
>+	if (rem_size < sizeof(struct intel_css_header)) {
>+		DRM_ERROR("Truncated DMC firmware, refusing.\n");
>+		return 0;
>+	}
>
>-	/* Extract CSS Header information*/
>-	css_header = (struct intel_css_header *)fw->data;
> 	if (sizeof(struct intel_css_header) !=
> 	    (css_header->header_len * 4)) {
> 		DRM_ERROR("DMC firmware has wrong CSS header length "
> 			  "(%u bytes)\n",
> 			  (css_header->header_len * 4));
>-		return NULL;
>+		return 0;
> 	}
>
> 	if (csr->required_version &&
>@@ -372,12 +358,42 @@ static u32 *parse_csr_fw(struct drm_i915_private
>*dev_priv,
> 			 CSR_VERSION_MINOR(css_header->version),
> 			 CSR_VERSION_MAJOR(csr->required_version),
> 			 CSR_VERSION_MINOR(csr->required_version));
>-		return NULL;
>+		return 0;
> 	}
>
> 	csr->version = css_header->version;
>
>-	readcount += sizeof(struct intel_css_header);
>+	return sizeof(struct intel_css_header); }
>+
>+static u32 *parse_csr_fw(struct drm_i915_private *dev_priv,
>+			 const struct firmware *fw)
>+{
>+	struct intel_css_header *css_header;
>+	struct intel_package_header *package_header;
>+	struct intel_dmc_header *dmc_header;
>+	struct intel_csr *csr = &dev_priv->csr;
>+	const struct stepping_info *si = intel_get_stepping_info(dev_priv);
>+	u32 dmc_offset, num_entries, max_entries, readcount = 0, nbytes;
>+	u32 i, r;
>+	u32 *dmc_payload;
>+	size_t fsize;
>+
>+	if (!fw)
>+		return NULL;
>+
>+	/* Extract CSS Header information */
>+	css_header = (struct intel_css_header *)fw->data;
>+	r = parse_csr_fw_css(csr, css_header, fw->size);
>+	if (!r)
>+		return NULL;
>+
>+	readcount += r;
>+	fsize = readcount +
>+		sizeof(struct intel_package_header) +
>+		sizeof(struct intel_dmc_header);
>+	if (fsize > fw->size)
>+		goto error_truncated;
>
> 	/* Extract Package Header information*/
> 	package_header = (struct intel_package_header *)
>--
>2.21.0