remoteproc: qcom_q6v5_mss: map/unmap mpss segments before/after use

The application processor accessing the mpss region when the Q6 modem is
running will lead to an XPU violation. Fix this by un-mapping the mpss
segments post copy during mpss authentication and coredumps.

Tested-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/20200415071619.6052-1-sibis@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/qcom_q6v5_mss.c

@@ -1116,7 +1116,13 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
 			goto release_firmware;
 		}
 
-		ptr = qproc->mpss_region + offset;
+		ptr = ioremap_wc(qproc->mpss_phys + offset, phdr->p_memsz);
+		if (!ptr) {
+			dev_err(qproc->dev,
+				"unable to map memory region: %pa+%zx-%x\n",
+				&qproc->mpss_phys, offset, phdr->p_memsz);
+			goto release_firmware;
+		}
 
 		if (phdr->p_filesz && phdr->p_offset < fw->size) {
 			/* Firmware is large enough to be non-split */
@@ -1125,6 +1131,7 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
 					"failed to load segment %d from truncated file %s\n",
 					i, fw_name);
 				ret = -EINVAL;
+				iounmap(ptr);
 				goto release_firmware;
 			}
 
@@ -1135,6 +1142,7 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
 			ret = request_firmware(&seg_fw, fw_name, qproc->dev);
 			if (ret) {
 				dev_err(qproc->dev, "failed to load %s\n", fw_name);
+				iounmap(ptr);
 				goto release_firmware;
 			}
 
@@ -1147,6 +1155,7 @@ static int q6v5_mpss_load(struct q6v5 *qproc)
 			memset(ptr + phdr->p_filesz, 0,
 			       phdr->p_memsz - phdr->p_filesz);
 		}
+		iounmap(ptr);
 		size += phdr->p_memsz;
 
 		code_length = readl(qproc->rmb_base + RMB_PMI_CODE_LENGTH_REG);
@@ -1196,7 +1205,8 @@ static void qcom_q6v5_dump_segment(struct rproc *rproc,
 	int ret = 0;
 	struct q6v5 *qproc = rproc->priv;
 	unsigned long mask = BIT((unsigned long)segment->priv);
-	void *ptr = rproc_da_to_va(rproc, segment->da, segment->size);
+	int offset = segment->da - qproc->mpss_reloc;
+	void *ptr = NULL;
 
 	/* Unlock mba before copying segments */
 	if (!qproc->dump_mba_loaded) {
@@ -1210,10 +1220,15 @@ static void qcom_q6v5_dump_segment(struct rproc *rproc,
 		}
 	}
 
-	if (!ptr || ret)
-		memset(dest, 0xff, segment->size);
-	else
+	if (!ret)
+		ptr = ioremap_wc(qproc->mpss_phys + offset, segment->size);
+
+	if (ptr) {
 		memcpy(dest, ptr, segment->size);
+		iounmap(ptr);
+	} else {
+		memset(dest, 0xff, segment->size);
+	}
 
 	qproc->dump_segment_mask |= mask;
 
@@ -1548,12 +1563,6 @@ static int q6v5_alloc_memory_region(struct q6v5 *qproc)
 
 	qproc->mpss_phys = qproc->mpss_reloc = r.start;
 	qproc->mpss_size = resource_size(&r);
-	qproc->mpss_region = devm_ioremap_wc(qproc->dev, qproc->mpss_phys, qproc->mpss_size);
-	if (!qproc->mpss_region) {
-		dev_err(qproc->dev, "unable to map memory region: %pa+%zx\n",
-			&r.start, qproc->mpss_size);
-		return -EBUSY;
-	}
 
 	return 0;
 }