[PATCH 04/14] drm/amdgpu: add amdgpu_discovery_get_mem_reserved_info_table

From: Feifei Xu <[email protected]>

Add interface to query the optional MEM_RESERVED_INFO table:

  - introduce amdgpu_discovery_get_mem_reserved_info_table() which
    resolves the table from the discovery binary and caches the pointer
    in adev->discovery.mem_reserved_table so subsequent lookups are
    cheap;
  - invoke it once at init time. Missing/invalid table is non-fatal.

Signed-off-by: Feifei Xu <[email protected]>
Reviewed-by: Hawking Zhang <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 55 ++++++++++++++++++-
 drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.h |  4 ++
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
index af1404ae2b70c..4d55933f033cc 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
@@ -684,6 +684,15 @@ static int amdgpu_discovery_table_check(struct amdgpu_device *adev,
 		check_table = false;
 		break;
 	}
+	case MEM_RESERVED_INFO: {
+		struct mem_reserved_info_header *mrhdr =
+			(struct mem_reserved_info_header *)(discovery_bin + offset);
+		act_val = le32_to_cpu(mrhdr->signature);
+		exp_val = MEM_RSV_TABLE_SIGNATURE;
+		table_size = le32_to_cpu(mrhdr->size);
+		table_name = "mem_reserved table";
+		break;
+	}
 	default:
 		dev_err(adev->dev, "invalid ip discovery table id %d specified\n", table_id);
 		check_table = false;
@@ -772,12 +781,17 @@ static int amdgpu_discovery_init(struct amdgpu_device *adev)
 		goto out;
 	}
 
-	for (table_id = 0; table_id <= MALL_INFO; table_id++) {
+	for (table_id = 0; table_id < TOTAL_TABLES; table_id++) {
 		r = amdgpu_discovery_table_check(adev, discovery_bin, table_id);
 		if (r)
 			goto out;
 	}
 
+	/*
+	 * Resolve the MEM_RESERVED_INFO table once at init time. The table
+	 * is optional, so missing it is not a fatal error.
+	 */
+	amdgpu_discovery_get_mem_reserved_info_table(adev);
 	return 0;
 
 out:
@@ -796,6 +810,8 @@ void amdgpu_discovery_fini(struct amdgpu_device *adev)
 
 	kfree(adev->discovery.bin);
 	adev->discovery.bin = NULL;
+	/* Cached pointer lives inside discovery.bin; drop it to avoid UAF. */
+	adev->discovery.mem_reserved_table = NULL;
 }
 
 static int amdgpu_discovery_validate_ip(struct amdgpu_device *adev,
@@ -2375,6 +2391,43 @@ int amdgpu_discovery_get_nps_info(struct amdgpu_device *adev,
 	return 0;
 }
 
+/*
+ * Resolve the MEM_RESERVED_INFO table from the IP discovery binary and
+ * cache it in adev->discovery.mem_reserved_table.
+ * Return: 0 on success, -ENOENT/-EINVAL if the table unavailable.
+ */
+int amdgpu_discovery_get_mem_reserved_info_table(struct amdgpu_device *adev)
+{
+	uint8_t *discovery_bin = adev->discovery.bin;
+	struct table_info *info;
+
+	/* If already queried, do not query again. */
+	if (adev->discovery.mem_reserved_table)
+		return 0;
+
+	if (!discovery_bin) {
+		dev_err(adev->dev, "ip discovery uninitialized\n");
+		return -ENOENT;
+	}
+
+	if (amdgpu_discovery_get_table_info(adev, &info, MEM_RESERVED_INFO)) {
+		dev_dbg(adev->dev, "MEM_RESERVED_INFO table entry not present\n");
+		return -EINVAL;
+	}
+
+	if (!le16_to_cpu(info->offset)) {
+		dev_dbg(adev->dev, "MEM_RESERVED_INFO table offset is 0, invalid!\n");
+		return -EINVAL;
+	}
+
+	/* Cache for subsequent lookups. */
+	adev->discovery.mem_reserved_table =
+		(struct mem_reserved_info_table_v1_0 *)(discovery_bin + le16_to_cpu(info->offset));
+
+	dev_dbg(adev->dev, "MEM_RESERVED_INFO table exist\n");
+	return 0;
+}
+
 static int amdgpu_discovery_set_common_ip_blocks(struct amdgpu_device *adev)
 {
 	/* what IP to use for this? */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.h
index 5b2b16f68576c..070b404c1944c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.h
@@ -25,6 +25,7 @@
 #define __AMDGPU_DISCOVERY__
 
 #include <linux/debugfs.h>
+#include "discovery.h"
 
 #define DISCOVERY_TMR_SIZE      (10 << 10)
 #define DISCOVERY_TMR_OFFSET    (64 << 10)
@@ -39,6 +40,7 @@ struct amdgpu_discovery_info {
 	uint32_t size;
 	uint8_t *bin;
 	bool reserve_tmr;
+	struct mem_reserved_info_table_v1_0 *mem_reserved_table;
 };
 
 void amdgpu_discovery_sysfs_fini(struct amdgpu_device *adev);
@@ -59,4 +61,6 @@ int amdgpu_discovery_sysfs_early_init(struct amdgpu_device *adev,
 				       struct pci_dev *pdev);
 void amdgpu_discovery_sysfs_early_fini(struct pci_dev *pdev);
 
+int amdgpu_discovery_get_mem_reserved_info_table(struct amdgpu_device *adev);
+
 #endif /* __AMDGPU_DISCOVERY__ */
-- 
2.55.0