drm/msm/dpu: don't allow overriding data from catalog

The data from catalog is marked as const, so it is a part of the RO
segment. Allowing userspace to write to it through debugfs can cause
protection faults. Set debugfs file mode to read-only for debug entries
corresponding to perf_cfg coming from catalog.

Fixes: abda0d9 ("drm/msm/dpu: Mark various data tables as const")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/582844/
Link: https://lore.kernel.org/r/20240314-dpu-perf-rework-v3-1-79fa4e065574@linaro.org
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>

drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c

@@ -459,15 +459,15 @@ int dpu_core_perf_debugfs_init(struct dpu_kms *dpu_kms, struct dentry *parent)
 			&perf->core_clk_rate);
 	debugfs_create_u32("enable_bw_release", 0600, entry,
 			(u32 *)&perf->enable_bw_release);
-	debugfs_create_u32("threshold_low", 0600, entry,
+	debugfs_create_u32("threshold_low", 0400, entry,
 			(u32 *)&perf->perf_cfg->max_bw_low);
-	debugfs_create_u32("threshold_high", 0600, entry,
+	debugfs_create_u32("threshold_high", 0400, entry,
 			(u32 *)&perf->perf_cfg->max_bw_high);
-	debugfs_create_u32("min_core_ib", 0600, entry,
+	debugfs_create_u32("min_core_ib", 0400, entry,
 			(u32 *)&perf->perf_cfg->min_core_ib);
-	debugfs_create_u32("min_llcc_ib", 0600, entry,
+	debugfs_create_u32("min_llcc_ib", 0400, entry,
 			(u32 *)&perf->perf_cfg->min_llcc_ib);
-	debugfs_create_u32("min_dram_ib", 0600, entry,
+	debugfs_create_u32("min_dram_ib", 0400, entry,
 			(u32 *)&perf->perf_cfg->min_dram_ib);
 	debugfs_create_file("perf_mode", 0600, entry,
 			(u32 *)perf, &dpu_core_perf_mode_fops);