[PATCH 5.4 94/98] ASoC: Intel: Skylake: Shield against no-NHLT configurations

[Greg Kroah-Hartman]

From: Cezary Rojewski <cezary.rojewski at intel.com>

commit 9e6c382f5a6161eb55115fb56614b9827f2e7da3 upstream.

Some configurations expose no NHLT table at all within their
/sys/firmware/acpi/tables. To prevent NULL-dereference errors from
occurring, adjust probe flow and append additional safety checks in
functions involved in NHLT lifecycle.

Signed-off-by: Cezary Rojewski <cezary.rojewski at intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Link: https://lore.kernel.org/r/20200305145314.32579-5-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie at kernel.org>
Cc: <stable at vger.kernel.org> # 5.4.x
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 sound/soc/intel/skylake/skl-nhlt.c |    3 ++-
 sound/soc/intel/skylake/skl.c      |    9 +++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

--- a/sound/soc/intel/skylake/skl-nhlt.c
+++ b/sound/soc/intel/skylake/skl-nhlt.c
@@ -182,7 +182,8 @@ void skl_nhlt_remove_sysfs(struct skl_de
 {
 	struct device *dev = &skl->pci->dev;
 
-	sysfs_remove_file(&dev->kobj, &dev_attr_platform_id.attr);
+	if (skl->nhlt)
+		sysfs_remove_file(&dev->kobj, &dev_attr_platform_id.attr);
 }
 
 /*
--- a/sound/soc/intel/skylake/skl.c
+++ b/sound/soc/intel/skylake/skl.c
@@ -632,6 +632,9 @@ static int skl_clock_device_register(str
 	struct platform_device_info pdevinfo = {NULL};
 	struct skl_clk_pdata *clk_pdata;
 
+	if (!skl->nhlt)
+		return 0;
+
 	clk_pdata = devm_kzalloc(&skl->pci->dev, sizeof(*clk_pdata),
 							GFP_KERNEL);
 	if (!clk_pdata)
@@ -1090,7 +1093,8 @@ out_dsp_free:
 out_clk_free:
 	skl_clock_device_unregister(skl);
 out_nhlt_free:
-	intel_nhlt_free(skl->nhlt);
+	if (skl->nhlt)
+		intel_nhlt_free(skl->nhlt);
 out_free:
 	skl_free(bus);
 
@@ -1139,7 +1143,8 @@ static void skl_remove(struct pci_dev *p
 	skl_dmic_device_unregister(skl);
 	skl_clock_device_unregister(skl);
 	skl_nhlt_remove_sysfs(skl);
-	intel_nhlt_free(skl->nhlt);
+	if (skl->nhlt)
+		intel_nhlt_free(skl->nhlt);
 	skl_free(bus);
 	dev_set_drvdata(&pci->dev, NULL);
 }