Commit ef1dacf4 authored Feb 03, 2022 by Sudeep Holla Committed by Suzuki K Poulose Mar 11, 2022

coresight: trbe: Move check for kernel page table isolation from EL0 to probe



Currently with the check present in the module initialisation, it shouts
on all the systems irrespective of presence of coresight trace buffer
extensions.

Similar to Arm SPE perf driver, move the check for kernel page table
isolation from  EL0 to the device probe stage instead of the module
initialisation so that it complains only on the systems that support TRBE.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: coresight@lists.linaro.org
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20220203190159.3145272-1-sudeep.holla@arm.com


Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

parent d05bbad0

drivers/hwtracing/coresight/coresight-trbe.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -1481,6 +1481,12 @@ static int arm_trbe_device_probe(struct platform_device *pdev)
		struct device *dev = &pdev->dev;
		int ret;

		/* Trace capture is not possible with kernel page table isolation */
		if (arm64_kernel_unmapped_at_el0()) {
		pr_err("TRBE wouldn't work if kernel gets unmapped at EL0\n");
		return -EOPNOTSUPP;
		}

		drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
		if (!drvdata)
		return -ENOMEM;
		@@ -1542,11 +1548,6 @@ static int __init arm_trbe_init(void)
		{
		int ret;

		if (arm64_kernel_unmapped_at_el0()) {
		pr_err("TRBE wouldn't work if kernel gets unmapped at EL0\n");
		return -EOPNOTSUPP;
		}

		ret = platform_driver_register(&arm_trbe_driver);
		if (!ret)
		return 0;