From ef1dacf4b3e23dae57d741bb592a3393428c5a7d Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Thu, 3 Feb 2022 19:01:59 +0000 Subject: [PATCH] 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 Cc: Suzuki K Poulose Cc: Mike Leach Cc: Leo Yan Cc: Anshuman Khandual Cc: coresight@lists.linaro.org Signed-off-by: Sudeep Holla Reviewed-by: Anshuman Khandual Link: https://lore.kernel.org/r/20220203190159.3145272-1-sudeep.holla@arm.com Signed-off-by: Suzuki K Poulose --- drivers/hwtracing/coresight/coresight-trbe.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index 75b608bc400b..2b386bb848f8 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -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;