From eaff392c1e34fb77cc61505a31b0191e5e46e271 Mon Sep 17 00:00:00 2001 From: Volodymyr Babchuk Date: Thu, 18 Jul 2024 11:33:23 +0530 Subject: [PATCH] soc: qcom: cmd-db: Map shared memory as WC, not WB commit f9bb896eab221618927ae6a2f1d566567999839d upstream. Linux does not write into cmd-db region. This region of memory is write protected by XPU. XPU may sometime falsely detect clean cache eviction as "write" into the write protected region leading to secure interrupt which causes an endless loop somewhere in Trust Zone. The only reason it is working right now is because Qualcomm Hypervisor maps the same region as Non-Cacheable memory in Stage 2 translation tables. The issue manifests if we want to use another hypervisor (like Xen or KVM), which does not know anything about those specific mappings. Changing the mapping of cmd-db memory from MEMREMAP_WB to MEMREMAP_WT/WC removes dependency on correct mappings in Stage 2 tables. This patch fixes the issue by updating the mapping to MEMREMAP_WC. I tested this on SA8155P with Xen. Fixes: 312416d9171a ("drivers: qcom: add command DB driver") Cc: stable@vger.kernel.org # 5.4+ Signed-off-by: Volodymyr Babchuk Tested-by: Nikita Travkin # sc7180 WoA in EL2 Signed-off-by: Maulik Shah Tested-by: Pavankumar Kondeti Reviewed-by: Caleb Connolly Link: https://lore.kernel.org/r/20240718-cmd_db_uncached-v2-1-f6cf53164c90@quicinc.com Signed-off-by: Bjorn Andersson Signed-off-by: Greg Kroah-Hartman --- drivers/soc/qcom/cmd-db.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/soc/qcom/cmd-db.c b/drivers/soc/qcom/cmd-db.c index b4803f2fde5e..6cb5e3956fc5 100644 --- a/drivers/soc/qcom/cmd-db.c +++ b/drivers/soc/qcom/cmd-db.c @@ -350,7 +350,7 @@ static int cmd_db_dev_probe(struct platform_device *pdev) return -EINVAL; } - cmd_db_header = memremap(rmem->base, rmem->size, MEMREMAP_WB); + cmd_db_header = memremap(rmem->base, rmem->size, MEMREMAP_WC); if (!cmd_db_header) { ret = -ENOMEM; cmd_db_header = NULL;