kernel.git/drivers/soc/qcom/cmd-db.c, branch linux-5.4.y

soc: qcom: cmd-db: Map shared memory as WC, not WB

2024-09-04T11:15:04Z

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

soc: qcom: cmd-db: Fix an error code in cmd_db_dev_probe()

2019-03-28T04:32:26Z

The memremap() function doesn't return error pointers, it returns NULL. This code is returning "ret = PTR_ERR(NULL);" which is success, but it should return -ENOMEM. Fixes: 312416d9171a ("drivers: qcom: add command DB driver") Signed-off-by: Dan Carpenter Signed-off-by: Bjorn Andersson Signed-off-by: Andy Gross

soc: qcom: cmd-db: Stop memcpy()ing in cmd_db_read_aux_data()

2018-11-14T18:06:24Z

Let's change the function signature to return the pointer to memory or an error pointer on failure, and take an argument that lets us return the size of the aux data read. This way we can remove the cmd_db_read_aux_data_len() API entirely and also get rid of the memcpy operation from cmd_db to the caller. Updating the only user of this code shows that making this change allows us to remove a function and put the lookup where the user is. Cc: Mahesh Sivasubramanian Cc: Lina Iyer Cc: Bjorn Andersson Cc: Evan Green Cc: Jordan Crouse Cc: Rob Clark Signed-off-by: Stephen Boyd Signed-off-by: Andy Gross

soc: qcom: cmd-db: Remove memcpy()ing from cmd_db_get_header()

2018-11-14T18:05:50Z

The cmd_db_get_header() function is a static local function that doesn't need to copy anything from one place to another. Instead, it can just point into the region by returning pointers to what we're looking for. If we do that, we should mark what we're returning as const so that code can't modify cmd-db without an obvious cast. Cc: Mahesh Sivasubramanian Cc: Lina Iyer Cc: Bjorn Andersson Cc: Evan Green Signed-off-by: Stephen Boyd Signed-off-by: Andy Gross

soc: qcom: cmd-db: Make endian-agnostic

2018-05-25T20:53:52Z

This driver deals with memory that is stored in little-endian format. Update the structures with the proper little-endian types and then do the proper conversions when reading the fields. Note that we compare the ids with a memcmp() because we already pad out the string 'id' field to exactly 8 bytes with the strncpy() onto the stack. Cc: Mahesh Sivasubramanian Cc: Lina Iyer Cc: Bjorn Andersson Cc: Evan Green Signed-off-by: Stephen Boyd Signed-off-by: Andy Gross

drivers: qcom: add command DB driver

2018-05-25T20:53:52Z

Command DB is a simple database in the shared memory of QCOM SoCs, that provides information regarding shared resources. Some shared resources in the SoC have properties that are probed dynamically at boot by the remote processor. The information pertaining to the SoC and the platform are made available in the shared memory. Drivers can query this information using predefined strings. Signed-off-by: Mahesh Sivasubramanian Signed-off-by: Lina Iyer Reviewed-by: Bjorn Andersson Reviewed-by: Stephen Boyd Signed-off-by: Andy Gross