kernel/linux.git/drivers/amba/bus.c, branch v6.12.80

ARM: 9416/1: amba: make amba_bustype constant

2024-09-04T14:01:17+00:00

Since commit d492cc2573a0 ("driver core: device.h: make struct bus_type a const *"), the driver core can properly handle constant struct bus_type, move the amba_bustype variable to be a constant structure as well, placing it into read-only memory which can not be modified at runtime. Cc: Greg Kroah-Hartman Suggested-by: Greg Kroah-Hartman Signed-off-by: Kunwu Chan Signed-off-by: Russell King (Oracle)

driver core: have match() callback in struct bus_type take a const *

2024-07-03T13:16:54+00:00

In the match() callback, the struct device_driver * should not be changed, so change the function callback to be a const *. This is one step of many towards making the driver core safe to have struct device_driver in read-only memory. Because the match() callback is in all busses, all busses are modified to handle this properly. This does entail switching some container_of() calls to container_of_const() to properly handle the constant *. For some busses, like PCI and USB and HV, the const * is cast away in the match callback as those busses do want to modify those structures at this point in time (they have a local lock in the driver structure.) That will have to be changed in the future if they wish to have their struct device * in read-only-memory. Cc: Rafael J. Wysocki Reviewed-by: Alex Elder Acked-by: Sumit Garg Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh Signed-off-by: Greg Kroah-Hartman

ARM: 9361/1: amba: store owner from modules with amba_driver_register()

2024-04-18T11:09:14+00:00

Modules registering driver with amba_driver_register() often forget to set .owner field. The field is used by some of other kernel parts for reference counting (try_module_get()), so it is expected that drivers will set it. Solve the problem by moving this task away from the drivers to the core amba bus code, just like we did for platform_driver in commit 9447057eaff8 ("platform_device: use a macro instead of platform_driver_register"). Link: https://lore.kernel.org/r/20240326-module-owner-amba-v1-1-4517b091385b@linaro.org Reviewed-by: Andi Shyti Acked-by: Suzuki K Poulose Signed-off-by: Krzysztof Kozlowski Signed-off-by: Russell King (Oracle)

amba: bus: balance firmware node reference counting

2023-10-17T18:37:35+00:00

Currently the ACPI code doesn't bump the reference count of the firmware node, while OF counter part does. Not that it's a problem right now, since ACPI doesn't really use the reference counting for firmware nodes, it still makes sense to make code robust against any changes done there. For this, - switch ACPI case to use device_set_node() to be unified with OF - move reference counting to amba_device_add() - switch to use firmware nodes instead of OF ones In the result we will have reference counting done in the same module for all callers independently on the nature of firmware node behind. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20231006145732.3419115-1-andriy.shevchenko@linux.intel.com Signed-off-by: Rob Herring

amba: bus: fix refcount leak

2023-08-22T13:50:57+00:00

commit 5de1540b7bc4 ("drivers/amba: create devices from device tree") increases the refcount of of_node, but not releases it in amba_device_release, so there is refcount leak. By using of_node_put to avoid refcount leak. Fixes: 5de1540b7bc4 ("drivers/amba: create devices from device tree") Signed-off-by: Peng Fan Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20230821023928.3324283-1-peng.fan@oss.nxp.com Signed-off-by: Greg Kroah-Hartman

driver core: make struct bus_type.uevent() take a const *

2023-01-27T12:45:52+00:00

The uevent() callback in struct bus_type should not be modifying the device that is passed into it, so mark it as a const * and propagate the function signature changes out into all relevant subsystems that use this callback. Acked-by: Rafael J. Wysocki Acked-by: Hans de Goede Link: https://lore.kernel.org/r/20230111113018.459199-16-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2022-12-13T23:22:14+00:00

Pull ARM updates from Russell King: - update unwinder to cope with module PLTs - enable UBSAN on ARM - improve kernel fault message - update UEFI runtime page tables dump - avoid clang's __aeabi_uldivmod generated in NWFPE code - disable FIQs on CPU shutdown paths - update XOR register usage - a number of build updates (using .arch, thread pointer, removal of lazy evaluation in Makefile) - conversion of stacktrace code to stackwalk - findbit assembly updates - hwcap feature updates for ARMv8 CPUs - instruction dump updates for big-endian platforms - support for function error injection * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (31 commits) ARM: 9279/1: support function error injection ARM: 9277/1: Make the dumped instructions are consistent with the disassembled ones ARM: 9276/1: Refactor dump_instr() ARM: 9275/1: Drop '-mthumb' from AFLAGS_ISA ARM: 9274/1: Add hwcap for Speculative Store Bypassing Safe ARM: 9273/1: Add hwcap for Speculation Barrier(SB) ARM: 9272/1: vfp: Add hwcap for FEAT_AA32I8MM ARM: 9271/1: vfp: Add hwcap for FEAT_AA32BF16 ARM: 9270/1: vfp: Add hwcap for FEAT_FHM ARM: 9269/1: vfp: Add hwcap for FEAT_DotProd ARM: 9268/1: vfp: Add hwcap FPHP and ASIMDHP for FEAT_FP16 ARM: 9267/1: Define Armv8 registers in AArch32 state ARM: findbit: add unwinder information ARM: findbit: operate by words ARM: findbit: convert to macros ARM: findbit: provide more efficient ARMv7 implementation ARM: findbit: document ARMv5 bit offset calculation ARM: 9259/1: stacktrace: Convert stacktrace to generic ARCH_STACKWALK ARM: 9258/1: stacktrace: Make stack walk callback consistent with generic code ARM: 9265/1: pass -march= only to compiler ...

ARM: 9261/1: amba: Drop redundant assignments of the system PM callbacks

2022-11-07T14:19:04+00:00

If the system PM callbacks haven't been assigned, the PM core falls back to invoke the corresponding the pm_generic_* helpers for the device. Let's rely on this behaviour and drop the redundant assignments. Signed-off-by: Ulf Hansson Signed-off-by: Russell King (Oracle)

ARM: 9229/1: amba: Fix use-after-free in amba_read_periphid()

2022-08-30T10:12:52+00:00

After commit f2d3b9a46e0e ("ARM: 9220/1: amba: Remove deferred device addition"), it became possible for amba_read_periphid() to be invoked concurrently from two threads for a particular AMBA device. Consider the case where a thread (T0) is registering an AMBA driver, and searching for all of the devices it can match with on the AMBA bus. Suppose that another thread (T1) is executing the deferred probe work, and is searching through all of the AMBA drivers on the bus for a driver that matches a particular AMBA device. Assume that both threads begin operating on the same AMBA device and the device's peripheral ID is still unknown. In this scenario, the amba_match() function will be invoked for the same AMBA device by both threads, which means amba_read_periphid() can also be invoked by both threads, and both threads will be able to manipulate the AMBA device's pclk pointer without any synchronization. It's possible that one thread will initialize the pclk pointer, then the other thread will re-initialize it, overwriting the previous value, and both will race to free the same pclk, resulting in a use-after-free for whichever thread frees the pclk last. Add a lock per AMBA device to synchronize the handling with detecting the peripheral ID to avoid the use-after-free scenario. The following KFENCE bug report helped detect this problem: ================================================================== BUG: KFENCE: use-after-free read in clk_disable+0x14/0x34 Use-after-free read at 0x(ptrval) (in kfence-#19): clk_disable+0x14/0x34 amba_read_periphid+0xdc/0x134 amba_match+0x3c/0x84 __driver_attach+0x20/0x158 bus_for_each_dev+0x74/0xc0 bus_add_driver+0x154/0x1e8 driver_register+0x88/0x11c do_one_initcall+0x8c/0x2fc kernel_init_freeable+0x190/0x220 kernel_init+0x10/0x108 ret_from_fork+0x14/0x3c 0x0 kfence-#19: 0x(ptrval)-0x(ptrval), size=36, cache=kmalloc-64 allocated by task 8 on cpu 0 at 11.629931s: clk_hw_create_clk+0x38/0x134 amba_get_enable_pclk+0x10/0x68 amba_read_periphid+0x28/0x134 amba_match+0x3c/0x84 __device_attach_driver+0x2c/0xc4 bus_for_each_drv+0x80/0xd0 __device_attach+0xb0/0x1f0 bus_probe_device+0x88/0x90 deferred_probe_work_func+0x8c/0xc0 process_one_work+0x23c/0x690 worker_thread+0x34/0x488 kthread+0xd4/0xfc ret_from_fork+0x14/0x3c 0x0 freed by task 8 on cpu 0 at 11.630095s: amba_read_periphid+0xec/0x134 amba_match+0x3c/0x84 __device_attach_driver+0x2c/0xc4 bus_for_each_drv+0x80/0xd0 __device_attach+0xb0/0x1f0 bus_probe_device+0x88/0x90 deferred_probe_work_func+0x8c/0xc0 process_one_work+0x23c/0x690 worker_thread+0x34/0x488 kthread+0xd4/0xfc ret_from_fork+0x14/0x3c 0x0 Cc: Saravana Kannan Cc: patches@armlinux.org.uk Fixes: f2d3b9a46e0e ("ARM: 9220/1: amba: Remove deferred device addition") Reported-by: Guenter Roeck Tested-by: Guenter Roeck Signed-off-by: Isaac J. Manjarres Signed-off-by: Russell King (Oracle)

ARM: 9220/1: amba: Remove deferred device addition

2022-07-28T14:09:23+00:00

The uevents generated for an amba device need PID and CID information that's available only when the amba device is powered on, clocked and out of reset. So, if those resources aren't available, the information can't be read to generate the uevents. To workaround this requirement, if the resources weren't available, the device addition was deferred and retried periodically. However, this deferred addition retry isn't based on resources becoming available. Instead, it's retried every 5 seconds and causes arbitrary probe delays for amba devices and their consumers. Also, maintaining a separate deferred-probe like mechanism is maintenance headache. With this commit, instead of deferring the device addition, we simply defer the generation of uevents for the device and probing of the device (because drivers needs PID and CID to match) until the PID and CID information can be read. This allows us to delete all the amba specific deferring code and also avoid the arbitrary probing delays. Cc: Rob Herring Cc: Ulf Hansson Cc: Saravana Kannan Cc: Linus Walleij Cc: Sudeep Holla Cc: Nicolas Saenz Julienne Cc: Geert Uytterhoeven Cc: Marek Szyprowski Cc: Kefeng Wang Cc: Greg Kroah-Hartman Cc: patches@armlinux.org.uk Signed-off-by: Saravana Kannan Tested-by: Marek Szyprowski Tested-by: Kefeng Wang Tested-by: Sudeep Holla Signed-off-by: Russell King (Oracle)