From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- Documentation/driver-api/zorro.rst | 104 +++++++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 Documentation/driver-api/zorro.rst (limited to 'Documentation/driver-api/zorro.rst') diff --git a/Documentation/driver-api/zorro.rst b/Documentation/driver-api/zorro.rst new file mode 100644 index 000000000..664072b01 --- /dev/null +++ b/Documentation/driver-api/zorro.rst @@ -0,0 +1,104 @@ +======================================== +Writing Device Drivers for Zorro Devices +======================================== + +:Author: Written by Geert Uytterhoeven +:Last revised: September 5, 2003 + + +Introduction +------------ + +The Zorro bus is the bus used in the Amiga family of computers. Thanks to +AutoConfig(tm), it's 100% Plug-and-Play. + +There are two types of Zorro buses, Zorro II and Zorro III: + + - The Zorro II address space is 24-bit and lies within the first 16 MB of the + Amiga's address map. + + - Zorro III is a 32-bit extension of Zorro II, which is backwards compatible + with Zorro II. The Zorro III address space lies outside the first 16 MB. + + +Probing for Zorro Devices +------------------------- + +Zorro devices are found by calling ``zorro_find_device()``, which returns a +pointer to the ``next`` Zorro device with the specified Zorro ID. A probe loop +for the board with Zorro ID ``ZORRO_PROD_xxx`` looks like:: + + struct zorro_dev *z = NULL; + + while ((z = zorro_find_device(ZORRO_PROD_xxx, z))) { + if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE, + "My explanation")) + ... + } + +``ZORRO_WILDCARD`` acts as a wildcard and finds any Zorro device. If your driver +supports different types of boards, you can use a construct like:: + + struct zorro_dev *z = NULL; + + while ((z = zorro_find_device(ZORRO_WILDCARD, z))) { + if (z->id != ZORRO_PROD_xxx1 && z->id != ZORRO_PROD_xxx2 && ...) + continue; + if (!zorro_request_region(z->resource.start+MY_START, MY_SIZE, + "My explanation")) + ... + } + + +Zorro Resources +--------------- + +Before you can access a Zorro device's registers, you have to make sure it's +not yet in use. This is done using the I/O memory space resource management +functions:: + + request_mem_region() + release_mem_region() + +Shortcuts to claim the whole device's address space are provided as well:: + + zorro_request_device + zorro_release_device + + +Accessing the Zorro Address Space +--------------------------------- + +The address regions in the Zorro device resources are Zorro bus address +regions. Due to the identity bus-physical address mapping on the Zorro bus, +they are CPU physical addresses as well. + +The treatment of these regions depends on the type of Zorro space: + + - Zorro II address space is always mapped and does not have to be mapped + explicitly using z_ioremap(). + + Conversion from bus/physical Zorro II addresses to kernel virtual addresses + and vice versa is done using:: + + virt_addr = ZTWO_VADDR(bus_addr); + bus_addr = ZTWO_PADDR(virt_addr); + + - Zorro III address space must be mapped explicitly using z_ioremap() first + before it can be accessed:: + + virt_addr = z_ioremap(bus_addr, size); + ... + z_iounmap(virt_addr); + + +References +---------- + +#. linux/include/linux/zorro.h +#. linux/include/uapi/linux/zorro.h +#. linux/include/uapi/linux/zorro_ids.h +#. linux/arch/m68k/include/asm/zorro.h +#. linux/drivers/zorro +#. /proc/bus/zorro + -- cgit v1.3.1