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 --- drivers/tc/tc.c | 208 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 208 insertions(+) create mode 100644 drivers/tc/tc.c (limited to 'drivers/tc/tc.c') diff --git a/drivers/tc/tc.c b/drivers/tc/tc.c new file mode 100644 index 000000000..ebc835cf1 --- /dev/null +++ b/drivers/tc/tc.c @@ -0,0 +1,208 @@ +/* + * TURBOchannel bus services. + * + * Copyright (c) Harald Koerfgen, 1998 + * Copyright (c) 2001, 2003, 2005, 2006, 2018 Maciej W. Rozycki + * Copyright (c) 2005 James Simmons + * + * This file is subject to the terms and conditions of the GNU + * General Public License. See the file "COPYING" in the main + * directory of this archive for more details. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +static struct tc_bus tc_bus = { + .name = "TURBOchannel", +}; + +/* + * Probing for TURBOchannel modules. + */ +static void __init tc_bus_add_devices(struct tc_bus *tbus) +{ + resource_size_t slotsize = tbus->info.slot_size << 20; + resource_size_t extslotsize = tbus->ext_slot_size; + resource_size_t slotaddr; + resource_size_t extslotaddr; + resource_size_t devsize; + void __iomem *module; + struct tc_dev *tdev; + int i, slot, err; + u8 pattern[4]; + long offset; + + for (slot = 0; slot < tbus->num_tcslots; slot++) { + slotaddr = tbus->slot_base + slot * slotsize; + extslotaddr = tbus->ext_slot_base + slot * extslotsize; + module = ioremap(slotaddr, slotsize); + BUG_ON(!module); + + offset = TC_OLDCARD; + + err = 0; + err |= tc_preadb(pattern + 0, module + offset + TC_PATTERN0); + err |= tc_preadb(pattern + 1, module + offset + TC_PATTERN1); + err |= tc_preadb(pattern + 2, module + offset + TC_PATTERN2); + err |= tc_preadb(pattern + 3, module + offset + TC_PATTERN3); + if (err) + goto out_err; + + if (pattern[0] != 0x55 || pattern[1] != 0x00 || + pattern[2] != 0xaa || pattern[3] != 0xff) { + offset = TC_NEWCARD; + + err = 0; + err |= tc_preadb(pattern + 0, + module + offset + TC_PATTERN0); + err |= tc_preadb(pattern + 1, + module + offset + TC_PATTERN1); + err |= tc_preadb(pattern + 2, + module + offset + TC_PATTERN2); + err |= tc_preadb(pattern + 3, + module + offset + TC_PATTERN3); + if (err) + goto out_err; + } + + if (pattern[0] != 0x55 || pattern[1] != 0x00 || + pattern[2] != 0xaa || pattern[3] != 0xff) + goto out_err; + + /* Found a board, allocate it an entry in the list */ + tdev = kzalloc_obj(*tdev); + if (!tdev) { + pr_err("tc%x: unable to allocate tc_dev\n", slot); + goto out_err; + } + dev_set_name(&tdev->dev, "tc%x", slot); + tdev->bus = tbus; + tdev->dev.parent = &tbus->dev; + tdev->dev.bus = &tc_bus_type; + tdev->slot = slot; + + /* TURBOchannel has 34-bit DMA addressing (16GiB space). */ + tdev->dma_mask = DMA_BIT_MASK(34); + tdev->dev.dma_mask = &tdev->dma_mask; + tdev->dev.coherent_dma_mask = DMA_BIT_MASK(34); + + for (i = 0; i < 8; i++) { + tdev->firmware[i] = + readb(module + offset + TC_FIRM_VER + 4 * i); + tdev->vendor[i] = + readb(module + offset + TC_VENDOR + 4 * i); + tdev->name[i] = + readb(module + offset + TC_MODULE + 4 * i); + } + tdev->firmware[8] = 0; + tdev->vendor[8] = 0; + tdev->name[8] = 0; + + pr_info("%s: %s %s %s\n", dev_name(&tdev->dev), tdev->vendor, + tdev->name, tdev->firmware); + + devsize = readb(module + offset + TC_SLOT_SIZE); + devsize <<= 22; + if (devsize <= slotsize) { + tdev->resource.start = slotaddr; + tdev->resource.end = slotaddr + devsize - 1; + } else if (devsize <= extslotsize) { + tdev->resource.start = extslotaddr; + tdev->resource.end = extslotaddr + devsize - 1; + } else { + pr_err("%s: Cannot provide slot space " + "(%ldMiB required, up to %ldMiB supported)\n", + dev_name(&tdev->dev), (long)(devsize >> 20), + (long)(max(slotsize, extslotsize) >> 20)); + kfree(tdev); + goto out_err; + } + tdev->resource.name = tdev->name; + tdev->resource.flags = IORESOURCE_MEM; + + tc_device_get_irq(tdev); + + if (device_register(&tdev->dev)) { + put_device(&tdev->dev); + goto out_err; + } + list_add_tail(&tdev->node, &tbus->devices); + +out_err: + iounmap(module); + } +} + +/* + * The main entry. + */ +static int __init tc_init(void) +{ + /* Initialize the TURBOchannel bus */ + if (tc_bus_get_info(&tc_bus)) + goto out_err; + + INIT_LIST_HEAD(&tc_bus.devices); + dev_set_name(&tc_bus.dev, "tc"); + if (device_register(&tc_bus.dev)) + goto out_err_device; + + if (tc_bus.info.slot_size) { + unsigned int tc_clock = tc_get_speed(&tc_bus) / 100000; + + pr_info("tc: TURBOchannel rev. %d at %u.%u MHz " + "(with%s parity)\n", tc_bus.info.revision, + tc_clock / 10, tc_clock % 10, + tc_bus.info.parity ? "" : "out"); + + tc_bus.resource[0].start = tc_bus.slot_base; + tc_bus.resource[0].end = tc_bus.slot_base + + (tc_bus.info.slot_size << 20) * + tc_bus.num_tcslots - 1; + tc_bus.resource[0].name = tc_bus.name; + tc_bus.resource[0].flags = IORESOURCE_MEM; + if (request_resource(&iomem_resource, + &tc_bus.resource[0]) < 0) { + pr_err("tc: Cannot reserve resource\n"); + goto out_err_device; + } + if (tc_bus.ext_slot_size) { + tc_bus.resource[1].start = tc_bus.ext_slot_base; + tc_bus.resource[1].end = tc_bus.ext_slot_base + + tc_bus.ext_slot_size * + tc_bus.num_tcslots - 1; + tc_bus.resource[1].name = tc_bus.name; + tc_bus.resource[1].flags = IORESOURCE_MEM; + if (request_resource(&iomem_resource, + &tc_bus.resource[1]) < 0) { + pr_err("tc: Cannot reserve resource\n"); + goto out_err_resource; + } + } + + tc_bus_add_devices(&tc_bus); + } + + return 0; + +out_err_resource: + release_resource(&tc_bus.resource[0]); +out_err_device: + put_device(&tc_bus.dev); +out_err: + return 0; +} + +subsys_initcall(tc_init); -- cgit v1.3.1