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/macintosh/macio-adb.c | 288 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 288 insertions(+) create mode 100644 drivers/macintosh/macio-adb.c (limited to 'drivers/macintosh/macio-adb.c') diff --git a/drivers/macintosh/macio-adb.c b/drivers/macintosh/macio-adb.c new file mode 100644 index 000000000..19c63959e --- /dev/null +++ b/drivers/macintosh/macio-adb.c @@ -0,0 +1,288 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Driver for the ADB controller in the Mac I/O (Hydra) chip. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +struct preg { + unsigned char r; + char pad[15]; +}; + +struct adb_regs { + struct preg intr; + struct preg data[9]; + struct preg intr_enb; + struct preg dcount; + struct preg error; + struct preg ctrl; + struct preg autopoll; + struct preg active_hi; + struct preg active_lo; + struct preg test; +}; + +/* Bits in intr and intr_enb registers */ +#define DFB 1 /* data from bus */ +#define TAG 2 /* transfer access grant */ + +/* Bits in dcount register */ +#define HMB 0x0f /* how many bytes */ +#define APD 0x10 /* auto-poll data */ + +/* Bits in error register */ +#define NRE 1 /* no response error */ +#define DLE 2 /* data lost error */ + +/* Bits in ctrl register */ +#define TAR 1 /* transfer access request */ +#define DTB 2 /* data to bus */ +#define CRE 4 /* command response expected */ +#define ADB_RST 8 /* ADB reset */ + +/* Bits in autopoll register */ +#define APE 1 /* autopoll enable */ + +static volatile struct adb_regs __iomem *adb; +static struct adb_request *current_req, *last_req; +static DEFINE_SPINLOCK(macio_lock); + +static int macio_probe(void); +static int macio_init(void); +static irqreturn_t macio_adb_interrupt(int irq, void *arg); +static int macio_send_request(struct adb_request *req, int sync); +static int macio_adb_autopoll(int devs); +static void macio_adb_poll(void); +static int macio_adb_reset_bus(void); + +struct adb_driver macio_adb_driver = { + .name = "MACIO", + .probe = macio_probe, + .init = macio_init, + .send_request = macio_send_request, + .autopoll = macio_adb_autopoll, + .poll = macio_adb_poll, + .reset_bus = macio_adb_reset_bus, +}; + +int macio_probe(void) +{ + struct device_node *np __free(device_node) = + of_find_compatible_node(NULL, "adb", "chrp,adb0"); + + if (np) + return 0; + + return -ENODEV; +} + +int macio_init(void) +{ + struct device_node *adbs __free(device_node) = + of_find_compatible_node(NULL, "adb", "chrp,adb0"); + struct resource r; + unsigned int irq; + + if (!adbs) + return -ENXIO; + + if (of_address_to_resource(adbs, 0, &r)) + return -ENXIO; + + adb = ioremap(r.start, sizeof(struct adb_regs)); + if (!adb) + return -ENOMEM; + + + out_8(&adb->ctrl.r, 0); + out_8(&adb->intr.r, 0); + out_8(&adb->error.r, 0); + out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */ + out_8(&adb->active_lo.r, 0xff); + out_8(&adb->autopoll.r, APE); + + irq = irq_of_parse_and_map(adbs, 0); + if (request_irq(irq, macio_adb_interrupt, 0, "ADB", (void *)0)) { + iounmap(adb); + printk(KERN_ERR "ADB: can't get irq %d\n", irq); + return -EAGAIN; + } + out_8(&adb->intr_enb.r, DFB | TAG); + + printk("adb: mac-io driver 1.0 for unified ADB\n"); + + return 0; +} + +static int macio_adb_autopoll(int devs) +{ + unsigned long flags; + + spin_lock_irqsave(&macio_lock, flags); + out_8(&adb->active_hi.r, devs >> 8); + out_8(&adb->active_lo.r, devs); + out_8(&adb->autopoll.r, devs? APE: 0); + spin_unlock_irqrestore(&macio_lock, flags); + return 0; +} + +static int macio_adb_reset_bus(void) +{ + unsigned long flags; + int timeout = 1000000; + + /* Hrm... we may want to not lock interrupts for so + * long ... oh well, who uses that chip anyway ? :) + * That function will be seldom used during boot + * on rare machines, so... + */ + spin_lock_irqsave(&macio_lock, flags); + out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST); + while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) { + if (--timeout == 0) { + out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST); + spin_unlock_irqrestore(&macio_lock, flags); + return -1; + } + } + spin_unlock_irqrestore(&macio_lock, flags); + return 0; +} + +/* Send an ADB command */ +static int macio_send_request(struct adb_request *req, int sync) +{ + unsigned long flags; + int i; + + if (req->data[0] != ADB_PACKET) + return -EINVAL; + + for (i = 0; i < req->nbytes - 1; ++i) + req->data[i] = req->data[i+1]; + --req->nbytes; + + req->next = NULL; + req->sent = 0; + req->complete = 0; + req->reply_len = 0; + + spin_lock_irqsave(&macio_lock, flags); + if (current_req) { + last_req->next = req; + last_req = req; + } else { + current_req = last_req = req; + out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR); + } + spin_unlock_irqrestore(&macio_lock, flags); + + if (sync) { + while (!req->complete) + macio_adb_poll(); + } + + return 0; +} + +static irqreturn_t macio_adb_interrupt(int irq, void *arg) +{ + int i, n, err; + struct adb_request *req = NULL; + unsigned char ibuf[16]; + int ibuf_len = 0; + int complete = 0; + int autopoll = 0; + int handled = 0; + + spin_lock(&macio_lock); + if (in_8(&adb->intr.r) & TAG) { + handled = 1; + req = current_req; + if (req) { + /* put the current request in */ + for (i = 0; i < req->nbytes; ++i) + out_8(&adb->data[i].r, req->data[i]); + out_8(&adb->dcount.r, req->nbytes & HMB); + req->sent = 1; + if (req->reply_expected) { + out_8(&adb->ctrl.r, DTB + CRE); + } else { + out_8(&adb->ctrl.r, DTB); + current_req = req->next; + complete = 1; + if (current_req) + out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR); + } + } + out_8(&adb->intr.r, 0); + } + + if (in_8(&adb->intr.r) & DFB) { + handled = 1; + err = in_8(&adb->error.r); + if (current_req && current_req->sent) { + /* this is the response to a command */ + req = current_req; + if (err == 0) { + req->reply_len = in_8(&adb->dcount.r) & HMB; + for (i = 0; i < req->reply_len; ++i) + req->reply[i] = in_8(&adb->data[i].r); + } + current_req = req->next; + complete = 1; + if (current_req) + out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR); + } else if (err == 0) { + /* autopoll data */ + n = in_8(&adb->dcount.r) & HMB; + for (i = 0; i < n; ++i) + ibuf[i] = in_8(&adb->data[i].r); + ibuf_len = n; + autopoll = (in_8(&adb->dcount.r) & APD) != 0; + } + out_8(&adb->error.r, 0); + out_8(&adb->intr.r, 0); + } + spin_unlock(&macio_lock); + if (complete && req) { + void (*done)(struct adb_request *) = req->done; + mb(); + req->complete = 1; + /* Here, we assume that if the request has a done member, the + * struct request will survive to setting req->complete to 1 + */ + if (done) + (*done)(req); + } + if (ibuf_len) + adb_input(ibuf, ibuf_len, autopoll); + + return IRQ_RETVAL(handled); +} + +static void macio_adb_poll(void) +{ + unsigned long flags; + + local_irq_save(flags); + if (in_8(&adb->intr.r) != 0) + macio_adb_interrupt(0, NULL); + local_irq_restore(flags); +} -- cgit v1.3.1