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/rtc/rtc-opal.c | 301 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 301 insertions(+) create mode 100644 drivers/rtc/rtc-opal.c (limited to 'drivers/rtc/rtc-opal.c') diff --git a/drivers/rtc/rtc-opal.c b/drivers/rtc/rtc-opal.c new file mode 100644 index 000000000..ad41aaf8a --- /dev/null +++ b/drivers/rtc/rtc-opal.c @@ -0,0 +1,301 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IBM OPAL RTC driver + * Copyright (C) 2014 IBM + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#define DRVNAME "rtc-opal" + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm) +{ + tm->tm_year = ((bcd2bin(y_m_d >> 24) * 100) + + bcd2bin((y_m_d >> 16) & 0xff)) - 1900; + tm->tm_mon = bcd2bin((y_m_d >> 8) & 0xff) - 1; + tm->tm_mday = bcd2bin(y_m_d & 0xff); + tm->tm_hour = bcd2bin((h_m_s_ms >> 56) & 0xff); + tm->tm_min = bcd2bin((h_m_s_ms >> 48) & 0xff); + tm->tm_sec = bcd2bin((h_m_s_ms >> 40) & 0xff); + + tm->tm_wday = -1; +} + +static void tm_to_opal(struct rtc_time *tm, u32 *y_m_d, u64 *h_m_s_ms) +{ + *y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) / 100)) << 24; + *y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) % 100)) << 16; + *y_m_d |= ((u32)bin2bcd((tm->tm_mon + 1))) << 8; + *y_m_d |= ((u32)bin2bcd(tm->tm_mday)); + + *h_m_s_ms |= ((u64)bin2bcd(tm->tm_hour)) << 56; + *h_m_s_ms |= ((u64)bin2bcd(tm->tm_min)) << 48; + *h_m_s_ms |= ((u64)bin2bcd(tm->tm_sec)) << 40; +} + +static int opal_get_rtc_time(struct device *dev, struct rtc_time *tm) +{ + s64 rc = OPAL_BUSY; + int retries = 10; + u32 y_m_d; + u64 h_m_s_ms; + __be32 __y_m_d; + __be64 __h_m_s_ms; + + while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { + rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms); + if (rc == OPAL_BUSY_EVENT) { + msleep(OPAL_BUSY_DELAY_MS); + opal_poll_events(NULL); + } else if (rc == OPAL_BUSY) { + msleep(OPAL_BUSY_DELAY_MS); + } else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) { + if (retries--) { + msleep(10); /* Wait 10ms before retry */ + rc = OPAL_BUSY; /* go around again */ + } + } + } + + if (rc != OPAL_SUCCESS) + return -EIO; + + y_m_d = be32_to_cpu(__y_m_d); + h_m_s_ms = be64_to_cpu(__h_m_s_ms); + opal_to_tm(y_m_d, h_m_s_ms, tm); + + return 0; +} + +static int opal_set_rtc_time(struct device *dev, struct rtc_time *tm) +{ + s64 rc = OPAL_BUSY; + int retries = 10; + u32 y_m_d = 0; + u64 h_m_s_ms = 0; + + tm_to_opal(tm, &y_m_d, &h_m_s_ms); + + while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { + rc = opal_rtc_write(y_m_d, h_m_s_ms); + if (rc == OPAL_BUSY_EVENT) { + msleep(OPAL_BUSY_DELAY_MS); + opal_poll_events(NULL); + } else if (rc == OPAL_BUSY) { + msleep(OPAL_BUSY_DELAY_MS); + } else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) { + if (retries--) { + msleep(10); /* Wait 10ms before retry */ + rc = OPAL_BUSY; /* go around again */ + } + } + } + + return rc == OPAL_SUCCESS ? 0 : -EIO; +} + +/* + * TPO Timed Power-On + * + * TPO get/set OPAL calls care about the hour and min and to make it consistent + * with the rtc utility time conversion functions, we use the 'u64' to store + * its value and perform bit shift by 32 before use.. + */ +static int opal_get_tpo_time(struct device *dev, struct rtc_wkalrm *alarm) +{ + __be32 __y_m_d, __h_m; + struct opal_msg msg; + int rc, token; + u64 h_m_s_ms; + u32 y_m_d; + + token = opal_async_get_token_interruptible(); + if (token < 0) { + if (token != -ERESTARTSYS) + pr_err("Failed to get the async token\n"); + + return token; + } + + rc = opal_tpo_read(token, &__y_m_d, &__h_m); + if (rc != OPAL_ASYNC_COMPLETION) { + rc = -EIO; + goto exit; + } + + rc = opal_async_wait_response(token, &msg); + if (rc) { + rc = -EIO; + goto exit; + } + + rc = opal_get_async_rc(msg); + if (rc != OPAL_SUCCESS) { + rc = -EIO; + goto exit; + } + + y_m_d = be32_to_cpu(__y_m_d); + h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32); + + /* check if no alarm is set */ + if (y_m_d == 0 && h_m_s_ms == 0) { + pr_debug("No alarm is set\n"); + rc = -ENOENT; + goto exit; + } else { + pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms); + } + + opal_to_tm(y_m_d, h_m_s_ms, &alarm->time); + +exit: + opal_async_release_token(token); + return rc; +} + +/* Set Timed Power-On */ +static int opal_set_tpo_time(struct device *dev, struct rtc_wkalrm *alarm) +{ + u64 h_m_s_ms = 0; + struct opal_msg msg; + u32 y_m_d = 0; + int token, rc; + + /* if alarm is enabled */ + if (alarm->enabled) { + tm_to_opal(&alarm->time, &y_m_d, &h_m_s_ms); + pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms); + + } else { + pr_debug("Alarm getting disabled\n"); + } + + token = opal_async_get_token_interruptible(); + if (token < 0) { + if (token != -ERESTARTSYS) + pr_err("Failed to get the async token\n"); + + return token; + } + + /* TPO, we care about hour and minute */ + rc = opal_tpo_write(token, y_m_d, + (u32)((h_m_s_ms >> 32) & 0xffff0000)); + if (rc != OPAL_ASYNC_COMPLETION) { + rc = -EIO; + goto exit; + } + + rc = opal_async_wait_response(token, &msg); + if (rc) { + rc = -EIO; + goto exit; + } + + rc = opal_get_async_rc(msg); + if (rc != OPAL_SUCCESS) + rc = -EIO; + +exit: + opal_async_release_token(token); + return rc; +} + +static int opal_tpo_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct rtc_wkalrm alarm = { .enabled = 0 }; + + /* + * TPO is automatically enabled when opal_set_tpo_time() is called with + * non-zero rtc-time. We only handle disable case which needs to be + * explicitly told to opal. + */ + return enabled ? 0 : opal_set_tpo_time(dev, &alarm); +} + +static const struct rtc_class_ops opal_rtc_ops = { + .read_time = opal_get_rtc_time, + .set_time = opal_set_rtc_time, + .read_alarm = opal_get_tpo_time, + .set_alarm = opal_set_tpo_time, + .alarm_irq_enable = opal_tpo_alarm_irq_enable, +}; + +static int opal_rtc_probe(struct platform_device *pdev) +{ + struct rtc_device *rtc; + + rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + if (pdev->dev.of_node && + (of_property_read_bool(pdev->dev.of_node, "wakeup-source") || + of_property_read_bool(pdev->dev.of_node, "has-tpo")/* legacy */)) + device_set_wakeup_capable(&pdev->dev, true); + else + clear_bit(RTC_FEATURE_ALARM, rtc->features); + + rtc->ops = &opal_rtc_ops; + rtc->range_min = RTC_TIMESTAMP_BEGIN_0000; + rtc->range_max = RTC_TIMESTAMP_END_9999; + clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features); + + return devm_rtc_register_device(rtc); +} + +static const struct of_device_id opal_rtc_match[] = { + { + .compatible = "ibm,opal-rtc", + }, + { } +}; +MODULE_DEVICE_TABLE(of, opal_rtc_match); + +static const struct platform_device_id opal_rtc_driver_ids[] = { + { + .name = "opal-rtc", + }, + { } +}; +MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids); + +static struct platform_driver opal_rtc_driver = { + .probe = opal_rtc_probe, + .id_table = opal_rtc_driver_ids, + .driver = { + .name = DRVNAME, + .of_match_table = opal_rtc_match, + }, +}; + +static int __init opal_rtc_init(void) +{ + if (!firmware_has_feature(FW_FEATURE_OPAL)) + return -ENODEV; + + return platform_driver_register(&opal_rtc_driver); +} + +static void __exit opal_rtc_exit(void) +{ + platform_driver_unregister(&opal_rtc_driver); +} + +MODULE_AUTHOR("Neelesh Gupta "); +MODULE_DESCRIPTION("IBM OPAL RTC driver"); +MODULE_LICENSE("GPL"); + +module_init(opal_rtc_init); +module_exit(opal_rtc_exit); -- cgit v1.3.1