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/memory/dfl-emif.c | 259 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 259 insertions(+) create mode 100644 drivers/memory/dfl-emif.c (limited to 'drivers/memory/dfl-emif.c') diff --git a/drivers/memory/dfl-emif.c b/drivers/memory/dfl-emif.c new file mode 100644 index 000000000..da06cd30a --- /dev/null +++ b/drivers/memory/dfl-emif.c @@ -0,0 +1,259 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * DFL device driver for EMIF private feature + * + * Copyright (C) 2020 Intel Corporation, Inc. + * + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define FME_FEATURE_ID_EMIF 0x9 + +#define EMIF_STAT 0x8 +#define EMIF_STAT_INIT_DONE_SFT 0 +#define EMIF_STAT_CALC_FAIL_SFT 8 +#define EMIF_STAT_CLEAR_BUSY_SFT 16 +#define EMIF_CTRL 0x10 +#define EMIF_CTRL_CLEAR_EN_SFT 0 +#define EMIF_CTRL_CLEAR_EN_MSK GENMASK_ULL(7, 0) + +#define EMIF_POLL_INVL 10000 /* us */ +#define EMIF_POLL_TIMEOUT 5000000 /* us */ + +/* + * The Capability Register replaces the Control Register (at the same + * offset) for EMIF feature revisions > 0. The bitmask that indicates + * the presence of memory channels exists in both the Capability Register + * and Control Register definitions. These can be thought of as a C union. + * The Capability Register definitions are used to check for the existence + * of a memory channel, and the Control Register definitions are used for + * managing the memory-clear functionality in revision 0. + */ +#define EMIF_CAPABILITY_BASE 0x10 +#define EMIF_CAPABILITY_CHN_MSK_V0 GENMASK_ULL(3, 0) +#define EMIF_CAPABILITY_CHN_MSK GENMASK_ULL(7, 0) + +struct dfl_emif { + struct device *dev; + void __iomem *base; + spinlock_t lock; /* Serialises access to EMIF_CTRL reg */ +}; + +struct emif_attr { + struct device_attribute attr; + u32 shift; + u32 index; +}; + +#define to_emif_attr(dev_attr) \ + container_of(dev_attr, struct emif_attr, attr) + +static ssize_t emif_state_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct emif_attr *eattr = to_emif_attr(attr); + struct dfl_emif *de = dev_get_drvdata(dev); + u64 val; + + val = readq(de->base + EMIF_STAT); + + return sysfs_emit(buf, "%u\n", + !!(val & BIT_ULL(eattr->shift + eattr->index))); +} + +static ssize_t emif_clear_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct emif_attr *eattr = to_emif_attr(attr); + struct dfl_emif *de = dev_get_drvdata(dev); + u64 clear_busy_msk, clear_en_msk, val; + void __iomem *base = de->base; + + if (!sysfs_streq(buf, "1")) + return -EINVAL; + + clear_busy_msk = BIT_ULL(EMIF_STAT_CLEAR_BUSY_SFT + eattr->index); + clear_en_msk = BIT_ULL(EMIF_CTRL_CLEAR_EN_SFT + eattr->index); + + spin_lock(&de->lock); + /* The CLEAR_EN field is WO, but other fields are RW */ + val = readq(base + EMIF_CTRL); + val &= ~EMIF_CTRL_CLEAR_EN_MSK; + val |= clear_en_msk; + writeq(val, base + EMIF_CTRL); + spin_unlock(&de->lock); + + if (readq_poll_timeout(base + EMIF_STAT, val, + !(val & clear_busy_msk), + EMIF_POLL_INVL, EMIF_POLL_TIMEOUT)) { + dev_err(de->dev, "timeout, fail to clear\n"); + return -ETIMEDOUT; + } + + return count; +} + +#define emif_state_attr(_name, _shift, _index) \ + static struct emif_attr emif_attr_##inf##_index##_##_name = \ + { .attr = __ATTR(inf##_index##_##_name, 0444, \ + emif_state_show, NULL), \ + .shift = (_shift), .index = (_index) } + +#define emif_clear_attr(_index) \ + static struct emif_attr emif_attr_##inf##_index##_clear = \ + { .attr = __ATTR(inf##_index##_clear, 0200, \ + NULL, emif_clear_store), \ + .index = (_index) } + +emif_state_attr(init_done, EMIF_STAT_INIT_DONE_SFT, 0); +emif_state_attr(init_done, EMIF_STAT_INIT_DONE_SFT, 1); +emif_state_attr(init_done, EMIF_STAT_INIT_DONE_SFT, 2); +emif_state_attr(init_done, EMIF_STAT_INIT_DONE_SFT, 3); +emif_state_attr(init_done, EMIF_STAT_INIT_DONE_SFT, 4); +emif_state_attr(init_done, EMIF_STAT_INIT_DONE_SFT, 5); +emif_state_attr(init_done, EMIF_STAT_INIT_DONE_SFT, 6); +emif_state_attr(init_done, EMIF_STAT_INIT_DONE_SFT, 7); + +emif_state_attr(cal_fail, EMIF_STAT_CALC_FAIL_SFT, 0); +emif_state_attr(cal_fail, EMIF_STAT_CALC_FAIL_SFT, 1); +emif_state_attr(cal_fail, EMIF_STAT_CALC_FAIL_SFT, 2); +emif_state_attr(cal_fail, EMIF_STAT_CALC_FAIL_SFT, 3); +emif_state_attr(cal_fail, EMIF_STAT_CALC_FAIL_SFT, 4); +emif_state_attr(cal_fail, EMIF_STAT_CALC_FAIL_SFT, 5); +emif_state_attr(cal_fail, EMIF_STAT_CALC_FAIL_SFT, 6); +emif_state_attr(cal_fail, EMIF_STAT_CALC_FAIL_SFT, 7); + + +emif_clear_attr(0); +emif_clear_attr(1); +emif_clear_attr(2); +emif_clear_attr(3); +emif_clear_attr(4); +emif_clear_attr(5); +emif_clear_attr(6); +emif_clear_attr(7); + + +static struct attribute *dfl_emif_attrs[] = { + &emif_attr_inf0_init_done.attr.attr, + &emif_attr_inf0_cal_fail.attr.attr, + &emif_attr_inf0_clear.attr.attr, + + &emif_attr_inf1_init_done.attr.attr, + &emif_attr_inf1_cal_fail.attr.attr, + &emif_attr_inf1_clear.attr.attr, + + &emif_attr_inf2_init_done.attr.attr, + &emif_attr_inf2_cal_fail.attr.attr, + &emif_attr_inf2_clear.attr.attr, + + &emif_attr_inf3_init_done.attr.attr, + &emif_attr_inf3_cal_fail.attr.attr, + &emif_attr_inf3_clear.attr.attr, + + &emif_attr_inf4_init_done.attr.attr, + &emif_attr_inf4_cal_fail.attr.attr, + &emif_attr_inf4_clear.attr.attr, + + &emif_attr_inf5_init_done.attr.attr, + &emif_attr_inf5_cal_fail.attr.attr, + &emif_attr_inf5_clear.attr.attr, + + &emif_attr_inf6_init_done.attr.attr, + &emif_attr_inf6_cal_fail.attr.attr, + &emif_attr_inf6_clear.attr.attr, + + &emif_attr_inf7_init_done.attr.attr, + &emif_attr_inf7_cal_fail.attr.attr, + &emif_attr_inf7_clear.attr.attr, + + NULL, +}; + +static umode_t dfl_emif_visible(struct kobject *kobj, + struct attribute *attr, int n) +{ + struct dfl_emif *de = dev_get_drvdata(kobj_to_dev(kobj)); + struct emif_attr *eattr = container_of(attr, struct emif_attr, + attr.attr); + struct dfl_device *ddev = to_dfl_dev(de->dev); + u64 val; + + /* + * This device supports up to 8 memory interfaces, but not all + * interfaces are used on different platforms. The read out value of + * CAPABILITY_CHN_MSK field (which is a bitmap) indicates which + * interfaces are available. + */ + if (ddev->revision > 0 && strstr(attr->name, "_clear")) + return 0; + + if (ddev->revision == 0) + val = FIELD_GET(EMIF_CAPABILITY_CHN_MSK_V0, + readq(de->base + EMIF_CAPABILITY_BASE)); + else + val = FIELD_GET(EMIF_CAPABILITY_CHN_MSK, + readq(de->base + EMIF_CAPABILITY_BASE)); + + return (val & BIT_ULL(eattr->index)) ? attr->mode : 0; +} + +static const struct attribute_group dfl_emif_group = { + .is_visible = dfl_emif_visible, + .attrs = dfl_emif_attrs, +}; + +static const struct attribute_group *dfl_emif_groups[] = { + &dfl_emif_group, + NULL, +}; + +static int dfl_emif_probe(struct dfl_device *ddev) +{ + struct device *dev = &ddev->dev; + struct dfl_emif *de; + + de = devm_kzalloc(dev, sizeof(*de), GFP_KERNEL); + if (!de) + return -ENOMEM; + + de->base = devm_ioremap_resource(dev, &ddev->mmio_res); + if (IS_ERR(de->base)) + return PTR_ERR(de->base); + + de->dev = dev; + spin_lock_init(&de->lock); + dev_set_drvdata(dev, de); + + return 0; +} + +static const struct dfl_device_id dfl_emif_ids[] = { + { FME_ID, FME_FEATURE_ID_EMIF }, + { } +}; +MODULE_DEVICE_TABLE(dfl, dfl_emif_ids); + +static struct dfl_driver dfl_emif_driver = { + .drv = { + .name = "dfl-emif", + .dev_groups = dfl_emif_groups, + }, + .id_table = dfl_emif_ids, + .probe = dfl_emif_probe, +}; +module_dfl_driver(dfl_emif_driver); + +MODULE_DESCRIPTION("DFL EMIF driver"); +MODULE_AUTHOR("Intel Corporation"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1