Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 291 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c
new file mode 100644
index 000000000..db3bdb171
--- /dev/null
+++ b/drivers/rtc/rtc-m48t86.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ST M48T86 / Dallas DS12887 RTC driver
+ * Copyright (c) 2006 Tower Technologies
+ *
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * This drivers only supports the clock running in BCD and 24H mode.
+ * If it will be ever adapted to binary and 12H mode, care must be taken
+ * to not introduce bugs.
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+#include <linux/bcd.h>
+#include <linux/io.h>
+
+#define M48T86_SEC		0x00
+#define M48T86_SECALRM		0x01
+#define M48T86_MIN		0x02
+#define M48T86_MINALRM		0x03
+#define M48T86_HOUR		0x04
+#define M48T86_HOURALRM		0x05
+#define M48T86_DOW		0x06 /* 1 = sunday */
+#define M48T86_DOM		0x07
+#define M48T86_MONTH		0x08 /* 1 - 12 */
+#define M48T86_YEAR		0x09 /* 0 - 99 */
+#define M48T86_A		0x0a
+#define M48T86_B		0x0b
+#define M48T86_B_SET		BIT(7)
+#define M48T86_B_DM		BIT(2)
+#define M48T86_B_H24		BIT(1)
+#define M48T86_C		0x0c
+#define M48T86_D		0x0d
+#define M48T86_D_VRT		BIT(7)
+#define M48T86_NVRAM(x)		(0x0e + (x))
+#define M48T86_NVRAM_LEN	114
+
+struct m48t86_rtc_info {
+	void __iomem *index_reg;
+	void __iomem *data_reg;
+};
+
+static unsigned char m48t86_readb(struct device *dev, unsigned long addr)
+{
+	struct m48t86_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char value;
+
+	writeb(addr, info->index_reg);
+	value = readb(info->data_reg);
+
+	return value;
+}
+
+static void m48t86_writeb(struct device *dev,
+			  unsigned char value, unsigned long addr)
+{
+	struct m48t86_rtc_info *info = dev_get_drvdata(dev);
+
+	writeb(addr, info->index_reg);
+	writeb(value, info->data_reg);
+}
+
+static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned char reg;
+
+	reg = m48t86_readb(dev, M48T86_B);
+
+	if (reg & M48T86_B_DM) {
+		/* data (binary) mode */
+		tm->tm_sec	= m48t86_readb(dev, M48T86_SEC);
+		tm->tm_min	= m48t86_readb(dev, M48T86_MIN);
+		tm->tm_hour	= m48t86_readb(dev, M48T86_HOUR) & 0x3f;
+		tm->tm_mday	= m48t86_readb(dev, M48T86_DOM);
+		/* tm_mon is 0-11 */
+		tm->tm_mon	= m48t86_readb(dev, M48T86_MONTH) - 1;
+		tm->tm_year	= m48t86_readb(dev, M48T86_YEAR) + 100;
+		tm->tm_wday	= m48t86_readb(dev, M48T86_DOW);
+	} else {
+		/* bcd mode */
+		tm->tm_sec	= bcd2bin(m48t86_readb(dev, M48T86_SEC));
+		tm->tm_min	= bcd2bin(m48t86_readb(dev, M48T86_MIN));
+		tm->tm_hour	= bcd2bin(m48t86_readb(dev, M48T86_HOUR) &
+					  0x3f);
+		tm->tm_mday	= bcd2bin(m48t86_readb(dev, M48T86_DOM));
+		/* tm_mon is 0-11 */
+		tm->tm_mon	= bcd2bin(m48t86_readb(dev, M48T86_MONTH)) - 1;
+		tm->tm_year	= bcd2bin(m48t86_readb(dev, M48T86_YEAR)) + 100;
+		tm->tm_wday	= bcd2bin(m48t86_readb(dev, M48T86_DOW));
+	}
+
+	/* correct the hour if the clock is in 12h mode */
+	if (!(reg & M48T86_B_H24))
+		if (m48t86_readb(dev, M48T86_HOUR) & 0x80)
+			tm->tm_hour += 12;
+
+	return 0;
+}
+
+static int m48t86_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned char reg;
+
+	reg = m48t86_readb(dev, M48T86_B);
+
+	/* update flag and 24h mode */
+	reg |= M48T86_B_SET | M48T86_B_H24;
+	m48t86_writeb(dev, reg, M48T86_B);
+
+	if (reg & M48T86_B_DM) {
+		/* data (binary) mode */
+		m48t86_writeb(dev, tm->tm_sec, M48T86_SEC);
+		m48t86_writeb(dev, tm->tm_min, M48T86_MIN);
+		m48t86_writeb(dev, tm->tm_hour, M48T86_HOUR);
+		m48t86_writeb(dev, tm->tm_mday, M48T86_DOM);
+		m48t86_writeb(dev, tm->tm_mon + 1, M48T86_MONTH);
+		m48t86_writeb(dev, tm->tm_year % 100, M48T86_YEAR);
+		m48t86_writeb(dev, tm->tm_wday, M48T86_DOW);
+	} else {
+		/* bcd mode */
+		m48t86_writeb(dev, bin2bcd(tm->tm_sec), M48T86_SEC);
+		m48t86_writeb(dev, bin2bcd(tm->tm_min), M48T86_MIN);
+		m48t86_writeb(dev, bin2bcd(tm->tm_hour), M48T86_HOUR);
+		m48t86_writeb(dev, bin2bcd(tm->tm_mday), M48T86_DOM);
+		m48t86_writeb(dev, bin2bcd(tm->tm_mon + 1), M48T86_MONTH);
+		m48t86_writeb(dev, bin2bcd(tm->tm_year % 100), M48T86_YEAR);
+		m48t86_writeb(dev, bin2bcd(tm->tm_wday), M48T86_DOW);
+	}
+
+	/* update ended */
+	reg &= ~M48T86_B_SET;
+	m48t86_writeb(dev, reg, M48T86_B);
+
+	return 0;
+}
+
+static int m48t86_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	unsigned char reg;
+
+	reg = m48t86_readb(dev, M48T86_B);
+
+	seq_printf(seq, "mode\t\t: %s\n",
+		   (reg & M48T86_B_DM) ? "binary" : "bcd");
+
+	reg = m48t86_readb(dev, M48T86_D);
+
+	seq_printf(seq, "battery\t\t: %s\n",
+		   (reg & M48T86_D_VRT) ? "ok" : "exhausted");
+
+	return 0;
+}
+
+static const struct rtc_class_ops m48t86_rtc_ops = {
+	.read_time	= m48t86_rtc_read_time,
+	.set_time	= m48t86_rtc_set_time,
+	.proc		= m48t86_rtc_proc,
+};
+
+static int m48t86_nvram_read(void *priv, unsigned int off, void *buf,
+			     size_t count)
+{
+	struct device *dev = priv;
+	unsigned int i;
+
+	for (i = 0; i < count; i++)
+		((u8 *)buf)[i] = m48t86_readb(dev, M48T86_NVRAM(off + i));
+
+	return 0;
+}
+
+static int m48t86_nvram_write(void *priv, unsigned int off, void *buf,
+			      size_t count)
+{
+	struct device *dev = priv;
+	unsigned int i;
+
+	for (i = 0; i < count; i++)
+		m48t86_writeb(dev, ((u8 *)buf)[i], M48T86_NVRAM(off + i));
+
+	return 0;
+}
+
+/*
+ * The RTC is an optional feature at purchase time on some Technologic Systems
+ * boards. Verify that it actually exists by checking if the last two bytes
+ * of the NVRAM can be changed.
+ *
+ * This is based on the method used in their rtc7800.c example.
+ */
+static bool m48t86_verify_chip(struct platform_device *pdev)
+{
+	unsigned int offset0 = M48T86_NVRAM(M48T86_NVRAM_LEN - 2);
+	unsigned int offset1 = M48T86_NVRAM(M48T86_NVRAM_LEN - 1);
+	unsigned char tmp0, tmp1;
+
+	tmp0 = m48t86_readb(&pdev->dev, offset0);
+	tmp1 = m48t86_readb(&pdev->dev, offset1);
+
+	m48t86_writeb(&pdev->dev, 0x00, offset0);
+	m48t86_writeb(&pdev->dev, 0x55, offset1);
+	if (m48t86_readb(&pdev->dev, offset1) == 0x55) {
+		m48t86_writeb(&pdev->dev, 0xaa, offset1);
+		if (m48t86_readb(&pdev->dev, offset1) == 0xaa &&
+		    m48t86_readb(&pdev->dev, offset0) == 0x00) {
+			m48t86_writeb(&pdev->dev, tmp0, offset0);
+			m48t86_writeb(&pdev->dev, tmp1, offset1);
+
+			return true;
+		}
+	}
+	return false;
+}
+
+static int m48t86_rtc_probe(struct platform_device *pdev)
+{
+	struct m48t86_rtc_info *info;
+	struct rtc_device *rtc;
+	unsigned char reg;
+	int err;
+	struct nvmem_config m48t86_nvmem_cfg = {
+		.name = "m48t86_nvram",
+		.word_size = 1,
+		.stride = 1,
+		.size = M48T86_NVRAM_LEN,
+		.reg_read = m48t86_nvram_read,
+		.reg_write = m48t86_nvram_write,
+		.priv = &pdev->dev,
+	};
+
+	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->index_reg = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(info->index_reg))
+		return PTR_ERR(info->index_reg);
+
+	info->data_reg = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(info->data_reg))
+		return PTR_ERR(info->data_reg);
+
+	dev_set_drvdata(&pdev->dev, info);
+
+	if (!m48t86_verify_chip(pdev)) {
+		dev_info(&pdev->dev, "RTC not present\n");
+		return -ENODEV;
+	}
+
+	rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	rtc->ops = &m48t86_rtc_ops;
+
+	err = devm_rtc_register_device(rtc);
+	if (err)
+		return err;
+
+	devm_rtc_nvmem_register(rtc, &m48t86_nvmem_cfg);
+
+	/* read battery status */
+	reg = m48t86_readb(&pdev->dev, M48T86_D);
+	dev_info(&pdev->dev, "battery %s\n",
+		 (reg & M48T86_D_VRT) ? "ok" : "exhausted");
+
+	return 0;
+}
+
+static const struct of_device_id m48t86_rtc_of_ids[] = {
+	{ .compatible = "st,m48t86" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, m48t86_rtc_of_ids);
+
+static struct platform_driver m48t86_rtc_platform_driver = {
+	.driver		= {
+		.name	= "rtc-m48t86",
+		.of_match_table = m48t86_rtc_of_ids,
+	},
+	.probe		= m48t86_rtc_probe,
+};
+
+module_platform_driver(m48t86_rtc_platform_driver);
+
+MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
+MODULE_DESCRIPTION("M48T86 RTC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-m48t86");