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, 169 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-xtensa.c b/drivers/gpio/gpio-xtensa.c
new file mode 100644
index 000000000..4418947a1
--- /dev/null
+++ b/drivers/gpio/gpio-xtensa.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2013 TangoTec Ltd.
+ * Author: Baruch Siach <baruch@tkos.co.il>
+ *
+ * Driver for the Xtensa LX4 GPIO32 Option
+ *
+ * Documentation: Xtensa LX4 Microprocessor Data Book, Section 2.22
+ *
+ * GPIO32 is a standard optional extension to the Xtensa architecture core that
+ * provides preconfigured output and input ports for intra SoC signaling. The
+ * GPIO32 option is implemented as 32bit Tensilica Instruction Extension (TIE)
+ * output state called EXPSTATE, and 32bit input wire called IMPWIRE. This
+ * driver treats input and output states as two distinct devices.
+ *
+ * Access to GPIO32 specific instructions is controlled by the CPENABLE
+ * (Coprocessor Enable Bits) register. By default Xtensa Linux startup code
+ * disables access to all coprocessors. This driver sets the CPENABLE bit
+ * corresponding to GPIO32 before any GPIO32 specific instruction, and restores
+ * CPENABLE state after that.
+ *
+ * This driver is currently incompatible with SMP. The GPIO32 extension is not
+ * guaranteed to be available in all cores. Moreover, each core controls a
+ * different set of IO wires. A theoretical SMP aware version of this driver
+ * would need to have a per core workqueue to do the actual GPIO manipulation.
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/gpio/driver.h>
+#include <linux/bitops.h>
+#include <linux/platform_device.h>
+
+#include <asm/coprocessor.h> /* CPENABLE read/write macros */
+
+#ifndef XCHAL_CP_ID_XTIOP
+#error GPIO32 option is not enabled for your xtensa core variant
+#endif
+
+#if XCHAL_HAVE_CP
+
+static inline unsigned long enable_cp(unsigned long *cpenable)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	*cpenable = xtensa_get_sr(cpenable);
+	xtensa_set_sr(*cpenable | BIT(XCHAL_CP_ID_XTIOP), cpenable);
+	return flags;
+}
+
+static inline void disable_cp(unsigned long flags, unsigned long cpenable)
+{
+	xtensa_set_sr(cpenable, cpenable);
+	local_irq_restore(flags);
+}
+
+#else
+
+static inline unsigned long enable_cp(unsigned long *cpenable)
+{
+	*cpenable = 0; /* avoid uninitialized value warning */
+	return 0;
+}
+
+static inline void disable_cp(unsigned long flags, unsigned long cpenable)
+{
+}
+
+#endif /* XCHAL_HAVE_CP */
+
+static int xtensa_impwire_get_direction(struct gpio_chip *gc, unsigned offset)
+{
+	return GPIO_LINE_DIRECTION_IN; /* input only */
+}
+
+static int xtensa_impwire_get_value(struct gpio_chip *gc, unsigned offset)
+{
+	unsigned long flags, saved_cpenable;
+	u32 impwire;
+
+	flags = enable_cp(&saved_cpenable);
+	__asm__ __volatile__("read_impwire %0" : "=a" (impwire));
+	disable_cp(flags, saved_cpenable);
+
+	return !!(impwire & BIT(offset));
+}
+
+static int xtensa_expstate_get_direction(struct gpio_chip *gc, unsigned offset)
+{
+	return GPIO_LINE_DIRECTION_OUT; /* output only */
+}
+
+static int xtensa_expstate_get_value(struct gpio_chip *gc, unsigned offset)
+{
+	unsigned long flags, saved_cpenable;
+	u32 expstate;
+
+	flags = enable_cp(&saved_cpenable);
+	__asm__ __volatile__("rur.expstate %0" : "=a" (expstate));
+	disable_cp(flags, saved_cpenable);
+
+	return !!(expstate & BIT(offset));
+}
+
+static int xtensa_expstate_set_value(struct gpio_chip *gc, unsigned int offset,
+				     int value)
+{
+	unsigned long flags, saved_cpenable;
+	u32 mask = BIT(offset);
+	u32 val = value ? BIT(offset) : 0;
+
+	flags = enable_cp(&saved_cpenable);
+	__asm__ __volatile__("wrmsk_expstate %0, %1"
+			     :: "a" (val), "a" (mask));
+	disable_cp(flags, saved_cpenable);
+
+	return 0;
+}
+
+static struct gpio_chip impwire_chip = {
+	.label		= "impwire",
+	.base		= -1,
+	.ngpio		= 32,
+	.get_direction	= xtensa_impwire_get_direction,
+	.get		= xtensa_impwire_get_value,
+};
+
+static struct gpio_chip expstate_chip = {
+	.label		= "expstate",
+	.base		= -1,
+	.ngpio		= 32,
+	.get_direction	= xtensa_expstate_get_direction,
+	.get		= xtensa_expstate_get_value,
+	.set		= xtensa_expstate_set_value,
+};
+
+static int xtensa_gpio_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = gpiochip_add_data(&impwire_chip, NULL);
+	if (ret)
+		return ret;
+	return gpiochip_add_data(&expstate_chip, NULL);
+}
+
+static struct platform_driver xtensa_gpio_driver = {
+	.driver		= {
+		.name		= "xtensa-gpio",
+	},
+	.probe		= xtensa_gpio_probe,
+};
+
+static int __init xtensa_gpio_init(void)
+{
+	struct platform_device *pdev;
+
+	pdev = platform_device_register_simple("xtensa-gpio", 0, NULL, 0);
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	return platform_driver_register(&xtensa_gpio_driver);
+}
+device_initcall(xtensa_gpio_init);
+
+MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
+MODULE_DESCRIPTION("Xtensa LX4 GPIO32 driver");
+MODULE_LICENSE("GPL");