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, 506 insertions, 0 deletions

diff --git a/drivers/dma/uniphier-mdmac.c b/drivers/dma/uniphier-mdmac.c
new file mode 100644
index 000000000..a8aa904b8
--- /dev/null
+++ b/drivers/dma/uniphier-mdmac.c
@@ -0,0 +1,506 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2018 Socionext Inc.
+//   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
+
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "virt-dma.h"
+
+/* registers common for all channels */
+#define UNIPHIER_MDMAC_CMD		0x000	/* issue DMA start/abort */
+#define   UNIPHIER_MDMAC_CMD_ABORT		BIT(31) /* 1: abort, 0: start */
+
+/* per-channel registers */
+#define UNIPHIER_MDMAC_CH_OFFSET	0x100
+#define UNIPHIER_MDMAC_CH_STRIDE	0x040
+
+#define UNIPHIER_MDMAC_CH_IRQ_STAT	0x010	/* current hw status (RO) */
+#define UNIPHIER_MDMAC_CH_IRQ_REQ	0x014	/* latched STAT (WOC) */
+#define UNIPHIER_MDMAC_CH_IRQ_EN	0x018	/* IRQ enable mask */
+#define UNIPHIER_MDMAC_CH_IRQ_DET	0x01c	/* REQ & EN (RO) */
+#define   UNIPHIER_MDMAC_CH_IRQ__ABORT		BIT(13)
+#define   UNIPHIER_MDMAC_CH_IRQ__DONE		BIT(1)
+#define UNIPHIER_MDMAC_CH_SRC_MODE	0x020	/* mode of source */
+#define UNIPHIER_MDMAC_CH_DEST_MODE	0x024	/* mode of destination */
+#define   UNIPHIER_MDMAC_CH_MODE__ADDR_INC	(0 << 4)
+#define   UNIPHIER_MDMAC_CH_MODE__ADDR_DEC	(1 << 4)
+#define   UNIPHIER_MDMAC_CH_MODE__ADDR_FIXED	(2 << 4)
+#define UNIPHIER_MDMAC_CH_SRC_ADDR	0x028	/* source address */
+#define UNIPHIER_MDMAC_CH_DEST_ADDR	0x02c	/* destination address */
+#define UNIPHIER_MDMAC_CH_SIZE		0x030	/* transfer bytes */
+
+#define UNIPHIER_MDMAC_SLAVE_BUSWIDTHS \
+	(BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
+	 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
+	 BIT(DMA_SLAVE_BUSWIDTH_3_BYTES) | \
+	 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))
+
+struct uniphier_mdmac_desc {
+	struct virt_dma_desc vd;
+	struct scatterlist *sgl;
+	unsigned int sg_len;
+	unsigned int sg_cur;
+	enum dma_transfer_direction dir;
+};
+
+struct uniphier_mdmac_chan {
+	struct virt_dma_chan vc;
+	struct uniphier_mdmac_device *mdev;
+	struct uniphier_mdmac_desc *md;
+	void __iomem *reg_ch_base;
+	unsigned int chan_id;
+};
+
+struct uniphier_mdmac_device {
+	struct dma_device ddev;
+	struct clk *clk;
+	void __iomem *reg_base;
+	struct uniphier_mdmac_chan channels[];
+};
+
+static struct uniphier_mdmac_chan *
+to_uniphier_mdmac_chan(struct virt_dma_chan *vc)
+{
+	return container_of(vc, struct uniphier_mdmac_chan, vc);
+}
+
+static struct uniphier_mdmac_desc *
+to_uniphier_mdmac_desc(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct uniphier_mdmac_desc, vd);
+}
+
+/* mc->vc.lock must be held by caller */
+static struct uniphier_mdmac_desc *
+uniphier_mdmac_next_desc(struct uniphier_mdmac_chan *mc)
+{
+	struct virt_dma_desc *vd;
+
+	vd = vchan_next_desc(&mc->vc);
+	if (!vd) {
+		mc->md = NULL;
+		return NULL;
+	}
+
+	list_del(&vd->node);
+
+	mc->md = to_uniphier_mdmac_desc(vd);
+
+	return mc->md;
+}
+
+/* mc->vc.lock must be held by caller */
+static void uniphier_mdmac_handle(struct uniphier_mdmac_chan *mc,
+				  struct uniphier_mdmac_desc *md)
+{
+	struct uniphier_mdmac_device *mdev = mc->mdev;
+	struct scatterlist *sg;
+	u32 irq_flag = UNIPHIER_MDMAC_CH_IRQ__DONE;
+	u32 src_mode, src_addr, dest_mode, dest_addr, chunk_size;
+
+	sg = &md->sgl[md->sg_cur];
+
+	if (md->dir == DMA_MEM_TO_DEV) {
+		src_mode = UNIPHIER_MDMAC_CH_MODE__ADDR_INC;
+		src_addr = sg_dma_address(sg);
+		dest_mode = UNIPHIER_MDMAC_CH_MODE__ADDR_FIXED;
+		dest_addr = 0;
+	} else {
+		src_mode = UNIPHIER_MDMAC_CH_MODE__ADDR_FIXED;
+		src_addr = 0;
+		dest_mode = UNIPHIER_MDMAC_CH_MODE__ADDR_INC;
+		dest_addr = sg_dma_address(sg);
+	}
+
+	chunk_size = sg_dma_len(sg);
+
+	writel(src_mode, mc->reg_ch_base + UNIPHIER_MDMAC_CH_SRC_MODE);
+	writel(dest_mode, mc->reg_ch_base + UNIPHIER_MDMAC_CH_DEST_MODE);
+	writel(src_addr, mc->reg_ch_base + UNIPHIER_MDMAC_CH_SRC_ADDR);
+	writel(dest_addr, mc->reg_ch_base + UNIPHIER_MDMAC_CH_DEST_ADDR);
+	writel(chunk_size, mc->reg_ch_base + UNIPHIER_MDMAC_CH_SIZE);
+
+	/* write 1 to clear */
+	writel(irq_flag, mc->reg_ch_base + UNIPHIER_MDMAC_CH_IRQ_REQ);
+
+	writel(irq_flag, mc->reg_ch_base + UNIPHIER_MDMAC_CH_IRQ_EN);
+
+	writel(BIT(mc->chan_id), mdev->reg_base + UNIPHIER_MDMAC_CMD);
+}
+
+/* mc->vc.lock must be held by caller */
+static void uniphier_mdmac_start(struct uniphier_mdmac_chan *mc)
+{
+	struct uniphier_mdmac_desc *md;
+
+	md = uniphier_mdmac_next_desc(mc);
+	if (md)
+		uniphier_mdmac_handle(mc, md);
+}
+
+/* mc->vc.lock must be held by caller */
+static int uniphier_mdmac_abort(struct uniphier_mdmac_chan *mc)
+{
+	struct uniphier_mdmac_device *mdev = mc->mdev;
+	u32 irq_flag = UNIPHIER_MDMAC_CH_IRQ__ABORT;
+	u32 val;
+
+	/* write 1 to clear */
+	writel(irq_flag, mc->reg_ch_base + UNIPHIER_MDMAC_CH_IRQ_REQ);
+
+	writel(UNIPHIER_MDMAC_CMD_ABORT | BIT(mc->chan_id),
+	       mdev->reg_base + UNIPHIER_MDMAC_CMD);
+
+	/*
+	 * Abort should be accepted soon. We poll the bit here instead of
+	 * waiting for the interrupt.
+	 */
+	return readl_poll_timeout(mc->reg_ch_base + UNIPHIER_MDMAC_CH_IRQ_REQ,
+				  val, val & irq_flag, 0, 20);
+}
+
+static irqreturn_t uniphier_mdmac_interrupt(int irq, void *dev_id)
+{
+	struct uniphier_mdmac_chan *mc = dev_id;
+	struct uniphier_mdmac_desc *md;
+	irqreturn_t ret = IRQ_HANDLED;
+	u32 irq_stat;
+
+	spin_lock(&mc->vc.lock);
+
+	irq_stat = readl(mc->reg_ch_base + UNIPHIER_MDMAC_CH_IRQ_DET);
+
+	/*
+	 * Some channels share a single interrupt line. If the IRQ status is 0,
+	 * this is probably triggered by a different channel.
+	 */
+	if (!irq_stat) {
+		ret = IRQ_NONE;
+		goto out;
+	}
+
+	/* write 1 to clear */
+	writel(irq_stat, mc->reg_ch_base + UNIPHIER_MDMAC_CH_IRQ_REQ);
+
+	/*
+	 * UNIPHIER_MDMAC_CH_IRQ__DONE interrupt is asserted even when the DMA
+	 * is aborted. To distinguish the normal completion and the abort,
+	 * check mc->md. If it is NULL, we are aborting.
+	 */
+	md = mc->md;
+	if (!md)
+		goto out;
+
+	md->sg_cur++;
+
+	if (md->sg_cur >= md->sg_len) {
+		vchan_cookie_complete(&md->vd);
+		md = uniphier_mdmac_next_desc(mc);
+		if (!md)
+			goto out;
+	}
+
+	uniphier_mdmac_handle(mc, md);
+
+out:
+	spin_unlock(&mc->vc.lock);
+
+	return ret;
+}
+
+static void uniphier_mdmac_free_chan_resources(struct dma_chan *chan)
+{
+	vchan_free_chan_resources(to_virt_chan(chan));
+}
+
+static struct dma_async_tx_descriptor *
+uniphier_mdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+			     unsigned int sg_len,
+			     enum dma_transfer_direction direction,
+			     unsigned long flags, void *context)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct uniphier_mdmac_desc *md;
+
+	if (!is_slave_direction(direction))
+		return NULL;
+
+	md = kzalloc_obj(*md, GFP_NOWAIT);
+	if (!md)
+		return NULL;
+
+	md->sgl = sgl;
+	md->sg_len = sg_len;
+	md->dir = direction;
+
+	return vchan_tx_prep(vc, &md->vd, flags);
+}
+
+static int uniphier_mdmac_terminate_all(struct dma_chan *chan)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct uniphier_mdmac_chan *mc = to_uniphier_mdmac_chan(vc);
+	unsigned long flags;
+	int ret = 0;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&vc->lock, flags);
+
+	if (mc->md) {
+		vchan_terminate_vdesc(&mc->md->vd);
+		mc->md = NULL;
+		ret = uniphier_mdmac_abort(mc);
+	}
+	vchan_get_all_descriptors(vc, &head);
+
+	spin_unlock_irqrestore(&vc->lock, flags);
+
+	vchan_dma_desc_free_list(vc, &head);
+
+	return ret;
+}
+
+static void uniphier_mdmac_synchronize(struct dma_chan *chan)
+{
+	vchan_synchronize(to_virt_chan(chan));
+}
+
+static enum dma_status uniphier_mdmac_tx_status(struct dma_chan *chan,
+						dma_cookie_t cookie,
+						struct dma_tx_state *txstate)
+{
+	struct virt_dma_chan *vc;
+	struct virt_dma_desc *vd;
+	struct uniphier_mdmac_chan *mc;
+	struct uniphier_mdmac_desc *md = NULL;
+	enum dma_status stat;
+	unsigned long flags;
+	int i;
+
+	stat = dma_cookie_status(chan, cookie, txstate);
+	/* Return immediately if we do not need to compute the residue. */
+	if (stat == DMA_COMPLETE || !txstate)
+		return stat;
+
+	vc = to_virt_chan(chan);
+
+	spin_lock_irqsave(&vc->lock, flags);
+
+	mc = to_uniphier_mdmac_chan(vc);
+
+	if (mc->md && mc->md->vd.tx.cookie == cookie) {
+		/* residue from the on-flight chunk */
+		txstate->residue = readl(mc->reg_ch_base +
+					 UNIPHIER_MDMAC_CH_SIZE);
+		md = mc->md;
+	}
+
+	if (!md) {
+		vd = vchan_find_desc(vc, cookie);
+		if (vd)
+			md = to_uniphier_mdmac_desc(vd);
+	}
+
+	if (md) {
+		/* residue from the queued chunks */
+		for (i = md->sg_cur; i < md->sg_len; i++)
+			txstate->residue += sg_dma_len(&md->sgl[i]);
+	}
+
+	spin_unlock_irqrestore(&vc->lock, flags);
+
+	return stat;
+}
+
+static void uniphier_mdmac_issue_pending(struct dma_chan *chan)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct uniphier_mdmac_chan *mc = to_uniphier_mdmac_chan(vc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&vc->lock, flags);
+
+	if (vchan_issue_pending(vc) && !mc->md)
+		uniphier_mdmac_start(mc);
+
+	spin_unlock_irqrestore(&vc->lock, flags);
+}
+
+static void uniphier_mdmac_desc_free(struct virt_dma_desc *vd)
+{
+	kfree(to_uniphier_mdmac_desc(vd));
+}
+
+static int uniphier_mdmac_chan_init(struct platform_device *pdev,
+				    struct uniphier_mdmac_device *mdev,
+				    int chan_id)
+{
+	struct device *dev = &pdev->dev;
+	struct uniphier_mdmac_chan *mc = &mdev->channels[chan_id];
+	char *irq_name;
+	int irq, ret;
+
+	irq = platform_get_irq(pdev, chan_id);
+	if (irq < 0)
+		return irq;
+
+	irq_name = devm_kasprintf(dev, GFP_KERNEL, "uniphier-mio-dmac-ch%d",
+				  chan_id);
+	if (!irq_name)
+		return -ENOMEM;
+
+	ret = devm_request_irq(dev, irq, uniphier_mdmac_interrupt,
+			       IRQF_SHARED, irq_name, mc);
+	if (ret)
+		return ret;
+
+	mc->mdev = mdev;
+	mc->reg_ch_base = mdev->reg_base + UNIPHIER_MDMAC_CH_OFFSET +
+					UNIPHIER_MDMAC_CH_STRIDE * chan_id;
+	mc->chan_id = chan_id;
+	mc->vc.desc_free = uniphier_mdmac_desc_free;
+	vchan_init(&mc->vc, &mdev->ddev);
+
+	return 0;
+}
+
+static int uniphier_mdmac_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct uniphier_mdmac_device *mdev;
+	struct dma_device *ddev;
+	int nr_chans, ret, i;
+
+	nr_chans = platform_irq_count(pdev);
+	if (nr_chans < 0)
+		return nr_chans;
+
+	ret = dma_set_mask(dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
+
+	mdev = devm_kzalloc(dev, struct_size(mdev, channels, nr_chans),
+			    GFP_KERNEL);
+	if (!mdev)
+		return -ENOMEM;
+
+	mdev->reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(mdev->reg_base))
+		return PTR_ERR(mdev->reg_base);
+
+	mdev->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(mdev->clk)) {
+		dev_err(dev, "failed to get clock\n");
+		return PTR_ERR(mdev->clk);
+	}
+
+	ret = clk_prepare_enable(mdev->clk);
+	if (ret)
+		return ret;
+
+	ddev = &mdev->ddev;
+	ddev->dev = dev;
+	dma_cap_set(DMA_PRIVATE, ddev->cap_mask);
+	ddev->src_addr_widths = UNIPHIER_MDMAC_SLAVE_BUSWIDTHS;
+	ddev->dst_addr_widths = UNIPHIER_MDMAC_SLAVE_BUSWIDTHS;
+	ddev->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM);
+	ddev->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+	ddev->device_free_chan_resources = uniphier_mdmac_free_chan_resources;
+	ddev->device_prep_slave_sg = uniphier_mdmac_prep_slave_sg;
+	ddev->device_terminate_all = uniphier_mdmac_terminate_all;
+	ddev->device_synchronize = uniphier_mdmac_synchronize;
+	ddev->device_tx_status = uniphier_mdmac_tx_status;
+	ddev->device_issue_pending = uniphier_mdmac_issue_pending;
+	INIT_LIST_HEAD(&ddev->channels);
+
+	for (i = 0; i < nr_chans; i++) {
+		ret = uniphier_mdmac_chan_init(pdev, mdev, i);
+		if (ret)
+			goto disable_clk;
+	}
+
+	ret = dma_async_device_register(ddev);
+	if (ret)
+		goto disable_clk;
+
+	ret = of_dma_controller_register(dev->of_node, of_dma_xlate_by_chan_id,
+					 ddev);
+	if (ret)
+		goto unregister_dmac;
+
+	platform_set_drvdata(pdev, mdev);
+
+	return 0;
+
+unregister_dmac:
+	dma_async_device_unregister(ddev);
+disable_clk:
+	clk_disable_unprepare(mdev->clk);
+
+	return ret;
+}
+
+static void uniphier_mdmac_remove(struct platform_device *pdev)
+{
+	struct uniphier_mdmac_device *mdev = platform_get_drvdata(pdev);
+	struct dma_chan *chan;
+	int ret;
+
+	/*
+	 * Before reaching here, almost all descriptors have been freed by the
+	 * ->device_free_chan_resources() hook. However, each channel might
+	 * be still holding one descriptor that was on-flight at that moment.
+	 * Terminate it to make sure this hardware is no longer running. Then,
+	 * free the channel resources once again to avoid memory leak.
+	 */
+	list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
+		ret = dmaengine_terminate_sync(chan);
+		if (ret) {
+			/*
+			 * This results in resource leakage and maybe also
+			 * use-after-free errors as e.g. *mdev is kfreed.
+			 */
+			dev_alert(&pdev->dev, "Failed to terminate channel %d (%pe)\n",
+				  chan->chan_id, ERR_PTR(ret));
+			return;
+		}
+		uniphier_mdmac_free_chan_resources(chan);
+	}
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&mdev->ddev);
+	clk_disable_unprepare(mdev->clk);
+}
+
+static const struct of_device_id uniphier_mdmac_match[] = {
+	{ .compatible = "socionext,uniphier-mio-dmac" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_mdmac_match);
+
+static struct platform_driver uniphier_mdmac_driver = {
+	.probe = uniphier_mdmac_probe,
+	.remove = uniphier_mdmac_remove,
+	.driver = {
+		.name = "uniphier-mio-dmac",
+		.of_match_table = uniphier_mdmac_match,
+	},
+};
+module_platform_driver(uniphier_mdmac_driver);
+
+MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
+MODULE_DESCRIPTION("UniPhier MIO DMAC driver");
+MODULE_LICENSE("GPL v2");