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, 828 insertions, 0 deletions

diff --git a/tools/perf/ui/browser.c b/tools/perf/ui/browser.c
new file mode 100644
index 000000000..321187b20
--- /dev/null
+++ b/tools/perf/ui/browser.c
@@ -0,0 +1,828 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "../util/string2.h"
+#include "../util/config.h"
+#include "libslang.h"
+#include "ui.h"
+#include "util.h"
+#include <linux/compiler.h>
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/string.h>
+#include <stdlib.h>
+#include <sys/ttydefaults.h>
+#include "browser.h"
+#include "helpline.h"
+#include "keysyms.h"
+#include "../util/color.h"
+#include <linux/ctype.h>
+#include <linux/zalloc.h>
+
+static int ui_browser__percent_color(struct ui_browser *browser,
+				     double percent, bool current)
+{
+	if (current && (!browser->use_navkeypressed || browser->navkeypressed))
+		return HE_COLORSET_SELECTED;
+	if (percent >= MIN_RED)
+		return HE_COLORSET_TOP;
+	if (percent >= MIN_GREEN)
+		return HE_COLORSET_MEDIUM;
+	return HE_COLORSET_NORMAL;
+}
+
+int ui_browser__set_color(struct ui_browser *browser, int color)
+{
+	int ret = browser->current_color;
+	browser->current_color = color;
+	SLsmg_set_color(color);
+	return ret;
+}
+
+void ui_browser__set_percent_color(struct ui_browser *browser,
+				   double percent, bool current)
+{
+	 int color = ui_browser__percent_color(browser, percent, current);
+	 ui_browser__set_color(browser, color);
+}
+
+void ui_browser__gotorc_title(struct ui_browser *browser, int y, int x)
+{
+	SLsmg_gotorc(browser->y + y, browser->x + x);
+}
+
+void ui_browser__gotorc(struct ui_browser *browser, int y, int x)
+{
+	SLsmg_gotorc(browser->y + y + browser->extra_title_lines, browser->x + x);
+}
+
+void ui_browser__write_nstring(struct ui_browser *browser __maybe_unused, const char *msg,
+			       unsigned int width)
+{
+	SLsmg_write_nstring(msg, width);
+}
+
+void ui_browser__vprintf(struct ui_browser *browser __maybe_unused, const char *fmt, va_list args)
+{
+	SLsmg_vprintf(fmt, args);
+}
+
+void ui_browser__printf(struct ui_browser *browser __maybe_unused, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	ui_browser__vprintf(browser, fmt, args);
+	va_end(args);
+}
+
+static struct list_head *
+ui_browser__list_head_filter_entries(struct ui_browser *browser,
+				     struct list_head *pos)
+{
+	do {
+		if (!browser->filter || !browser->filter(browser, pos))
+			return pos;
+		pos = pos->next;
+	} while (pos != browser->entries);
+
+	return NULL;
+}
+
+static struct list_head *
+ui_browser__list_head_filter_prev_entries(struct ui_browser *browser,
+					  struct list_head *pos)
+{
+	do {
+		if (!browser->filter || !browser->filter(browser, pos))
+			return pos;
+		pos = pos->prev;
+	} while (pos != browser->entries);
+
+	return NULL;
+}
+
+void ui_browser__list_head_seek(struct ui_browser *browser, off_t offset, int whence)
+{
+	struct list_head *head = browser->entries;
+	struct list_head *pos;
+
+	if (browser->nr_entries == 0)
+		return;
+
+	switch (whence) {
+	case SEEK_SET:
+		pos = ui_browser__list_head_filter_entries(browser, head->next);
+		break;
+	case SEEK_CUR:
+		pos = browser->top;
+		break;
+	case SEEK_END:
+		pos = ui_browser__list_head_filter_prev_entries(browser, head->prev);
+		break;
+	default:
+		return;
+	}
+
+	assert(pos != NULL);
+
+	if (offset > 0) {
+		while (offset-- != 0)
+			pos = ui_browser__list_head_filter_entries(browser, pos->next);
+	} else {
+		while (offset++ != 0)
+			pos = ui_browser__list_head_filter_prev_entries(browser, pos->prev);
+	}
+
+	browser->top = pos;
+}
+
+void ui_browser__rb_tree_seek(struct ui_browser *browser, off_t offset, int whence)
+{
+	struct rb_root *root = browser->entries;
+	struct rb_node *nd;
+
+	switch (whence) {
+	case SEEK_SET:
+		nd = rb_first(root);
+		break;
+	case SEEK_CUR:
+		nd = browser->top;
+		break;
+	case SEEK_END:
+		nd = rb_last(root);
+		break;
+	default:
+		return;
+	}
+
+	if (offset > 0) {
+		while (offset-- != 0)
+			nd = rb_next(nd);
+	} else {
+		while (offset++ != 0)
+			nd = rb_prev(nd);
+	}
+
+	browser->top = nd;
+}
+
+unsigned int ui_browser__rb_tree_refresh(struct ui_browser *browser)
+{
+	struct rb_node *nd;
+	int row = 0;
+
+	if (browser->top == NULL)
+                browser->top = rb_first(browser->entries);
+
+	nd = browser->top;
+
+	while (nd != NULL) {
+		ui_browser__gotorc(browser, row, 0);
+		browser->write(browser, nd, row);
+		if (++row == browser->rows)
+			break;
+		nd = rb_next(nd);
+	}
+
+	return row;
+}
+
+bool ui_browser__is_current_entry(struct ui_browser *browser, unsigned row)
+{
+	return browser->top_idx + row == browser->index;
+}
+
+void ui_browser__refresh_dimensions(struct ui_browser *browser)
+{
+	browser->width = SLtt_Screen_Cols - 1;
+	browser->height = browser->rows = SLtt_Screen_Rows - 2;
+	browser->rows -= browser->extra_title_lines;
+	browser->y = 1;
+	browser->x = 0;
+}
+
+void ui_browser__handle_resize(struct ui_browser *browser)
+{
+	ui__refresh_dimensions(false);
+	ui_browser__show(browser, browser->title ?: "", ui_helpline__current);
+	ui_browser__refresh(browser);
+}
+
+int ui_browser__warning(struct ui_browser *browser, int timeout,
+			const char *format, ...)
+{
+	va_list args;
+	char *text;
+	int key = 0, err;
+
+	va_start(args, format);
+	err = vasprintf(&text, format, args);
+	va_end(args);
+
+	if (err < 0) {
+		va_start(args, format);
+		ui_helpline__vpush(format, args);
+		va_end(args);
+	} else {
+		while ((key = ui__question_window("Warning!", text,
+						   "Press any key...",
+						   timeout)) == K_RESIZE)
+			ui_browser__handle_resize(browser);
+		free(text);
+	}
+
+	return key;
+}
+
+int ui_browser__warn_unhandled_hotkey(struct ui_browser *browser, int key, int timeout, const char *help)
+{
+	char kname[32];
+
+	key_name(key, kname, sizeof(kname));
+	return ui_browser__warning(browser, timeout, "\n'%s' key not associated%s!\n", kname, help ?: "");
+}
+
+int ui_browser__help_window(struct ui_browser *browser, const char *text)
+{
+	int key;
+
+	while ((key = ui__help_window(text)) == K_RESIZE)
+		ui_browser__handle_resize(browser);
+
+	return key;
+}
+
+bool ui_browser__dialog_yesno(struct ui_browser *browser, const char *text)
+{
+	int key;
+
+	while ((key = ui__dialog_yesno(text)) == K_RESIZE)
+		ui_browser__handle_resize(browser);
+
+	return key == K_ENTER || toupper(key) == 'Y';
+}
+
+void ui_browser__reset_index(struct ui_browser *browser)
+{
+	browser->index = browser->top_idx = 0;
+	browser->seek(browser, 0, SEEK_SET);
+}
+
+void __ui_browser__show_title(struct ui_browser *browser, const char *title)
+{
+	SLsmg_gotorc(0, 0);
+	ui_browser__set_color(browser, HE_COLORSET_ROOT);
+	ui_browser__write_nstring(browser, title, browser->width + 1);
+}
+
+void ui_browser__show_title(struct ui_browser *browser, const char *title)
+{
+	mutex_lock(&ui__lock);
+	__ui_browser__show_title(browser, title);
+	mutex_unlock(&ui__lock);
+}
+
+int ui_browser__show(struct ui_browser *browser, const char *title,
+		     const char *helpline, ...)
+{
+	int err;
+	va_list ap;
+
+	if (browser->refresh_dimensions == NULL)
+		browser->refresh_dimensions = ui_browser__refresh_dimensions;
+
+	browser->refresh_dimensions(browser);
+
+	mutex_lock(&ui__lock);
+	__ui_browser__show_title(browser, title);
+
+	free(browser->title);
+	browser->title = strdup(title);
+	zfree(&browser->helpline);
+
+	va_start(ap, helpline);
+	err = vasprintf(&browser->helpline, helpline, ap);
+	va_end(ap);
+	if (err > 0)
+		ui_helpline__push(browser->helpline);
+	mutex_unlock(&ui__lock);
+	return err ? 0 : -1;
+}
+
+void ui_browser__hide(struct ui_browser *browser)
+{
+	mutex_lock(&ui__lock);
+	ui_helpline__pop();
+	zfree(&browser->helpline);
+	zfree(&browser->title);
+	mutex_unlock(&ui__lock);
+}
+
+static void ui_browser__scrollbar_set(struct ui_browser *browser)
+{
+	int height = browser->height, h = 0, pct = 0,
+	    col = browser->width,
+	    row = 0;
+
+	if (browser->nr_entries > 1) {
+		pct = ((browser->index * (browser->height - 1)) /
+		       (browser->nr_entries - 1));
+	}
+
+	SLsmg_set_char_set(1);
+
+	while (h < height) {
+	        ui_browser__gotorc(browser, row++, col);
+		SLsmg_write_char(h == pct ? SLSMG_DIAMOND_CHAR : SLSMG_CKBRD_CHAR);
+		++h;
+	}
+
+	SLsmg_set_char_set(0);
+}
+
+static int __ui_browser__refresh(struct ui_browser *browser)
+{
+	int row;
+	int width = browser->width;
+
+	row = browser->refresh(browser);
+	ui_browser__set_color(browser, HE_COLORSET_NORMAL);
+
+	if (!browser->use_navkeypressed || browser->navkeypressed)
+		ui_browser__scrollbar_set(browser);
+	else
+		width += 1;
+
+	SLsmg_fill_region(browser->y + row + browser->extra_title_lines, browser->x,
+			  browser->rows - row, width, ' ');
+
+	if (browser->nr_entries == 0 && browser->no_samples_msg)
+		__ui__info_window(NULL, browser->no_samples_msg, NULL);
+	return 0;
+}
+
+int ui_browser__refresh(struct ui_browser *browser)
+{
+	mutex_lock(&ui__lock);
+	__ui_browser__refresh(browser);
+	mutex_unlock(&ui__lock);
+
+	return 0;
+}
+
+/*
+ * Here we're updating nr_entries _after_ we started browsing, i.e.  we have to
+ * forget about any reference to any entry in the underlying data structure,
+ * that is why we do a SEEK_SET. Think about 'perf top' in the hists browser
+ * after an output_resort and hist decay.
+ */
+void ui_browser__update_nr_entries(struct ui_browser *browser, u32 nr_entries)
+{
+	off_t offset = nr_entries - browser->nr_entries;
+
+	browser->nr_entries = nr_entries;
+
+	if (offset < 0) {
+		if (browser->top_idx < (u64)-offset)
+			offset = -browser->top_idx;
+
+		browser->index += offset;
+		browser->top_idx += offset;
+	}
+
+	browser->top = NULL;
+	browser->seek(browser, browser->top_idx, SEEK_SET);
+}
+
+int ui_browser__run(struct ui_browser *browser, int delay_secs)
+{
+	int err, key;
+
+	while (1) {
+		off_t offset;
+
+		mutex_lock(&ui__lock);
+		err = __ui_browser__refresh(browser);
+		SLsmg_refresh();
+		mutex_unlock(&ui__lock);
+		if (err < 0)
+			break;
+
+		key = ui__getch(delay_secs);
+
+		if (key == K_RESIZE) {
+			ui__refresh_dimensions(false);
+			browser->refresh_dimensions(browser);
+			__ui_browser__show_title(browser, browser->title);
+			ui_helpline__puts(browser->helpline);
+			continue;
+		}
+
+		if (browser->use_navkeypressed && !browser->navkeypressed) {
+			if (key == K_DOWN || key == K_UP ||
+			    (browser->columns && (key == K_LEFT || key == K_RIGHT)) ||
+			    key == K_PGDN || key == K_PGUP ||
+			    key == K_HOME || key == K_END ||
+			    key == ' ') {
+				browser->navkeypressed = true;
+				continue;
+			} else
+				return key;
+		}
+
+		switch (key) {
+		case K_DOWN:
+			if (browser->index == browser->nr_entries - 1)
+				break;
+			++browser->index;
+			if (browser->index == browser->top_idx + browser->rows) {
+				++browser->top_idx;
+				browser->seek(browser, +1, SEEK_CUR);
+			}
+			break;
+		case K_UP:
+			if (browser->index == 0)
+				break;
+			--browser->index;
+			if (browser->index < browser->top_idx) {
+				--browser->top_idx;
+				browser->seek(browser, -1, SEEK_CUR);
+			}
+			break;
+		case K_RIGHT:
+			if (!browser->columns)
+				goto out;
+			if (browser->horiz_scroll < browser->columns - 1)
+				++browser->horiz_scroll;
+			break;
+		case K_LEFT:
+			if (!browser->columns)
+				goto out;
+			if (browser->horiz_scroll != 0)
+				--browser->horiz_scroll;
+			else
+				goto out;
+			break;
+		case K_PGDN:
+		case ' ':
+			if (browser->top_idx + browser->rows > browser->nr_entries - 1)
+				break;
+
+			offset = browser->rows;
+			if (browser->index + offset > browser->nr_entries - 1)
+				offset = browser->nr_entries - 1 - browser->index;
+			browser->index += offset;
+			browser->top_idx += offset;
+			browser->seek(browser, +offset, SEEK_CUR);
+			break;
+		case K_PGUP:
+			if (browser->top_idx == 0)
+				break;
+
+			if (browser->top_idx < browser->rows)
+				offset = browser->top_idx;
+			else
+				offset = browser->rows;
+
+			browser->index -= offset;
+			browser->top_idx -= offset;
+			browser->seek(browser, -offset, SEEK_CUR);
+			break;
+		case K_HOME:
+			ui_browser__reset_index(browser);
+			break;
+		case K_END:
+			offset = browser->rows - 1;
+			if (offset >= browser->nr_entries)
+				offset = browser->nr_entries - 1;
+
+			browser->index = browser->nr_entries - 1;
+			browser->top_idx = browser->index - offset;
+			browser->seek(browser, -offset, SEEK_END);
+			break;
+		default:
+		out:
+			return key;
+		}
+	}
+	return -1;
+}
+
+unsigned int ui_browser__list_head_refresh(struct ui_browser *browser)
+{
+	struct list_head *pos;
+	struct list_head *head = browser->entries;
+	int row = 0;
+
+	if (browser->nr_entries == 0)
+		return 0;
+
+	if (browser->top == NULL || browser->top == browser->entries)
+                browser->top = ui_browser__list_head_filter_entries(browser, head->next);
+
+	pos = browser->top;
+
+	list_for_each_from(pos, head) {
+		if (!browser->filter || !browser->filter(browser, pos)) {
+			ui_browser__gotorc(browser, row, 0);
+			browser->write(browser, pos, row);
+			if (++row == browser->rows)
+				break;
+		}
+	}
+
+	return row;
+}
+
+static struct ui_browser_colorset {
+	const char *name, *fg, *bg;
+	int colorset;
+} ui_browser__colorsets[] = {
+	{
+		.colorset = HE_COLORSET_TOP,
+		.name	  = "top",
+		.fg	  = "red",
+		.bg	  = "default",
+	},
+	{
+		.colorset = HE_COLORSET_MEDIUM,
+		.name	  = "medium",
+		.fg	  = "green",
+		.bg	  = "default",
+	},
+	{
+		.colorset = HE_COLORSET_NORMAL,
+		.name	  = "normal",
+		.fg	  = "default",
+		.bg	  = "default",
+	},
+	{
+		.colorset = HE_COLORSET_SELECTED,
+		.name	  = "selected",
+		.fg	  = "black",
+		.bg	  = "yellow",
+	},
+	{
+		.colorset = HE_COLORSET_JUMP_ARROWS,
+		.name	  = "jump_arrows",
+		.fg	  = "blue",
+		.bg	  = "default",
+	},
+	{
+		.colorset = HE_COLORSET_ADDR,
+		.name	  = "addr",
+		.fg	  = "magenta",
+		.bg	  = "default",
+	},
+	{
+		.colorset = HE_COLORSET_ROOT,
+		.name	  = "root",
+		.fg	  = "white",
+		.bg	  = "blue",
+	},
+	{
+		.name = NULL,
+	}
+};
+
+
+static int ui_browser__color_config(const char *var, const char *value,
+				    void *data __maybe_unused)
+{
+	char *fg = NULL, *bg;
+	int i;
+
+	/* same dir for all commands */
+	if (!strstarts(var, "colors.") != 0)
+		return 0;
+
+	for (i = 0; ui_browser__colorsets[i].name != NULL; ++i) {
+		const char *name = var + 7;
+
+		if (strcmp(ui_browser__colorsets[i].name, name) != 0)
+			continue;
+
+		fg = strdup(value);
+		if (fg == NULL)
+			break;
+
+		bg = strchr(fg, ',');
+		if (bg == NULL)
+			break;
+
+		*bg = '\0';
+		bg = skip_spaces(bg + 1);
+		ui_browser__colorsets[i].bg = bg;
+		ui_browser__colorsets[i].fg = fg;
+		return 0;
+	}
+
+	free(fg);
+	return -1;
+}
+
+void ui_browser__argv_seek(struct ui_browser *browser, off_t offset, int whence)
+{
+	switch (whence) {
+	case SEEK_SET:
+		browser->top = browser->entries;
+		break;
+	case SEEK_CUR:
+		browser->top = (char **)browser->top + offset;
+		break;
+	case SEEK_END:
+		browser->top = (char **)browser->entries + browser->nr_entries - 1 + offset;
+		break;
+	default:
+		return;
+	}
+	assert((char **)browser->top < (char **)browser->entries + browser->nr_entries);
+	assert((char **)browser->top >= (char **)browser->entries);
+}
+
+unsigned int ui_browser__argv_refresh(struct ui_browser *browser)
+{
+	unsigned int row = 0, idx = browser->top_idx;
+	char **pos;
+
+	if (browser->top == NULL)
+		browser->top = browser->entries;
+
+	pos = (char **)browser->top;
+	while (idx < browser->nr_entries &&
+	       row < (unsigned)SLtt_Screen_Rows - 1) {
+		assert(pos < (char **)browser->entries + browser->nr_entries);
+		if (!browser->filter || !browser->filter(browser, *pos)) {
+			ui_browser__gotorc(browser, row, 0);
+			browser->write(browser, pos, row);
+			if (++row == browser->rows)
+				break;
+		}
+
+		++idx;
+		++pos;
+	}
+
+	return row;
+}
+
+void __ui_browser__vline(struct ui_browser *browser, unsigned int column,
+			 u16 start, u16 end)
+{
+	SLsmg_set_char_set(1);
+	ui_browser__gotorc(browser, start, column);
+	SLsmg_draw_vline(end - start + 1);
+	SLsmg_set_char_set(0);
+}
+
+void ui_browser__write_graph(struct ui_browser *browser __maybe_unused,
+			     int graph)
+{
+	SLsmg_set_char_set(1);
+	SLsmg_write_char(graph);
+	SLsmg_set_char_set(0);
+}
+
+static void __ui_browser__line_arrow_up(struct ui_browser *browser,
+					unsigned int column,
+					u64 start, u64 end)
+{
+	unsigned int row, end_row;
+
+	SLsmg_set_char_set(1);
+
+	if (start < browser->top_idx + browser->rows) {
+		row = start - browser->top_idx;
+		ui_browser__gotorc(browser, row, column);
+		SLsmg_write_char(SLSMG_LLCORN_CHAR);
+		ui_browser__gotorc(browser, row, column + 1);
+		SLsmg_draw_hline(2);
+
+		if (row-- == 0)
+			goto out;
+	} else
+		row = browser->rows - 1;
+
+	if (end > browser->top_idx)
+		end_row = end - browser->top_idx;
+	else
+		end_row = 0;
+
+	ui_browser__gotorc(browser, end_row, column);
+	SLsmg_draw_vline(row - end_row + 1);
+
+	ui_browser__gotorc(browser, end_row, column);
+	if (end >= browser->top_idx) {
+		SLsmg_write_char(SLSMG_ULCORN_CHAR);
+		ui_browser__gotorc(browser, end_row, column + 1);
+		SLsmg_write_char(SLSMG_HLINE_CHAR);
+		ui_browser__gotorc(browser, end_row, column + 2);
+		SLsmg_write_char(SLSMG_RARROW_CHAR);
+	}
+out:
+	SLsmg_set_char_set(0);
+}
+
+static void __ui_browser__line_arrow_down(struct ui_browser *browser,
+					  unsigned int column,
+					  u64 start, u64 end)
+{
+	unsigned int row, end_row;
+
+	SLsmg_set_char_set(1);
+
+	if (start >= browser->top_idx) {
+		row = start - browser->top_idx;
+		ui_browser__gotorc(browser, row, column);
+		SLsmg_write_char(SLSMG_ULCORN_CHAR);
+		ui_browser__gotorc(browser, row, column + 1);
+		SLsmg_draw_hline(2);
+
+		if (++row == 0)
+			goto out;
+	} else
+		row = 0;
+
+	if (end >= browser->top_idx + browser->rows)
+		end_row = browser->rows - 1;
+	else
+		end_row = end - browser->top_idx;
+
+	ui_browser__gotorc(browser, row, column);
+	SLsmg_draw_vline(end_row - row + 1);
+
+	ui_browser__gotorc(browser, end_row, column);
+	if (end < browser->top_idx + browser->rows) {
+		SLsmg_write_char(SLSMG_LLCORN_CHAR);
+		ui_browser__gotorc(browser, end_row, column + 1);
+		SLsmg_write_char(SLSMG_HLINE_CHAR);
+		ui_browser__gotorc(browser, end_row, column + 2);
+		SLsmg_write_char(SLSMG_RARROW_CHAR);
+	}
+out:
+	SLsmg_set_char_set(0);
+}
+
+void __ui_browser__line_arrow(struct ui_browser *browser, unsigned int column,
+			      u64 start, u64 end)
+{
+	if (start > end)
+		__ui_browser__line_arrow_up(browser, column, start, end);
+	else
+		__ui_browser__line_arrow_down(browser, column, start, end);
+}
+
+void ui_browser__mark_fused(struct ui_browser *browser, unsigned int column,
+			    unsigned int row, int diff, bool arrow_down)
+{
+	int end_row;
+
+	if (diff <= 0)
+		return;
+
+	SLsmg_set_char_set(1);
+
+	if (arrow_down) {
+		if (row + diff <= browser->top_idx)
+			return;
+
+		end_row = row + diff - browser->top_idx;
+		ui_browser__gotorc(browser, end_row, column - 1);
+		SLsmg_write_char(SLSMG_LTEE_CHAR);
+
+		while (--end_row >= 0 && end_row > (int)(row - browser->top_idx)) {
+			ui_browser__gotorc(browser, end_row, column - 1);
+			SLsmg_draw_vline(1);
+		}
+
+		end_row = (int)(row - browser->top_idx);
+		if (end_row >= 0) {
+			ui_browser__gotorc(browser, end_row, column - 1);
+			SLsmg_write_char(SLSMG_ULCORN_CHAR);
+			ui_browser__gotorc(browser, end_row, column);
+			SLsmg_draw_hline(2);
+		}
+	} else {
+		if (row < browser->top_idx)
+			return;
+
+		end_row = row - browser->top_idx;
+		ui_browser__gotorc(browser, end_row, column - 1);
+		SLsmg_write_char(SLSMG_LTEE_CHAR);
+		ui_browser__gotorc(browser, end_row, column);
+		SLsmg_draw_hline(2);
+	}
+
+	SLsmg_set_char_set(0);
+}
+
+void ui_browser__init(void)
+{
+	int i = 0;
+
+	perf_config(ui_browser__color_config, NULL);
+
+	while (ui_browser__colorsets[i].name) {
+		struct ui_browser_colorset *c = &ui_browser__colorsets[i++];
+		SLtt_set_color(c->colorset, c->name, c->fg, c->bg);
+	}
+}