Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 625 insertions, 0 deletions

diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c
new file mode 100644
index 0000000000..974e917e65
--- /dev/null
+++ b/arch/x86/events/intel/bts.c
@@ -0,0 +1,625 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * BTS PMU driver for perf
+ * Copyright (c) 2013-2014, Intel Corporation.
+ */
+
+#undef DEBUG
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bitops.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/coredump.h>
+
+#include <linux/sizes.h>
+#include <asm/perf_event.h>
+
+#include "../perf_event.h"
+
+struct bts_ctx {
+	struct perf_output_handle	handle;
+	struct debug_store		ds_back;
+	int				state;
+};
+
+/* BTS context states: */
+enum {
+	/* no ongoing AUX transactions */
+	BTS_STATE_STOPPED = 0,
+	/* AUX transaction is on, BTS tracing is disabled */
+	BTS_STATE_INACTIVE,
+	/* AUX transaction is on, BTS tracing is running */
+	BTS_STATE_ACTIVE,
+};
+
+static DEFINE_PER_CPU(struct bts_ctx, bts_ctx);
+
+#define BTS_RECORD_SIZE		24
+#define BTS_SAFETY_MARGIN	4080
+
+struct bts_phys {
+	struct page	*page;
+	unsigned long	size;
+	unsigned long	offset;
+	unsigned long	displacement;
+};
+
+struct bts_buffer {
+	size_t		real_size;	/* multiple of BTS_RECORD_SIZE */
+	unsigned int	nr_pages;
+	unsigned int	nr_bufs;
+	unsigned int	cur_buf;
+	bool		snapshot;
+	local_t		data_size;
+	local_t		head;
+	unsigned long	end;
+	void		**data_pages;
+	struct bts_phys	buf[];
+};
+
+static struct pmu bts_pmu;
+
+static int buf_nr_pages(struct page *page)
+{
+	if (!PagePrivate(page))
+		return 1;
+
+	return 1 << page_private(page);
+}
+
+static size_t buf_size(struct page *page)
+{
+	return buf_nr_pages(page) * PAGE_SIZE;
+}
+
+static void *
+bts_buffer_setup_aux(struct perf_event *event, void **pages,
+		     int nr_pages, bool overwrite)
+{
+	struct bts_buffer *buf;
+	struct page *page;
+	int cpu = event->cpu;
+	int node = (cpu == -1) ? cpu : cpu_to_node(cpu);
+	unsigned long offset;
+	size_t size = nr_pages << PAGE_SHIFT;
+	int pg, nbuf, pad;
+
+	/* count all the high order buffers */
+	for (pg = 0, nbuf = 0; pg < nr_pages;) {
+		page = virt_to_page(pages[pg]);
+		pg += buf_nr_pages(page);
+		nbuf++;
+	}
+
+	/*
+	 * to avoid interrupts in overwrite mode, only allow one physical
+	 */
+	if (overwrite && nbuf > 1)
+		return NULL;
+
+	buf = kzalloc_node(offsetof(struct bts_buffer, buf[nbuf]), GFP_KERNEL, node);
+	if (!buf)
+		return NULL;
+
+	buf->nr_pages = nr_pages;
+	buf->nr_bufs = nbuf;
+	buf->snapshot = overwrite;
+	buf->data_pages = pages;
+	buf->real_size = size - size % BTS_RECORD_SIZE;
+
+	for (pg = 0, nbuf = 0, offset = 0, pad = 0; nbuf < buf->nr_bufs; nbuf++) {
+		unsigned int __nr_pages;
+
+		page = virt_to_page(pages[pg]);
+		__nr_pages = buf_nr_pages(page);
+		buf->buf[nbuf].page = page;
+		buf->buf[nbuf].offset = offset;
+		buf->buf[nbuf].displacement = (pad ? BTS_RECORD_SIZE - pad : 0);
+		buf->buf[nbuf].size = buf_size(page) - buf->buf[nbuf].displacement;
+		pad = buf->buf[nbuf].size % BTS_RECORD_SIZE;
+		buf->buf[nbuf].size -= pad;
+
+		pg += __nr_pages;
+		offset += __nr_pages << PAGE_SHIFT;
+	}
+
+	return buf;
+}
+
+static void bts_buffer_free_aux(void *data)
+{
+	kfree(data);
+}
+
+static unsigned long bts_buffer_offset(struct bts_buffer *buf, unsigned int idx)
+{
+	return buf->buf[idx].offset + buf->buf[idx].displacement;
+}
+
+static void
+bts_config_buffer(struct bts_buffer *buf)
+{
+	int cpu = raw_smp_processor_id();
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	struct bts_phys *phys = &buf->buf[buf->cur_buf];
+	unsigned long index, thresh = 0, end = phys->size;
+	struct page *page = phys->page;
+
+	index = local_read(&buf->head);
+
+	if (!buf->snapshot) {
+		if (buf->end < phys->offset + buf_size(page))
+			end = buf->end - phys->offset - phys->displacement;
+
+		index -= phys->offset + phys->displacement;
+
+		if (end - index > BTS_SAFETY_MARGIN)
+			thresh = end - BTS_SAFETY_MARGIN;
+		else if (end - index > BTS_RECORD_SIZE)
+			thresh = end - BTS_RECORD_SIZE;
+		else
+			thresh = end;
+	}
+
+	ds->bts_buffer_base = (u64)(long)page_address(page) + phys->displacement;
+	ds->bts_index = ds->bts_buffer_base + index;
+	ds->bts_absolute_maximum = ds->bts_buffer_base + end;
+	ds->bts_interrupt_threshold = !buf->snapshot
+		? ds->bts_buffer_base + thresh
+		: ds->bts_absolute_maximum + BTS_RECORD_SIZE;
+}
+
+static void bts_buffer_pad_out(struct bts_phys *phys, unsigned long head)
+{
+	unsigned long index = head - phys->offset;
+
+	memset(page_address(phys->page) + index, 0, phys->size - index);
+}
+
+static void bts_update(struct bts_ctx *bts)
+{
+	int cpu = raw_smp_processor_id();
+	struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+	struct bts_buffer *buf = perf_get_aux(&bts->handle);
+	unsigned long index = ds->bts_index - ds->bts_buffer_base, old, head;
+
+	if (!buf)
+		return;
+
+	head = index + bts_buffer_offset(buf, buf->cur_buf);
+	old = local_xchg(&buf->head, head);
+
+	if (!buf->snapshot) {
+		if (old == head)
+			return;
+
+		if (ds->bts_index >= ds->bts_absolute_maximum)
+			perf_aux_output_flag(&bts->handle,
+			                     PERF_AUX_FLAG_TRUNCATED);
+
+		/*
+		 * old and head are always in the same physical buffer, so we
+		 * can subtract them to get the data size.
+		 */
+		local_add(head - old, &buf->data_size);
+	} else {
+		local_set(&buf->data_size, head);
+	}
+
+	/*
+	 * Since BTS is coherent, just add compiler barrier to ensure
+	 * BTS updating is ordered against bts::handle::event.
+	 */
+	barrier();
+}
+
+static int
+bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle);
+
+/*
+ * Ordering PMU callbacks wrt themselves and the PMI is done by means
+ * of bts::state, which:
+ *  - is set when bts::handle::event is valid, that is, between
+ *    perf_aux_output_begin() and perf_aux_output_end();
+ *  - is zero otherwise;
+ *  - is ordered against bts::handle::event with a compiler barrier.
+ */
+
+static void __bts_event_start(struct perf_event *event)
+{
+	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
+	struct bts_buffer *buf = perf_get_aux(&bts->handle);
+	u64 config = 0;
+
+	if (!buf->snapshot)
+		config |= ARCH_PERFMON_EVENTSEL_INT;
+	if (!event->attr.exclude_kernel)
+		config |= ARCH_PERFMON_EVENTSEL_OS;
+	if (!event->attr.exclude_user)
+		config |= ARCH_PERFMON_EVENTSEL_USR;
+
+	bts_config_buffer(buf);
+
+	/*
+	 * local barrier to make sure that ds configuration made it
+	 * before we enable BTS and bts::state goes ACTIVE
+	 */
+	wmb();
+
+	/* INACTIVE/STOPPED -> ACTIVE */
+	WRITE_ONCE(bts->state, BTS_STATE_ACTIVE);
+
+	intel_pmu_enable_bts(config);
+
+}
+
+static void bts_event_start(struct perf_event *event, int flags)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
+	struct bts_buffer *buf;
+
+	buf = perf_aux_output_begin(&bts->handle, event);
+	if (!buf)
+		goto fail_stop;
+
+	if (bts_buffer_reset(buf, &bts->handle))
+		goto fail_end_stop;
+
+	bts->ds_back.bts_buffer_base = cpuc->ds->bts_buffer_base;
+	bts->ds_back.bts_absolute_maximum = cpuc->ds->bts_absolute_maximum;
+	bts->ds_back.bts_interrupt_threshold = cpuc->ds->bts_interrupt_threshold;
+
+	perf_event_itrace_started(event);
+	event->hw.state = 0;
+
+	__bts_event_start(event);
+
+	return;
+
+fail_end_stop:
+	perf_aux_output_end(&bts->handle, 0);
+
+fail_stop:
+	event->hw.state = PERF_HES_STOPPED;
+}
+
+static void __bts_event_stop(struct perf_event *event, int state)
+{
+	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
+
+	/* ACTIVE -> INACTIVE(PMI)/STOPPED(->stop()) */
+	WRITE_ONCE(bts->state, state);
+
+	/*
+	 * No extra synchronization is mandated by the documentation to have
+	 * BTS data stores globally visible.
+	 */
+	intel_pmu_disable_bts();
+}
+
+static void bts_event_stop(struct perf_event *event, int flags)
+{
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
+	struct bts_buffer *buf = NULL;
+	int state = READ_ONCE(bts->state);
+
+	if (state == BTS_STATE_ACTIVE)
+		__bts_event_stop(event, BTS_STATE_STOPPED);
+
+	if (state != BTS_STATE_STOPPED)
+		buf = perf_get_aux(&bts->handle);
+
+	event->hw.state |= PERF_HES_STOPPED;
+
+	if (flags & PERF_EF_UPDATE) {
+		bts_update(bts);
+
+		if (buf) {
+			if (buf->snapshot)
+				bts->handle.head =
+					local_xchg(&buf->data_size,
+						   buf->nr_pages << PAGE_SHIFT);
+			perf_aux_output_end(&bts->handle,
+			                    local_xchg(&buf->data_size, 0));
+		}
+
+		cpuc->ds->bts_index = bts->ds_back.bts_buffer_base;
+		cpuc->ds->bts_buffer_base = bts->ds_back.bts_buffer_base;
+		cpuc->ds->bts_absolute_maximum = bts->ds_back.bts_absolute_maximum;
+		cpuc->ds->bts_interrupt_threshold = bts->ds_back.bts_interrupt_threshold;
+	}
+}
+
+void intel_bts_enable_local(void)
+{
+	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
+	int state = READ_ONCE(bts->state);
+
+	/*
+	 * Here we transition from INACTIVE to ACTIVE;
+	 * if we instead are STOPPED from the interrupt handler,
+	 * stay that way. Can't be ACTIVE here though.
+	 */
+	if (WARN_ON_ONCE(state == BTS_STATE_ACTIVE))
+		return;
+
+	if (state == BTS_STATE_STOPPED)
+		return;
+
+	if (bts->handle.event)
+		__bts_event_start(bts->handle.event);
+}
+
+void intel_bts_disable_local(void)
+{
+	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
+
+	/*
+	 * Here we transition from ACTIVE to INACTIVE;
+	 * do nothing for STOPPED or INACTIVE.
+	 */
+	if (READ_ONCE(bts->state) != BTS_STATE_ACTIVE)
+		return;
+
+	if (bts->handle.event)
+		__bts_event_stop(bts->handle.event, BTS_STATE_INACTIVE);
+}
+
+static int
+bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle)
+{
+	unsigned long head, space, next_space, pad, gap, skip, wakeup;
+	unsigned int next_buf;
+	struct bts_phys *phys, *next_phys;
+	int ret;
+
+	if (buf->snapshot)
+		return 0;
+
+	head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
+
+	phys = &buf->buf[buf->cur_buf];
+	space = phys->offset + phys->displacement + phys->size - head;
+	pad = space;
+	if (space > handle->size) {
+		space = handle->size;
+		space -= space % BTS_RECORD_SIZE;
+	}
+	if (space <= BTS_SAFETY_MARGIN) {
+		/* See if next phys buffer has more space */
+		next_buf = buf->cur_buf + 1;
+		if (next_buf >= buf->nr_bufs)
+			next_buf = 0;
+		next_phys = &buf->buf[next_buf];
+		gap = buf_size(phys->page) - phys->displacement - phys->size +
+		      next_phys->displacement;
+		skip = pad + gap;
+		if (handle->size >= skip) {
+			next_space = next_phys->size;
+			if (next_space + skip > handle->size) {
+				next_space = handle->size - skip;
+				next_space -= next_space % BTS_RECORD_SIZE;
+			}
+			if (next_space > space || !space) {
+				if (pad)
+					bts_buffer_pad_out(phys, head);
+				ret = perf_aux_output_skip(handle, skip);
+				if (ret)
+					return ret;
+				/* Advance to next phys buffer */
+				phys = next_phys;
+				space = next_space;
+				head = phys->offset + phys->displacement;
+				/*
+				 * After this, cur_buf and head won't match ds
+				 * anymore, so we must not be racing with
+				 * bts_update().
+				 */
+				buf->cur_buf = next_buf;
+				local_set(&buf->head, head);
+			}
+		}
+	}
+
+	/* Don't go far beyond wakeup watermark */
+	wakeup = BTS_SAFETY_MARGIN + BTS_RECORD_SIZE + handle->wakeup -
+		 handle->head;
+	if (space > wakeup) {
+		space = wakeup;
+		space -= space % BTS_RECORD_SIZE;
+	}
+
+	buf->end = head + space;
+
+	/*
+	 * If we have no space, the lost notification would have been sent when
+	 * we hit absolute_maximum - see bts_update()
+	 */
+	if (!space)
+		return -ENOSPC;
+
+	return 0;
+}
+
+int intel_bts_interrupt(void)
+{
+	struct debug_store *ds = this_cpu_ptr(&cpu_hw_events)->ds;
+	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
+	struct perf_event *event = bts->handle.event;
+	struct bts_buffer *buf;
+	s64 old_head;
+	int err = -ENOSPC, handled = 0;
+
+	/*
+	 * The only surefire way of knowing if this NMI is ours is by checking
+	 * the write ptr against the PMI threshold.
+	 */
+	if (ds && (ds->bts_index >= ds->bts_interrupt_threshold))
+		handled = 1;
+
+	/*
+	 * this is wrapped in intel_bts_enable_local/intel_bts_disable_local,
+	 * so we can only be INACTIVE or STOPPED
+	 */
+	if (READ_ONCE(bts->state) == BTS_STATE_STOPPED)
+		return handled;
+
+	buf = perf_get_aux(&bts->handle);
+	if (!buf)
+		return handled;
+
+	/*
+	 * Skip snapshot counters: they don't use the interrupt, but
+	 * there's no other way of telling, because the pointer will
+	 * keep moving
+	 */
+	if (buf->snapshot)
+		return 0;
+
+	old_head = local_read(&buf->head);
+	bts_update(bts);
+
+	/* no new data */
+	if (old_head == local_read(&buf->head))
+		return handled;
+
+	perf_aux_output_end(&bts->handle, local_xchg(&buf->data_size, 0));
+
+	buf = perf_aux_output_begin(&bts->handle, event);
+	if (buf)
+		err = bts_buffer_reset(buf, &bts->handle);
+
+	if (err) {
+		WRITE_ONCE(bts->state, BTS_STATE_STOPPED);
+
+		if (buf) {
+			/*
+			 * BTS_STATE_STOPPED should be visible before
+			 * cleared handle::event
+			 */
+			barrier();
+			perf_aux_output_end(&bts->handle, 0);
+		}
+	}
+
+	return 1;
+}
+
+static void bts_event_del(struct perf_event *event, int mode)
+{
+	bts_event_stop(event, PERF_EF_UPDATE);
+}
+
+static int bts_event_add(struct perf_event *event, int mode)
+{
+	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
+	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
+	struct hw_perf_event *hwc = &event->hw;
+
+	event->hw.state = PERF_HES_STOPPED;
+
+	if (test_bit(INTEL_PMC_IDX_FIXED_BTS, cpuc->active_mask))
+		return -EBUSY;
+
+	if (bts->handle.event)
+		return -EBUSY;
+
+	if (mode & PERF_EF_START) {
+		bts_event_start(event, 0);
+		if (hwc->state & PERF_HES_STOPPED)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void bts_event_destroy(struct perf_event *event)
+{
+	x86_release_hardware();
+	x86_del_exclusive(x86_lbr_exclusive_bts);
+}
+
+static int bts_event_init(struct perf_event *event)
+{
+	int ret;
+
+	if (event->attr.type != bts_pmu.type)
+		return -ENOENT;
+
+	/*
+	 * BTS leaks kernel addresses even when CPL0 tracing is
+	 * disabled, so disallow intel_bts driver for unprivileged
+	 * users on paranoid systems since it provides trace data
+	 * to the user in a zero-copy fashion.
+	 *
+	 * Note that the default paranoia setting permits unprivileged
+	 * users to profile the kernel.
+	 */
+	if (event->attr.exclude_kernel) {
+		ret = perf_allow_kernel(&event->attr);
+		if (ret)
+			return ret;
+	}
+
+	if (x86_add_exclusive(x86_lbr_exclusive_bts))
+		return -EBUSY;
+
+	ret = x86_reserve_hardware();
+	if (ret) {
+		x86_del_exclusive(x86_lbr_exclusive_bts);
+		return ret;
+	}
+
+	event->destroy = bts_event_destroy;
+
+	return 0;
+}
+
+static void bts_event_read(struct perf_event *event)
+{
+}
+
+static __init int bts_init(void)
+{
+	if (!boot_cpu_has(X86_FEATURE_DTES64) || !x86_pmu.bts)
+		return -ENODEV;
+
+	if (boot_cpu_has(X86_FEATURE_PTI)) {
+		/*
+		 * BTS hardware writes through a virtual memory map we must
+		 * either use the kernel physical map, or the user mapping of
+		 * the AUX buffer.
+		 *
+		 * However, since this driver supports per-CPU and per-task inherit
+		 * we cannot use the user mapping since it will not be available
+		 * if we're not running the owning process.
+		 *
+		 * With PTI we can't use the kernel map either, because its not
+		 * there when we run userspace.
+		 *
+		 * For now, disable this driver when using PTI.
+		 */
+		return -ENODEV;
+	}
+
+	bts_pmu.capabilities	= PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_ITRACE |
+				  PERF_PMU_CAP_EXCLUSIVE;
+	bts_pmu.task_ctx_nr	= perf_sw_context;
+	bts_pmu.event_init	= bts_event_init;
+	bts_pmu.add		= bts_event_add;
+	bts_pmu.del		= bts_event_del;
+	bts_pmu.start		= bts_event_start;
+	bts_pmu.stop		= bts_event_stop;
+	bts_pmu.read		= bts_event_read;
+	bts_pmu.setup_aux	= bts_buffer_setup_aux;
+	bts_pmu.free_aux	= bts_buffer_free_aux;
+
+	return perf_pmu_register(&bts_pmu, "intel_bts", -1);
+}
+arch_initcall(bts_init);