1 files changed, 371 insertions, 150 deletions

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index d3dc2274ddd4..1db7a51d9792 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -204,9 +204,9 @@ static int __init pt_pmu_hw_init(void)
 
 	/* model-specific quirks */
 	switch (boot_cpu_data.x86_model) {
-	case INTEL_FAM6_BROADWELL_CORE:
-	case INTEL_FAM6_BROADWELL_XEON_D:
-	case INTEL_FAM6_BROADWELL_GT3E:
+	case INTEL_FAM6_BROADWELL:
+	case INTEL_FAM6_BROADWELL_D:
+	case INTEL_FAM6_BROADWELL_G:
 	case INTEL_FAM6_BROADWELL_X:
 		/* not setting BRANCH_EN will #GP, erratum BDM106 */
 		pt_pmu.branch_en_always_on = true;
@@ -397,6 +397,20 @@ static bool pt_event_valid(struct perf_event *event)
  * These all are cpu affine and operate on a local PT
  */
 
+static void pt_config_start(struct perf_event *event)
+{
+	struct pt *pt = this_cpu_ptr(&pt_ctx);
+	u64 ctl = event->hw.config;
+
+	ctl |= RTIT_CTL_TRACEEN;
+	if (READ_ONCE(pt->vmx_on))
+		perf_aux_output_flag(&pt->handle, PERF_AUX_FLAG_PARTIAL);
+	else
+		wrmsrl(MSR_IA32_RTIT_CTL, ctl);
+
+	WRITE_ONCE(event->hw.config, ctl);
+}
+
 /* Address ranges and their corresponding msr configuration registers */
 static const struct pt_address_range {
 	unsigned long	msr_a;
@@ -469,6 +483,7 @@ static u64 pt_config_filters(struct perf_event *event)
 static void pt_config(struct perf_event *event)
 {
 	struct pt *pt = this_cpu_ptr(&pt_ctx);
+	struct pt_buffer *buf = perf_get_aux(&pt->handle);
 	u64 reg;
 
 	/* First round: clear STATUS, in particular the PSB byte counter. */
@@ -478,7 +493,9 @@ static void pt_config(struct perf_event *event)
 	}
 
 	reg = pt_config_filters(event);
-	reg |= RTIT_CTL_TOPA | RTIT_CTL_TRACEEN;
+	reg |= RTIT_CTL_TRACEEN;
+	if (!buf->single)
+		reg |= RTIT_CTL_TOPA;
 
 	/*
 	 * Previously, we had BRANCH_EN on by default, but now that PT has
@@ -501,10 +518,7 @@ static void pt_config(struct perf_event *event)
 	reg |= (event->attr.config & PT_CONFIG_MASK);
 
 	event->hw.config = reg;
-	if (READ_ONCE(pt->vmx_on))
-		perf_aux_output_flag(&pt->handle, PERF_AUX_FLAG_PARTIAL);
-	else
-		wrmsrl(MSR_IA32_RTIT_CTL, reg);
+	pt_config_start(event);
 }
 
 static void pt_config_stop(struct perf_event *event)
@@ -533,45 +547,89 @@ static void pt_config_stop(struct perf_event *event)
 	wmb();
 }
 
-static void pt_config_buffer(void *buf, unsigned int topa_idx,
-			     unsigned int output_off)
-{
-	u64 reg;
-
-	wrmsrl(MSR_IA32_RTIT_OUTPUT_BASE, virt_to_phys(buf));
-
-	reg = 0x7f | ((u64)topa_idx << 7) | ((u64)output_off << 32);
-
-	wrmsrl(MSR_IA32_RTIT_OUTPUT_MASK, reg);
-}
-
-/*
- * Keep ToPA table-related metadata on the same page as the actual table,
- * taking up a few words from the top
- */
-
-#define TENTS_PER_PAGE (((PAGE_SIZE - 40) / sizeof(struct topa_entry)) - 1)
-
 /**
- * struct topa - page-sized ToPA table with metadata at the top
- * @table:	actual ToPA table entries, as understood by PT hardware
+ * struct topa - ToPA metadata
  * @list:	linkage to struct pt_buffer's list of tables
- * @phys:	physical address of this page
  * @offset:	offset of the first entry in this table in the buffer
  * @size:	total size of all entries in this table
  * @last:	index of the last initialized entry in this table
+ * @z_count:	how many times the first entry repeats
  */
 struct topa {
-	struct topa_entry	table[TENTS_PER_PAGE];
 	struct list_head	list;
-	u64			phys;
 	u64			offset;
 	size_t			size;
 	int			last;
+	unsigned int		z_count;
 };
 
+/*
+ * Keep ToPA table-related metadata on the same page as the actual table,
+ * taking up a few words from the top
+ */
+
+#define TENTS_PER_PAGE	\
+	((PAGE_SIZE - sizeof(struct topa)) / sizeof(struct topa_entry))
+
+/**
+ * struct topa_page - page-sized ToPA table with metadata at the top
+ * @table:	actual ToPA table entries, as understood by PT hardware
+ * @topa:	metadata
+ */
+struct topa_page {
+	struct topa_entry	table[TENTS_PER_PAGE];
+	struct topa		topa;
+};
+
+static inline struct topa_page *topa_to_page(struct topa *topa)
+{
+	return container_of(topa, struct topa_page, topa);
+}
+
+static inline struct topa_page *topa_entry_to_page(struct topa_entry *te)
+{
+	return (struct topa_page *)((unsigned long)te & PAGE_MASK);
+}
+
+static inline phys_addr_t topa_pfn(struct topa *topa)
+{
+	return PFN_DOWN(virt_to_phys(topa_to_page(topa)));
+}
+
 /* make -1 stand for the last table entry */
-#define TOPA_ENTRY(t, i) ((i) == -1 ? &(t)->table[(t)->last] : &(t)->table[(i)])
+#define TOPA_ENTRY(t, i)				\
+	((i) == -1					\
+		? &topa_to_page(t)->table[(t)->last]	\
+		: &topa_to_page(t)->table[(i)])
+#define TOPA_ENTRY_SIZE(t, i) (sizes(TOPA_ENTRY((t), (i))->size))
+#define TOPA_ENTRY_PAGES(t, i) (1 << TOPA_ENTRY((t), (i))->size)
+
+static void pt_config_buffer(struct pt_buffer *buf)
+{
+	struct pt *pt = this_cpu_ptr(&pt_ctx);
+	u64 reg, mask;
+	void *base;
+
+	if (buf->single) {
+		base = buf->data_pages[0];
+		mask = (buf->nr_pages * PAGE_SIZE - 1) >> 7;
+	} else {
+		base = topa_to_page(buf->cur)->table;
+		mask = (u64)buf->cur_idx;
+	}
+
+	reg = virt_to_phys(base);
+	if (pt->output_base != reg) {
+		pt->output_base = reg;
+		wrmsrl(MSR_IA32_RTIT_OUTPUT_BASE, reg);
+	}
+
+	reg = 0x7f | (mask << 7) | ((u64)buf->output_off << 32);
+	if (pt->output_mask != reg) {
+		pt->output_mask = reg;
+		wrmsrl(MSR_IA32_RTIT_OUTPUT_MASK, reg);
+	}
+}
 
 /**
  * topa_alloc() - allocate page-sized ToPA table
@@ -583,27 +641,26 @@ struct topa {
 static struct topa *topa_alloc(int cpu, gfp_t gfp)
 {
 	int node = cpu_to_node(cpu);
-	struct topa *topa;
+	struct topa_page *tp;
 	struct page *p;
 
 	p = alloc_pages_node(node, gfp | __GFP_ZERO, 0);
 	if (!p)
 		return NULL;
 
-	topa = page_address(p);
-	topa->last = 0;
-	topa->phys = page_to_phys(p);
+	tp = page_address(p);
+	tp->topa.last = 0;
 
 	/*
 	 * In case of singe-entry ToPA, always put the self-referencing END
 	 * link as the 2nd entry in the table
 	 */
 	if (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries)) {
-		TOPA_ENTRY(topa, 1)->base = topa->phys >> TOPA_SHIFT;
-		TOPA_ENTRY(topa, 1)->end = 1;
+		TOPA_ENTRY(&tp->topa, 1)->base = page_to_phys(p) >> TOPA_SHIFT;
+		TOPA_ENTRY(&tp->topa, 1)->end = 1;
 	}
 
-	return topa;
+	return &tp->topa;
 }
 
 /**
@@ -643,7 +700,7 @@ static void topa_insert_table(struct pt_buffer *buf, struct topa *topa)
 
 	BUG_ON(last->last != TENTS_PER_PAGE - 1);
 
-	TOPA_ENTRY(last, -1)->base = topa->phys >> TOPA_SHIFT;
+	TOPA_ENTRY(last, -1)->base = topa_pfn(topa);
 	TOPA_ENTRY(last, -1)->end = 1;
 }
 
@@ -670,7 +727,7 @@ static bool topa_table_full(struct topa *topa)
  *
  * Return:	0 on success or error code.
  */
-static int topa_insert_pages(struct pt_buffer *buf, gfp_t gfp)
+static int topa_insert_pages(struct pt_buffer *buf, int cpu, gfp_t gfp)
 {
 	struct topa *topa = buf->last;
 	int order = 0;
@@ -681,13 +738,18 @@ static int topa_insert_pages(struct pt_buffer *buf, gfp_t gfp)
 		order = page_private(p);
 
 	if (topa_table_full(topa)) {
-		topa = topa_alloc(buf->cpu, gfp);
+		topa = topa_alloc(cpu, gfp);
 		if (!topa)
 			return -ENOMEM;
 
 		topa_insert_table(buf, topa);
 	}
 
+	if (topa->z_count == topa->last - 1) {
+		if (order == TOPA_ENTRY(topa, topa->last - 1)->size)
+			topa->z_count++;
+	}
+
 	TOPA_ENTRY(topa, -1)->base = page_to_phys(p) >> TOPA_SHIFT;
 	TOPA_ENTRY(topa, -1)->size = order;
 	if (!buf->snapshot &&
@@ -713,23 +775,26 @@ static void pt_topa_dump(struct pt_buffer *buf)
 	struct topa *topa;
 
 	list_for_each_entry(topa, &buf->tables, list) {
+		struct topa_page *tp = topa_to_page(topa);
 		int i;
 
-		pr_debug("# table @%p (%016Lx), off %llx size %zx\n", topa->table,
-			 topa->phys, topa->offset, topa->size);
+		pr_debug("# table @%p, off %llx size %zx\n", tp->table,
+			 topa->offset, topa->size);
 		for (i = 0; i < TENTS_PER_PAGE; i++) {
 			pr_debug("# entry @%p (%lx sz %u %c%c%c) raw=%16llx\n",
-				 &topa->table[i],
-				 (unsigned long)topa->table[i].base << TOPA_SHIFT,
-				 sizes(topa->table[i].size),
-				 topa->table[i].end ?  'E' : ' ',
-				 topa->table[i].intr ? 'I' : ' ',
-				 topa->table[i].stop ? 'S' : ' ',
-				 *(u64 *)&topa->table[i]);
+				 &tp->table[i],
+				 (unsigned long)tp->table[i].base << TOPA_SHIFT,
+				 sizes(tp->table[i].size),
+				 tp->table[i].end ?  'E' : ' ',
+				 tp->table[i].intr ? 'I' : ' ',
+				 tp->table[i].stop ? 'S' : ' ',
+				 *(u64 *)&tp->table[i]);
 			if ((intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries) &&
-			     topa->table[i].stop) ||
-			    topa->table[i].end)
+			     tp->table[i].stop) ||
+			    tp->table[i].end)
 				break;
+			if (!i && topa->z_count)
+				i += topa->z_count;
 		}
 	}
 }
@@ -766,12 +831,17 @@ static void pt_update_head(struct pt *pt)
 	struct pt_buffer *buf = perf_get_aux(&pt->handle);
 	u64 topa_idx, base, old;
 
+	if (buf->single) {
+		local_set(&buf->data_size, buf->output_off);
+		return;
+	}
+
 	/* offset of the first region in this table from the beginning of buf */
 	base = buf->cur->offset + buf->output_off;
 
 	/* offset of the current output region within this table */
 	for (topa_idx = 0; topa_idx < buf->cur_idx; topa_idx++)
-		base += sizes(buf->cur->table[topa_idx].size);
+		base += TOPA_ENTRY_SIZE(buf->cur, topa_idx);
 
 	if (buf->snapshot) {
 		local_set(&buf->data_size, base);
@@ -791,7 +861,7 @@ static void pt_update_head(struct pt *pt)
  */
 static void *pt_buffer_region(struct pt_buffer *buf)
 {
-	return phys_to_virt(buf->cur->table[buf->cur_idx].base << TOPA_SHIFT);
+	return phys_to_virt(TOPA_ENTRY(buf->cur, buf->cur_idx)->base << TOPA_SHIFT);
 }
 
 /**
@@ -800,7 +870,7 @@ static void *pt_buffer_region(struct pt_buffer *buf)
  */
 static size_t pt_buffer_region_size(struct pt_buffer *buf)
 {
-	return sizes(buf->cur->table[buf->cur_idx].size);
+	return TOPA_ENTRY_SIZE(buf->cur, buf->cur_idx);
 }
 
 /**
@@ -830,7 +900,7 @@ static void pt_handle_status(struct pt *pt)
 		 * know.
 		 */
 		if (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries) ||
-		    buf->output_off == sizes(TOPA_ENTRY(buf->cur, buf->cur_idx)->size)) {
+		    buf->output_off == pt_buffer_region_size(buf)) {
 			perf_aux_output_flag(&pt->handle,
 			                     PERF_AUX_FLAG_TRUNCATED);
 			advance++;
@@ -867,41 +937,114 @@ static void pt_handle_status(struct pt *pt)
  */
 static void pt_read_offset(struct pt_buffer *buf)
 {
-	u64 offset, base_topa;
+	struct pt *pt = this_cpu_ptr(&pt_ctx);
+	struct topa_page *tp;
 
-	rdmsrl(MSR_IA32_RTIT_OUTPUT_BASE, base_topa);
-	buf->cur = phys_to_virt(base_topa);
+	if (!buf->single) {
+		rdmsrl(MSR_IA32_RTIT_OUTPUT_BASE, pt->output_base);
+		tp = phys_to_virt(pt->output_base);
+		buf->cur = &tp->topa;
+	}
 
-	rdmsrl(MSR_IA32_RTIT_OUTPUT_MASK, offset);
+	rdmsrl(MSR_IA32_RTIT_OUTPUT_MASK, pt->output_mask);
 	/* offset within current output region */
-	buf->output_off = offset >> 32;
+	buf->output_off = pt->output_mask >> 32;
 	/* index of current output region within this table */
-	buf->cur_idx = (offset & 0xffffff80) >> 7;
+	if (!buf->single)
+		buf->cur_idx = (pt->output_mask & 0xffffff80) >> 7;
 }
 
-/**
- * pt_topa_next_entry() - obtain index of the first page in the next ToPA entry
- * @buf:	PT buffer.
- * @pg:		Page offset in the buffer.
- *
- * When advancing to the next output region (ToPA entry), given a page offset
- * into the buffer, we need to find the offset of the first page in the next
- * region.
- */
-static unsigned int pt_topa_next_entry(struct pt_buffer *buf, unsigned int pg)
+static struct topa_entry *
+pt_topa_entry_for_page(struct pt_buffer *buf, unsigned int pg)
 {
-	struct topa_entry *te = buf->topa_index[pg];
+	struct topa_page *tp;
+	struct topa *topa;
+	unsigned int idx, cur_pg = 0, z_pg = 0, start_idx = 0;
 
-	/* one region */
-	if (buf->first == buf->last && buf->first->last == 1)
-		return pg;
+	/*
+	 * Indicates a bug in the caller.
+	 */
+	if (WARN_ON_ONCE(pg >= buf->nr_pages))
+		return NULL;
 
-	do {
-		pg++;
-		pg &= buf->nr_pages - 1;
-	} while (buf->topa_index[pg] == te);
+	/*
+	 * First, find the ToPA table where @pg fits. With high
+	 * order allocations, there shouldn't be many of these.
+	 */
+	list_for_each_entry(topa, &buf->tables, list) {
+		if (topa->offset + topa->size > pg << PAGE_SHIFT)
+			goto found;
+	}
 
-	return pg;
+	/*
+	 * Hitting this means we have a problem in the ToPA
+	 * allocation code.
+	 */
+	WARN_ON_ONCE(1);
+
+	return NULL;
+
+found:
+	/*
+	 * Indicates a problem in the ToPA allocation code.
+	 */
+	if (WARN_ON_ONCE(topa->last == -1))
+		return NULL;
+
+	tp = topa_to_page(topa);
+	cur_pg = PFN_DOWN(topa->offset);
+	if (topa->z_count) {
+		z_pg = TOPA_ENTRY_PAGES(topa, 0) * (topa->z_count + 1);
+		start_idx = topa->z_count + 1;
+	}
+
+	/*
+	 * Multiple entries at the beginning of the table have the same size,
+	 * ideally all of them; if @pg falls there, the search is done.
+	 */
+	if (pg >= cur_pg && pg < cur_pg + z_pg) {
+		idx = (pg - cur_pg) / TOPA_ENTRY_PAGES(topa, 0);
+		return &tp->table[idx];
+	}
+
+	/*
+	 * Otherwise, slow path: iterate through the remaining entries.
+	 */
+	for (idx = start_idx, cur_pg += z_pg; idx < topa->last; idx++) {
+		if (cur_pg + TOPA_ENTRY_PAGES(topa, idx) > pg)
+			return &tp->table[idx];
+
+		cur_pg += TOPA_ENTRY_PAGES(topa, idx);
+	}
+
+	/*
+	 * Means we couldn't find a ToPA entry in the table that does match.
+	 */
+	WARN_ON_ONCE(1);
+
+	return NULL;
+}
+
+static struct topa_entry *
+pt_topa_prev_entry(struct pt_buffer *buf, struct topa_entry *te)
+{
+	unsigned long table = (unsigned long)te & ~(PAGE_SIZE - 1);
+	struct topa_page *tp;
+	struct topa *topa;
+
+	tp = (struct topa_page *)table;
+	if (tp->table != te)
+		return --te;
+
+	topa = &tp->topa;
+	if (topa == buf->first)
+		topa = buf->last;
+	else
+		topa = list_prev_entry(topa, list);
+
+	tp = topa_to_page(topa);
+
+	return &tp->table[topa->last - 1];
 }
 
 /**
@@ -924,9 +1067,11 @@ static int pt_buffer_reset_markers(struct pt_buffer *buf,
 	unsigned long head = local64_read(&buf->head);
 	unsigned long idx, npages, wakeup;
 
+	if (buf->single)
+		return 0;
+
 	/* can't stop in the middle of an output region */
-	if (buf->output_off + handle->size + 1 <
-	    sizes(TOPA_ENTRY(buf->cur, buf->cur_idx)->size)) {
+	if (buf->output_off + handle->size + 1 < pt_buffer_region_size(buf)) {
 		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
 		return -EINVAL;
 	}
@@ -937,9 +1082,13 @@ static int pt_buffer_reset_markers(struct pt_buffer *buf,
 		return 0;
 
 	/* clear STOP and INT from current entry */
-	buf->topa_index[buf->stop_pos]->stop = 0;
-	buf->topa_index[buf->stop_pos]->intr = 0;
-	buf->topa_index[buf->intr_pos]->intr = 0;
+	if (buf->stop_te) {
+		buf->stop_te->stop = 0;
+		buf->stop_te->intr = 0;
+	}
+
+	if (buf->intr_te)
+		buf->intr_te->intr = 0;
 
 	/* how many pages till the STOP marker */
 	npages = handle->size >> PAGE_SHIFT;
@@ -950,7 +1099,12 @@ static int pt_buffer_reset_markers(struct pt_buffer *buf,
 
 	idx = (head >> PAGE_SHIFT) + npages;
 	idx &= buf->nr_pages - 1;
-	buf->stop_pos = idx;
+
+	if (idx != buf->stop_pos) {
+		buf->stop_pos = idx;
+		buf->stop_te = pt_topa_entry_for_page(buf, idx);
+		buf->stop_te = pt_topa_prev_entry(buf, buf->stop_te);
+	}
 
 	wakeup = handle->wakeup >> PAGE_SHIFT;
 
@@ -960,51 +1114,20 @@ static int pt_buffer_reset_markers(struct pt_buffer *buf,
 		idx = wakeup;
 
 	idx &= buf->nr_pages - 1;
-	buf->intr_pos = idx;
+	if (idx != buf->intr_pos) {
+		buf->intr_pos = idx;
+		buf->intr_te = pt_topa_entry_for_page(buf, idx);
+		buf->intr_te = pt_topa_prev_entry(buf, buf->intr_te);
+	}
 
-	buf->topa_index[buf->stop_pos]->stop = 1;
-	buf->topa_index[buf->stop_pos]->intr = 1;
-	buf->topa_index[buf->intr_pos]->intr = 1;
+	buf->stop_te->stop = 1;
+	buf->stop_te->intr = 1;
+	buf->intr_te->intr = 1;
 
 	return 0;
 }
 
 /**
- * pt_buffer_setup_topa_index() - build topa_index[] table of regions
- * @buf:	PT buffer.
- *
- * topa_index[] references output regions indexed by offset into the
- * buffer for purposes of quick reverse lookup.
- */
-static void pt_buffer_setup_topa_index(struct pt_buffer *buf)
-{
-	struct topa *cur = buf->first, *prev = buf->last;
-	struct topa_entry *te_cur = TOPA_ENTRY(cur, 0),
-		*te_prev = TOPA_ENTRY(prev, prev->last - 1);
-	int pg = 0, idx = 0;
-
-	while (pg < buf->nr_pages) {
-		int tidx;
-
-		/* pages within one topa entry */
-		for (tidx = 0; tidx < 1 << te_cur->size; tidx++, pg++)
-			buf->topa_index[pg] = te_prev;
-
-		te_prev = te_cur;
-
-		if (idx == cur->last - 1) {
-			/* advance to next topa table */
-			idx = 0;
-			cur = list_entry(cur->list.next, struct topa, list);
-		} else {
-			idx++;
-		}
-		te_cur = TOPA_ENTRY(cur, idx);
-	}
-
-}
-
-/**
  * pt_buffer_reset_offsets() - adjust buffer's write pointers from aux_head
  * @buf:	PT buffer.
  * @head:	Write pointer (aux_head) from AUX buffer.
@@ -1021,18 +1144,24 @@ static void pt_buffer_setup_topa_index(struct pt_buffer *buf)
  */
 static void pt_buffer_reset_offsets(struct pt_buffer *buf, unsigned long head)
 {
+	struct topa_page *cur_tp;
+	struct topa_entry *te;
 	int pg;
 
 	if (buf->snapshot)
 		head &= (buf->nr_pages << PAGE_SHIFT) - 1;
 
-	pg = (head >> PAGE_SHIFT) & (buf->nr_pages - 1);
-	pg = pt_topa_next_entry(buf, pg);
+	if (!buf->single) {
+		pg = (head >> PAGE_SHIFT) & (buf->nr_pages - 1);
+		te = pt_topa_entry_for_page(buf, pg);
 
-	buf->cur = (struct topa *)((unsigned long)buf->topa_index[pg] & PAGE_MASK);
-	buf->cur_idx = ((unsigned long)buf->topa_index[pg] -
-			(unsigned long)buf->cur) / sizeof(struct topa_entry);
-	buf->output_off = head & (sizes(buf->cur->table[buf->cur_idx].size) - 1);
+		cur_tp = topa_entry_to_page(te);
+		buf->cur = &cur_tp->topa;
+		buf->cur_idx = te - TOPA_ENTRY(buf->cur, 0);
+		buf->output_off = head & (pt_buffer_region_size(buf) - 1);
+	} else {
+		buf->output_off = head;
+	}
 
 	local64_set(&buf->head, head);
 	local_set(&buf->data_size, 0);
@@ -1046,6 +1175,9 @@ static void pt_buffer_fini_topa(struct pt_buffer *buf)
 {
 	struct topa *topa, *iter;
 
+	if (buf->single)
+		return;
+
 	list_for_each_entry_safe(topa, iter, &buf->tables, list) {
 		/*
 		 * right now, this is in free_aux() path only, so
@@ -1061,31 +1193,29 @@ static void pt_buffer_fini_topa(struct pt_buffer *buf)
  * @size:	Total size of all regions within this ToPA.
  * @gfp:	Allocation flags.
  */
-static int pt_buffer_init_topa(struct pt_buffer *buf, unsigned long nr_pages,
-			       gfp_t gfp)
+static int pt_buffer_init_topa(struct pt_buffer *buf, int cpu,
+			       unsigned long nr_pages, gfp_t gfp)
 {
 	struct topa *topa;
 	int err;
 
-	topa = topa_alloc(buf->cpu, gfp);
+	topa = topa_alloc(cpu, gfp);
 	if (!topa)
 		return -ENOMEM;
 
 	topa_insert_table(buf, topa);
 
 	while (buf->nr_pages < nr_pages) {
-		err = topa_insert_pages(buf, gfp);
+		err = topa_insert_pages(buf, cpu, gfp);
 		if (err) {
 			pt_buffer_fini_topa(buf);
 			return -ENOMEM;
 		}
 	}
 
-	pt_buffer_setup_topa_index(buf);
-
 	/* link last table to the first one, unless we're double buffering */
 	if (intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries)) {
-		TOPA_ENTRY(buf->last, -1)->base = buf->first->phys >> TOPA_SHIFT;
+		TOPA_ENTRY(buf->last, -1)->base = topa_pfn(buf->first);
 		TOPA_ENTRY(buf->last, -1)->end = 1;
 	}
 
@@ -1093,6 +1223,36 @@ static int pt_buffer_init_topa(struct pt_buffer *buf, unsigned long nr_pages,
 	return 0;
 }
 
+static int pt_buffer_try_single(struct pt_buffer *buf, int nr_pages)
+{
+	struct page *p = virt_to_page(buf->data_pages[0]);
+	int ret = -ENOTSUPP, order = 0;
+
+	/*
+	 * We can use single range output mode
+	 * + in snapshot mode, where we don't need interrupts;
+	 * + if the hardware supports it;
+	 * + if the entire buffer is one contiguous allocation.
+	 */
+	if (!buf->snapshot)
+		goto out;
+
+	if (!intel_pt_validate_hw_cap(PT_CAP_single_range_output))
+		goto out;
+
+	if (PagePrivate(p))
+		order = page_private(p);
+
+	if (1 << order != nr_pages)
+		goto out;
+
+	buf->single = true;
+	buf->nr_pages = nr_pages;
+	ret = 0;
+out:
+	return ret;
+}
+
 /**
  * pt_buffer_setup_aux() - set up topa tables for a PT buffer
  * @cpu:	Cpu on which to allocate, -1 means current.
@@ -1115,22 +1275,33 @@ pt_buffer_setup_aux(struct perf_event *event, void **pages,
 	if (!nr_pages)
 		return NULL;
 
+	/*
+	 * Only support AUX sampling in snapshot mode, where we don't
+	 * generate NMIs.
+	 */
+	if (event->attr.aux_sample_size && !snapshot)
+		return NULL;
+
 	if (cpu == -1)
 		cpu = raw_smp_processor_id();
 	node = cpu_to_node(cpu);
 
-	buf = kzalloc_node(offsetof(struct pt_buffer, topa_index[nr_pages]),
-			   GFP_KERNEL, node);
+	buf = kzalloc_node(sizeof(struct pt_buffer), GFP_KERNEL, node);
 	if (!buf)
 		return NULL;
 
-	buf->cpu = cpu;
 	buf->snapshot = snapshot;
 	buf->data_pages = pages;
+	buf->stop_pos = -1;
+	buf->intr_pos = -1;
 
 	INIT_LIST_HEAD(&buf->tables);
 
-	ret = pt_buffer_init_topa(buf, nr_pages, GFP_KERNEL);
+	ret = pt_buffer_try_single(buf, nr_pages);
+	if (!ret)
+		return buf;
+
+	ret = pt_buffer_init_topa(buf, cpu, nr_pages, GFP_KERNEL);
 	if (ret) {
 		kfree(buf);
 		return NULL;
@@ -1296,9 +1467,8 @@ void intel_pt_interrupt(void)
 			return;
 		}
 
-		pt_config_buffer(buf->cur->table, buf->cur_idx,
-				 buf->output_off);
-		pt_config(event);
+		pt_config_buffer(buf);
+		pt_config_start(event);
 	}
 }
 
@@ -1361,8 +1531,7 @@ static void pt_event_start(struct perf_event *event, int mode)
 	WRITE_ONCE(pt->handle_nmi, 1);
 	hwc->state = 0;
 
-	pt_config_buffer(buf->cur->table, buf->cur_idx,
-			 buf->output_off);
+	pt_config_buffer(buf);
 	pt_config(event);
 
 	return;
@@ -1413,6 +1582,52 @@ static void pt_event_stop(struct perf_event *event, int mode)
 	}
 }
 
+static long pt_event_snapshot_aux(struct perf_event *event,
+				  struct perf_output_handle *handle,
+				  unsigned long size)
+{
+	struct pt *pt = this_cpu_ptr(&pt_ctx);
+	struct pt_buffer *buf = perf_get_aux(&pt->handle);
+	unsigned long from = 0, to;
+	long ret;
+
+	if (WARN_ON_ONCE(!buf))
+		return 0;
+
+	/*
+	 * Sampling is only allowed on snapshot events;
+	 * see pt_buffer_setup_aux().
+	 */
+	if (WARN_ON_ONCE(!buf->snapshot))
+		return 0;
+
+	/*
+	 * Here, handle_nmi tells us if the tracing is on
+	 */
+	if (READ_ONCE(pt->handle_nmi))
+		pt_config_stop(event);
+
+	pt_read_offset(buf);
+	pt_update_head(pt);
+
+	to = local_read(&buf->data_size);
+	if (to < size)
+		from = buf->nr_pages << PAGE_SHIFT;
+	from += to - size;
+
+	ret = perf_output_copy_aux(&pt->handle, handle, from, to);
+
+	/*
+	 * If the tracing was on when we turned up, restart it.
+	 * Compiler barrier not needed as we couldn't have been
+	 * preempted by anything that touches pt->handle_nmi.
+	 */
+	if (pt->handle_nmi)
+		pt_config_start(event);
+
+	return ret;
+}
+
 static void pt_event_del(struct perf_event *event, int mode)
 {
 	pt_event_stop(event, PERF_EF_UPDATE);
@@ -1481,6 +1696,11 @@ void cpu_emergency_stop_pt(void)
 		pt_event_stop(pt->handle.event, PERF_EF_UPDATE);
 }
 
+int is_intel_pt_event(struct perf_event *event)
+{
+	return event->pmu == &pt_pmu.pmu;
+}
+
 static __init int pt_init(void)
 {
 	int ret, cpu, prior_warn = 0;
@@ -1527,6 +1747,7 @@ static __init int pt_init(void)
 	pt_pmu.pmu.del			 = pt_event_del;
 	pt_pmu.pmu.start		 = pt_event_start;
 	pt_pmu.pmu.stop			 = pt_event_stop;
+	pt_pmu.pmu.snapshot_aux		 = pt_event_snapshot_aux;
 	pt_pmu.pmu.read			 = pt_event_read;
 	pt_pmu.pmu.setup_aux		 = pt_buffer_setup_aux;
 	pt_pmu.pmu.free_aux		 = pt_buffer_free_aux;