perf/x86/intel/pt: Add Intel PT PMU driver

Add support for Intel Processor Trace (PT) to kernel's perf events.
PT is an extension of Intel Architecture that collects information about
software execuction such as control flow, execution modes and timings and
formats it into highly compressed binary packets. Even being compressed,
these packets are generated at hundreds of megabytes per second per core,
which makes it impractical to decode them on the fly in the kernel.

This driver exports trace data by through AUX space in the perf ring
buffer, which is zero-copy mapped into userspace for faster data retrieval.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1422614392-114498-1-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 131 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/intel_pt.h b/arch/x86/kernel/cpu/intel_pt.h
new file mode 100644
index 0000000..1c338b0
--- /dev/null
+++ b/arch/x86/kernel/cpu/intel_pt.h
@@ -0,0 +1,131 @@
+/*
+ * Intel(R) Processor Trace PMU driver for perf
+ * Copyright (c) 2013-2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * Intel PT is specified in the Intel Architecture Instruction Set Extensions
+ * Programming Reference:
+ * http://software.intel.com/en-us/intel-isa-extensions
+ */
+
+#ifndef __INTEL_PT_H__
+#define __INTEL_PT_H__
+
+/*
+ * Single-entry ToPA: when this close to region boundary, switch
+ * buffers to avoid losing data.
+ */
+#define TOPA_PMI_MARGIN 512
+
+/*
+ * Table of Physical Addresses bits
+ */
+enum topa_sz {
+	TOPA_4K	= 0,
+	TOPA_8K,
+	TOPA_16K,
+	TOPA_32K,
+	TOPA_64K,
+	TOPA_128K,
+	TOPA_256K,
+	TOPA_512K,
+	TOPA_1MB,
+	TOPA_2MB,
+	TOPA_4MB,
+	TOPA_8MB,
+	TOPA_16MB,
+	TOPA_32MB,
+	TOPA_64MB,
+	TOPA_128MB,
+	TOPA_SZ_END,
+};
+
+static inline unsigned int sizes(enum topa_sz tsz)
+{
+	return 1 << (tsz + 12);
+};
+
+struct topa_entry {
+	u64	end	: 1;
+	u64	rsvd0	: 1;
+	u64	intr	: 1;
+	u64	rsvd1	: 1;
+	u64	stop	: 1;
+	u64	rsvd2	: 1;
+	u64	size	: 4;
+	u64	rsvd3	: 2;
+	u64	base	: 36;
+	u64	rsvd4	: 16;
+};
+
+#define TOPA_SHIFT 12
+#define PT_CPUID_LEAVES 2
+
+enum pt_capabilities {
+	PT_CAP_max_subleaf = 0,
+	PT_CAP_cr3_filtering,
+	PT_CAP_topa_output,
+	PT_CAP_topa_multiple_entries,
+	PT_CAP_payloads_lip,
+};
+
+struct pt_pmu {
+	struct pmu		pmu;
+	u32			caps[4 * PT_CPUID_LEAVES];
+};
+
+/**
+ * struct pt_buffer - buffer configuration; one buffer per task_struct or
+ *		cpu, depending on perf event configuration
+ * @cpu:	cpu for per-cpu allocation
+ * @tables:	list of ToPA tables in this buffer
+ * @first:	shorthand for first topa table
+ * @last:	shorthand for last topa table
+ * @cur:	current topa table
+ * @nr_pages:	buffer size in pages
+ * @cur_idx:	current output region's index within @cur table
+ * @output_off:	offset within the current output region
+ * @data_size:	running total of the amount of data in this buffer
+ * @lost:	if data was lost/truncated
+ * @head:	logical write offset inside the buffer
+ * @snapshot:	if this is for a snapshot/overwrite counter
+ * @stop_pos:	STOP topa entry in the buffer
+ * @intr_pos:	INT topa entry in the buffer
+ * @data_pages:	array of pages from perf
+ * @topa_index:	table of topa entries indexed by page offset
+ */
+struct pt_buffer {
+	int			cpu;
+	struct list_head	tables;
+	struct topa		*first, *last, *cur;
+	unsigned int		cur_idx;
+	size_t			output_off;
+	unsigned long		nr_pages;
+	local_t			data_size;
+	local_t			lost;
+	local64_t		head;
+	bool			snapshot;
+	unsigned long		stop_pos, intr_pos;
+	void			**data_pages;
+	struct topa_entry	*topa_index[0];
+};
+
+/**
+ * struct pt - per-cpu pt context
+ * @handle:	perf output handle
+ * @handle_nmi:	do handle PT PMI on this cpu, there's an active event
+ */
+struct pt {
+	struct perf_output_handle handle;
+	int			handle_nmi;
+};
+
+#endif /* __INTEL_PT_H__ */