perf bpf: Pull in bpf_program__get_prog_info_linear()

To prepare for impending deprecation of libbpf's bpf_program__get_prog_info_linear(),
pull in the function and associated helpers into the perf codebase and migrate
existing uses to the perf copy.

Since libbpf's deprecated definitions will still be visible to perf, it is necessary
to rename perf's definitions.

Signed-off-by: Dave Marchevsky <[e-mail]>
Acked-by: Andrii Nakryiko <[e-mail]>
Acked-by: Song Liu <[e-mail]>
Cc: Alexei Starovoitov <[e-mail]>
Cc: Daniel Borkmann <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf.data-file-format.txt

···
 
         HEADER_BPF_PROG_INFO = 25,
 
-struct bpf_prog_info_linear, which contains detailed information about
+struct perf_bpil, which contains detailed information about
 a BPF program, including type, id, tag, jited/xlated instructions, etc.
 
         HEADER_BPF_BTF = 26,

tools/perf/util/Build

···
 perf-y += perf-hooks.o
 
 perf-$(CONFIG_LIBBPF) += bpf-event.o
+perf-$(CONFIG_LIBBPF) += bpf-utils.o
 
 perf-$(CONFIG_CXX) += c++/
 

tools/perf/util/annotate.c

···
 #include "evsel.h"
 #include "evlist.h"
 #include "bpf-event.h"
+#include "bpf-utils.h"
 #include "block-range.h"
 #include "string2.h"
 #include "util/event.h"
···
 {
 	struct annotation *notes = symbol__annotation(sym);
 	struct annotation_options *opts = args->options;
-	struct bpf_prog_info_linear *info_linear;
 	struct bpf_prog_linfo *prog_linfo = NULL;
 	struct bpf_prog_info_node *info_node;
 	int len = sym->end - sym->start;
 	disassembler_ftype disassemble;
 	struct map *map = args->ms.map;
+	struct perf_bpil *info_linear;
 	struct disassemble_info info;
 	struct dso *dso = map->dso;
 	int pc = 0, count, sub_id;

tools/perf/util/bpf-event.c

···
 #include <internal/lib.h>
 #include <symbol/kallsyms.h>
 #include "bpf-event.h"
+#include "bpf-utils.h"
 #include "debug.h"
 #include "dso.h"
 #include "symbol.h"
···
        return err ? ERR_PTR(err) : btf;
 }
 
-#define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))
-
 static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
 {
 	int ret = 0;
···
 					   union perf_event *event,
 					   struct perf_sample *sample __maybe_unused)
 {
-	struct bpf_prog_info_linear *info_linear;
 	struct bpf_prog_info_node *info_node;
 	struct perf_env *env = machine->env;
+	struct perf_bpil *info_linear;
 	int id = event->bpf.id;
 	unsigned int i;
 
···
 {
 	struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
 	struct perf_record_bpf_event *bpf_event = &event->bpf;
-	struct bpf_prog_info_linear *info_linear;
 	struct perf_tool *tool = session->tool;
 	struct bpf_prog_info_node *info_node;
+	struct perf_bpil *info_linear;
 	struct bpf_prog_info *info;
 	struct btf *btf = NULL;
 	struct perf_env *env;
···
 	 */
 	env = session->data ? &session->header.env : &perf_env;
 
-	arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
-	arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
-	arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
-	arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
-	arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
-	arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
-	arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
+	arrays = 1UL << PERF_BPIL_JITED_KSYMS;
+	arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
+	arrays |= 1UL << PERF_BPIL_FUNC_INFO;
+	arrays |= 1UL << PERF_BPIL_PROG_TAGS;
+	arrays |= 1UL << PERF_BPIL_JITED_INSNS;
+	arrays |= 1UL << PERF_BPIL_LINE_INFO;
+	arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
 
-	info_linear = bpf_program__get_prog_info_linear(fd, arrays);
+	info_linear = get_bpf_prog_info_linear(fd, arrays);
 	if (IS_ERR_OR_NULL(info_linear)) {
 		info_linear = NULL;
 		pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
···
 
 static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 {
-	struct bpf_prog_info_linear *info_linear;
 	struct bpf_prog_info_node *info_node;
+	struct perf_bpil *info_linear;
 	struct btf *btf = NULL;
 	u64 arrays;
 	u32 btf_id;
···
 	if (fd < 0)
 		return;
 
-	arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
-	arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
-	arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
-	arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
-	arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
-	arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
-	arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;
+	arrays = 1UL << PERF_BPIL_JITED_KSYMS;
+	arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
+	arrays |= 1UL << PERF_BPIL_FUNC_INFO;
+	arrays |= 1UL << PERF_BPIL_PROG_TAGS;
+	arrays |= 1UL << PERF_BPIL_JITED_INSNS;
+	arrays |= 1UL << PERF_BPIL_LINE_INFO;
+	arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
 
-	info_linear = bpf_program__get_prog_info_linear(fd, arrays);
+	info_linear = get_bpf_prog_info_linear(fd, arrays);
 	if (IS_ERR_OR_NULL(info_linear)) {
 		pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 		goto out;

tools/perf/util/bpf-event.h

···
 struct target;
 
 struct bpf_prog_info_node {
-	struct bpf_prog_info_linear	*info_linear;
+	struct perf_bpil		*info_linear;
 	struct rb_node			rb_node;
 };
 

tools/perf/util/bpf-utils.c

···
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <errno.h>
+#include <stdlib.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <bpf/bpf.h>
+#include "bpf-utils.h"
+#include "debug.h"
+
+struct bpil_array_desc {
+	int	array_offset;	/* e.g. offset of jited_prog_insns */
+	int	count_offset;	/* e.g. offset of jited_prog_len */
+	int	size_offset;	/* > 0: offset of rec size,
+				 * < 0: fix size of -size_offset
+				 */
+};
+
+static struct bpil_array_desc bpil_array_desc[] = {
+	[PERF_BPIL_JITED_INSNS] = {
+		offsetof(struct bpf_prog_info, jited_prog_insns),
+		offsetof(struct bpf_prog_info, jited_prog_len),
+		-1,
+	},
+	[PERF_BPIL_XLATED_INSNS] = {
+		offsetof(struct bpf_prog_info, xlated_prog_insns),
+		offsetof(struct bpf_prog_info, xlated_prog_len),
+		-1,
+	},
+	[PERF_BPIL_MAP_IDS] = {
+		offsetof(struct bpf_prog_info, map_ids),
+		offsetof(struct bpf_prog_info, nr_map_ids),
+		-(int)sizeof(__u32),
+	},
+	[PERF_BPIL_JITED_KSYMS] = {
+		offsetof(struct bpf_prog_info, jited_ksyms),
+		offsetof(struct bpf_prog_info, nr_jited_ksyms),
+		-(int)sizeof(__u64),
+	},
+	[PERF_BPIL_JITED_FUNC_LENS] = {
+		offsetof(struct bpf_prog_info, jited_func_lens),
+		offsetof(struct bpf_prog_info, nr_jited_func_lens),
+		-(int)sizeof(__u32),
+	},
+	[PERF_BPIL_FUNC_INFO] = {
+		offsetof(struct bpf_prog_info, func_info),
+		offsetof(struct bpf_prog_info, nr_func_info),
+		offsetof(struct bpf_prog_info, func_info_rec_size),
+	},
+	[PERF_BPIL_LINE_INFO] = {
+		offsetof(struct bpf_prog_info, line_info),
+		offsetof(struct bpf_prog_info, nr_line_info),
+		offsetof(struct bpf_prog_info, line_info_rec_size),
+	},
+	[PERF_BPIL_JITED_LINE_INFO] = {
+		offsetof(struct bpf_prog_info, jited_line_info),
+		offsetof(struct bpf_prog_info, nr_jited_line_info),
+		offsetof(struct bpf_prog_info, jited_line_info_rec_size),
+	},
+	[PERF_BPIL_PROG_TAGS] = {
+		offsetof(struct bpf_prog_info, prog_tags),
+		offsetof(struct bpf_prog_info, nr_prog_tags),
+		-(int)sizeof(__u8) * BPF_TAG_SIZE,
+	},
+
+};
+
+static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info,
+					   int offset)
+{
+	__u32 *array = (__u32 *)info;
+
+	if (offset >= 0)
+		return array[offset / sizeof(__u32)];
+	return -(int)offset;
+}
+
+static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info,
+					   int offset)
+{
+	__u64 *array = (__u64 *)info;
+
+	if (offset >= 0)
+		return array[offset / sizeof(__u64)];
+	return -(int)offset;
+}
+
+static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
+					 __u32 val)
+{
+	__u32 *array = (__u32 *)info;
+
+	if (offset >= 0)
+		array[offset / sizeof(__u32)] = val;
+}
+
+static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
+					 __u64 val)
+{
+	__u64 *array = (__u64 *)info;
+
+	if (offset >= 0)
+		array[offset / sizeof(__u64)] = val;
+}
+
+struct perf_bpil *
+get_bpf_prog_info_linear(int fd, __u64 arrays)
+{
+	struct bpf_prog_info info = {};
+	struct perf_bpil *info_linear;
+	__u32 info_len = sizeof(info);
+	__u32 data_len = 0;
+	int i, err;
+	void *ptr;
+
+	if (arrays >> PERF_BPIL_LAST_ARRAY)
+		return ERR_PTR(-EINVAL);
+
+	/* step 1: get array dimensions */
+	err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
+	if (err) {
+		pr_debug("can't get prog info: %s", strerror(errno));
+		return ERR_PTR(-EFAULT);
+	}
+
+	/* step 2: calculate total size of all arrays */
+	for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
+		bool include_array = (arrays & (1UL << i)) > 0;
+		struct bpil_array_desc *desc;
+		__u32 count, size;
+
+		desc = bpil_array_desc + i;
+
+		/* kernel is too old to support this field */
+		if (info_len < desc->array_offset + sizeof(__u32) ||
+		    info_len < desc->count_offset + sizeof(__u32) ||
+		    (desc->size_offset > 0 && info_len < (__u32)desc->size_offset))
+			include_array = false;
+
+		if (!include_array) {
+			arrays &= ~(1UL << i);	/* clear the bit */
+			continue;
+		}
+
+		count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
+		size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
+
+		data_len += count * size;
+	}
+
+	/* step 3: allocate continuous memory */
+	data_len = roundup(data_len, sizeof(__u64));
+	info_linear = malloc(sizeof(struct perf_bpil) + data_len);
+	if (!info_linear)
+		return ERR_PTR(-ENOMEM);
+
+	/* step 4: fill data to info_linear->info */
+	info_linear->arrays = arrays;
+	memset(&info_linear->info, 0, sizeof(info));
+	ptr = info_linear->data;
+
+	for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
+		struct bpil_array_desc *desc;
+		__u32 count, size;
+
+		if ((arrays & (1UL << i)) == 0)
+			continue;
+
+		desc  = bpil_array_desc + i;
+		count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
+		size  = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
+		bpf_prog_info_set_offset_u32(&info_linear->info,
+					     desc->count_offset, count);
+		bpf_prog_info_set_offset_u32(&info_linear->info,
+					     desc->size_offset, size);
+		bpf_prog_info_set_offset_u64(&info_linear->info,
+					     desc->array_offset,
+					     ptr_to_u64(ptr));
+		ptr += count * size;
+	}
+
+	/* step 5: call syscall again to get required arrays */
+	err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
+	if (err) {
+		pr_debug("can't get prog info: %s", strerror(errno));
+		free(info_linear);
+		return ERR_PTR(-EFAULT);
+	}
+
+	/* step 6: verify the data */
+	for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
+		struct bpil_array_desc *desc;
+		__u32 v1, v2;
+
+		if ((arrays & (1UL << i)) == 0)
+			continue;
+
+		desc = bpil_array_desc + i;
+		v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
+		v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
+						   desc->count_offset);
+		if (v1 != v2)
+			pr_warning("%s: mismatch in element count\n", __func__);
+
+		v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
+		v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
+						   desc->size_offset);
+		if (v1 != v2)
+			pr_warning("%s: mismatch in rec size\n", __func__);
+	}
+
+	/* step 7: update info_len and data_len */
+	info_linear->info_len = sizeof(struct bpf_prog_info);
+	info_linear->data_len = data_len;
+
+	return info_linear;
+}
+
+void bpil_addr_to_offs(struct perf_bpil *info_linear)
+{
+	int i;
+
+	for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
+		struct bpil_array_desc *desc;
+		__u64 addr, offs;
+
+		if ((info_linear->arrays & (1UL << i)) == 0)
+			continue;
+
+		desc = bpil_array_desc + i;
+		addr = bpf_prog_info_read_offset_u64(&info_linear->info,
+						     desc->array_offset);
+		offs = addr - ptr_to_u64(info_linear->data);
+		bpf_prog_info_set_offset_u64(&info_linear->info,
+					     desc->array_offset, offs);
+	}
+}
+
+void bpil_offs_to_addr(struct perf_bpil *info_linear)
+{
+	int i;
+
+	for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {
+		struct bpil_array_desc *desc;
+		__u64 addr, offs;
+
+		if ((info_linear->arrays & (1UL << i)) == 0)
+			continue;
+
+		desc = bpil_array_desc + i;
+		offs = bpf_prog_info_read_offset_u64(&info_linear->info,
+						     desc->array_offset);
+		addr = offs + ptr_to_u64(info_linear->data);
+		bpf_prog_info_set_offset_u64(&info_linear->info,
+					     desc->array_offset, addr);
+	}
+}

tools/perf/util/bpf-utils.h

···
+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
+
+#ifndef __PERF_BPF_UTILS_H
+#define __PERF_BPF_UTILS_H
+
+#define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))
+
+#ifdef HAVE_LIBBPF_SUPPORT
+
+#include <bpf/libbpf.h>
+
+/*
+ * Get bpf_prog_info in continuous memory
+ *
+ * struct bpf_prog_info has multiple arrays. The user has option to choose
+ * arrays to fetch from kernel. The following APIs provide an uniform way to
+ * fetch these data. All arrays in bpf_prog_info are stored in a single
+ * continuous memory region. This makes it easy to store the info in a
+ * file.
+ *
+ * Before writing perf_bpil to files, it is necessary to
+ * translate pointers in bpf_prog_info to offsets. Helper functions
+ * bpil_addr_to_offs() and bpil_offs_to_addr()
+ * are introduced to switch between pointers and offsets.
+ *
+ * Examples:
+ *   # To fetch map_ids and prog_tags:
+ *   __u64 arrays = (1UL << PERF_BPIL_MAP_IDS) |
+ *           (1UL << PERF_BPIL_PROG_TAGS);
+ *   struct perf_bpil *info_linear =
+ *           get_bpf_prog_info_linear(fd, arrays);
+ *
+ *   # To save data in file
+ *   bpil_addr_to_offs(info_linear);
+ *   write(f, info_linear, sizeof(*info_linear) + info_linear->data_len);
+ *
+ *   # To read data from file
+ *   read(f, info_linear, <proper_size>);
+ *   bpil_offs_to_addr(info_linear);
+ */
+enum perf_bpil_array_types {
+	PERF_BPIL_FIRST_ARRAY = 0,
+	PERF_BPIL_JITED_INSNS = 0,
+	PERF_BPIL_XLATED_INSNS,
+	PERF_BPIL_MAP_IDS,
+	PERF_BPIL_JITED_KSYMS,
+	PERF_BPIL_JITED_FUNC_LENS,
+	PERF_BPIL_FUNC_INFO,
+	PERF_BPIL_LINE_INFO,
+	PERF_BPIL_JITED_LINE_INFO,
+	PERF_BPIL_PROG_TAGS,
+	PERF_BPIL_LAST_ARRAY,
+};
+
+struct perf_bpil {
+	/* size of struct bpf_prog_info, when the tool is compiled */
+	__u32			info_len;
+	/* total bytes allocated for data, round up to 8 bytes */
+	__u32			data_len;
+	/* which arrays are included in data */
+	__u64			arrays;
+	struct bpf_prog_info	info;
+	__u8			data[];
+};
+
+struct perf_bpil *
+get_bpf_prog_info_linear(int fd, __u64 arrays);
+
+void
+bpil_addr_to_offs(struct perf_bpil *info_linear);
+
+void
+bpil_offs_to_addr(struct perf_bpil *info_linear);
+
+#endif /* HAVE_LIBBPF_SUPPORT */
+#endif /* __PERF_BPF_UTILS_H */

tools/perf/util/bpf_counter.c

···
 #include <perf/bpf_perf.h>
 
 #include "bpf_counter.h"
+#include "bpf-utils.h"
 #include "counts.h"
 #include "debug.h"
 #include "evsel.h"
···
 
 static char *bpf_target_prog_name(int tgt_fd)
 {
-	struct bpf_prog_info_linear *info_linear;
 	struct bpf_func_info *func_info;
+	struct perf_bpil *info_linear;
 	const struct btf_type *t;
 	struct btf *btf = NULL;
 	char *name = NULL;
 
-	info_linear = bpf_program__get_prog_info_linear(
-		tgt_fd, 1UL << BPF_PROG_INFO_FUNC_INFO);
+	info_linear = get_bpf_prog_info_linear(tgt_fd, 1UL << PERF_BPIL_FUNC_INFO);
 	if (IS_ERR_OR_NULL(info_linear)) {
 		pr_debug("failed to get info_linear for prog FD %d\n", tgt_fd);
 		return NULL;

tools/perf/util/dso.c

···
 #ifdef HAVE_LIBBPF_SUPPORT
 #include <bpf/libbpf.h>
 #include "bpf-event.h"
+#include "bpf-utils.h"
 #endif
 #include "compress.h"
 #include "env.h"

tools/perf/util/env.c

···
 
 #ifdef HAVE_LIBBPF_SUPPORT
 #include "bpf-event.h"
+#include "bpf-utils.h"
 #include <bpf/libbpf.h>
 
 void perf_env__insert_bpf_prog_info(struct perf_env *env,

tools/perf/util/header.c

···
 #include "util/util.h" // perf_exe()
 #include "cputopo.h"
 #include "bpf-event.h"
+#include "bpf-utils.h"
 #include "clockid.h"
 #include "pmu-hybrid.h"
 
···
 
 		node = rb_entry(next, struct bpf_prog_info_node, rb_node);
 		next = rb_next(&node->rb_node);
-		len = sizeof(struct bpf_prog_info_linear) +
+		len = sizeof(struct perf_bpil) +
 			node->info_linear->data_len;
 
 		/* before writing to file, translate address to offset */
-		bpf_program__bpil_addr_to_offs(node->info_linear);
+		bpil_addr_to_offs(node->info_linear);
 		ret = do_write(ff, node->info_linear, len);
 		/*
 		 * translate back to address even when do_write() fails,
 		 * so that this function never changes the data.
 		 */
-		bpf_program__bpil_offs_to_addr(node->info_linear);
+		bpil_offs_to_addr(node->info_linear);
 		if (ret < 0)
 			goto out;
 	}
···
 #ifdef HAVE_LIBBPF_SUPPORT
 static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
 {
-	struct bpf_prog_info_linear *info_linear;
 	struct bpf_prog_info_node *info_node;
 	struct perf_env *env = &ff->ph->env;
+	struct perf_bpil *info_linear;
 	u32 count, i;
 	int err = -1;
 
···
 			goto out;
 		}
 
-		info_linear = malloc(sizeof(struct bpf_prog_info_linear) +
+		info_linear = malloc(sizeof(struct perf_bpil) +
 				     data_len);
 		if (!info_linear)
 			goto out;
···
 			goto out;
 
 		/* after reading from file, translate offset to address */
-		bpf_program__bpil_offs_to_addr(info_linear);
+		bpil_offs_to_addr(info_linear);
 		info_node->info_linear = info_linear;
 		perf_env__insert_bpf_prog_info(env, info_node);
 	}