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btf_encoder.c
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btf_encoder.c
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/*
SPDX-License-Identifier: GPL-2.0-only
Copyright (C) 2019 Facebook
Derived from ctf_encoder.c, which is:
Copyright (C) Arnaldo Carvalho de Melo <acme@redhat.com>
Copyright (C) Red Hat Inc
*/
#include <linux/btf.h>
#include "dwarves.h"
#include "elf_symtab.h"
#include "btf_encoder.h"
#include "gobuffer.h"
#include <bpf/btf.h>
#include <bpf/libbpf.h>
#include <ctype.h> /* for isalpha() and isalnum() */
#include <stdlib.h> /* for qsort() and bsearch() */
#include <inttypes.h>
#include <limits.h>
#include <search.h> /* for tsearch(), tfind() and tdstroy() */
#include <pthread.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdint.h>
struct elf_function {
const char *name;
bool generated;
size_t prefixlen;
};
#define MAX_PERCPU_VAR_CNT 4096
struct var_info {
uint64_t addr;
const char *name;
uint32_t sz;
};
/*
* cu: cu being processed.
*/
struct btf_encoder {
struct list_head node;
struct btf_encoder *parent;
struct btf *btf;
struct cu *cu;
struct gobuffer percpu_secinfo;
const char *filename;
struct elf_symtab *symtab;
uint32_t type_id_off;
uint32_t unspecified_type;
void *saved_func_tree;
int saved_func_cnt;
pthread_mutex_t saved_func_lock;
bool has_index_type,
need_index_type,
skip_encoding_vars,
raw_output,
verbose,
force,
gen_floats,
is_rel;
uint32_t array_index_id;
struct {
struct var_info vars[MAX_PERCPU_VAR_CNT];
int var_cnt;
uint32_t shndx;
uint64_t base_addr;
uint64_t sec_sz;
} percpu;
struct {
struct elf_function *entries;
int allocated;
int cnt;
int suffix_cnt; /* number of .isra, .part etc */
} functions;
};
static void btf_encoder__add_saved_funcs(struct btf_encoder *encoder);
void btf_encoders__add(struct list_head *encoders, struct btf_encoder *encoder)
{
list_add_tail(&encoder->node, encoders);
}
struct btf_encoder *btf_encoders__first(struct list_head *encoders)
{
return list_first_entry(encoders, struct btf_encoder, node);
}
struct btf_encoder *btf_encoders__next(struct btf_encoder *encoder)
{
return list_next_entry(encoder, node);
}
#define PERCPU_SECTION ".data..percpu"
/*
* This depends on the GNU extension to eliminate the stray comma in the zero
* arguments case.
*
* The difference between elf_errmsg(-1) and elf_errmsg(elf_errno()) is that the
* latter clears the current error.
*/
#define elf_error(fmt, ...) \
fprintf(stderr, "%s: " fmt ": %s.\n", __func__, ##__VA_ARGS__, elf_errmsg(-1))
/*
* This depends on the GNU extension to eliminate the stray comma in the zero
* arguments case.
*
* The difference between elf_errmsg(-1) and elf_errmsg(elf_errno()) is that the
* latter clears the current error.
*/
#define elf_error(fmt, ...) \
fprintf(stderr, "%s: " fmt ": %s.\n", __func__, ##__VA_ARGS__, elf_errmsg(-1))
static int btf_var_secinfo_cmp(const void *a, const void *b)
{
const struct btf_var_secinfo *av = a;
const struct btf_var_secinfo *bv = b;
return av->offset - bv->offset;
}
#define BITS_PER_BYTE 8
#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
#define BITS_ROUNDUP_BYTES(bits) (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
static const char * const btf_kind_str[] = {
[BTF_KIND_UNKN] = "UNKNOWN",
[BTF_KIND_INT] = "INT",
[BTF_KIND_PTR] = "PTR",
[BTF_KIND_ARRAY] = "ARRAY",
[BTF_KIND_STRUCT] = "STRUCT",
[BTF_KIND_UNION] = "UNION",
[BTF_KIND_ENUM] = "ENUM",
[BTF_KIND_FWD] = "FWD",
[BTF_KIND_TYPEDEF] = "TYPEDEF",
[BTF_KIND_VOLATILE] = "VOLATILE",
[BTF_KIND_CONST] = "CONST",
[BTF_KIND_RESTRICT] = "RESTRICT",
[BTF_KIND_FUNC] = "FUNC",
[BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
[BTF_KIND_VAR] = "VAR",
[BTF_KIND_DATASEC] = "DATASEC",
[BTF_KIND_FLOAT] = "FLOAT",
[BTF_KIND_DECL_TAG] = "DECL_TAG",
[BTF_KIND_TYPE_TAG] = "TYPE_TAG",
[BTF_KIND_ENUM64] = "ENUM64",
};
static const char *btf__printable_name(const struct btf *btf, uint32_t offset)
{
if (!offset)
return "(anon)";
else
return btf__str_by_offset(btf, offset);
}
static const char * btf__int_encoding_str(uint8_t encoding)
{
if (encoding == 0)
return "(none)";
else if (encoding == BTF_INT_SIGNED)
return "SIGNED";
else if (encoding == BTF_INT_CHAR)
return "CHAR";
else if (encoding == BTF_INT_BOOL)
return "BOOL";
else
return "UNKN";
}
__attribute ((format (printf, 5, 6)))
static void btf__log_err(const struct btf *btf, int kind, const char *name,
bool output_cr, const char *fmt, ...)
{
fprintf(stderr, "[%u] %s %s", btf__type_cnt(btf),
btf_kind_str[kind], name ?: "(anon)");
if (fmt && *fmt) {
va_list ap;
fprintf(stderr, " ");
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
}
if (output_cr)
fprintf(stderr, "\n");
}
__attribute ((format (printf, 5, 6)))
static void btf_encoder__log_type(const struct btf_encoder *encoder, const struct btf_type *t,
bool err, bool output_cr, const char *fmt, ...)
{
const struct btf *btf = encoder->btf;
uint8_t kind;
FILE *out;
if (!encoder->verbose && !err)
return;
kind = BTF_INFO_KIND(t->info);
out = err ? stderr : stdout;
fprintf(out, "[%u] %s %s",
btf__type_cnt(btf) - 1, btf_kind_str[kind],
btf__printable_name(btf, t->name_off));
if (fmt && *fmt) {
va_list ap;
fprintf(out, " ");
va_start(ap, fmt);
vfprintf(out, fmt, ap);
va_end(ap);
}
if (output_cr)
fprintf(out, "\n");
}
__attribute ((format (printf, 5, 6)))
static void btf_encoder__log_member(const struct btf_encoder *encoder, const struct btf_type *t,
const struct btf_member *member, bool err, const char *fmt, ...)
{
const struct btf *btf = encoder->btf;
FILE *out;
if (!encoder->verbose && !err)
return;
out = err ? stderr : stdout;
if (btf_kflag(t))
fprintf(out, "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
btf__printable_name(btf, member->name_off),
member->type,
BTF_MEMBER_BITFIELD_SIZE(member->offset),
BTF_MEMBER_BIT_OFFSET(member->offset));
else
fprintf(out, "\t%s type_id=%u bits_offset=%u",
btf__printable_name(btf, member->name_off),
member->type,
member->offset);
if (fmt && *fmt) {
va_list ap;
fprintf(out, " ");
va_start(ap, fmt);
vfprintf(out, fmt, ap);
va_end(ap);
}
fprintf(out, "\n");
}
__attribute ((format (printf, 6, 7)))
static void btf_encoder__log_func_param(struct btf_encoder *encoder, const char *name, uint32_t type,
bool err, bool is_last_param, const char *fmt, ...)
{
FILE *out;
if (!encoder->verbose && !err)
return;
out = err ? stderr : stdout;
if (is_last_param && !type)
fprintf(out, "vararg)\n");
else
fprintf(out, "%u %s%s", type, name, is_last_param ? ")\n" : ", ");
if (fmt && *fmt) {
va_list ap;
fprintf(out, " ");
va_start(ap, fmt);
vfprintf(out, fmt, ap);
va_end(ap);
}
}
static int32_t btf_encoder__add_float(struct btf_encoder *encoder, const struct base_type *bt, const char *name)
{
int32_t id = btf__add_float(encoder->btf, name, BITS_ROUNDUP_BYTES(bt->bit_size));
if (id < 0) {
btf__log_err(encoder->btf, BTF_KIND_FLOAT, name, true, "Error emitting BTF type");
} else {
const struct btf_type *t;
t = btf__type_by_id(encoder->btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u nr_bits=%u", t->size, bt->bit_size);
}
return id;
}
static int32_t btf_encoder__add_base_type(struct btf_encoder *encoder, const struct base_type *bt, const char *name)
{
const struct btf_type *t;
uint8_t encoding = 0;
uint16_t byte_sz;
int32_t id;
if (bt->is_signed) {
encoding = BTF_INT_SIGNED;
} else if (bt->is_bool) {
encoding = BTF_INT_BOOL;
} else if (bt->float_type && encoder->gen_floats) {
/*
* Encode floats as BTF_KIND_FLOAT if allowed, otherwise (in
* compatibility mode) encode them as BTF_KIND_INT - that's not
* fully correct, but that's what it used to be.
*/
if (bt->float_type == BT_FP_SINGLE ||
bt->float_type == BT_FP_DOUBLE ||
bt->float_type == BT_FP_LDBL)
return btf_encoder__add_float(encoder, bt, name);
fprintf(stderr, "Complex, interval and imaginary float types are not supported\n");
return -1;
}
/* dwarf5 may emit DW_ATE_[un]signed_{num} base types where
* {num} is not power of 2 and may exceed 128. Such attributes
* are mostly used to record operation for an actual parameter
* or variable.
* For example,
* DW_AT_location (indexed (0x3c) loclist = 0x00008fb0:
* [0xffffffff82808812, 0xffffffff82808817):
* DW_OP_breg0 RAX+0,
* DW_OP_convert (0x000e97d5) "DW_ATE_unsigned_64",
* DW_OP_convert (0x000e97df) "DW_ATE_unsigned_8",
* DW_OP_stack_value,
* DW_OP_piece 0x1,
* DW_OP_breg0 RAX+0,
* DW_OP_convert (0x000e97d5) "DW_ATE_unsigned_64",
* DW_OP_convert (0x000e97da) "DW_ATE_unsigned_32",
* DW_OP_lit8,
* DW_OP_shr,
* DW_OP_convert (0x000e97da) "DW_ATE_unsigned_32",
* DW_OP_convert (0x000e97e4) "DW_ATE_unsigned_24",
* DW_OP_stack_value, DW_OP_piece 0x3
* DW_AT_name ("ebx")
* DW_AT_decl_file ("/linux/arch/x86/events/intel/core.c")
*
* In the above example, at some point, one unsigned_32 value
* is right shifted by 8 and the result is converted to unsigned_32
* and then unsigned_24.
*
* BTF does not need such DW_OP_* information so let us sanitize
* these non-regular int types to avoid libbpf/kernel complaints.
*/
byte_sz = BITS_ROUNDUP_BYTES(bt->bit_size);
if (!byte_sz || (byte_sz & (byte_sz - 1))) {
name = "__SANITIZED_FAKE_INT__";
byte_sz = 4;
}
id = btf__add_int(encoder->btf, name, byte_sz, encoding);
if (id < 0) {
btf__log_err(encoder->btf, BTF_KIND_INT, name, true, "Error emitting BTF type");
} else {
t = btf__type_by_id(encoder->btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u nr_bits=%u encoding=%s%s",
t->size, bt->bit_size, btf__int_encoding_str(encoding),
id < 0 ? " Error in emitting BTF" : "" );
}
return id;
}
static int32_t btf_encoder__add_ref_type(struct btf_encoder *encoder, uint16_t kind, uint32_t type,
const char *name, bool kind_flag)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id;
switch (kind) {
case BTF_KIND_PTR:
id = btf__add_ptr(btf, type);
break;
case BTF_KIND_VOLATILE:
id = btf__add_volatile(btf, type);
break;
case BTF_KIND_CONST:
id = btf__add_const(btf, type);
break;
case BTF_KIND_RESTRICT:
id = btf__add_restrict(btf, type);
break;
case BTF_KIND_TYPEDEF:
id = btf__add_typedef(btf, name, type);
break;
case BTF_KIND_TYPE_TAG:
id = btf__add_type_tag(btf, name, type);
break;
case BTF_KIND_FWD:
id = btf__add_fwd(btf, name, kind_flag);
break;
case BTF_KIND_FUNC:
id = btf__add_func(btf, name, BTF_FUNC_STATIC, type);
break;
default:
btf__log_err(btf, kind, name, true, "Unexpected kind for reference");
return -1;
}
if (id > 0) {
t = btf__type_by_id(btf, id);
if (kind == BTF_KIND_FWD)
btf_encoder__log_type(encoder, t, false, true, "%s", kind_flag ? "union" : "struct");
else
btf_encoder__log_type(encoder, t, false, true, "type_id=%u", t->type);
} else {
btf__log_err(btf, kind, name, true, "Error emitting BTF type");
}
return id;
}
static int32_t btf_encoder__add_array(struct btf_encoder *encoder, uint32_t type, uint32_t index_type, uint32_t nelems)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
const struct btf_array *array;
int32_t id;
id = btf__add_array(btf, index_type, type, nelems);
if (id > 0) {
t = btf__type_by_id(btf, id);
array = btf_array(t);
btf_encoder__log_type(encoder, t, false, true, "type_id=%u index_type_id=%u nr_elems=%u",
array->type, array->index_type, array->nelems);
} else {
btf__log_err(btf, BTF_KIND_ARRAY, NULL, true,
"type_id=%u index_type_id=%u nr_elems=%u Error emitting BTF type",
type, index_type, nelems);
}
return id;
}
static int btf_encoder__add_field(struct btf_encoder *encoder, const char *name, uint32_t type, uint32_t bitfield_size, uint32_t offset)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
const struct btf_member *m;
int err;
err = btf__add_field(btf, name, type, offset, bitfield_size);
t = btf__type_by_id(btf, btf__type_cnt(btf) - 1);
if (err) {
fprintf(stderr, "[%u] %s %s's field '%s' offset=%u bit_size=%u type=%u Error emitting field\n",
btf__type_cnt(btf) - 1, btf_kind_str[btf_kind(t)],
btf__printable_name(btf, t->name_off),
name, offset, bitfield_size, type);
} else {
m = &btf_members(t)[btf_vlen(t) - 1];
btf_encoder__log_member(encoder, t, m, false, NULL);
}
return err;
}
static int32_t btf_encoder__add_struct(struct btf_encoder *encoder, uint8_t kind, const char *name, uint32_t size)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id;
switch (kind) {
case BTF_KIND_STRUCT:
id = btf__add_struct(btf, name, size);
break;
case BTF_KIND_UNION:
id = btf__add_union(btf, name, size);
break;
default:
btf__log_err(btf, kind, name, true, "Unexpected kind of struct");
return -1;
}
if (id < 0) {
btf__log_err(btf, kind, name, true, "Error emitting BTF type");
} else {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u", t->size);
}
return id;
}
#if LIBBPF_MAJOR_VERSION < 1
static inline int libbpf_err(int ret)
{
if (ret < 0)
errno = -ret;
return ret;
}
static
int btf__add_enum64(struct btf *btf __maybe_unused, const char *name __maybe_unused,
__u32 byte_sz __maybe_unused, bool is_signed __maybe_unused)
{
return libbpf_err(-ENOTSUP);
}
static
int btf__add_enum64_value(struct btf *btf __maybe_unused, const char *name __maybe_unused,
__u64 value __maybe_unused)
{
return libbpf_err(-ENOTSUP);
}
#endif
static int32_t btf_encoder__add_enum(struct btf_encoder *encoder, const char *name, struct type *etype,
struct conf_load *conf_load)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id, size;
bool is_enum32;
size = BITS_ROUNDUP_BYTES(etype->size);
is_enum32 = size <= 4 || conf_load->skip_encoding_btf_enum64;
if (is_enum32)
id = btf__add_enum(btf, name, size);
else
id = btf__add_enum64(btf, name, size, etype->is_signed_enum);
if (id > 0) {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u", t->size);
} else {
btf__log_err(btf, is_enum32 ? BTF_KIND_ENUM : BTF_KIND_ENUM64, name, true,
"size=%u Error emitting BTF type", size);
}
return id;
}
static int btf_encoder__add_enum_val(struct btf_encoder *encoder, const char *name, int64_t value,
struct type *etype, struct conf_load *conf_load)
{
const char *fmt_str;
int err;
/* If enum64 is not allowed, generate enum32 with unsigned int value. In enum64-supported
* libbpf library, btf__add_enum_value() will set the kflag (sign bit) in common_type
* if the value is negative.
*/
if (conf_load->skip_encoding_btf_enum64)
err = btf__add_enum_value(encoder->btf, name, (uint32_t)value);
else if (etype->size > 32)
err = btf__add_enum64_value(encoder->btf, name, value);
else
err = btf__add_enum_value(encoder->btf, name, value);
if (!err) {
if (encoder->verbose) {
if (conf_load->skip_encoding_btf_enum64) {
printf("\t%s val=%u\n", name, (uint32_t)value);
} else {
fmt_str = etype->is_signed_enum ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
printf(fmt_str, name, (unsigned long long)value);
}
}
} else {
if (conf_load->skip_encoding_btf_enum64) {
fprintf(stderr, "\t%s val=%u Error emitting BTF enum value\n", name, (uint32_t)value);
} else {
fmt_str = etype->is_signed_enum ? "\t%s val=%lld Error emitting BTF enum value\n"
: "\t%s val=%llu Error emitting BTF enum value\n";
fprintf(stderr, fmt_str, name, (unsigned long long)value);
}
}
return err;
}
static int32_t btf_encoder__add_func_param(struct btf_encoder *encoder, const char *name, uint32_t type, bool is_last_param)
{
int err = btf__add_func_param(encoder->btf, name, type);
if (!err) {
btf_encoder__log_func_param(encoder, name, type, false, is_last_param, NULL);
return 0;
} else {
btf_encoder__log_func_param(encoder, name, type, true, is_last_param, "Error adding func param");
return -1;
}
}
static int32_t btf_encoder__tag_type(struct btf_encoder *encoder, uint32_t tag_type)
{
if (tag_type == 0)
return 0;
if (tag_type == encoder->unspecified_type) {
// No provision for encoding this, turn it into void.
return 0;
}
return encoder->type_id_off + tag_type;
}
static int32_t btf_encoder__add_func_proto(struct btf_encoder *encoder, struct ftype *ftype)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
struct parameter *param;
uint16_t nr_params, param_idx;
int32_t id, type_id;
/* add btf_type for func_proto */
nr_params = ftype->nr_parms + (ftype->unspec_parms ? 1 : 0);
type_id = btf_encoder__tag_type(encoder, ftype->tag.type);
id = btf__add_func_proto(btf, type_id);
if (id > 0) {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, false, "return=%u args=(%s", t->type, !nr_params ? "void)\n" : "");
} else {
btf__log_err(btf, BTF_KIND_FUNC_PROTO, NULL, true,
"return=%u vlen=%u Error emitting BTF type",
type_id, nr_params);
return id;
}
/* add parameters */
param_idx = 0;
ftype__for_each_parameter(ftype, param) {
const char *name = parameter__name(param);
type_id = param->tag.type == 0 ? 0 : encoder->type_id_off + param->tag.type;
++param_idx;
if (btf_encoder__add_func_param(encoder, name, type_id, param_idx == nr_params))
return -1;
}
++param_idx;
if (ftype->unspec_parms)
if (btf_encoder__add_func_param(encoder, NULL, 0, param_idx == nr_params))
return -1;
return id;
}
static int32_t btf_encoder__add_var(struct btf_encoder *encoder, uint32_t type, const char *name, uint32_t linkage)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id;
id = btf__add_var(btf, name, linkage, type);
if (id > 0) {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "type=%u linkage=%u", t->type, btf_var(t)->linkage);
} else {
btf__log_err(btf, BTF_KIND_VAR, name, true,
"type=%u linkage=%u Error emitting BTF type",
type, linkage);
}
return id;
}
static int32_t btf_encoder__add_var_secinfo(struct btf_encoder *encoder, uint32_t type,
uint32_t offset, uint32_t size)
{
struct btf_var_secinfo si = {
.type = type,
.offset = offset,
.size = size,
};
return gobuffer__add(&encoder->percpu_secinfo, &si, sizeof(si));
}
int32_t btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder *other)
{
struct gobuffer *var_secinfo_buf = &other->percpu_secinfo;
size_t sz = gobuffer__size(var_secinfo_buf);
uint16_t nr_var_secinfo = sz / sizeof(struct btf_var_secinfo);
uint32_t type_id;
uint32_t next_type_id = btf__type_cnt(encoder->btf);
int32_t i, id;
struct btf_var_secinfo *vsi;
for (i = 0; i < nr_var_secinfo; i++) {
vsi = (struct btf_var_secinfo *)var_secinfo_buf->entries + i;
type_id = next_type_id + vsi->type - 1; /* Type ID starts from 1 */
id = btf_encoder__add_var_secinfo(encoder, type_id, vsi->offset, vsi->size);
if (id < 0)
return id;
}
/* for multi-threaded case, saved functions are added to each encoder's
* BTF, prior to it being merged with the parent encoder.
*/
btf_encoder__add_saved_funcs(encoder);
return btf__add_btf(encoder->btf, other->btf);
}
static int32_t btf_encoder__add_datasec(struct btf_encoder *encoder, const char *section_name)
{
struct gobuffer *var_secinfo_buf = &encoder->percpu_secinfo;
struct btf *btf = encoder->btf;
size_t sz = gobuffer__size(var_secinfo_buf);
uint16_t nr_var_secinfo = sz / sizeof(struct btf_var_secinfo);
struct btf_var_secinfo *last_vsi, *vsi;
const struct btf_type *t;
uint32_t datasec_sz;
int32_t err, id, i;
qsort(var_secinfo_buf->entries, nr_var_secinfo,
sizeof(struct btf_var_secinfo), btf_var_secinfo_cmp);
last_vsi = (struct btf_var_secinfo *)var_secinfo_buf->entries + nr_var_secinfo - 1;
datasec_sz = last_vsi->offset + last_vsi->size;
id = btf__add_datasec(btf, section_name, datasec_sz);
if (id < 0) {
btf__log_err(btf, BTF_KIND_DATASEC, section_name, true,
"size=%u vlen=%u Error emitting BTF type",
datasec_sz, nr_var_secinfo);
} else {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "size=%u vlen=%u", t->size, nr_var_secinfo);
}
for (i = 0; i < nr_var_secinfo; i++) {
vsi = (struct btf_var_secinfo *)var_secinfo_buf->entries + i;
err = btf__add_datasec_var_info(btf, vsi->type, vsi->offset, vsi->size);
if (!err) {
if (encoder->verbose)
printf("\ttype=%u offset=%u size=%u\n",
vsi->type, vsi->offset, vsi->size);
} else {
fprintf(stderr, "\ttype=%u offset=%u size=%u Error emitting BTF datasec var info\n",
vsi->type, vsi->offset, vsi->size);
return -1;
}
}
return id;
}
static int32_t btf_encoder__add_decl_tag(struct btf_encoder *encoder, const char *value, uint32_t type,
int component_idx)
{
struct btf *btf = encoder->btf;
const struct btf_type *t;
int32_t id;
id = btf__add_decl_tag(btf, value, type, component_idx);
if (id > 0) {
t = btf__type_by_id(btf, id);
btf_encoder__log_type(encoder, t, false, true, "type_id=%u component_idx=%d",
t->type, component_idx);
} else {
btf__log_err(btf, BTF_KIND_DECL_TAG, value, true, "component_idx=%d Error emitting BTF type",
component_idx);
}
return id;
}
static int function__compare(const void *a, const void *b)
{
struct function *fa = (struct function *)a, *fb = (struct function *)b;
return strcmp(function__name(fa), function__name(fb));
}
#define BTF_ENCODER_MAX_PARAMETERS 10
struct btf_encoder_state {
struct btf_encoder *encoder;
uint32_t type_id_off;
bool got_parameter_names;
const char *parameter_names[BTF_ENCODER_MAX_PARAMETERS];
};
void parameter_names__get(struct ftype *ftype, size_t nr_parameters, const char **parameter_names)
{
struct parameter *parameter;
int i = 0;
ftype__for_each_parameter(ftype, parameter) {
if (i >= nr_parameters)
break;
parameter_names[i++] = parameter__name(parameter);
}
}
/*
* static functions are not added yet - we need to observe across
* all CUs to see if the static function has optimized-out parameters
* in any CU, or inconsistent function prototypes; in either case,
* it should not be included in the final BTF. For the optimized-out
* case, NF_HOOK.constprop.0() is a case in point - it has optimized-out
* parameters in some CUs but not others. Similarly, a static function
* like enable_store() has inconsistent function prototypes in different
* CUs so should not be present. In order to have consistency (since
* we do not know which instance the BTF-specified function signature
* will apply to), we simply skip adding functions which have
* optimized-out parameters/inconsistent function prototypes anywhere.
*/
static int32_t btf_encoder__save_func(struct btf_encoder *encoder, struct function *fn)
{
struct btf_encoder *parent = encoder->parent ? encoder->parent : encoder;
const char *name = function__name(fn);
struct function **nodep;
int ret = 0;
pthread_mutex_lock(&parent->saved_func_lock);
nodep = tsearch(fn, &parent->saved_func_tree, function__compare);
if (nodep == NULL) {
fprintf(stderr, "error: out of memory adding local function '%s'\n",
name);
ret = -1;
goto out;
}
/* If we find an existing entry, we want to merge observations
* across both functions, checking that the "seen optimized-out
* parameters"/inconsistent proto status is reflected in tree entry.
* If the entry is new, record encoder state required
* to add the local function later (encoder + type_id_off)
* such that we can add the function later. Parameter names are
* also stored in state to speed up multiple static function
* comparisons.
*/
if (*nodep != fn) {
struct function *ofn = *nodep;
ofn->proto.optimized_parms |= fn->proto.optimized_parms;
/* compare parameters to see if signatures match */
if (ofn->proto.inconsistent_proto)
goto out;
if (ofn->proto.nr_parms != fn->proto.nr_parms) {
ofn->proto.inconsistent_proto = 1;
goto out;
}
if (ofn->proto.nr_parms > 0) {
struct btf_encoder_state *state = ofn->priv;
const char *parameter_names[BTF_ENCODER_MAX_PARAMETERS];
int i;
if (!state->got_parameter_names) {
parameter_names__get(&ofn->proto, BTF_ENCODER_MAX_PARAMETERS,
state->parameter_names);
state->got_parameter_names = true;
}
parameter_names__get(&fn->proto, BTF_ENCODER_MAX_PARAMETERS,
parameter_names);
for (i = 0; i < ofn->proto.nr_parms; i++) {
if (!state->parameter_names[i]) {
if (!parameter_names[i])
continue;
} else if (parameter_names[i]) {
if (strcmp(state->parameter_names[i],
parameter_names[i]) == 0)
continue;
}
ofn->proto.inconsistent_proto = 1;
goto out;
}
}
} else {
struct btf_encoder_state *state = zalloc(sizeof(*state));
if (state == NULL) {
fprintf(stderr, "error: out of memory adding local function '%s'\n",
name);
ret = -1;
goto out;
}
state->encoder = encoder;
state->type_id_off = encoder->type_id_off;
fn->priv = state;
encoder->saved_func_cnt++;
if (encoder->verbose)
printf("added local function '%s'%s\n", name,
fn->proto.optimized_parms ?
", optimized-out params" : "");
}
out:
pthread_mutex_unlock(&parent->saved_func_lock);
return ret;
}
static int32_t btf_encoder__add_func(struct btf_encoder *encoder, struct function *fn)
{
int btf_fnproto_id, btf_fn_id, tag_type_id;
struct llvm_annotation *annot;
const char *name;
btf_fnproto_id = btf_encoder__add_func_proto(encoder, &fn->proto);
name = function__name(fn);
btf_fn_id = btf_encoder__add_ref_type(encoder, BTF_KIND_FUNC, btf_fnproto_id, name, false);
if (btf_fnproto_id < 0 || btf_fn_id < 0) {
printf("error: failed to encode function '%s'\n", function__name(fn));
return -1;
}
list_for_each_entry(annot, &fn->annots, node) {
tag_type_id = btf_encoder__add_decl_tag(encoder, annot->value, btf_fn_id, annot->component_idx);
if (tag_type_id < 0) {
fprintf(stderr, "error: failed to encode tag '%s' to func %s with component_idx %d\n",
annot->value, name, annot->component_idx);
return -1;
}
}
return 0;
}
/* visit each node once, adding associated function */
static void btf_encoder__add_saved_func(const void *nodep, const VISIT which,
const int depth __maybe_unused)
{
struct btf_encoder_state *state;
struct btf_encoder *encoder;
struct function *fn = NULL;
switch (which) {
case preorder:
case endorder:
break;
case postorder:
case leaf:
fn = *((struct function **)nodep);
break;
}
if (!fn || !fn->priv)
return;
state = (struct btf_encoder_state *)fn->priv;
encoder = state->encoder;
encoder->type_id_off = state->type_id_off;
/* we can safely free encoder state since we visit each node once */
free(fn->priv);
fn->priv = NULL;
if (fn->proto.optimized_parms || fn->proto.inconsistent_proto) {
if (encoder->verbose)
printf("skipping addition of '%s' due to %s\n",
function__name(fn),
fn->proto.optimized_parms ? "optimized-out parameters" :
"multiple inconsistent function prototypes");
} else {
btf_encoder__add_func(encoder, fn);
}
}
void saved_func__free(void *nodep __maybe_unused)
{
/* nothing to do, functions are freed when the cu is. */
}
static void btf_encoder__add_saved_funcs(struct btf_encoder *encoder)
{
if (!encoder->parent && encoder->saved_func_tree) {
encoder->type_id_off = 0;
twalk(encoder->saved_func_tree, btf_encoder__add_saved_func);
tdestroy(encoder->saved_func_tree, saved_func__free);
encoder->saved_func_tree = NULL;
}
}
/*
* This corresponds to the same macro defined in
* include/linux/kallsyms.h
*/
#define KSYM_NAME_LEN 128
static int functions_cmp(const void *_a, const void *_b)
{
const struct elf_function *a = _a;
const struct elf_function *b = _b;
/* if search key allows prefix match, verify target has matching
* prefix len and prefix matches.
*/
if (a->prefixlen && a->prefixlen == b->prefixlen)
return strncmp(a->name, b->name, b->prefixlen);
return strcmp(a->name, b->name);