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AJvYcCUxM+WF8O1iQ1YjeBzF+wfEdE3uBzLcREkSscm4onhnv+KuO2bw/nNqLYT96HfzmEaGhDrVQyOBDp5FpL7NGwqL6vT/SBXQVVxXjAwmYqg+2AaGrn0cBZTtzb5JL/ehRn+eQ7HD//tKJ0zbAB4sLw== X-Gm-Message-State: AOJu0Yziwi1zgOoQigDX7h45DJGH21v+u3kmttKepxJucXOz5sPJajRL l1703uhGFi6HigasLS7UuXMKaMCjy1Bs+P9CPcQJRhI2TqHwTZnw X-Google-Smtp-Source: AGHT+IHEDKX5YUMGycdZtbZwf9LMvNFKsQr+9vx63j501bDOihrYJh6U/YHtgfDh386V6vXcUFkBDQ== X-Received: by 2002:a05:6871:28c:b0:261:7af:719c with SMTP id 586e51a60fabf-26fe5be0376mr5628203fac.35.1723685808695; Wed, 14 Aug 2024 18:36:48 -0700 (PDT) Received: from localhost.localdomain ([120.229.49.183]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7127aef412bsm196842b3a.123.2024.08.14.18.36.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Aug 2024 18:36:48 -0700 (PDT) From: Howard Chu To: acme@kernel.org Cc: adrian.hunter@intel.com, irogers@google.com, jolsa@kernel.org, kan.liang@linux.intel.com, namhyung@kernel.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 03/10] perf trace: Add trace__bpf_sys_enter_beauty_map() to prepare for fetching data in BPF Date: Thu, 15 Aug 2024 09:36:19 +0800 Message-ID: <20240815013626.935097-4-howardchu95@gmail.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240815013626.935097-1-howardchu95@gmail.com> References: <20240815013626.935097-1-howardchu95@gmail.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Set up beauty_map, load it to BPF, in such format: if argument No.3 is a struct of size 32 bytes (of syscall number 114) beauty_map[114][2] = 32; if argument No.3 is a string (of syscall number 114) beauty_map[114][2] = 1; if argument No.3 is a buffer, its size is indicated by argument No.4 (of syscall number 114) beauty_map[114][2] = -4; /* -1 ~ -6, we'll read this buffer size in BPF */ Signed-off-by: Howard Chu --- tools/perf/builtin-trace.c | 106 +++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 97076b962688..e7e8c89d9538 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -113,6 +113,7 @@ struct syscall_arg_fmt { bool show_zero; #ifdef HAVE_LIBBPF_SUPPORT const struct btf_type *type; + int type_id; /* used in btf_dump */ #endif }; @@ -926,6 +927,23 @@ static void syscall_arg_fmt__cache_btf_enum(struct syscall_arg_fmt *arg_fmt, str arg_fmt->type = btf__type_by_id(btf, id); } +static int syscall_arg_fmt__cache_btf_struct(struct syscall_arg_fmt *arg_fmt, struct btf *btf, char *type) +{ + int id; + + if (arg_fmt->type != NULL) + return -1; + + id = btf__find_by_name(btf, type); + if (id < 0) + return -1; + + arg_fmt->type = btf__type_by_id(btf, id); + arg_fmt->type_id = id; + + return 0; +} + static bool syscall_arg__strtoul_btf_enum(char *bf, size_t size, struct syscall_arg *arg, u64 *val) { const struct btf_type *bt = arg->fmt->type; @@ -3520,6 +3538,83 @@ static int trace__bpf_prog_sys_exit_fd(struct trace *trace, int id) return sc ? bpf_program__fd(sc->bpf_prog.sys_exit) : bpf_program__fd(trace->skel->progs.syscall_unaugmented); } +static int trace__bpf_sys_enter_beauty_map(struct trace *trace, int key, unsigned int *beauty_array) +{ + struct tep_format_field *field; + struct syscall *sc = trace__syscall_info(trace, NULL, key); + const struct btf_type *bt; + char *struct_offset, *tmp, name[32]; + bool can_augment = false; + int i, cnt; + + if (sc == NULL) + return -1; + + trace__load_vmlinux_btf(trace); + if (trace->btf == NULL) + return -1; + + for (i = 0, field = sc->args; field; ++i, field = field->next) { + struct_offset = strstr(field->type, "struct "); + + if (field->flags & TEP_FIELD_IS_POINTER && struct_offset) { /* struct */ + struct_offset += 7; + + /* for 'struct foo *', we only want 'foo' */ + for (tmp = struct_offset, cnt = 0; *tmp != ' ' && *tmp != '\0'; ++tmp, ++cnt) { + } + + strncpy(name, struct_offset, cnt); + name[cnt] = '\0'; + + /* cache struct's btf_type and type_id */ + if (syscall_arg_fmt__cache_btf_struct(&sc->arg_fmt[i], trace->btf, name)) + continue; + + bt = sc->arg_fmt[i].type; + beauty_array[i] = bt->size; + can_augment = true; + } else if (field->flags & TEP_FIELD_IS_POINTER && /* string */ + strcmp(field->type, "const char *") == 0 && + (strstr(field->name, "name") || + strstr(field->name, "path") || + strstr(field->name, "file") || + strstr(field->name, "root") || + strstr(field->name, "key") || + strstr(field->name, "special") || + strstr(field->name, "type") || + strstr(field->name, "description"))) { + beauty_array[i] = 1; + can_augment = true; + } else if (field->flags & TEP_FIELD_IS_POINTER && /* buffer */ + strstr(field->type, "char *") && + (strstr(field->name, "buf") || + strstr(field->name, "val") || + strstr(field->name, "msg"))) { + int j; + struct tep_format_field *field_tmp; + + /* find the size of the buffer that appears in pairs with buf */ + for (j = 0, field_tmp = sc->args; field_tmp; ++j, field_tmp = field_tmp->next) { + if (!(field_tmp->flags & TEP_FIELD_IS_POINTER) && /* only integers */ + (strstr(field_tmp->name, "count") || + strstr(field_tmp->name, "siz") || /* size, bufsiz */ + (strstr(field_tmp->name, "len") && strcmp(field_tmp->name, "filename")))) { + /* filename's got 'len' in it, we don't want that */ + beauty_array[i] = -(j + 1); + can_augment = true; + break; + } + } + } + } + + if (can_augment) + return 0; + + return -1; +} + static struct bpf_program *trace__find_usable_bpf_prog_entry(struct trace *trace, struct syscall *sc) { struct tep_format_field *field, *candidate_field; @@ -3624,7 +3719,9 @@ static int trace__init_syscalls_bpf_prog_array_maps(struct trace *trace) { int map_enter_fd = bpf_map__fd(trace->skel->maps.syscalls_sys_enter); int map_exit_fd = bpf_map__fd(trace->skel->maps.syscalls_sys_exit); + int beauty_map_fd = bpf_map__fd(trace->skel->maps.beauty_map_enter); int err = 0; + unsigned int beauty_array[6]; for (int i = 0; i < trace->sctbl->syscalls.nr_entries; ++i) { int prog_fd, key = syscalltbl__id_at_idx(trace->sctbl, i); @@ -3643,6 +3740,15 @@ static int trace__init_syscalls_bpf_prog_array_maps(struct trace *trace) err = bpf_map_update_elem(map_exit_fd, &key, &prog_fd, BPF_ANY); if (err) break; + + /* use beauty_map to tell BPF how many bytes to collect, set beauty_map's value here */ + memset(beauty_array, 0, sizeof(beauty_array)); + err = trace__bpf_sys_enter_beauty_map(trace, key, (unsigned int *)beauty_array); + if (err) + continue; + err = bpf_map_update_elem(beauty_map_fd, &key, beauty_array, BPF_ANY); + if (err) + break; } /* -- 2.45.2