From patchwork Thu Nov 9 23:59:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Namhyung Kim X-Patchwork-Id: 13451900 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9287432189; Fri, 10 Nov 2023 00:01:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="EfHKOtdI" Received: from mail-pg1-x533.google.com (mail-pg1-x533.google.com [IPv6:2607:f8b0:4864:20::533]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2B645257; Thu, 9 Nov 2023 16:01:05 -0800 (PST) Received: by mail-pg1-x533.google.com with SMTP id 41be03b00d2f7-5a9bc2ec556so1108808a12.0; Thu, 09 Nov 2023 16:01:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1699574465; x=1700179265; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:sender:from:to:cc:subject:date :message-id:reply-to; bh=xjEl3q6T8aZ2C9UHCLhYA2cSxHBerxf7uY5QArHiSe8=; b=EfHKOtdIgzEaTPWORXYZsLBAYYYLAc6iYVEdnPbGHNHVituPjYOELHxNHPONiYmtTp glzEL5U9IPfCgn+2YSFu9JPPHlxbDjJ2EfSq9w3BUPSWC92hkNkAZLegTG/udKZMxgdy effHaJyRHTlc5YpeBF9jANXonykrAQR3oU7IHxaJzfQo72hneBFjt0fki0T3tgAKM/6k Uttwdq8XJSkRotp9BFGPXHBqGzZHwAu/dy349indyyKtg4rURZO6tuOc1RZdk1THrYKs JBkL+sa/rqsPv7k91u8d+x/xbPW3QjpPz+kv/MCkEeb/UI0OpIGXYX5oQI1iEAq7wIy3 ZtMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1699574465; x=1700179265; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:sender:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=xjEl3q6T8aZ2C9UHCLhYA2cSxHBerxf7uY5QArHiSe8=; b=LVz5Mp0AwoBxHcgW74EmPpkDLLoq3f++rMjeYJJbNwx4mXv/pSULEliSrJKAaBSeNX V24ywjukl7nPNHr11y95sOQ8UG0uxd5vlFmO6eJbF+waQ8fYXRY78Q7v4wo3SiTfN2Hi Vp45N9SSimhEsNw0B5EYD0Gqj+yNQJgW4lecLumUbYQf8dr31kv5yP91tWJs/8BhVp/9 1e7bwbdi/lBHo1r0w7LVZZFi4G3O5B6okHF09l4DvxfBGO/EgBQMH7NKOwj1tDhLswhq I2HRgnyvoEgZTqjFkgk4j3cRV9Yjnh0xUlNxVCR2G06ePs9bGvNm6HhU0PxsJhs79jHF xxGw== X-Gm-Message-State: AOJu0Yx29oQqymQkFE0ikp+iRGlA7AnuNU/lcqvkW7hUDMTcndobdk5+ 6vUFT30sVZK/9C8jpa3J+Dw= X-Google-Smtp-Source: AGHT+IFe4ieLldc6KrSz5mKX86U9BuRX1+txGq4lZdQQfJRXwcmIPzy9i1H8w2j1Lv6jrfTUdQ9XxA== X-Received: by 2002:a17:90b:4a91:b0:27d:1538:e324 with SMTP id lp17-20020a17090b4a9100b0027d1538e324mr3249850pjb.32.1699574465081; Thu, 09 Nov 2023 16:01:05 -0800 (PST) Received: from bangji.corp.google.com ([2620:15c:2c0:5:d45c:ae16:d959:a5f1]) by smtp.gmail.com with ESMTPSA id k32-20020a17090a4ca300b002635db431a0sm371312pjh.45.2023.11.09.16.01.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Nov 2023 16:01:04 -0800 (PST) Sender: Namhyung Kim From: Namhyung Kim To: Arnaldo Carvalho de Melo , Jiri Olsa , Peter Zijlstra Cc: Ian Rogers , Adrian Hunter , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Linus Torvalds , Stephane Eranian , Masami Hiramatsu , Andi Kleen , linux-trace-devel@vger.kernel.org, linux-toolchains@vger.kernel.org Subject: [PATCH 32/52] perf dwarf-aux: Add die_find_variable_by_addr() Date: Thu, 9 Nov 2023 15:59:51 -0800 Message-ID: <20231110000012.3538610-33-namhyung@kernel.org> X-Mailer: git-send-email 2.42.0.869.gea05f2083d-goog In-Reply-To: <20231110000012.3538610-1-namhyung@kernel.org> References: <20231110000012.3538610-1-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The die_find_variable_by_addr() is to find a variables in the given DIE using given (PC-relative) address. Global variables will have a location expression with DW_OP_addr which has an address so can simply compare it with the address. <1><143a7>: Abbrev Number: 2 (DW_TAG_variable) <143a8> DW_AT_name : loops_per_jiffy <143ac> DW_AT_type : <0x1cca> <143b0> DW_AT_external : 1 <143b0> DW_AT_decl_file : 193 <143b1> DW_AT_decl_line : 213 <143b2> DW_AT_location : 9 byte block: 3 b0 46 41 82 ff ff ff ff (DW_OP_addr: ffffffff824146b0) Note that the type-offset should be calculated from the base address of the global variable. Acked-by: Masami Hiramatsu (Google) Signed-off-by: Namhyung Kim --- tools/perf/util/dwarf-aux.c | 79 +++++++++++++++++++++++++++++++++++++ tools/perf/util/dwarf-aux.h | 14 +++++++ 2 files changed, 93 insertions(+) diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 4bdcd3dea28f..7aa5fee0da19 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -1266,8 +1266,12 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf) struct find_var_data { /* Target instruction address */ Dwarf_Addr pc; + /* Target memory address (for global data) */ + Dwarf_Addr addr; /* Target register */ unsigned reg; + /* Access offset, set for global data */ + int offset; }; /* Max number of registers DW_OP_regN supports */ @@ -1328,6 +1332,81 @@ Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die, Dwarf_Addr pc, int reg, }; return die_find_child(sc_die, __die_find_var_reg_cb, &data, die_mem); } + +/* Only checks direct child DIEs in the given scope */ +static int __die_find_var_addr_cb(Dwarf_Die *die_mem, void *arg) +{ + struct find_var_data *data = arg; + int tag = dwarf_tag(die_mem); + ptrdiff_t off = 0; + Dwarf_Attribute attr; + Dwarf_Addr base, start, end; + Dwarf_Word size; + Dwarf_Die type_die; + Dwarf_Op *ops; + size_t nops; + + if (tag != DW_TAG_variable) + return DIE_FIND_CB_SIBLING; + + if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL) + return DIE_FIND_CB_SIBLING; + + while ((off = dwarf_getlocations(&attr, off, &base, &start, &end, &ops, &nops)) > 0) { + if (ops->atom != DW_OP_addr) + continue; + + if (data->addr < ops->number) + continue; + + if (data->addr == ops->number) { + /* Update offset relative to the start of the variable */ + data->offset = 0; + return DIE_FIND_CB_END; + } + + if (die_get_real_type(die_mem, &type_die) == NULL) + continue; + + if (dwarf_aggregate_size(&type_die, &size) < 0) + continue; + + if (data->addr >= ops->number + size) + continue; + + /* Update offset relative to the start of the variable */ + data->offset = data->addr - ops->number; + return DIE_FIND_CB_END; + } + return DIE_FIND_CB_SIBLING; +} + +/** + * die_find_variable_by_addr - Find variable located at given address + * @sc_die: a scope DIE + * @pc: the program address to find + * @addr: the data address to find + * @die_mem: a buffer to save the resulting DIE + * @offset: the offset in the resulting type + * + * Find the variable DIE located at the given address (in PC-relative mode). + * This is usually for global variables. + */ +Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr pc, + Dwarf_Addr addr, Dwarf_Die *die_mem, + int *offset) +{ + struct find_var_data data = { + .pc = pc, + .addr = addr, + }; + Dwarf_Die *result; + + result = die_find_child(sc_die, __die_find_var_addr_cb, &data, die_mem); + if (result) + *offset = data.offset; + return result; +} #endif /* diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h index f9763d3b7572..4e64caac6df8 100644 --- a/tools/perf/util/dwarf-aux.h +++ b/tools/perf/util/dwarf-aux.h @@ -144,6 +144,11 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf); Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die, Dwarf_Addr pc, int reg, Dwarf_Die *die_mem); +/* Find a (global) variable located in the 'addr' */ +Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr pc, + Dwarf_Addr addr, Dwarf_Die *die_mem, + int *offset); + #else /* HAVE_DWARF_GETLOCATIONS_SUPPORT */ static inline int die_get_var_range(Dwarf_Die *sp_die __maybe_unused, @@ -161,6 +166,15 @@ static inline Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die __maybe_unus return NULL; } +static inline Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die __maybe_unused, + Dwarf_Addr pc __maybe_unused, + Dwarf_Addr addr __maybe_unused, + Dwarf_Die *die_mem __maybe_unused, + int *offset __maybe_unused) +{ + return NULL; +} + #endif /* HAVE_DWARF_GETLOCATIONS_SUPPORT */ #endif /* _DWARF_AUX_H */