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AJvYcCV89RU1KIQjCA/+l8hudNU7MxivgGam7uaW30pyc4GLXaNb9Uwm8uFYRF3TnE5u2Pn/RxjKcA==@lists.linux.dev X-Gm-Message-State: AOJu0Yy4QHiGi9uolmPdYx3ksDjlvc0gNzyRhUZkwfVtTrZtzqgTIUPl gHaL6j0Sq47i5bYSVKK5g4EG4D0Ec5qN6MzD46IXPEMF884g8ZDbxCUtRriKbks= X-Gm-Gg: ASbGnctRctsSnKpQNnFZOu4zG/ieHi9By97SL2nKNqOTvlnfh9hno1gsA4mY25UxisV UdizBIUg4icdKoNsj9nVKgWZg5UrW7NsYj+OUQ+BriEeqjY4IC6aYzq2Dd+CPVlyHDuPN/r84KR sTxK56D3cbYySlFsg1eH1Clr5JFR7oeDwe5dkaHl+lQeqSWZpya/T+D2gNOwZQnhVF6hZ+0X2Dt uZmQr5ouC49upIwVdYXcbZ6TPC5wQOW6Gne1hHRvgMrkrN4gEBdAA== X-Google-Smtp-Source: AGHT+IHdMxsweQVSvkIE89/cartjnOdmknoW4rycIDu/WM156Nv5fZKnY0Cvww8TcwuaRagOlY68cw== X-Received: by 2002:a5d:5f46:0:b0:385:fb59:8358 with SMTP id ffacd0b85a97d-385fb598458mr236029f8f.53.1733155732003; Mon, 02 Dec 2024 08:08:52 -0800 (PST) Received: from [10.100.51.161] ([193.86.92.181]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-385ccd68c1bsm13165465f8f.84.2024.12.02.08.08.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 02 Dec 2024 08:08:51 -0800 (PST) Message-ID: Date: Mon, 2 Dec 2024 17:08:49 +0100 Precedence: bulk X-Mailing-List: asahi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 02/18] gendwarfksyms: Add address matching To: Sami Tolvanen Cc: Masahiro Yamada , Luis Chamberlain , Miguel Ojeda , Greg Kroah-Hartman , Matthew Maurer , Alex Gaynor , Gary Guo , Petr Pavlu , Daniel Gomez , Neal Gompa , Hector Martin , Janne Grunau , Miroslav Benes , Asahi Linux , Sedat Dilek , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, rust-for-linux@vger.kernel.org References: <20241121204220.2378181-20-samitolvanen@google.com> <20241121204220.2378181-22-samitolvanen@google.com> Content-Language: en-US From: Petr Pavlu In-Reply-To: <20241121204220.2378181-22-samitolvanen@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/21/24 21:42, Sami Tolvanen wrote: > The compiler may choose not to emit type information in DWARF for all > aliases, but it's possible for each alias to be exported separately. > To ensure we find type information for the aliases as well, read > {section, address} tuples from the symbol table and match symbols also > by address. > > Signed-off-by: Sami Tolvanen > --- [...] > @@ -82,6 +118,130 @@ struct symbol *symbol_get(const char *name) > return sym; > } > > +typedef void (*elf_symbol_callback_t)(const char *name, GElf_Sym *sym, > + Elf32_Word xndx, void *arg); > + > +static void elf_for_each_global(int fd, elf_symbol_callback_t func, void *arg) > +{ > + size_t sym_size; > + GElf_Shdr shdr_mem; > + GElf_Shdr *shdr; > + Elf_Data *xndx_data = NULL; > + Elf_Scn *scn; > + Elf *elf; > + > + if (elf_version(EV_CURRENT) != EV_CURRENT) > + error("elf_version failed: %s", elf_errmsg(-1)); > + > + elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); > + if (!elf) > + error("elf_begin failed: %s", elf_errmsg(-1)); > + > + scn = elf_nextscn(elf, NULL); > + > + while (scn) { > + shdr = gelf_getshdr(scn, &shdr_mem); > + if (!shdr) > + error("gelf_getshdr failed: %s", elf_errmsg(-1)); > + > + if (shdr->sh_type == SHT_SYMTAB_SHNDX) { > + xndx_data = elf_getdata(scn, NULL); > + if (!xndx_data) > + error("elf_getdata failed: %s", elf_errmsg(-1)); > + break; > + } > + > + scn = elf_nextscn(elf, scn); > + } > + > + sym_size = gelf_fsize(elf, ELF_T_SYM, 1, EV_CURRENT); > + scn = elf_nextscn(elf, NULL); > + > + while (scn) { > + shdr = gelf_getshdr(scn, &shdr_mem); > + if (!shdr) > + error("gelf_getshdr failed: %s", elf_errmsg(-1)); > + > + if (shdr->sh_type == SHT_SYMTAB) { > + unsigned int nsyms; > + unsigned int n; > + Elf_Data *data = elf_getdata(scn, NULL); > + > + if (!data) > + error("elf_getdata failed: %s", elf_errmsg(-1)); > + > + if (shdr->sh_entsize != sym_size) > + error("expected sh_entsize (%lu) to be %zu", > + shdr->sh_entsize, sym_size); > + > + nsyms = shdr->sh_size / shdr->sh_entsize; > + > + for (n = 1; n < nsyms; ++n) { > + const char *name = NULL; > + Elf32_Word xndx = 0; > + GElf_Sym sym_mem; > + GElf_Sym *sym; > + > + sym = gelf_getsymshndx(data, xndx_data, n, > + &sym_mem, &xndx); > + > + if (!sym || > + GELF_ST_BIND(sym->st_info) == STB_LOCAL) > + continue; Doesn't NULL returned by gelf_getsymshndx() indicate an error? If yes then I think it should be reported instead of silently skipping the symbol. With this addressed, feel free to add: Reviewed-by: Petr Pavlu -- Thanks, Petr