From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by sourceware.org (Postfix) with ESMTPS id 87F9E3858409 for ; Tue, 18 Jan 2022 21:54:35 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 87F9E3858409 Received: by mail-pj1-x1035.google.com with SMTP id d12-20020a17090a628c00b001b4f47e2f51so968543pjj.3 for ; Tue, 18 Jan 2022 13:54:35 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=1c37e2aWlvETUO3lPA1UTgj0s9nVkUEZsxMeH6xm7Us=; b=tSZVy2SmTDWq/hw6iSKhqzZS88E8c730c+LQs1U+oSlWmFibrk4OCLXLmlnjwVYBO5 MtqnwsYfdDPmUVTI82uzm0nMlMpiTXVqQb7GjvUdLQ9bCqVBamYd30k9zIzlzaIqKNXI jn9xY72J3rO/RzF95zNZPD2aBCbSZ5/TEAYL+OVKHbs5AvHB97d1HWW5ovDI+rybqhmh 7pIDDYt8QlHQiHuOguduQMCZF1EDox4alaTA9jZEocPuZRg3OKlcH5dKZaNdp//PH+CZ PMKXtBS0p/jo3STJhCPwCJDfKCBaIg+Vv0hEPeCq9KcVZ6St5Q1u7ZXtUFolqYBadQ4i iaLg== X-Gm-Message-State: AOAM530uNJj6uiGt0jMp0SJCNm6ZIdxCVNdW4zYKScbjad6RoKsqXJ5m UWYjl7KQSB8dsGwpBjMKYrHoNaP4Yv08Ll83swQJKJ2fUHQ= X-Google-Smtp-Source: ABdhPJzKwKYfm3Y5YUMDqFHKEtSdDtm7Y4QisQW4L1ThMlllEUmsrDsa5LDRF84q5sdxt2Szo2Kh1MB6pUXL0M1LwFQ= X-Received: by 2002:a17:90a:f3c6:: with SMTP id ha6mr696143pjb.28.1642542874476; Tue, 18 Jan 2022 13:54:34 -0800 (PST) MIME-Version: 1.0 References: <20220103230433.1907240-1-hjl.tools@gmail.com> <20220103230433.1907240-3-hjl.tools@gmail.com> <5d0957aa-5128-601e-fece-837cdc6e6a20@linaro.org> In-Reply-To: <5d0957aa-5128-601e-fece-837cdc6e6a20@linaro.org> From: "H.J. Lu" Date: Tue, 18 Jan 2022 13:53:58 -0800 Message-ID: Subject: Re: [PATCH v7 2/4] elf: Add a test for PT_LOAD segments with mixed p_align [BZ #28676] To: Adhemerval Zanella Cc: GNU C Library , Florian Weimer Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3027.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Jan 2022 21:54:38 -0000 On Tue, Jan 18, 2022 at 8:26 AM Adhemerval Zanella wrote: > > > > On 03/01/2022 20:04, H.J. Lu wrote: > > Add tst-p_alignmod1-edit to edit the copy of tst-alignmod3.so to reduce > > p_align of the first PT_LOAD segment by half and verify that the shared > > library is mapped with the maximum p_align of all PT_LOAD segments. > > --- > > elf/Makefile | 18 ++++++ > > elf/tst-elf-edit.h | 126 +++++++++++++++++++++++++++++++++++++ > > elf/tst-p_align1.c | 27 ++++++++ > > elf/tst-p_alignmod1-edit.c | 34 ++++++++++ > > 4 files changed, 205 insertions(+) > > create mode 100644 elf/tst-elf-edit.h > > create mode 100644 elf/tst-p_align1.c > > create mode 100644 elf/tst-p_alignmod1-edit.c > > > > diff --git a/elf/Makefile b/elf/Makefile > > index 883578ee36..9c831faac1 100644 > > --- a/elf/Makefile > > +++ b/elf/Makefile > > @@ -403,6 +403,13 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \ > > tst-dl_find_object-mod8 \ > > tst-dl_find_object-mod9 \ > > > > +ifeq (yes,$(build-shared)) > > +tests += \ > > + tst-p_alignmod1-edit \ > > + tst-p_align1 \ > > + > > +endif > > + > > # Most modules build with _ISOMAC defined, but those filtered out > > # depend on internal headers. > > modules-names-tests = $(filter-out ifuncmod% tst-tlsmod%,\ > > @@ -2079,3 +2086,14 @@ CFLAGS-tst-dl_find_object-mod6.c += -funwind-tables > > CFLAGS-tst-dl_find_object-mod7.c += -funwind-tables > > CFLAGS-tst-dl_find_object-mod8.c += -funwind-tables > > CFLAGS-tst-dl_find_object-mod9.c += -funwind-tables > > + > > +$(objpfx)tst-p_align1: $(objpfx)tst-p_alignmod1.so > > + > > +# Make a copy of tst-alignmod3.so and lower p_align of the first PT_LOAD > > +# segment. > > +$(objpfx)tst-p_alignmod1.so: $(objpfx)tst-p_alignmod1-edit \ > > + $(objpfx)tst-alignmod3.so > > tst-alignmod3.so is only provided in the last patch, I think it would be better > to move to this patch as tst-alignmod-base, not and it instead by copying and changing > on each test. It is tst-alignmod3.so, not tst-p_alignmod3.so. In any case, I added tst-p_alignmod-base.so. > > + rm -f $@ > > + cp $(objpfx)tst-alignmod3.so $@ > > + $(test-wrapper-env) $(run-program-env) $(rtld-prefix) \ > > + $(objpfx)tst-p_alignmod1-edit $@ > > diff --git a/elf/tst-elf-edit.h b/elf/tst-elf-edit.h > > new file mode 100644 > > index 0000000000..ce98cf012c > > --- /dev/null > > +++ b/elf/tst-elf-edit.h > > @@ -0,0 +1,126 @@ > > +/* Update p_align of the first PT_LOAD segment. > > + Copyright (C) 2021 Free Software Foundation, Inc. > > + This file is part of the GNU C Library. > > + > > + The GNU C Library is free software; you can redistribute it and/or > > + modify it under the terms of the GNU Lesser General Public > > + License as published by the Free Software Foundation; either > > + version 2.1 of the License, or (at your option) any later version. > > + > > + The GNU C Library is distributed in the hope that it will be useful, > > + but WITHOUT ANY WARRANTY; without even the implied warranty of > > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > > + Lesser General Public License for more details. > > + > > + You should have received a copy of the GNU Lesser General Public > > + License along with the GNU C Library; if not, see > > + . */ > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +const char *file_name; > > + > > +static size_t update_p_align (size_t); > > + > > +int > > +main (int argc, char ** argv) > > +{ > > + if (argc != 2) > > + { > > + printf ("Usage: %s: file\n", argv[0]); > > + return 0; > > + } > > + > > + file_name = argv[1]; > > + struct stat statbuf; > > + int errno_saved; > > + > > + if (stat (file_name, &statbuf) < 0) > > + error (1, errno, "%s: not exist", file_name); > > + > > + ElfW(Ehdr) *ehdr; > > + > > + if (statbuf.st_size < sizeof (*ehdr)) > > + error (1, 0, "%s: too small", file_name); > > + > > + int fd = open (file_name, O_RDWR); > > + if (fd < 0) > > + error (1, errno, "%s: can't open", file_name); > > + > > + /* Map in the whole file. */ > > + void *base = mmap (NULL, statbuf.st_size, PROT_READ | PROT_WRITE, > > + MAP_SHARED, fd, 0); > > + if (base == MAP_FAILED) > > + { > > + errno_saved = errno; > > + close (fd); > > + error (1, errno_saved, "%s: failed to map", file_name); > > + } > > + > > + ehdr = (ElfW(Ehdr) *) base; > > + if (ehdr->e_ident[EI_MAG0] != ELFMAG0 > > + || ehdr->e_ident[EI_MAG1] != ELFMAG1 > > + || ehdr->e_ident[EI_MAG2] != ELFMAG2 > > + || ehdr->e_ident[EI_MAG3] != ELFMAG3) > > + { > > + close (fd); > > + error (1, 0, "%s: bad ELF header", file_name); > > + } > > + > > + if (ehdr->e_type != ET_DYN) > > + { > > + close (fd); > > + error (1, 0, "%s: not shared library", file_name); > > + } > > + > > + bool unsupported_class = true; > > + switch (ehdr->e_ident[EI_CLASS]) > > + { > > + default: > > + break; > > + > > + case ELFCLASS32: > > + unsupported_class = __ELF_NATIVE_CLASS != 32; > > + break; > > + > > + case ELFCLASS64: > > + unsupported_class = __ELF_NATIVE_CLASS != 64; > > + break; > > + } > > + > > + if (unsupported_class) > > + { > > + close (fd); > > + error (1, 0, "%s: unsupported ELF class: %d", > > + file_name, ehdr->e_ident[EI_CLASS]); > > + } > > + > > + size_t phdr_size = sizeof (ElfW(Phdr)) * ehdr->e_phentsize; > > + if (statbuf.st_size < (ehdr->e_phoff + phdr_size)) > > + { > > + close (fd); > > + error (1, 0, "%s: too small", file_name); > > + } > > + > > + ElfW(Phdr) *phdr = (ElfW(Phdr) *) (base + ehdr->e_phoff); > > + for (int i = 0; i < ehdr->e_phnum; i++, phdr++) > > + if (phdr->p_type == PT_LOAD) > > + { > > + /* Update p_align of the first PT_LOAD segment. */ > > + phdr->p_align = update_p_align (phdr->p_align); > > + break; > > + } > > + > > + munmap (base, statbuf.st_size); > > + close (fd); > > + > > + return 0; > > +} > > Look ok, although I think it would be simpler to build it once and use an > argument of how to change the alignment instead of build once binary > per test. I am not if it is worth to use libsupport here. This can be more flexible than an argument. I prefer to keep it ASIS. > > diff --git a/elf/tst-p_align1.c b/elf/tst-p_align1.c > > new file mode 100644 > > index 0000000000..cab9793220 > > --- /dev/null > > +++ b/elf/tst-p_align1.c > > @@ -0,0 +1,27 @@ > > +/* Check different alignments of PT_LOAD segments in a shared library. > > + Copyright (C) 2021 Free Software Foundation, Inc. > > + This file is part of the GNU C Library. > > + > > + The GNU C Library is free software; you can redistribute it and/or > > + modify it under the terms of the GNU Lesser General Public > > + License as published by the Free Software Foundation; either > > + version 2.1 of the License, or (at your option) any later version. > > + > > + The GNU C Library is distributed in the hope that it will be useful, > > + but WITHOUT ANY WARRANTY; without even the implied warranty of > > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > > + Lesser General Public License for more details. > > + > > + You should have received a copy of the GNU Lesser General Public > > + License along with the GNU C Library; if not, see > > + . */ > > + > > +extern int do_load_test (void); > > The do_load_test is defined as returning void on elf/tst-alignmod3.c, > but it redefined here as returning 'int'. This is causing a failure > on aarch64. > > Maybe it would better to move it to a proper header. Done. > > + > > +static int > > +do_test (void) > > +{ > > + return do_load_test (); > > +} > > + > > +#include > > And I think 'is_aligned' from sysdeps/generic/tst-stack-align.h > seems to have the inverted semantic that makes things confusing > (elf/tst-alignmod3.c check if it is equal to 0 to actually check > if pointer is aligned). > > Maybe it would be better to return bool and 'true' if the pointer > is indeed aligned (similar to what IS_ALIGNED/PTR_IS_ALIGNED > internal macros do). Fixed. > bool > __attribute__ ((weak, noclone, noinline)) > is_aligned (void *p, int align) > { > return (((uintptr_t) p) & (align - 1)) == 0; > } > > > diff --git a/elf/tst-p_alignmod1-edit.c b/elf/tst-p_alignmod1-edit.c > > new file mode 100644 > > index 0000000000..2aa0e7ccdd > > --- /dev/null > > +++ b/elf/tst-p_alignmod1-edit.c > > @@ -0,0 +1,34 @@ > > +/* Reduce p_align of the first PT_LOAD segment by half. > > + Copyright (C) 2021 Free Software Foundation, Inc. > > + This file is part of the GNU C Library. > > + > > + The GNU C Library is free software; you can redistribute it and/or > > + modify it under the terms of the GNU Lesser General Public > > + License as published by the Free Software Foundation; either > > + version 2.1 of the License, or (at your option) any later version. > > + > > + The GNU C Library is distributed in the hope that it will be useful, > > + but WITHOUT ANY WARRANTY; without even the implied warranty of > > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > > + Lesser General Public License for more details. > > + > > + You should have received a copy of the GNU Lesser General Public > > + License along with the GNU C Library; if not, see > > + . */ > > + > > +#include "tst-elf-edit.h" > > + > > +/* Reduce p_align by half. */ > > + > > +static size_t > > +update_p_align (size_t p_align) > > +{ > > + size_t pagesize = sysconf (_SC_PAGESIZE); > > + size_t new_p_align = p_align >> 1; > > + > > + if (new_p_align < pagesize) > > + error (1, 0, "%s: new p_align (0x%zx) < page size (0x%zx)", > > + file_name, new_p_align, pagesize); > > + > > + return new_p_align; > > +} Thanks. -- H.J.