From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47865C433E0 for ; Thu, 18 Jun 2020 20:42:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27EA9208C3 for ; Thu, 18 Jun 2020 20:42:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729375AbgFRUmo (ORCPT ); Thu, 18 Jun 2020 16:42:44 -0400 Received: from ex13-edg-ou-001.vmware.com ([208.91.0.189]:4267 "EHLO EX13-EDG-OU-001.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731295AbgFRUjV (ORCPT ); Thu, 18 Jun 2020 16:39:21 -0400 Received: from sc9-mailhost2.vmware.com (10.113.161.72) by EX13-EDG-OU-001.vmware.com (10.113.208.155) with Microsoft SMTP Server id 15.0.1156.6; Thu, 18 Jun 2020 13:39:15 -0700 Received: from sc9-mailhost2.vmware.com (unknown [10.129.221.29]) by sc9-mailhost2.vmware.com (Postfix) with ESMTP id 33CFAB2656; Thu, 18 Jun 2020 16:39:19 -0400 (EDT) From: Matt Helsley To: CC: Josh Poimboeuf , Peter Zijlstra , Steven Rostedt , Julien Thierry , Kamalesh Babulal , Matt Helsley Subject: [RFC][PATCH v5 26/51] objtool: mcount: Remove unused file mapping Date: Thu, 18 Jun 2020 13:38:12 -0700 Message-ID: <79d29ed011f2afda285691a47b157363ab547204.1592510545.git.mhelsley@vmware.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII Received-SPF: None (EX13-EDG-OU-001.vmware.com: mhelsley@vmware.com does not designate permitted sender hosts) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The ELF data is now accessed completely through objtool's ELF code. We can remove the mapping of the original ELF file and propagate elf_open_read(), elf_close(), and malloc() up in place of mmap_file(), mmap_cleanup(), and umalloc() respectively. This also eliminates the last use of the umalloc() wrapper, reduces the number of global variables, and limits the use of globals to: The struct elf for the file we're working on. This saves passing it to nearly every function as a parameter. Variables set depending on the ELF file endian, wordsize, and arch so that the appropriate relocation structures, offset sizes, architecture quirks, and nop encodings will be used. One command-line option Note that we're still using the recordmcount wrapper to change variable sizes and structure definitions we use to build the mcount relocation data and call instruction offsets. Signed-off-by: Matt Helsley --- tools/objtool/recordmcount.c | 99 +++--------------------------------- tools/objtool/recordmcount.h | 4 +- 2 files changed, 9 insertions(+), 94 deletions(-) diff --git a/tools/objtool/recordmcount.c b/tools/objtool/recordmcount.c index f8699e52e7e5..a263062c9c64 100644 --- a/tools/objtool/recordmcount.c +++ b/tools/objtool/recordmcount.c @@ -41,104 +41,14 @@ #define R_AARCH64_ABS64 257 #endif -#define R_ARM_PC24 1 #define R_ARM_THM_CALL 10 -#define R_ARM_CALL 28 -static int fd_map; /* File descriptor for file being modified. */ -static int mmap_failed; /* Boolean flag. */ static char gpfx; /* prefix for global symbol name (sometimes '_') */ static const char *altmcount; /* alternate mcount symbol name */ extern int warn_on_notrace_sect; /* warn when section has mcount not being recorded */ -static void *file_map; /* pointer of the mapped file */ -static size_t file_map_size; /* original ELF file size */ static struct elf *lf; -static void mmap_cleanup(void) -{ - if (!mmap_failed) - munmap(file_map, file_map_size); - else - free(file_map); - file_map = NULL; - if (lf) - elf_close(lf); - lf = NULL; -} - -static void * umalloc(size_t size) -{ - void *const addr = malloc(size); - if (addr == 0) { - fprintf(stderr, "malloc failed: %zu bytes\n", size); - mmap_cleanup(); - return NULL; - } - return addr; -} - -/* - * Get the whole file as a programming convenience in order to avoid - * malloc+lseek+read+free of many pieces. If successful, then mmap - * avoids copying unused pieces; else just read the whole file. - * Open for both read and write; new info will be appended to the file. - * Use MAP_PRIVATE so that a few changes to the in-memory ElfXX_Ehdr - * do not propagate to the file until an explicit overwrite at the last. - * This preserves most aspects of consistency (all except .st_size) - * for simultaneous readers of the file while we are appending to it. - * However, multiple writers still are bad. We choose not to use - * locking because it is expensive and the use case of kernel build - * makes multiple writers unlikely. - */ -static void *mmap_file(char const *fname) -{ - struct stat sb; - - /* Avoid problems if early cleanup() */ - fd_map = -1; - mmap_failed = 1; - file_map = NULL; - file_map_size = 0; - - lf = elf_open_read(fname, O_RDWR); - if (!lf) { - perror(fname); - return NULL; - } - fd_map = lf->fd; - if (fstat(fd_map, &sb) < 0) { - perror(fname); - goto out; - } - if (!S_ISREG(sb.st_mode)) { - fprintf(stderr, "not a regular file: %s\n", fname); - goto out; - } - file_map = mmap(0, sb.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, - fd_map, 0); - if (file_map == MAP_FAILED) { - mmap_failed = 1; - file_map = umalloc(sb.st_size); - if (!file_map) { - perror(fname); - goto out; - } - if (read(fd_map, file_map, sb.st_size) != sb.st_size) { - perror(fname); - mmap_cleanup(); - goto out; - } - } else - mmap_failed = 0; - file_map_size = sb.st_size; -out: - fd_map = -1; - - return file_map; -} - - static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 }; static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 }; static unsigned char *ideal_nop; @@ -527,8 +437,11 @@ static int do_file(char const *const fname) unsigned int reltype = 0; int rc = -1; - if (!mmap_file(fname)) + lf = elf_open_read(fname, O_RDWR); + if (!lf) { + perror(fname); goto out; + } w = w4nat; w2 = w2nat; @@ -658,7 +571,9 @@ static int do_file(char const *const fname) } /* end switch */ out: - mmap_cleanup(); + if (lf) + elf_close(lf); + lf = NULL; return rc; } diff --git a/tools/objtool/recordmcount.h b/tools/objtool/recordmcount.h index 5ca488f3471c..fcc4f1a74d60 100644 --- a/tools/objtool/recordmcount.h +++ b/tools/objtool/recordmcount.h @@ -184,13 +184,13 @@ static int do_func(unsigned const reltype) totrelsz = tot_relsize(&rel_entsize); if (totrelsz == 0) return 0; - mrel0 = umalloc(totrelsz); + mrel0 = malloc(totrelsz); mrelp = mrel0; if (!mrel0) return -1; /* 2*sizeof(address) <= sizeof(Elf_Rel) */ - mloc0 = umalloc(totrelsz>>1); + mloc0 = malloc(totrelsz>>1); mlocp = mloc0; if (!mloc0) { free(mrel0); -- 2.20.1