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 54F8DC433DF for ; Thu, 18 Jun 2020 20:40:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34EE720732 for ; Thu, 18 Jun 2020 20:40:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732235AbgFRUkm (ORCPT ); Thu, 18 Jun 2020 16:40:42 -0400 Received: from ex13-edg-ou-001.vmware.com ([208.91.0.189]:40437 "EHLO EX13-EDG-OU-001.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731038AbgFRUji (ORCPT ); Thu, 18 Jun 2020 16:39:38 -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 13:39:34 -0700 Received: from sc9-mailhost2.vmware.com (unknown [10.129.221.29]) by sc9-mailhost2.vmware.com (Postfix) with ESMTP id 29829B2656; Thu, 18 Jun 2020 16:39:37 -0400 (EDT) From: Matt Helsley To: CC: Josh Poimboeuf , Peter Zijlstra , Steven Rostedt , Julien Thierry , Kamalesh Babulal , Matt Helsley Subject: [RFC][PATCH v5 44/51] objtool: mcount: Keep lists locations and relocations Date: Thu, 18 Jun 2020 13:38:30 -0700 Message-ID: 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 To reduce the need for an initial pass through the sections we need to keep lists of mcount call locations and suitable relocations. A subsequent patch will eliminate the need for the first pass entirely. Introduce a new list for the locations and reuse objtool's relocation lists respectively. Signed-off-by: Matt Helsley --- tools/objtool/mcount.c | 133 +++++++++++++++++++++++------------------ 1 file changed, 75 insertions(+), 58 deletions(-) diff --git a/tools/objtool/mcount.c b/tools/objtool/mcount.c index 7fbde6ce6eb8..7d7843f7cd44 100644 --- a/tools/objtool/mcount.c +++ b/tools/objtool/mcount.c @@ -43,9 +43,15 @@ #define R_ARM_THM_CALL 10 +struct mcount_loc { + struct list_head list; + GElf_Addr loc; +}; + extern int warn_on_notrace_sect; /* warn when section has mcount not being recorded */ static struct elf *lf; +static struct list_head mcount_locs; static const char ip_relative_call_x86[5] = { 0xe8, 0x00, 0x00, 0x00, 0x00 }; static const char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 }; @@ -294,20 +300,17 @@ static char const *has_rel_mcount(const struct section * const rels) return txts->name; } -static unsigned tot_relsize(unsigned int *rel_entsize) +static void tot_relsize(unsigned int *rel_entsize) { const struct section *sec; - unsigned totrelsz = 0; char const *txtname; list_for_each_entry(sec, &lf->sections, list) { txtname = has_rel_mcount(sec); if (!(txtname && is_mcounted_section_name(txtname))) continue; - totrelsz += sec->sh.sh_size; *rel_entsize = sec->sh.sh_entsize; } - return totrelsz; } /* zero or a small negative offset added to get the start of the call @@ -323,55 +326,89 @@ static size_t loc_size; * Accumulate the section offsets that are found, and their relocation info, * onto the end of the existing arrays. */ -static void sift_rel_mcount(GElf_Addr **mlocpp, - GElf_Sxword *r_offsetp, - void **const mrelpp, +static void sift_rel_mcount(GElf_Sxword *r_offsetp, const struct section * const rels, + struct section *mc_relocs, + struct section *mc_locs, unsigned const recsym_index, unsigned long const recval, unsigned const reltype, bool is_rela) { - GElf_Rel *mrelp = *mrelpp; - GElf_Rela *mrelap = *mrelpp; struct reloc *reloc; list_for_each_entry(reloc, &rels->reloc_list, list) { unsigned long addend; + struct mcount_loc *mc_loc; + struct reloc *mc_reloc; + + if (reloc->sym->class != SYM_MCOUNT || is_fake_mcount(reloc)) + continue; - if (reloc->sym->class == SYM_MCOUNT || is_fake_mcount(reloc)) + mc_loc = malloc(sizeof(*mc_loc)); + if (!mc_loc) { + perror("malloc"); continue; + } + mc_reloc = malloc(sizeof(*mc_reloc)); + if (!mc_reloc) { + perror("malloc"); + free(mc_loc); + continue; + } + memset(mc_reloc, 0, sizeof(*mc_reloc)); + memset(mc_loc, 0, sizeof(*mc_loc)); + mc_reloc->sec = mc_relocs; addend = reloc->offset - recval + mcount_adjust; if (is_rela) { - mrelap->r_offset = *r_offsetp; - mrelap->r_info = GELF_R_INFO(recsym_index, reltype); - mrelap->r_addend = addend; - mrelap++; - **mlocpp = 0; + mc_reloc->rela.r_offset = *r_offsetp; + mc_reloc->rela.r_info = GELF_R_INFO(recsym_index, reltype); + mc_reloc->rela.r_addend = addend; + mc_loc->loc = 0; } else { - mrelp->r_offset = *r_offsetp; - mrelp->r_info = GELF_R_INFO(recsym_index, reltype); - mrelp++; - **mlocpp = addend; + mc_reloc->rel.r_offset = *r_offsetp; + mc_reloc->rel.r_info = GELF_R_INFO(recsym_index, reltype); + mc_loc->loc = addend; } - (*mlocpp)++; + mc_reloc->offset = *r_offsetp; + mc_reloc->type = reltype; + mc_reloc->sec = mc_locs; + elf_add_reloc(lf, mc_reloc); + + list_add_tail(&mc_loc->list, &mcount_locs); *r_offsetp += loc_size; } - *mrelpp = is_rela ? (void *)mrelap : (void *)mrelp; } -/* Overall supervision for Elf32 ET_REL file. */ -static int do_mcount(unsigned const reltype, size_t rela_size) +/* Convert list of mcount locations to an array/buffer for libelf */ +static void fill_mcount_locs(GElf_Sxword r_offset, GElf_Addr **rbuf, + size_t *rsize) { - /* Upper bound on space: assume all relevant relocs are for mcount. */ - unsigned totrelsz; + GElf_Addr *buf, *loc; + struct mcount_loc *entry, *next; + size_t size = sizeof(*loc) * r_offset / loc_size; + + buf = malloc(size); + if (!buf) { + perror("malloc"); + return; + } - void *mrel0; - void *mrelp; + loc = buf; + list_for_each_entry_safe(entry, next, &mcount_locs, list) { + *loc = entry->loc; + list_del(&entry->list); + free(entry); + loc++; + } + *rbuf = buf; + *rsize = size; +} - GElf_Addr *mloc0; - GElf_Addr *mlocp; +/* Overall supervision for Elf32 ET_REL file. */ +static int do_mcount(unsigned const reltype, size_t rela_size) +{ GElf_Sxword r_offset = 0; struct section *sec, *mlocs, *mrels; @@ -384,33 +421,16 @@ static int do_mcount(unsigned const reltype, size_t rela_size) if (find_section_by_name(lf, "__mcount_loc") != NULL) return 0; - totrelsz = tot_relsize(&rel_entsize); - if (totrelsz == 0) - return 0; - - mrel0 = malloc(totrelsz); - mrelp = mrel0; - if (!mrel0) - return -1; - - /* 2*sizeof(address) <= sizeof(Elf_Rel) */ - mloc0 = malloc(totrelsz>>1); - mlocp = mloc0; - if (!mloc0) { - free(mrel0); - return -1; - } - + tot_relsize(&rel_entsize); is_rela = (rela_size == rel_entsize); /* add section: __mcount_loc */ - mlocs = elf_create_section(lf, mc_name, sizeof(*mloc0), 0); + mlocs = elf_create_section(lf, mc_name, sizeof(GElf_Addr), 0); if (!mlocs) goto out; mlocs->sh.sh_link = 0; mlocs->sh.sh_info = 0; mlocs->sh.sh_addralign = 8; - mlocs->data->d_buf = mloc0; mlocs->data->d_type = ELF_T_ADDR; /* elf_xlatetof() conversion */ /* add section .rel[a]__mcount_loc */ @@ -419,7 +439,6 @@ static int do_mcount(unsigned const reltype, size_t rela_size) if (!mrels) goto out; mrels->sh.sh_flags = 0; /* clear SHF_INFO_LINK */ - mrels->data->d_buf = mrel0; list_for_each_entry(sec, &lf->sections, list) { char const *txtname; @@ -433,7 +452,7 @@ static int do_mcount(unsigned const reltype, size_t rela_size) txtname, &recval, &recsym)) goto out; - sift_rel_mcount(&mlocp, &r_offset, &mrelp, sec, + sift_rel_mcount(&r_offset, sec, mrels, mlocs, recsym, recval, reltype, is_rela); } else if (txtname && (warn_on_notrace_sect || make_nop)) { /* @@ -445,25 +464,21 @@ static int do_mcount(unsigned const reltype, size_t rela_size) } } - if (mloc0 != mlocp) { + if (!list_empty(&mcount_locs)) { + fill_mcount_locs(r_offset, (GElf_Addr **)&mlocs->data->d_buf, + &mlocs->sh.sh_size); /* Update the section size and Elf_Data size */ - mlocs->sh.sh_size = (void *)mlocp - (void *)mloc0; mlocs->len = mlocs->sh.sh_size; mlocs->data->d_size = mlocs->len; elf_flagdata(mlocs->data, ELF_C_SET, ELF_F_DIRTY); - mrels->sh.sh_size = mrelp - mrel0; - mrels->len = mrels->sh.sh_size; - mrels->data->d_size = mrels->len; - elf_flagdata(mrels->data, ELF_C_SET, ELF_F_DIRTY); + elf_rebuild_reloc_section(lf, mrels); /* overwrite the ELF file */ result = elf_write(lf); } else result = 0; out: - free(mrel0); - free(mloc0); return result; } @@ -490,6 +505,8 @@ static int do_file(char const *const fname) goto out; } + INIT_LIST_HEAD(&mcount_locs); + switch (lf->ehdr.e_ident[EI_DATA]) { default: fprintf(stderr, "unrecognized ELF data encoding %d: %s\n", -- 2.20.1