From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755570AbcIEWWW (ORCPT ); Mon, 5 Sep 2016 18:22:22 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:56569 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755372AbcIEWWD (ORCPT ); Mon, 5 Sep 2016 18:22:03 -0400 X-IBM-Helo: d24dlp01.br.ibm.com X-IBM-MailFrom: bauerman@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: Thiago Jung Bauermann To: kexec@lists.infradead.org Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, x86@kernel.org, Eric Biederman , Dave Young , Vivek Goyal , Baoquan He , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Stewart Smith , Samuel Mendoza-Jonas , Mimi Zohar , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Morton , Stephen Rothwell , Thiago Jung Bauermann Subject: [PATCH v8 07/13] powerpc: Adapt elf64_apply_relocate_add for kexec_file_load. Date: Mon, 5 Sep 2016 19:20:08 -0300 X-Mailer: git-send-email 1.9.1 In-Reply-To: <1473114014-20769-1-git-send-email-bauerman@linux.vnet.ibm.com> References: <1473114014-20769-1-git-send-email-bauerman@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16090522-0024-0000-0000-000000FC30A9 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16090522-0025-0000-0000-000015904F7E Message-Id: <1473114014-20769-8-git-send-email-bauerman@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-09-05_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1609050326 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Extend elf64_apply_relocate_add to support relative symbols. This is necessary because there is a difference between how the module loading mechanism and the kexec purgatory loading code use Elf64_Sym.st_value at relocation time: the former changes st_value to point to the absolute memory address before relocating the module, while the latter does that adjustment during relocation of the purgatory. Also, add a check_symbols argument so that the kexec code can be stricter about undefined symbols. Finally, add relocation types used by the purgatory. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Thiago Jung Bauermann Signed-off-by: Andrew Morton --- arch/powerpc/include/asm/elf_util.h | 2 + arch/powerpc/kernel/elf_util_64.c | 100 +++++++++++++++++++++++++++++++++--- arch/powerpc/kernel/module_64.c | 6 ++- 3 files changed, 99 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/include/asm/elf_util.h b/arch/powerpc/include/asm/elf_util.h index a012ba03282d..5a27e8ceb88a 100644 --- a/arch/powerpc/include/asm/elf_util.h +++ b/arch/powerpc/include/asm/elf_util.h @@ -20,6 +20,7 @@ #include struct elf_info { + const struct elfhdr *ehdr; struct elf_shdr *sechdrs; /* Index of stubs section. */ @@ -67,6 +68,7 @@ int elf64_apply_relocate_add(const struct elf_info *elf_info, const char *strtab, const Elf64_Rela *rela, unsigned int num_rela, void *syms_base, void *loc_base, Elf64_Addr addr_base, + bool relative_symbols, bool check_symbols, const char *obj_name); #endif /* _ASM_POWERPC_ELF_UTIL_H */ diff --git a/arch/powerpc/kernel/elf_util_64.c b/arch/powerpc/kernel/elf_util_64.c index 8e5d400ac9f2..1b17df71fb8d 100644 --- a/arch/powerpc/kernel/elf_util_64.c +++ b/arch/powerpc/kernel/elf_util_64.c @@ -74,6 +74,8 @@ static void squash_toc_save_inst(const char *name, unsigned long addr) { } * @syms_base: Contents of the associated symbol table. * @loc_base: Contents of the section to which relocations apply. * @addr_base: The address where the section will be loaded in memory. + * @relative_symbols: Are the symbols' st_value members relative? + * @check_symbols: Fail if an unexpected symbol is found? * @obj_name: The name of the ELF binary, for information messages. * * Applies RELA relocations to an ELF file already at its final location @@ -84,12 +86,15 @@ int elf64_apply_relocate_add(const struct elf_info *elf_info, const char *strtab, const Elf64_Rela *rela, unsigned int num_rela, void *syms_base, void *loc_base, Elf64_Addr addr_base, + bool relative_symbols, bool check_symbols, const char *obj_name) { unsigned int i; unsigned long *location; unsigned long address; + unsigned long sec_base; unsigned long value; + int reloc_type; const char *name; Elf64_Sym *sym; @@ -116,15 +121,44 @@ int elf64_apply_relocate_add(const struct elf_info *elf_info, else name = ""; - pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n", - location, (long)ELF64_R_TYPE(rela[i].r_info), - name, (unsigned long)sym->st_value, + reloc_type = ELF64_R_TYPE(rela[i].r_info); + + pr_debug("RELOC at %p: %i-type as %s (0x%lx) + %li\n", + location, reloc_type, name, (unsigned long)sym->st_value, (long)rela[i].r_addend); + if (check_symbols) { + /* + * TOC symbols appear as undefined but should be + * resolved as well, so allow them to be processed. + */ + if (sym->st_shndx == SHN_UNDEF && + strcmp(name, ".TOC.") != 0 && + reloc_type != R_PPC64_TOC) { + pr_err("Undefined symbol: %s\n", name); + return -ENOEXEC; + } else if (sym->st_shndx == SHN_COMMON) { + pr_err("Symbol '%s' in common section.\n", + name); + return -ENOEXEC; + } + } + + if (relative_symbols && sym->st_shndx != SHN_ABS) { + if (sym->st_shndx >= elf_info->ehdr->e_shnum) { + pr_err("Invalid section %d for symbol %s\n", + sym->st_shndx, name); + return -ENOEXEC; + } + + sec_base = elf_info->sechdrs[sym->st_shndx].sh_addr; + } else + sec_base = 0; + /* `Everything is relative'. */ - value = sym->st_value + rela[i].r_addend; + value = sym->st_value + sec_base + rela[i].r_addend; - switch (ELF64_R_TYPE(rela[i].r_info)) { + switch (reloc_type) { case R_PPC64_ADDR32: /* Simply set it */ *(u32 *)location = value; @@ -135,6 +169,11 @@ int elf64_apply_relocate_add(const struct elf_info *elf_info, *(unsigned long *)location = value; break; + case R_PPC64_REL32: + *(uint32_t *) location = + value - (uint32_t)(uint64_t) location; + break; + case R_PPC64_TOC: *(unsigned long *)location = my_r2(elf_info); break; @@ -186,6 +225,14 @@ int elf64_apply_relocate_add(const struct elf_info *elf_info, | (value & 0xfffc); break; + case R_PPC64_TOC16_HI: + /* Subtract TOC pointer */ + value -= my_r2(elf_info); + value = value >> 16; + *((uint16_t *) location) + = (*((uint16_t *) location) & ~0xffff) + | (value & 0xffff); + case R_PPC64_TOC16_HA: /* Subtract TOC pointer */ value -= my_r2(elf_info); @@ -195,6 +242,21 @@ int elf64_apply_relocate_add(const struct elf_info *elf_info, | (value & 0xffff); break; + case R_PPC64_REL14: + /* Convert value to relative */ + value -= address; + if (value + 0x8000 > 0xffff || (value & 3) != 0) { + pr_err("%s: REL14 %li out of range!\n", + obj_name, (long int) value); + return -ENOEXEC; + } + + /* Only replace bits 2 through 16 */ + *(uint32_t *)location + = (*(uint32_t *)location & ~0xfffc) + | (value & 0xfffc); + break; + case R_PPC_REL24: /* FIXME: Handle weak symbols here --RR */ if (sym->st_shndx == SHN_UNDEF) { @@ -263,6 +325,29 @@ int elf64_apply_relocate_add(const struct elf_info *elf_info, ((uint32_t *)location)[1] = 0x38420000 + PPC_LO(value); break; + case R_PPC64_ADDR16_LO: + *(uint16_t *)location = value & 0xffff; + break; + + case R_PPC64_ADDR16_HI: + *(uint16_t *)location = (value >> 16) & 0xffff; + break; + + case R_PPC64_ADDR16_HA: + *(uint16_t *)location = (((value + 0x8000) >> 16) & + 0xffff); + break; + + case R_PPC64_ADDR16_HIGHER: + *(uint16_t *)location = (((uint64_t)value >> 32) & + 0xffff); + break; + + case R_PPC64_ADDR16_HIGHEST: + *(uint16_t *)location = (((uint64_t)value >> 48) & + 0xffff); + break; + case R_PPC64_REL16_HA: /* Subtract location pointer */ value -= address; @@ -281,9 +366,8 @@ int elf64_apply_relocate_add(const struct elf_info *elf_info, break; default: - pr_err("%s: Unknown ADD relocation: %lu\n", - obj_name, - (unsigned long)ELF64_R_TYPE(rela[i].r_info)); + pr_err("%s: Unknown ADD relocation: %d\n", obj_name, + reloc_type); return -ENOEXEC; } } diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c index 590e2413974f..ff9ab8194188 100644 --- a/arch/powerpc/kernel/module_64.c +++ b/arch/powerpc/kernel/module_64.c @@ -341,6 +341,7 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr, sechdrs[me->arch.elf_info.stubs_section].sh_size = get_stubs_size(hdr, sechdrs); /* For the elf_util functions. */ + me->arch.elf_info.ehdr = hdr; me->arch.elf_info.sechdrs = sechdrs; return 0; @@ -443,6 +444,9 @@ int restore_r2(u32 *instruction, const char *obj_name) * When this function is called, the module is already at its final location in * memory, so Elf64_Shdr.sh_addr can be used for accessing the section * contents as well as the base address for relocations. + * + * Also, simplify_symbols already changed all symbols' st_value members + * to absolute addresses. */ int apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab, @@ -472,7 +476,7 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, return elf64_apply_relocate_add(&me->arch.elf_info, strtab, rela, num_rela, syms_base, (void *) addr_base, - addr_base, me->name); + addr_base, false, false, me->name); } #ifdef CONFIG_DYNAMIC_FTRACE -- 1.9.1