From 0646c28b417b7fe307c9da72ca1c508e43b57dc0 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 14 Nov 2022 23:27:47 +0530 Subject: objtool: Use target file endianness instead of a compiled constant Some architectures like powerpc support both endianness, it's therefore not possible to fix the endianness via arch/endianness.h because there is no easy way to get the target endianness at build time. Use the endianness recorded in the file objtool is working on. Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Acked-by: Josh Poimboeuf Acked-by: Peter Zijlstra (Intel) Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-10-sv@linux.ibm.com --- tools/objtool/include/objtool/endianness.h | 32 +++++++++++++++--------------- 1 file changed, 16 insertions(+), 16 deletions(-) (limited to 'tools/objtool/include') diff --git a/tools/objtool/include/objtool/endianness.h b/tools/objtool/include/objtool/endianness.h index 10241341eff3..4d2aa9b0fe2f 100644 --- a/tools/objtool/include/objtool/endianness.h +++ b/tools/objtool/include/objtool/endianness.h @@ -2,33 +2,33 @@ #ifndef _OBJTOOL_ENDIANNESS_H #define _OBJTOOL_ENDIANNESS_H -#include #include #include - -#ifndef __TARGET_BYTE_ORDER -#error undefined arch __TARGET_BYTE_ORDER -#endif - -#if __BYTE_ORDER != __TARGET_BYTE_ORDER -#define __NEED_BSWAP 1 -#else -#define __NEED_BSWAP 0 -#endif +#include /* - * Does a byte swap if target endianness doesn't match the host, i.e. cross + * Does a byte swap if target file endianness doesn't match the host, i.e. cross * compilation for little endian on big endian and vice versa. * To be used for multi-byte values conversion, which are read from / about * to be written to a target native endianness ELF file. */ -#define bswap_if_needed(val) \ +static inline bool need_bswap(struct elf *elf) +{ + return (__BYTE_ORDER == __LITTLE_ENDIAN) ^ + (elf->ehdr.e_ident[EI_DATA] == ELFDATA2LSB); +} + +#define bswap_if_needed(elf, val) \ ({ \ __typeof__(val) __ret; \ + bool __need_bswap = need_bswap(elf); \ switch (sizeof(val)) { \ - case 8: __ret = __NEED_BSWAP ? bswap_64(val) : (val); break; \ - case 4: __ret = __NEED_BSWAP ? bswap_32(val) : (val); break; \ - case 2: __ret = __NEED_BSWAP ? bswap_16(val) : (val); break; \ + case 8: \ + __ret = __need_bswap ? bswap_64(val) : (val); break; \ + case 4: \ + __ret = __need_bswap ? bswap_32(val) : (val); break; \ + case 2: \ + __ret = __need_bswap ? bswap_16(val) : (val); break; \ default: \ BUILD_BUG(); break; \ } \ -- cgit v1.2.3 From 86ea7f361537f825a699e86fdc9e49be19f128d1 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 14 Nov 2022 23:27:48 +0530 Subject: objtool: Use target file class size instead of a compiled constant In order to allow using objtool on cross-built kernels, determine size of long from elf data instead of using sizeof(long) at build time. For the time being this covers only mcount. [Sathvika Vasireddy: Rename variable "size" to "addrsize" and function "elf_class_size()" to "elf_class_addrsize()", and modify create_mcount_loc_sections() function to follow reverse christmas tree format to order local variable declarations.] Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Acked-by: Josh Poimboeuf Acked-by: Peter Zijlstra (Intel) Signed-off-by: Christophe Leroy Signed-off-by: Sathvika Vasireddy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-11-sv@linux.ibm.com --- tools/objtool/check.c | 18 ++++++++++-------- tools/objtool/elf.c | 8 ++++++-- tools/objtool/include/objtool/elf.h | 8 ++++++++ 3 files changed, 24 insertions(+), 10 deletions(-) (limited to 'tools/objtool/include') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index ad5dab175701..b64518c7c7b4 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -852,9 +852,9 @@ static int create_ibt_endbr_seal_sections(struct objtool_file *file) static int create_mcount_loc_sections(struct objtool_file *file) { - struct section *sec; - unsigned long *loc; + int addrsize = elf_class_addrsize(file->elf); struct instruction *insn; + struct section *sec; int idx; sec = find_section_by_name(file->elf, "__mcount_loc"); @@ -871,23 +871,25 @@ static int create_mcount_loc_sections(struct objtool_file *file) list_for_each_entry(insn, &file->mcount_loc_list, call_node) idx++; - sec = elf_create_section(file->elf, "__mcount_loc", 0, sizeof(unsigned long), idx); + sec = elf_create_section(file->elf, "__mcount_loc", 0, addrsize, idx); if (!sec) return -1; + sec->sh.sh_addralign = addrsize; + idx = 0; list_for_each_entry(insn, &file->mcount_loc_list, call_node) { + void *loc; - loc = (unsigned long *)sec->data->d_buf + idx; - memset(loc, 0, sizeof(unsigned long)); + loc = sec->data->d_buf + idx; + memset(loc, 0, addrsize); - if (elf_add_reloc_to_insn(file->elf, sec, - idx * sizeof(unsigned long), + if (elf_add_reloc_to_insn(file->elf, sec, idx, R_X86_64_64, insn->sec, insn->offset)) return -1; - idx++; + idx += addrsize; } return 0; diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c index 7e24b09b1163..33739865735b 100644 --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -1129,6 +1129,7 @@ static struct section *elf_create_rela_reloc_section(struct elf *elf, struct sec { char *relocname; struct section *sec; + int addrsize = elf_class_addrsize(elf); relocname = malloc(strlen(base->name) + strlen(".rela") + 1); if (!relocname) { @@ -1138,7 +1139,10 @@ static struct section *elf_create_rela_reloc_section(struct elf *elf, struct sec strcpy(relocname, ".rela"); strcat(relocname, base->name); - sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rela), 0); + if (addrsize == sizeof(u32)) + sec = elf_create_section(elf, relocname, 0, sizeof(Elf32_Rela), 0); + else + sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rela), 0); free(relocname); if (!sec) return NULL; @@ -1147,7 +1151,7 @@ static struct section *elf_create_rela_reloc_section(struct elf *elf, struct sec sec->base = base; sec->sh.sh_type = SHT_RELA; - sec->sh.sh_addralign = 8; + sec->sh.sh_addralign = addrsize; sec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx; sec->sh.sh_info = base->idx; sec->sh.sh_flags = SHF_INFO_LINK; diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h index 16f4067b82ae..78b3aa2e546d 100644 --- a/tools/objtool/include/objtool/elf.h +++ b/tools/objtool/include/objtool/elf.h @@ -142,6 +142,14 @@ static inline bool has_multiple_files(struct elf *elf) return elf->num_files > 1; } +static inline int elf_class_addrsize(struct elf *elf) +{ + if (elf->ehdr.e_ident[EI_CLASS] == ELFCLASS32) + return sizeof(u32); + else + return sizeof(u64); +} + struct elf *elf_open_read(const char *name, int flags); struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr); -- cgit v1.2.3 From 280981d6994e0700abd36647b141e73059851e66 Mon Sep 17 00:00:00 2001 From: Sathvika Vasireddy Date: Mon, 14 Nov 2022 23:27:49 +0530 Subject: objtool: Add --mnop as an option to --mcount Some architectures (powerpc) may not support ftrace locations being nop'ed out at build time. Introduce CONFIG_HAVE_OBJTOOL_NOP_MCOUNT for objtool, as a means for architectures to enable nop'ing of ftrace locations. Add --mnop as an option to objtool --mcount, to indicate support for the same. Also, make sure that --mnop can be passed as an option to objtool only when --mcount is passed. Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Acked-by: Josh Poimboeuf Reviewed-by: Christophe Leroy Signed-off-by: Sathvika Vasireddy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-12-sv@linux.ibm.com --- Makefile | 4 +++- arch/x86/Kconfig | 1 + kernel/trace/Kconfig | 7 +++++++ scripts/Makefile.lib | 3 +++ tools/objtool/builtin-check.c | 14 ++++++++++++++ tools/objtool/check.c | 19 ++++++++++--------- tools/objtool/include/objtool/builtin.h | 1 + 7 files changed, 39 insertions(+), 10 deletions(-) (limited to 'tools/objtool/include') diff --git a/Makefile b/Makefile index d148a55bfd0f..53c2b715d0bf 100644 --- a/Makefile +++ b/Makefile @@ -933,7 +933,9 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_CC endif endif ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL - CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT + ifdef CONFIG_HAVE_OBJTOOL_NOP_MCOUNT + CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT + endif endif ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT ifdef CONFIG_HAVE_C_RECORDMCOUNT diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 67745ceab0db..4be7c06a5d18 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -195,6 +195,7 @@ config X86 select HAVE_CONTEXT_TRACKING_USER_OFFSTACK if HAVE_CONTEXT_TRACKING_USER select HAVE_C_RECORDMCOUNT select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL + select HAVE_OBJTOOL_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT select HAVE_BUILDTIME_MCOUNT_SORT select HAVE_DEBUG_KMEMLEAK select HAVE_DMA_CONTIGUOUS diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index e9e95c790b8e..2b782321376a 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -82,6 +82,13 @@ config HAVE_OBJTOOL_MCOUNT help Arch supports objtool --mcount +config HAVE_OBJTOOL_NOP_MCOUNT + bool + help + Arch supports the objtool options --mcount with --mnop. + An architecture can select this if it wants to enable nop'ing + of ftrace locations. + config HAVE_C_RECORDMCOUNT bool help diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 3aa384cec76b..658f541c2782 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -256,6 +256,9 @@ objtool-args-$(CONFIG_HAVE_JUMP_LABEL_HACK) += --hacks=jump_label objtool-args-$(CONFIG_HAVE_NOINSTR_HACK) += --hacks=noinstr objtool-args-$(CONFIG_X86_KERNEL_IBT) += --ibt objtool-args-$(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL) += --mcount +ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL +objtool-args-$(CONFIG_HAVE_OBJTOOL_NOP_MCOUNT) += --mnop +endif objtool-args-$(CONFIG_UNWINDER_ORC) += --orc objtool-args-$(CONFIG_RETPOLINE) += --retpoline objtool-args-$(CONFIG_RETHUNK) += --rethunk diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 24fbe803a0d3..9bd347d3c244 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -82,6 +82,7 @@ const struct option check_options[] = { OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"), OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"), OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"), + OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"), OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"), OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"), OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"), @@ -150,6 +151,16 @@ static bool opts_valid(void) return false; } +static bool mnop_opts_valid(void) +{ + if (opts.mnop && !opts.mcount) { + ERROR("--mnop requires --mcount"); + return false; + } + + return true; +} + static bool link_opts_valid(struct objtool_file *file) { if (opts.link) @@ -198,6 +209,9 @@ int objtool_run(int argc, const char **argv) if (!file) return 1; + if (!mnop_opts_valid()) + return 1; + if (!link_opts_valid(file)) return 1; diff --git a/tools/objtool/check.c b/tools/objtool/check.c index b64518c7c7b4..71cf4b4ba1da 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1256,17 +1256,18 @@ static void annotate_call_site(struct objtool_file *file, if (opts.mcount && sym->fentry) { if (sibling) WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset); + if (opts.mnop) { + if (reloc) { + reloc->type = R_NONE; + elf_write_reloc(file->elf, reloc); + } - if (reloc) { - reloc->type = R_NONE; - elf_write_reloc(file->elf, reloc); - } - - elf_write_insn(file->elf, insn->sec, - insn->offset, insn->len, - arch_nop_insn(insn->len)); + elf_write_insn(file->elf, insn->sec, + insn->offset, insn->len, + arch_nop_insn(insn->len)); - insn->type = INSN_NOP; + insn->type = INSN_NOP; + } list_add_tail(&insn->call_node, &file->mcount_loc_list); return; diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h index 42a52f1a0add..0785707c5a92 100644 --- a/tools/objtool/include/objtool/builtin.h +++ b/tools/objtool/include/objtool/builtin.h @@ -31,6 +31,7 @@ struct opts { bool backup; bool dryrun; bool link; + bool mnop; bool module; bool no_unreachable; bool sec_address; -- cgit v1.2.3 From 4ca993d498987332ceeedee5380101b84accaf35 Mon Sep 17 00:00:00 2001 From: Sathvika Vasireddy Date: Mon, 14 Nov 2022 23:27:52 +0530 Subject: objtool: Add arch specific function arch_ftrace_match() Add architecture specific function to look for relocation records pointing to architecture specific symbols. Suggested-by: Christophe Leroy Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Reviewed-by: Christophe Leroy Acked-by: Josh Poimboeuf Signed-off-by: Sathvika Vasireddy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-15-sv@linux.ibm.com --- tools/objtool/arch/x86/decode.c | 5 +++++ tools/objtool/check.c | 2 +- tools/objtool/include/objtool/arch.h | 2 ++ 3 files changed, 8 insertions(+), 1 deletion(-) (limited to 'tools/objtool/include') diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index 1c253b4b7ce0..af7ad09c926c 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -23,6 +23,11 @@ #include #include +int arch_ftrace_match(char *name) +{ + return !strcmp(name, "__fentry__"); +} + static int is_x86_64(const struct elf *elf) { switch (elf->ehdr.e_machine) { diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 2d7153b5d5d1..7580c66ca5c8 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2316,7 +2316,7 @@ static int classify_symbols(struct objtool_file *file) if (arch_is_rethunk(func)) func->return_thunk = true; - if (!strcmp(func->name, "__fentry__")) + if (arch_ftrace_match(func->name)) func->fentry = true; if (is_profiling_func(func->name)) diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h index beb2f3aa94ff..5149330f400f 100644 --- a/tools/objtool/include/objtool/arch.h +++ b/tools/objtool/include/objtool/arch.h @@ -69,6 +69,8 @@ struct stack_op { struct instruction; +int arch_ftrace_match(char *name); + void arch_initial_func_cfi_state(struct cfi_init_state *state); int arch_decode_instruction(struct objtool_file *file, const struct section *sec, -- cgit v1.2.3 From a39818a3fb2bf12ae945a7c5fba8c5d9048a0e96 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 23 Nov 2022 21:26:10 +1100 Subject: objtool/powerpc: Implement arch_pc_relative_reloc() Provide an implementation for arch_pc_relative_reloc(). It is needed to pass the build once 61c6065ef7ec ("objtool: Allow !PC relative relocations") is merged. Signed-off-by: Michael Ellerman --- tools/objtool/arch/powerpc/decode.c | 9 +++++++++ tools/objtool/include/objtool/arch.h | 2 ++ 2 files changed, 11 insertions(+) (limited to 'tools/objtool/include') diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c index 01cade98b49e..9c653805a08a 100644 --- a/tools/objtool/arch/powerpc/decode.c +++ b/tools/objtool/arch/powerpc/decode.c @@ -82,6 +82,15 @@ unsigned long arch_jump_destination(struct instruction *insn) return insn->offset + insn->immediate; } +bool arch_pc_relative_reloc(struct reloc *reloc) +{ + /* + * The powerpc build only allows certain relocation types, see + * relocs_check.sh, and none of those accepted are PC relative. + */ + return false; +} + void arch_initial_func_cfi_state(struct cfi_init_state *state) { int i; diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h index 5149330f400f..4ecb480131c7 100644 --- a/tools/objtool/include/objtool/arch.h +++ b/tools/objtool/include/objtool/arch.h @@ -95,4 +95,6 @@ bool arch_is_rethunk(struct symbol *sym); int arch_rewrite_retpolines(struct objtool_file *file); +bool arch_pc_relative_reloc(struct reloc *reloc); + #endif /* _ARCH_H */ -- cgit v1.2.3