[PATCH v3 11/16] objtool: Add --mnop as an option to --mcount
From: Sathvika Vasireddy <hidden>
Date: 2022-09-12 08:22:58
Also in:
lkml
Subsystem:
kernel build + files below scripts/ (unless maintained elsewhere), objtool, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Nathan Chancellor, Nicolas Schier, Josh Poimboeuf, Peter Zijlstra, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Some architectures (powerpc) may not support ftrace locations being nop'ed out at build time. Introduce --mnop as an option to objtool for enabling nop'ing of ftrace locations. Re-purpose CONFIG_HAVE_NOP_MCOUNT as a means for architectures to indicate support for the same. Also, make sure that --mnop can be passed as an option to objtool only when --mcount is passed. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Christophe Leroy <redacted> Signed-off-by: Sathvika Vasireddy <redacted> --- Makefile | 4 +++- arch/x86/Kconfig | 1 + scripts/Makefile.lib | 1 + tools/objtool/builtin-check.c | 14 ++++++++++++++ tools/objtool/check.c | 19 ++++++++++--------- tools/objtool/include/objtool/builtin.h | 1 + 6 files changed, 30 insertions(+), 10 deletions(-)
diff --git a/Makefile b/Makefile
index a4f71076cacb..9c1f4b038f65 100644
--- a/Makefile
+++ b/Makefile@@ -857,7 +857,9 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_CC endif endif ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL - CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT + ifdef CONFIG_HAVE_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 f9920f1341c8..a8dd138df637 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig@@ -189,6 +189,7 @@ 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_NOP_MCOUNT if HAVE_OBJTOOL_MCOUNT select HAVE_BUILDTIME_MCOUNT_SORT select HAVE_DEBUG_KMEMLEAK select HAVE_DMA_CONTIGUOUS
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 3fb6a99e78c4..0610078e057a 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib@@ -234,6 +234,7 @@ objtool_args = \ $(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr) \ $(if $(CONFIG_X86_KERNEL_IBT), --ibt) \ $(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount) \ + $(if $(CONFIG_HAVE_NOP_MCOUNT), --mnop) \ $(if $(CONFIG_UNWINDER_ORC), --orc) \ $(if $(CONFIG_RETPOLINE), --retpoline) \ $(if $(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 738de23cb9e8..35827e6c6df9 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c@@ -1233,17 +1233,18 @@ 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;
--
2.31.1