lkml.org 
[lkml]   [2022]   [Jun]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH v3 04/12] objtool: Add --mnop as an option to --mcount
Date
Architectures can select HAVE_NOP_MCOUNT if they choose
to nop out mcount call sites. If that config option is
selected, then --mnop is passed as an option to objtool,
along with --mcount.

Also, make sure that --mnop can be passed as an option
to objtool only when --mcount is passed.

Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
---
Makefile | 4 +++-
arch/x86/Kconfig | 1 +
scripts/Makefile.build | 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 250707647359..acaf88e3c694 100644
--- a/Makefile
+++ b/Makefile
@@ -851,7 +851,9 @@ 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 1847d6e974a1..4a41bfb644f0 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -189,6 +189,7 @@ config X86
select HAVE_CONTEXT_TRACKING_OFFSTACK if HAVE_CONTEXT_TRACKING
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.build b/scripts/Makefile.build
index ac8167227bc0..2e0c3f9c1459 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -231,6 +231,7 @@ 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_SLS), --sls) \
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index f4c3a5091737..b05e2108c0c3 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -80,6 +80,7 @@ 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"),
@@ -142,6 +143,16 @@ 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)
@@ -185,6 +196,9 @@ 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 fabc0ea88747..7f0dc504dd92 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1177,17 +1177,18 @@ 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 280ea18b7f2b..71ed3152a18e 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -29,6 +29,7 @@ struct opts {
bool backup;
bool dryrun;
bool link;
+ bool mnop;
bool module;
bool no_unreachable;
bool sec_address;
--
2.25.1
\
 
 \ /
  Last update: 2022-06-24 20:36    [W:0.290 / U:1.296 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site