linux-kernel - [PATCH v3 31/59] objtool: Add --hacks=skylake

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Message-ID: <20220915111146.120821440@infradead.org>
Date:   Thu, 15 Sep 2022 13:11:10 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org, x86@...nel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Josh Poimboeuf <jpoimboe@...nel.org>,
        Andrew Cooper <Andrew.Cooper3@...rix.com>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Johannes Wikner <kwikner@...z.ch>,
        Alyssa Milburn <alyssa.milburn@...ux.intel.com>,
        Jann Horn <jannh@...gle.com>, "H.J. Lu" <hjl.tools@...il.com>,
        Joao Moreira <joao.moreira@...el.com>,
        Joseph Nuzman <joseph.nuzman@...el.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Juergen Gross <jgross@...e.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        K Prateek Nayak <kprateek.nayak@....com>,
        Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH v3 31/59] objtool: Add --hacks=skylake

From: Peter Zijlstra <peterz@...radead.org>

Make the call/func sections selectable via the --hacks option.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 scripts/Makefile.lib                    |    3 ++-
 tools/objtool/builtin-check.c           |    7 ++++++-
 tools/objtool/check.c                   |   10 ++++++----
 tools/objtool/include/objtool/builtin.h |    1 +
 4 files changed, 15 insertions(+), 6 deletions(-)

--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -231,7 +231,8 @@ objtool := $(objtree)/tools/objtool/objt
 
 objtool_args =								\
 	$(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label)	\
-	$(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr)		\
+	$(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr)              \
+	$(if $(CONFIG_CALL_DEPTH_TRACKING), --hacks=skylake)            \
 	$(if $(CONFIG_X86_KERNEL_IBT), --ibt)				\
 	$(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount)		\
 	$(if $(CONFIG_UNWINDER_ORC), --orc)				\
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -57,12 +57,17 @@ static int parse_hacks(const struct opti
 		found = true;
 	}
 
+	if (!str || strstr(str, "skylake")) {
+		opts.hack_skylake = true;
+		found = true;
+	}
+
 	return found ? 0 : -1;
 }
 
 const struct option check_options[] = {
 	OPT_GROUP("Actions:"),
-	OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr", "patch toolchain bugs/limitations", parse_hacks),
+	OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
 	OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
 	OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
 	OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -4321,10 +4321,12 @@ int check(struct objtool_file *file)
 			goto out;
 		warnings += ret;
 
-		ret = create_direct_call_sections(file);
-		if (ret < 0)
-			goto out;
-		warnings += ret;
+		if (opts.hack_skylake) {
+			ret = create_direct_call_sections(file);
+			if (ret < 0)
+				goto out;
+			warnings += ret;
+		}
 	}
 
 	if (opts.mcount) {
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -14,6 +14,7 @@ struct opts {
 	bool dump_orc;
 	bool hack_jump_label;
 	bool hack_noinstr;
+	bool hack_skylake;
 	bool ibt;
 	bool mcount;
 	bool noinstr;