4.14-stable review patch. If anyone has any objections, please let me know.
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From: Peter Zijlstra peterz@infradead.org
commit ca41b97ed9124fd62323a162de5852f6e28f94b8 upstream.
David allowed retpolines in .init.text, except for modules, which will trip up objtool retpoline validation, fix that.
Requested-by: David Woodhouse dwmw2@infradead.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Acked-by: Thomas Gleixner tglx@linutronix.de Acked-by: Josh Poimboeuf jpoimboe@redhat.com Cc: Andy Lutomirski luto@kernel.org Cc: Arjan van de Ven arjan@linux.intel.com Cc: Borislav Petkov bp@alien8.de Cc: Dan Williams dan.j.williams@intel.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: David Woodhouse dwmw2@infradead.org Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- scripts/Makefile.build | 2 ++ tools/objtool/builtin-check.c | 3 ++- tools/objtool/builtin.h | 2 +- tools/objtool/check.c | 9 +++++++++ 4 files changed, 14 insertions(+), 2 deletions(-)
--- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -261,6 +261,8 @@ __objtool_obj := $(objtree)/tools/objtoo
objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
+objtool_args += $(if $(part-of-module), --module,) + ifndef CONFIG_FRAME_POINTER objtool_args += --no-fp endif --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -29,7 +29,7 @@ #include "builtin.h" #include "check.h"
-bool no_fp, no_unreachable, retpoline; +bool no_fp, no_unreachable, retpoline, module;
static const char * const check_usage[] = { "objtool check [<options>] file.o", @@ -40,6 +40,7 @@ const struct option check_options[] = { OPT_BOOLEAN('f', "no-fp", &no_fp, "Skip frame pointer validation"), OPT_BOOLEAN('u', "no-unreachable", &no_unreachable, "Skip 'unreachable instruction' warnings"), OPT_BOOLEAN('r', "retpoline", &retpoline, "Validate retpoline assumptions"), + OPT_BOOLEAN('m', "module", &module, "Indicates the object will be part of a kernel module"), OPT_END(), };
--- a/tools/objtool/builtin.h +++ b/tools/objtool/builtin.h @@ -20,7 +20,7 @@ #include <subcmd/parse-options.h>
extern const struct option check_options[]; -extern bool no_fp, no_unreachable, retpoline; +extern bool no_fp, no_unreachable, retpoline, module;
extern int cmd_check(int argc, const char **argv); extern int cmd_orc(int argc, const char **argv); --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1957,6 +1957,15 @@ static int validate_retpoline(struct obj if (insn->retpoline_safe) continue;
+ /* + * .init.text code is ran before userspace and thus doesn't + * strictly need retpolines, except for modules which are + * loaded late, they very much do need retpoline in their + * .init.text + */ + if (!strcmp(insn->sec->name, ".init.text") && !module) + continue; + WARN_FUNC("indirect %s found in RETPOLINE build", insn->sec, insn->offset, insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call");