[tip: objtool/core] objtool: Add check_kcov_mode() to the uaccess safelist

[tip-bot2 for Josh Poimboeuf]

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     ae033f088f277efd5b3c6d681ce9e7682380efff
Gitweb:        https://git.kernel.org/tip/ae033f088f277efd5b3c6d681ce9e7682380efff
Author:        Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate:    Wed, 29 Apr 2020 14:09:04 -05:00
Committer:     Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
CommitterDate: Wed, 20 May 2020 08:30:43 -05:00

objtool: Add check_kcov_mode() to the uaccess safelist

check_kcov_mode() is called by write_comp_data() and
__sanitizer_cov_trace_pc(), which are already on the uaccess safe list.
It's notrace and doesn't call out to anything else, so add it to the
list too.

This fixes the following warnings:

  kernel/kcov.o: warning: objtool: __sanitizer_cov_trace_pc()+0x15: call to check_kcov_mode() with UACCESS enabled
  kernel/kcov.o: warning: objtool: write_comp_data()+0x1b: call to check_kcov_mode() with UACCESS enabled

Reported-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 tools/objtool/check.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index e36a818..7a47ff9 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -507,6 +507,7 @@ static const char *uaccess_safe_builtin[] = {
 	"__asan_report_store16_noabort",
 	/* KCOV */
 	"write_comp_data",
+	"check_kcov_mode",
 	"__sanitizer_cov_trace_pc",
 	"__sanitizer_cov_trace_const_cmp1",
 	"__sanitizer_cov_trace_const_cmp2",