linux-kernel - [PATCH] init/Kconfig: fix CC_HAS_ASM_GOTO_TIED

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Message-Id: <20220804190320.262510-1-alexandre.belloni@bootlin.com>
Date:   Thu,  4 Aug 2022 21:03:20 +0200
From:   alexandre.belloni@...tlin.com
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     Alexandre Belloni <alexandre.belloni@...tlin.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash

From: Alexandre Belloni <alexandre.belloni@...tlin.com>

When using dash as /bin/sh, the CC_HAS_ASM_GOTO_TIED_OUTPUT test fails
with a syntax error which is not the one we are looking for:

<stdin>: In function ‘foo’:
<stdin>:1:29: warning: missing terminating " character
<stdin>:1:29: error: missing terminating " character
<stdin>:2:5: error: expected ‘:’ before ‘+’ token
<stdin>:2:7: warning: missing terminating " character
<stdin>:2:7: error: missing terminating " character
<stdin>:2:5: error: expected declaration or statement at end of input

Move all the CC_HAS_ASM_GOTO tests to scripts/gcc-goto.sh to solve the
escaping issues.

Fixes: 1aa0e8b144b6 ("Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug")
Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---
 init/Kconfig        |  6 +++---
 scripts/gcc-goto.sh | 31 +++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index c984afc489de..9903a11cfe7d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -71,16 +71,16 @@ config CC_CAN_LINK_STATIC
 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag) -static)
 
 config CC_HAS_ASM_GOTO
-	def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
+	def_bool $(success,$(srctree)/scripts/gcc-goto.sh goto $(CC))
 
 config CC_HAS_ASM_GOTO_OUTPUT
 	depends on CC_HAS_ASM_GOTO
-	def_bool $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null)
+	def_bool $(success,$(srctree)/scripts/gcc-goto.sh goto_output $(CC))
 
 config CC_HAS_ASM_GOTO_TIED_OUTPUT
 	depends on CC_HAS_ASM_GOTO_OUTPUT
 	# Detect buggy gcc and clang, fixed in gcc-11 clang-14.
-	def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .\n": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null)
+	def_bool $(success,$(srctree)/scripts/gcc-goto.sh goto_tied_output $(CC))
 
 config TOOLS_SUPPORT_RELR
 	def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh)
diff --git a/scripts/gcc-goto.sh b/scripts/gcc-goto.sh
index 8b980fb2270a..aa9498b74df8 100755
--- a/scripts/gcc-goto.sh
+++ b/scripts/gcc-goto.sh
@@ -3,6 +3,11 @@
 # Test for gcc 'asm goto' support
 # Copyright (C) 2010, Jason Baron <jbaron@...hat.com>
 
+TEST=$1
+shift
+
+case $TEST in
+    "goto")
 cat << "END" | $@ -x c - -fno-PIE -c -o /dev/null
 int main(void)
 {
@@ -20,3 +25,29 @@ entry:
 	return 0;
 }
 END
+    ;;
+
+    "goto_output")
+cat << "END" | $@ -x c - -c -o /dev/null
+int foo(int x) {
+	asm goto ("": "=r"(x) ::: bar);
+	return x;
+	bar: return 0;
+}
+END
+    ;;
+
+    "goto_tied_output")
+cat << "END" | $@ -x c - -c -o /dev/null
+int foo(int *x) {
+	asm goto (".long (%l[bar]) - .\n": "+m"(*x) ::: bar);
+	return *x;
+	bar: return 0;
+}
+END
+    ;;
+
+    *)
+	exit -1
+    ;;
+esac
-- 
2.37.1