linux-kernel - [PATCH v2 1/6] x86: Remove stack protector test scripts

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Date:   Tue, 30 Nov 2021 15:55:44 -0500
From:   Brian Gerst <brgerst@...il.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Andy Lutomirski <luto@...nel.org>, Borislav Petkov <bp@...en8.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Brian Gerst <brgerst@...il.com>
Subject: [PATCH v2 1/6] x86: Remove stack protector test scripts

For 64-bit, this test for the stack protector was added in 2006 to
make sure the compiler had the PR28281 patch applied.  With GCC 5.1
being the minimum supported compiler now, this test is no longer
necessary.

For 32-bit, testing for compiler option support can be done directly
in Kconfig.

Signed-off-by: Brian Gerst <brgerst@...il.com>
---
 arch/x86/Kconfig                          | 7 +++----
 scripts/gcc-x86_32-has-stack-protector.sh | 8 --------
 scripts/gcc-x86_64-has-stack-protector.sh | 4 ----
 3 files changed, 3 insertions(+), 16 deletions(-)
 delete mode 100755 scripts/gcc-x86_32-has-stack-protector.sh
 delete mode 100755 scripts/gcc-x86_64-has-stack-protector.sh

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8ef4c24cc569..82ed7fdddc75 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -392,12 +392,11 @@ config PGTABLE_LEVELS
 
 config CC_HAS_SANE_STACKPROTECTOR
 	bool
-	default $(success,$(srctree)/scripts/gcc-x86_64-has-stack-protector.sh $(CC)) if 64BIT
-	default $(success,$(srctree)/scripts/gcc-x86_32-has-stack-protector.sh $(CC))
+	default y if 64BIT
+	default $(cc-option,-mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard)
 	help
 	   We have to make sure stack protector is unconditionally disabled if
-	   the compiler produces broken code or if it does not let us control
-	   the segment on 32-bit kernels.
+	   the compiler does not let us control the segment and symbol.
 
 menu "Processor type and features"
 
diff --git a/scripts/gcc-x86_32-has-stack-protector.sh b/scripts/gcc-x86_32-has-stack-protector.sh
deleted file mode 100755
index 825c75c5b715..000000000000
--- a/scripts/gcc-x86_32-has-stack-protector.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-
-# This requires GCC 8.1 or better.  Specifically, we require
-# -mstack-protector-guard-reg, added by
-# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81708
-
-echo "int foo(void) { char X[200]; return 3; }" | $* -S -x c -c -m32 -O0 -fstack-protector -mstack-protector-guard-reg=fs -mstack-protector-guard-symbol=__stack_chk_guard - -o - 2> /dev/null | grep -q "%fs"
diff --git a/scripts/gcc-x86_64-has-stack-protector.sh b/scripts/gcc-x86_64-has-stack-protector.sh
deleted file mode 100755
index 75e4e22b986a..000000000000
--- a/scripts/gcc-x86_64-has-stack-protector.sh
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-
-echo "int foo(void) { char X[200]; return 3; }" | $* -S -x c -c -m64 -O0 -mcmodel=kernel -fno-PIE -fstack-protector - -o - 2> /dev/null | grep -q "%gs"
-- 
2.31.1