linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Will Deacon <will@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, kernel-team@android.com,
	Will Deacon <will@kernel.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Segher Boessenkool <segher@kernel.crashing.org>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Peter Oberparleiter <oberpar@linux.ibm.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Subject: [PATCH v2 09/10] compiler/gcc: Raise minimum GCC version for kernel builds to 4.8
Date: Thu, 23 Jan 2020 15:33:40 +0000	[thread overview]
Message-ID: <20200123153341.19947-10-will@kernel.org> (raw)
In-Reply-To: <20200123153341.19947-1-will@kernel.org>

It is very rare to see versions of GCC prior to 4.8 being used to build
the mainline kernel. These old compilers are also know to have codegen
issues which can lead to silent miscompilation:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145

Raise the minimum GCC version for kernel build to 4.8 and remove some
tautological Kconfig dependencies as a consequence.

Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
 Documentation/process/changes.rst |  2 +-
 arch/arm/crypto/Kconfig           | 12 ++++++------
 crypto/Kconfig                    |  1 -
 include/linux/compiler-gcc.h      |  5 ++---
 init/Kconfig                      |  1 -
 scripts/Kconfig.include           |  3 ---
 scripts/gcc-plugins/Kconfig       |  4 +---
 7 files changed, 10 insertions(+), 18 deletions(-)

diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index 2284f2221f02..f2cbfa901cc8 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -29,7 +29,7 @@ you probably needn't concern yourself with pcmciautils.
 ====================== ===============  ========================================
         Program        Minimal version       Command to check the version
 ====================== ===============  ========================================
-GNU C                  4.6              gcc --version
+GNU C                  4.8              gcc --version
 GNU make               3.81             make --version
 binutils               2.21             ld -v
 flex                   2.5.35           flex --version
diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig
index 2674de6ada1f..c9bf2df85cb9 100644
--- a/arch/arm/crypto/Kconfig
+++ b/arch/arm/crypto/Kconfig
@@ -30,7 +30,7 @@ config CRYPTO_SHA1_ARM_NEON
 
 config CRYPTO_SHA1_ARM_CE
 	tristate "SHA1 digest algorithm (ARM v8 Crypto Extensions)"
-	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
+	depends on KERNEL_MODE_NEON
 	select CRYPTO_SHA1_ARM
 	select CRYPTO_HASH
 	help
@@ -39,7 +39,7 @@ config CRYPTO_SHA1_ARM_CE
 
 config CRYPTO_SHA2_ARM_CE
 	tristate "SHA-224/256 digest algorithm (ARM v8 Crypto Extensions)"
-	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
+	depends on KERNEL_MODE_NEON
 	select CRYPTO_SHA256_ARM
 	select CRYPTO_HASH
 	help
@@ -96,7 +96,7 @@ config CRYPTO_AES_ARM_BS
 
 config CRYPTO_AES_ARM_CE
 	tristate "Accelerated AES using ARMv8 Crypto Extensions"
-	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
+	depends on KERNEL_MODE_NEON
 	select CRYPTO_SKCIPHER
 	select CRYPTO_LIB_AES
 	select CRYPTO_SIMD
@@ -106,7 +106,7 @@ config CRYPTO_AES_ARM_CE
 
 config CRYPTO_GHASH_ARM_CE
 	tristate "PMULL-accelerated GHASH using NEON/ARMv8 Crypto Extensions"
-	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
+	depends on KERNEL_MODE_NEON
 	select CRYPTO_HASH
 	select CRYPTO_CRYPTD
 	select CRYPTO_GF128MUL
@@ -118,13 +118,13 @@ config CRYPTO_GHASH_ARM_CE
 
 config CRYPTO_CRCT10DIF_ARM_CE
 	tristate "CRCT10DIF digest algorithm using PMULL instructions"
-	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
+	depends on KERNEL_MODE_NEON
 	depends on CRC_T10DIF
 	select CRYPTO_HASH
 
 config CRYPTO_CRC32_ARM_CE
 	tristate "CRC32(C) digest algorithm using CRC and/or PMULL instructions"
-	depends on KERNEL_MODE_NEON && (CC_IS_CLANG || GCC_VERSION >= 40800)
+	depends on KERNEL_MODE_NEON
 	depends on CRC32
 	select CRYPTO_HASH
 
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 5575d48473bd..bd8540f56efc 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -320,7 +320,6 @@ config CRYPTO_AEGIS128
 config CRYPTO_AEGIS128_SIMD
 	bool "Support SIMD acceleration for AEGIS-128"
 	depends on CRYPTO_AEGIS128 && ((ARM || ARM64) && KERNEL_MODE_NEON)
-	depends on !ARM || CC_IS_CLANG || GCC_VERSION >= 40800
 	default y
 
 config CRYPTO_AEGIS128_AESNI_SSE2
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index d7ee4c6bad48..e2f725273261 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -10,7 +10,8 @@
 		     + __GNUC_MINOR__ * 100	\
 		     + __GNUC_PATCHLEVEL__)
 
-#if GCC_VERSION < 40600
+/* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 */
+#if GCC_VERSION < 40800
 # error Sorry, your compiler is too old - please upgrade it.
 #endif
 
@@ -126,9 +127,7 @@
 #if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
 #define __HAVE_BUILTIN_BSWAP32__
 #define __HAVE_BUILTIN_BSWAP64__
-#if GCC_VERSION >= 40800
 #define __HAVE_BUILTIN_BSWAP16__
-#endif
 #endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
 
 #if GCC_VERSION >= 70000
diff --git a/init/Kconfig b/init/Kconfig
index bdc2f1b1667b..46729aa2ca0b 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1257,7 +1257,6 @@ config LD_DEAD_CODE_DATA_ELIMINATION
 	bool "Dead code and data elimination (EXPERIMENTAL)"
 	depends on HAVE_LD_DEAD_CODE_DATA_ELIMINATION
 	depends on EXPERT
-	depends on !(FUNCTION_TRACER && CC_IS_GCC && GCC_VERSION < 40800)
 	depends on $(cc-option,-ffunction-sections -fdata-sections)
 	depends on $(ld-option,--gc-sections)
 	help
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index 4e645a798b56..5b7dc6635c4e 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -43,6 +43,3 @@ gcc-version := $(shell,$(srctree)/scripts/gcc-version.sh $(CC))
 
 # Return y if the compiler is GCC, n otherwise
 cc-is-gcc := $(success,$(CC) --version | head -n 1 | grep -q gcc)
-
-# Warn if the compiler is GCC prior to 4.8
-$(warning-if,$(if-success,[ $(gcc-version) -lt 40800 ],$(cc-is-gcc),n),"Your compiler is old and may miscompile the kernel due to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 - please upgrade it.")
diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index e3569543bdac..a0f669cd224f 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -1,9 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
-preferred-plugin-hostcc := $(if-success,[ $(gcc-version) -ge 40800 ],$(HOSTCXX),$(HOSTCC))
-
 config PLUGIN_HOSTCC
 	string
-	default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(preferred-plugin-hostcc)" "$(HOSTCXX)" "$(CC)")" if CC_IS_GCC
+	default "$(shell,$(srctree)/scripts/gcc-plugin.sh "$(HOSTCXX)" "$(HOSTCXX)" "$(CC)")" if CC_IS_GCC
 	help
 	  Host compiler used to build GCC plugins.  This can be $(HOSTCXX),
 	  $(HOSTCC), or a null string if GCC plugin is unsupported.
-- 
2.25.0.341.g760bfbb309-goog


  parent reply	other threads:[~2020-01-23 15:34 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-23 15:33 [PATCH v2 00/10] Rework READ_ONCE() to improve codegen Will Deacon
2020-01-23 15:33 ` [PATCH v2 01/10] compiler/gcc: Emit build-time warning for GCC prior to version 4.8 Will Deacon
2020-01-23 15:33 ` [PATCH v2 02/10] netfilter: Avoid assigning 'const' pointer to non-const pointer Will Deacon
2020-01-23 19:07   ` Nick Desaulniers
2020-01-24  8:24     ` Peter Zijlstra
2020-01-24 17:20       ` Nick Desaulniers
2020-01-27 12:04         ` David Laight
2020-01-24 17:36       ` Linus Torvalds
2020-01-24 22:00         ` Peter Zijlstra
2020-01-27 12:21         ` David Laight
2020-01-23 15:33 ` [PATCH v2 03/10] fault_inject: Don't rely on "return value" from WRITE_ONCE() Will Deacon
2020-01-23 15:33 ` [PATCH v2 04/10] READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() Will Deacon
2020-01-23 15:33 ` [PATCH v2 05/10] READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses Will Deacon
2020-01-25  8:27   ` Peter Zijlstra
2020-01-29 10:49     ` Peter Zijlstra
2020-01-23 15:33 ` [PATCH v2 06/10] READ_ONCE: Drop pointer qualifiers when reading from scalar types Will Deacon
2020-01-23 15:33 ` [PATCH v2 07/10] locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros Will Deacon
2020-01-23 15:33 ` [PATCH v2 08/10] arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros Will Deacon
2020-01-23 15:33 ` Will Deacon [this message]
2020-01-23 18:36   ` [PATCH v2 09/10] compiler/gcc: Raise minimum GCC version for kernel builds to 4.8 Nick Desaulniers
2020-01-24  8:26     ` Peter Zijlstra
2020-01-24 17:05       ` Nick Desaulniers
2020-01-24 23:29         ` Peter Zijlstra
2020-01-25 10:34         ` Michael Ellerman
2020-01-23 15:33 ` [PATCH v2 10/10] gcov: Remove old GCC 3.4 support Will Deacon
2020-01-23 18:51   ` Nick Desaulniers
2020-01-28 14:56   ` Peter Oberparleiter
2020-01-23 17:07 ` [PATCH v2 00/10] Rework READ_ONCE() to improve codegen David Laight
2020-01-23 17:16   ` Will Deacon
2020-01-23 17:32     ` David Laight
2020-01-23 18:45       ` Nick Desaulniers
2020-01-23 19:01         ` Arvind Sankar
2020-01-24 10:11           ` David Laight
2020-01-26  1:10           ` Qais Yousef
2020-01-27  7:26             ` Arnd Bergmann
2020-01-23 17:59 ` Linus Torvalds
2020-01-24  8:33   ` Peter Zijlstra
2020-01-24 10:41     ` Peter Zijlstra
2020-02-10  9:50     ` Masahiro Yamada
2020-02-10  9:59       ` Will Deacon
2020-01-31 10:20 ` David Howells

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200123153341.19947-10-will@kernel.org \
    --to=will@kernel.org \
    --cc=arnd@arndb.de \
    --cc=borntraeger@de.ibm.com \
    --cc=kernel-team@android.com \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luc.vanoostenryck@gmail.com \
    --cc=masahiroy@kernel.org \
    --cc=mpe@ellerman.id.au \
    --cc=ndesaulniers@google.com \
    --cc=oberpar@linux.ibm.com \
    --cc=peterz@infradead.org \
    --cc=segher@kernel.crashing.org \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: [PATCH v2 09/10] compiler/gcc: Raise minimum GCC version for kernel builds to 4.8' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).