[patch 104/166] compiler: remove CONFIG_OPTIMIZE_INLINING entirely

Andrew Morton
2020-04-07T03:09:36Z

From: Masahiro Yamada <masahiroy@kernel.org>
Subject: compiler: remove CONFIG_OPTIMIZE_INLINING entirely

Commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly") made this always-on option. We released v5.4 and v5.5
including that commit.

Remove the CONFIG option and clean up the code now.

Link: http://lkml.kernel.org/r/20200220110807.32534-2-masahiroy@kernel.org
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Miller <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

arch/x86/configs/i386_defconfig | 1 -
arch/x86/configs/x86_64_defconfig | 1 -
include/linux/compiler_types.h | 11 +----------
kernel/configs/tiny.config | 1 -
lib/Kconfig.debug | 12 ------------
5 files changed, 1 insertion(+), 25 deletions(-)

--- a/arch/x86/configs/i386_defconfig~compiler-remove-config_optimize_inlining-entirely
+++ a/arch/x86/configs/i386_defconfig
@@ -285,7 +285,6 @@ CONFIG_EARLY_PRINTK_DBGP=y
CONFIG_DEBUG_STACKOVERFLOW=y
# CONFIG_DEBUG_RODATA_TEST is not set
CONFIG_DEBUG_BOOT_PARAMS=y
-CONFIG_OPTIMIZE_INLINING=y
CONFIG_SECURITY=y
CONFIG_SECURITY_NETWORK=y
CONFIG_SECURITY_SELINUX=y
--- a/arch/x86/configs/x86_64_defconfig~compiler-remove-config_optimize_inlining-entirely
+++ a/arch/x86/configs/x86_64_defconfig
@@ -282,7 +282,6 @@ CONFIG_EARLY_PRINTK_DBGP=y
CONFIG_DEBUG_STACKOVERFLOW=y
# CONFIG_DEBUG_RODATA_TEST is not set
CONFIG_DEBUG_BOOT_PARAMS=y
-CONFIG_OPTIMIZE_INLINING=y
CONFIG_UNWINDER_ORC=y
CONFIG_SECURITY=y
CONFIG_SECURITY_NETWORK=y
--- a/include/linux/compiler_types.h~compiler-remove-config_optimize_inlining-entirely
+++ a/include/linux/compiler_types.h
@@ -129,22 +129,13 @@ struct ftrace_likely_data {
#define __compiler_offsetof(a, b) __builtin_offsetof(a, b)

/*
- * Force always-inline if the user requests it so via the .config.
* Prefer gnu_inline, so that extern inline functions do not emit an
* externally visible function. This makes extern inline behave as per gnu89
* semantics rather than c99. This prevents multiple symbol definition errors
* of extern inline functions at link time.
* A lot of inline functions can cause havoc with function tracing.
- * Do not use __always_inline here, since currently it expands to inline again
- * (which would break users of __always_inline).
*/
-#if !defined(CONFIG_OPTIMIZE_INLINING)
-#define inline inline __attribute__((__always_inline__)) __gnu_inline \
- __inline_maybe_unused notrace
-#else
-#define inline inline __gnu_inline \
- __inline_maybe_unused notrace
-#endif
+#define inline inline __gnu_inline __inline_maybe_unused notrace

/*
* gcc provides both __inline__ and __inline as alternate spellings of
--- a/kernel/configs/tiny.config~compiler-remove-config_optimize_inlining-entirely
+++ a/kernel/configs/tiny.config
@@ -6,7 +6,6 @@ CONFIG_CC_OPTIMIZE_FOR_SIZE=y
CONFIG_KERNEL_XZ=y
# CONFIG_KERNEL_LZO is not set
# CONFIG_KERNEL_LZ4 is not set
-CONFIG_OPTIMIZE_INLINING=y
# CONFIG_SLAB is not set
# CONFIG_SLUB is not set
CONFIG_SLOB=y
--- a/lib/Kconfig.debug~compiler-remove-config_optimize_inlining-entirely
+++ a/lib/Kconfig.debug
@@ -305,18 +305,6 @@ config HEADERS_INSTALL
user-space program samples. It is also needed by some features such
as uapi header sanity checks.

-config OPTIMIZE_INLINING
- def_bool y
- help
- This option determines if the kernel forces gcc to inline the functions
- developers have marked 'inline'. Doing so takes away freedom from gcc to
- do what it thinks is best, which is desirable for the gcc 3.x series of
- compilers. The gcc 4.x series have a rewritten inlining algorithm and
- enabling this option will generate a smaller kernel there. Hopefully
- this algorithm is so good that allowing gcc 4.x and above to make the
- decision will become the default in the future. Until then this option
- is there to test gcc for this.
-
config DEBUG_SECTION_MISMATCH
bool "Enable full Section mismatch analysis"
help
_