kbuild: Remove GCC minimal function alignment

Signed-off-by: Alexandre Frade <[email protected]>

Makefile

@@ -967,15 +967,8 @@ export CC_FLAGS_FPU
 export CC_FLAGS_NO_FPU
 
 ifneq ($(CONFIG_FUNCTION_ALIGNMENT),0)
-# Set the minimal function alignment. Use the newer GCC option
-# -fmin-function-alignment if it is available, or fall back to -falign-funtions.
-# See also CONFIG_CC_HAS_SANE_FUNCTION_ALIGNMENT.
-ifdef CONFIG_CC_HAS_MIN_FUNCTION_ALIGNMENT
-KBUILD_CFLAGS += -fmin-function-alignment=$(CONFIG_FUNCTION_ALIGNMENT)
-else
 KBUILD_CFLAGS += -falign-functions=$(CONFIG_FUNCTION_ALIGNMENT)
 endif
-endif
 
 # arch Makefile may override CC so keep this after arch Makefile is included
 NOSTDINC_FLAGS += -nostdinc

arch/Kconfig

@@ -1628,18 +1628,6 @@ config FUNCTION_ALIGNMENT
 	default 4 if FUNCTION_ALIGNMENT_4B
 	default 0
 
-config CC_HAS_MIN_FUNCTION_ALIGNMENT
-	# Detect availability of the GCC option -fmin-function-alignment which
-	# guarantees minimal alignment for all functions, unlike
-	# -falign-functions which the compiler ignores for cold functions.
-	def_bool $(cc-option, -fmin-function-alignment=8)
-
-config CC_HAS_SANE_FUNCTION_ALIGNMENT
-	# Set if the guaranteed alignment with -fmin-function-alignment is
-	# available or extra care is required in the kernel. Clang provides
-	# strict alignment always, even with -falign-functions.
-	def_bool CC_HAS_MIN_FUNCTION_ALIGNMENT || CC_IS_CLANG
-
 config ARCH_NEED_CMPXCHG_1_EMU
 	bool
 

include/linux/compiler_types.h

@@ -99,17 +99,17 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { }
  *   gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute
  *
  * When -falign-functions=N is in use, we must avoid the cold attribute as
- * GCC drops the alignment for cold functions. Worse, GCC can implicitly mark
- * callees of cold functions as cold themselves, so it's not sufficient to add
- * __function_aligned here as that will not ensure that callees are correctly
- * aligned.
+ * contemporary versions of GCC drop the alignment for cold functions. Worse,
+ * GCC can implicitly mark callees of cold functions as cold themselves, so
+ * it's not sufficient to add __function_aligned here as that will not ensure
+ * that callees are correctly aligned.
  *
  * See:
  *
  *   https://lore.kernel.org/lkml/Y77%2FqVgvaJidFpYt@FVFF77S0Q05N
  *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c9
  */
-#if defined(CONFIG_CC_HAS_SANE_FUNCTION_ALIGNMENT) || (CONFIG_FUNCTION_ALIGNMENT == 0)
+#if !defined(CONFIG_CC_IS_GCC) || (CONFIG_FUNCTION_ALIGNMENT == 0)
 #define __cold				__attribute__((__cold__))
 #else
 #define __cold