77 lines
3.0 KiB
Diff
77 lines
3.0 KiB
Diff
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From 867a311f231e89b4c9194579e40718f751761ffc Mon Sep 17 00:00:00 2001
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From: Alexandre Frade <kernel@xanmod.org>
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Date: Sat, 31 Aug 2024 16:57:41 +0000
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Subject: [PATCH 04/19] kbuild: Remove GCC minimal function alignment
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Signed-off-by: Alexandre Frade <kernel@xanmod.org>
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---
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Makefile | 7 -------
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arch/Kconfig | 12 ------------
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include/linux/compiler_types.h | 10 +++++-----
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3 files changed, 5 insertions(+), 24 deletions(-)
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--- a/Makefile
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+++ b/Makefile
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@@ -981,15 +981,8 @@ export CC_FLAGS_FPU
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export CC_FLAGS_NO_FPU
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ifneq ($(CONFIG_FUNCTION_ALIGNMENT),0)
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-# Set the minimal function alignment. Use the newer GCC option
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-# -fmin-function-alignment if it is available, or fall back to -falign-funtions.
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-# See also CONFIG_CC_HAS_SANE_FUNCTION_ALIGNMENT.
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-ifdef CONFIG_CC_HAS_MIN_FUNCTION_ALIGNMENT
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-KBUILD_CFLAGS += -fmin-function-alignment=$(CONFIG_FUNCTION_ALIGNMENT)
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-else
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KBUILD_CFLAGS += -falign-functions=$(CONFIG_FUNCTION_ALIGNMENT)
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endif
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-endif
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# arch Makefile may override CC so keep this after arch Makefile is included
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NOSTDINC_FLAGS += -nostdinc
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--- a/arch/Kconfig
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+++ b/arch/Kconfig
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@@ -1628,18 +1628,6 @@ config FUNCTION_ALIGNMENT
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default 4 if FUNCTION_ALIGNMENT_4B
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default 0
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-config CC_HAS_MIN_FUNCTION_ALIGNMENT
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- # Detect availability of the GCC option -fmin-function-alignment which
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- # guarantees minimal alignment for all functions, unlike
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- # -falign-functions which the compiler ignores for cold functions.
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- def_bool $(cc-option, -fmin-function-alignment=8)
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-
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-config CC_HAS_SANE_FUNCTION_ALIGNMENT
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- # Set if the guaranteed alignment with -fmin-function-alignment is
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- # available or extra care is required in the kernel. Clang provides
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- # strict alignment always, even with -falign-functions.
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- def_bool CC_HAS_MIN_FUNCTION_ALIGNMENT || CC_IS_CLANG
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-
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config ARCH_NEED_CMPXCHG_1_EMU
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bool
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--- a/include/linux/compiler_types.h
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+++ b/include/linux/compiler_types.h
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@@ -99,17 +99,17 @@ static inline void __chk_io_ptr(const vo
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* gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute
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*
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* When -falign-functions=N is in use, we must avoid the cold attribute as
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- * GCC drops the alignment for cold functions. Worse, GCC can implicitly mark
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- * callees of cold functions as cold themselves, so it's not sufficient to add
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- * __function_aligned here as that will not ensure that callees are correctly
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- * aligned.
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+ * contemporary versions of GCC drop the alignment for cold functions. Worse,
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+ * GCC can implicitly mark callees of cold functions as cold themselves, so
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+ * it's not sufficient to add __function_aligned here as that will not ensure
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+ * that callees are correctly aligned.
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*
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* See:
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*
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* https://lore.kernel.org/lkml/Y77%2FqVgvaJidFpYt@FVFF77S0Q05N
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* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c9
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*/
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-#if defined(CONFIG_CC_HAS_SANE_FUNCTION_ALIGNMENT) || (CONFIG_FUNCTION_ALIGNMENT == 0)
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+#if !defined(CONFIG_CC_IS_GCC) || (CONFIG_FUNCTION_ALIGNMENT == 0)
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#define __cold __attribute__((__cold__))
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#else
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#define __cold
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