Commit db0b2991 authored Nov 02, 2024 by Rong Xu Committed by Masahiro Yamada Nov 27, 2024

vmlinux.lds.h: Add markers for text_unlikely and text_hot sections



Add markers like __hot_text_start, __hot_text_end, __unlikely_text_start,
and __unlikely_text_end which will be included in System.map. These markers
indicate how the compiler groups functions, providing valuable information
to developers about the layout and optimization of the code.

Co-developed-by: Han Shen <shenhan@google.com>
Signed-off-by: Han Shen <shenhan@google.com>
Signed-off-by: Rong Xu <xur@google.com>
Suggested-by: Sriraman Tallam <tmsriram@google.com>
Tested-by: Yonghong Song <yonghong.song@linux.dev>
Tested-by: Yabin Cui <yabinc@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

parent 0043ecea

include/asm-generic/vmlinux.lds.h

+12 −2

Original line number	Diff line number	Diff line
		@@ -549,6 +549,16 @@
		__cpuidle_text_end = .; \
		__noinstr_text_end = .;

		#define TEXT_UNLIKELY \
		__unlikely_text_start = .; \
		(.text.unlikely .text.unlikely.) \
		__unlikely_text_end = .;

		#define TEXT_HOT \
		__hot_text_start = .; \
		(.text.hot .text.hot.) \
		__hot_text_end = .;

		/*
		* .text section. Map to function alignment to avoid address changes
		* during second ld run in second ld pass when generating System.map
		@@ -565,9 +575,9 @@
		ALIGN_FUNCTION(); \
		(.text.asan. .text.tsan.*) \
		(.text.unknown .text.unknown.) \
		(.text.unlikely .text.unlikely.) \
		TEXT_UNLIKELY \
		. = ALIGN(PAGE_SIZE); \
		(.text.hot .text.hot.) \
		TEXT_HOT \
		*(TEXT_MAIN .text.fixup) \
		NOINSTR_TEXT \
		*(.ref.text)