Re: [PATCH 2/2] init/modpost: conditionally check section mismatch to __meminit*

[Wei Yang]

On Sun, Jul 07, 2024 at 01:05:06AM +0900, Masahiro Yamada wrote:
>This reverts commit eb8f689046b8 ("Use separate sections for __dev/
>_cpu/__mem code/data").
>
>Check section mismatch to __meminit* only when CONFIG_MEMORY_HOTPLUG=y.
>
>With this change, the linker script and modpost become simpler, and we
>can get rid of the __ref annotations from the memory hotplug code.
>

Oh, totally get rid of .meminit.*. Looks nice.
Maybe we can plan a __ref cleanup after this on is merged?

Reviewed-by: Wei Yang <richard.weiyang@xxxxxxxxx>

>Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
>---
>
> include/asm-generic/vmlinux.lds.h | 18 ++----------------
> include/linux/init.h              | 14 +++++++++-----
> scripts/mod/modpost.c             | 19 ++++---------------
> 3 files changed, 15 insertions(+), 36 deletions(-)
>
>diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
>index 62b4cb0462e6..c23f7d0645ad 100644
>--- a/include/asm-generic/vmlinux.lds.h
>+++ b/include/asm-generic/vmlinux.lds.h
>@@ -141,14 +141,6 @@
>  * often happens at runtime)
>  */
> 
>-#if defined(CONFIG_MEMORY_HOTPLUG)
>-#define MEM_KEEP(sec)    *(.mem##sec)
>-#define MEM_DISCARD(sec)
>-#else
>-#define MEM_KEEP(sec)
>-#define MEM_DISCARD(sec) *(.mem##sec)
>-#endif
>-
> #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
> #define KEEP_PATCHABLE		KEEP(*(__patchable_function_entries))
> #define PATCHABLE_DISCARDS
>@@ -357,7 +349,6 @@
> 	*(.data..decrypted)						\
> 	*(.ref.data)							\
> 	*(.data..shared_aligned) /* percpu related */			\
>-	MEM_KEEP(init.data*)						\
> 	*(.data.unlikely)						\
> 	__start_once = .;						\
> 	*(.data.once)							\
>@@ -523,7 +514,6 @@
> 	/* __*init sections */						\
> 	__init_rodata : AT(ADDR(__init_rodata) - LOAD_OFFSET) {		\
> 		*(.ref.rodata)						\
>-		MEM_KEEP(init.rodata)					\
> 	}								\
> 									\
> 	/* Built-in module parameters. */				\
>@@ -574,8 +564,7 @@
> 		*(.text.unknown .text.unknown.*)			\
> 		NOINSTR_TEXT						\
> 		*(.ref.text)						\
>-		*(.text.asan.* .text.tsan.*)				\
>-	MEM_KEEP(init.text*)						\
>+		*(.text.asan.* .text.tsan.*)
> 
> 
> /* sched.text is aling to function alignment to secure we have same
>@@ -682,7 +671,6 @@
> #define INIT_DATA							\
> 	KEEP(*(SORT(___kentry+*)))					\
> 	*(.init.data .init.data.*)					\
>-	MEM_DISCARD(init.data*)						\
> 	KERNEL_CTORS()							\
> 	MCOUNT_REC()							\
> 	*(.init.rodata .init.rodata.*)					\
>@@ -690,7 +678,6 @@
> 	TRACE_SYSCALLS()						\
> 	KPROBE_BLACKLIST()						\
> 	ERROR_INJECT_WHITELIST()					\
>-	MEM_DISCARD(init.rodata)					\
> 	CLK_OF_TABLES()							\
> 	RESERVEDMEM_OF_TABLES()						\
> 	TIMER_OF_TABLES()						\
>@@ -708,8 +695,7 @@
> 
> #define INIT_TEXT							\
> 	*(.init.text .init.text.*)					\
>-	*(.text.startup)						\
>-	MEM_DISCARD(init.text*)
>+	*(.text.startup)
> 
> #define EXIT_DATA							\
> 	*(.exit.data .exit.data.*)					\
>diff --git a/include/linux/init.h b/include/linux/init.h
>index b2e9dfff8691..ee1309473bc6 100644
>--- a/include/linux/init.h
>+++ b/include/linux/init.h
>@@ -84,11 +84,15 @@
> 
> #define __exit          __section(".exit.text") __exitused __cold notrace
> 
>-/* Used for MEMORY_HOTPLUG */
>-#define __meminit        __section(".meminit.text") __cold notrace \
>-						  __latent_entropy
>-#define __meminitdata    __section(".meminit.data")
>-#define __meminitconst   __section(".meminit.rodata")
>+#ifdef CONFIG_MEMORY_HOTPLUG
>+#define __meminit
>+#define __meminitdata
>+#define __meminitconst
>+#else
>+#define __meminit	__init
>+#define __meminitdata	__initdata
>+#define __meminitconst	__initconst
>+#endif
> 
> /* For assembly routines */
> #define __HEAD		.section	".head.text","ax"
>diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
>index 3e5313ed6065..8c8ad7485f73 100644
>--- a/scripts/mod/modpost.c
>+++ b/scripts/mod/modpost.c
>@@ -776,17 +776,14 @@ static void check_section(const char *modname, struct elf_info *elf,
> 
> 
> #define ALL_INIT_DATA_SECTIONS \
>-	".init.setup", ".init.rodata", ".meminit.rodata", \
>-	".init.data", ".meminit.data"
>+	".init.setup", ".init.rodata", ".init.data"
> 
> #define ALL_PCI_INIT_SECTIONS	\
> 	".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
> 	".pci_fixup_enable", ".pci_fixup_resume", \
> 	".pci_fixup_resume_early", ".pci_fixup_suspend"
> 
>-#define ALL_XXXINIT_SECTIONS ".meminit.*"
>-
>-#define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
>+#define ALL_INIT_SECTIONS ".init.*"
> #define ALL_EXIT_SECTIONS ".exit.*"
> 
> #define DATA_SECTIONS ".data", ".data.rel"
>@@ -797,9 +794,7 @@ static void check_section(const char *modname, struct elf_info *elf,
> 		".fixup", ".entry.text", ".exception.text", \
> 		".coldtext", ".softirqentry.text"
> 
>-#define INIT_SECTIONS      ".init.*"
>-
>-#define ALL_TEXT_SECTIONS  ".init.text", ".meminit.text", ".exit.text", \
>+#define ALL_TEXT_SECTIONS  ".init.text", ".exit.text", \
> 		TEXT_SECTIONS, OTHER_TEXT_SECTIONS
> 
> enum mismatch {
>@@ -839,12 +834,6 @@ static const struct sectioncheck sectioncheck[] = {
> 	.bad_tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL },
> 	.mismatch = TEXTDATA_TO_ANY_INIT_EXIT,
> },
>-/* Do not reference init code/data from meminit code/data */
>-{
>-	.fromsec = { ALL_XXXINIT_SECTIONS, NULL },
>-	.bad_tosec = { INIT_SECTIONS, NULL },
>-	.mismatch = XXXINIT_TO_SOME_INIT,
>-},
> /* Do not use exit code/data from init code */
> {
> 	.fromsec = { ALL_INIT_SECTIONS, NULL },
>@@ -859,7 +848,7 @@ static const struct sectioncheck sectioncheck[] = {
> },
> {
> 	.fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
>-	.bad_tosec = { INIT_SECTIONS, NULL },
>+	.bad_tosec = { ALL_INIT_SECTIONS, NULL },
> 	.mismatch = ANY_INIT_TO_ANY_EXIT,
> },
> {
>-- 
>2.43.0

-- 
Wei Yang
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