linux-kernel - [PATCH 1/3] init: Declare rodata_enabled and mark_rodata

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Date: Thu, 21 Dec 2023 10:02:46 +0100
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Arnd Bergmann <arnd@...db.de>,
	Luis Chamberlain <mcgrof@...nel.org>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
	linux-kernel@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org,
	linux-modules@...r.kernel.org
Subject: [PATCH 1/3] init: Declare rodata_enabled and mark_rodata_ro() at all time

Declaring rodata_enabled and mark_rodata_ro() at all time
helps removing related #ifdefery in C files.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 include/linux/init.h |  4 ----
 init/main.c          | 21 +++++++--------------
 2 files changed, 7 insertions(+), 18 deletions(-)

diff --git a/include/linux/init.h b/include/linux/init.h
index 01b52c9c7526..d2b47be38a07 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -168,12 +168,8 @@ extern initcall_entry_t __initcall_end[];
 
 extern struct file_system_type rootfs_fs_type;
 
-#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
 extern bool rodata_enabled;
-#endif
-#ifdef CONFIG_STRICT_KERNEL_RWX
 void mark_rodata_ro(void);
-#endif
 
 extern void (*late_time_init)(void);
 
diff --git a/init/main.c b/init/main.c
index e24b0780fdff..807df08c501f 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1396,10 +1396,9 @@ static int __init set_debug_rodata(char *str)
 early_param("rodata", set_debug_rodata);
 #endif
 
-#ifdef CONFIG_STRICT_KERNEL_RWX
 static void mark_readonly(void)
 {
-	if (rodata_enabled) {
+	if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) && rodata_enabled) {
 		/*
 		 * load_module() results in W+X mappings, which are cleaned
 		 * up with call_rcu().  Let's make sure that queued work is
@@ -1409,20 +1408,14 @@ static void mark_readonly(void)
 		rcu_barrier();
 		mark_rodata_ro();
 		rodata_test();
-	} else
+	} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
 		pr_info("Kernel memory protection disabled.\n");
+	} else if (IS_ENABLED(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)) {
+		pr_warn("Kernel memory protection not selected by kernel config.\n");
+	} else {
+		pr_warn("This architecture does not have kernel memory protection.\n");
+	}
 }
-#elif defined(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)
-static inline void mark_readonly(void)
-{
-	pr_warn("Kernel memory protection not selected by kernel config.\n");
-}
-#else
-static inline void mark_readonly(void)
-{
-	pr_warn("This architecture does not have kernel memory protection.\n");
-}
-#endif
 
 void __weak free_initmem(void)
 {
-- 
2.41.0