From bb43a59944f45e89aa158740b8a16ba8f0b0fa2b Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 7 Nov 2024 01:14:40 +0900 Subject: Rename .data.unlikely to .data..unlikely Commit 7ccaba5314ca ("consolidate WARN_...ONCE() static variables") was intended to collect all .data.unlikely sections into one chunk. However, this has not worked when CONFIG_LD_DEAD_CODE_DATA_ELIMINATION or CONFIG_LTO_CLANG is enabled, because .data.unlikely matches the .data.[0-9a-zA-Z_]* pattern in the DATA_MAIN macro. Commit cb87481ee89d ("kbuild: linker script do not match C names unless LD_DEAD_CODE_DATA_ELIMINATION is configured") was introduced to suppress the issue for the default CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=n case, providing a minimal fix for stable backporting. We were aware this did not address the issue for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. The plan was to apply correct fixes and then revert cb87481ee89d. [1] Seven years have passed since then, yet the #ifdef workaround remains in place. Using a ".." separator in the section name fixes the issue for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION and CONFIG_LTO_CLANG. [1]: https://lore.kernel.org/linux-kbuild/CAK7LNASck6BfdLnESxXUeECYL26yUDm0cwRZuM4gmaWUkxjL5g@mail.gmail.com/ Fixes: cb87481ee89d ("kbuild: linker script do not match C names unless LD_DEAD_CODE_DATA_ELIMINATION is configured") Signed-off-by: Masahiro Yamada --- include/linux/rcupdate.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 58d84c59f3dd..48e5c03df1dd 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -401,7 +401,7 @@ static inline int debug_lockdep_rcu_enabled(void) */ #define RCU_LOCKDEP_WARN(c, s) \ do { \ - static bool __section(".data.unlikely") __warned; \ + static bool __section(".data..unlikely") __warned; \ if (debug_lockdep_rcu_enabled() && (c) && \ debug_lockdep_rcu_enabled() && !__warned) { \ __warned = true; \ -- cgit v1.2.3 From dbefa1f31a91670c9e7dac9b559625336206466f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 7 Nov 2024 01:14:41 +0900 Subject: Rename .data.once to .data..once to fix resetting WARN*_ONCE Commit b1fca27d384e ("kernel debug: support resetting WARN*_ONCE") added support for clearing the state of once warnings. However, it is not functional when CONFIG_LD_DEAD_CODE_DATA_ELIMINATION or CONFIG_LTO_CLANG is enabled, because .data.once matches the .data.[0-9a-zA-Z_]* pattern in the DATA_MAIN macro. Commit cb87481ee89d ("kbuild: linker script do not match C names unless LD_DEAD_CODE_DATA_ELIMINATION is configured") was introduced to suppress the issue for the default CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=n case, providing a minimal fix for stable backporting. We were aware this did not address the issue for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y. The plan was to apply correct fixes and then revert cb87481ee89d. [1] Seven years have passed since then, yet the #ifdef workaround remains in place. Meanwhile, commit b1fca27d384e introduced the .data.once section, and commit dc5723b02e52 ("kbuild: add support for Clang LTO") extended the #ifdef. Using a ".." separator in the section name fixes the issue for CONFIG_LD_DEAD_CODE_DATA_ELIMINATION and CONFIG_LTO_CLANG. [1]: https://lore.kernel.org/linux-kbuild/CAK7LNASck6BfdLnESxXUeECYL26yUDm0cwRZuM4gmaWUkxjL5g@mail.gmail.com/ Fixes: b1fca27d384e ("kernel debug: support resetting WARN*_ONCE") Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO") Signed-off-by: Masahiro Yamada --- include/linux/mmdebug.h | 6 +++--- include/linux/once.h | 4 ++-- include/linux/once_lite.h | 2 +- 3 files changed, 6 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h index 39a7714605a7..d7cb1e5ecbda 100644 --- a/include/linux/mmdebug.h +++ b/include/linux/mmdebug.h @@ -46,7 +46,7 @@ void vma_iter_dump_tree(const struct vma_iterator *vmi); } \ } while (0) #define VM_WARN_ON_ONCE_PAGE(cond, page) ({ \ - static bool __section(".data.once") __warned; \ + static bool __section(".data..once") __warned; \ int __ret_warn_once = !!(cond); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ @@ -66,7 +66,7 @@ void vma_iter_dump_tree(const struct vma_iterator *vmi); unlikely(__ret_warn); \ }) #define VM_WARN_ON_ONCE_FOLIO(cond, folio) ({ \ - static bool __section(".data.once") __warned; \ + static bool __section(".data..once") __warned; \ int __ret_warn_once = !!(cond); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ @@ -77,7 +77,7 @@ void vma_iter_dump_tree(const struct vma_iterator *vmi); unlikely(__ret_warn_once); \ }) #define VM_WARN_ON_ONCE_MM(cond, mm) ({ \ - static bool __section(".data.once") __warned; \ + static bool __section(".data..once") __warned; \ int __ret_warn_once = !!(cond); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ diff --git a/include/linux/once.h b/include/linux/once.h index bc714d414448..30346fcdc799 100644 --- a/include/linux/once.h +++ b/include/linux/once.h @@ -46,7 +46,7 @@ void __do_once_sleepable_done(bool *done, struct static_key_true *once_key, #define DO_ONCE(func, ...) \ ({ \ bool ___ret = false; \ - static bool __section(".data.once") ___done = false; \ + static bool __section(".data..once") ___done = false; \ static DEFINE_STATIC_KEY_TRUE(___once_key); \ if (static_branch_unlikely(&___once_key)) { \ unsigned long ___flags; \ @@ -64,7 +64,7 @@ void __do_once_sleepable_done(bool *done, struct static_key_true *once_key, #define DO_ONCE_SLEEPABLE(func, ...) \ ({ \ bool ___ret = false; \ - static bool __section(".data.once") ___done = false; \ + static bool __section(".data..once") ___done = false; \ static DEFINE_STATIC_KEY_TRUE(___once_key); \ if (static_branch_unlikely(&___once_key)) { \ ___ret = __do_once_sleepable_start(&___done); \ diff --git a/include/linux/once_lite.h b/include/linux/once_lite.h index b7bce4983638..27de7bc32a06 100644 --- a/include/linux/once_lite.h +++ b/include/linux/once_lite.h @@ -12,7 +12,7 @@ #define __ONCE_LITE_IF(condition) \ ({ \ - static bool __section(".data.once") __already_done; \ + static bool __section(".data..once") __already_done; \ bool __ret_cond = !!(condition); \ bool __ret_once = false; \ \ -- cgit v1.2.3 From 054a9cd395a79f4a5595f2cd24542e9bca8723c8 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 20 Nov 2024 08:56:52 +0900 Subject: modpost: rename alias symbol for MODULE_DEVICE_TABLE() This commit renames the alias symbol, __mod____device_table to __mod_device_table____. This change simplifies the code slightly, as there is no longer a need to check both the prefix and suffix. Signed-off-by: Masahiro Yamada --- include/linux/module.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/module.h b/include/linux/module.h index 88ecc5e9f523..3dd79a3d0cbf 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -247,7 +247,7 @@ extern void cleanup_module(void); #ifdef MODULE /* Creates an alias so file2alias.c can find device table. */ #define MODULE_DEVICE_TABLE(type, name) \ -extern typeof(name) __mod_##type##__##name##_device_table \ +extern typeof(name) __mod_device_table__##type##__##name \ __attribute__ ((unused, alias(__stringify(name)))) #else /* !MODULE */ #define MODULE_DEVICE_TABLE(type, name) -- cgit v1.2.3