[tip: x86/urgent] bug: Have __warn() prototype defined unconditionally

[tip-bot2 for Shida Zhang]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     1fa568e26f001e951b634d62ef3accdc80a87c7b
Gitweb:        https://git.kernel.org/tip/1fa568e26f001e951b634d62ef3accdc80a87c7b
Author:        Shida Zhang <zhangshida@xxxxxxxxxx>
AuthorDate:    Tue, 26 Apr 2022 11:20:07 +08:00
Committer:     Borislav Petkov <bp@xxxxxxx>
CommitterDate: Tue, 26 Apr 2022 10:59:57 +02:00

bug: Have __warn() prototype defined unconditionally

The __warn() prototype is declared in CONFIG_BUG scope but the function
definition in panic.c is unconditional. The IBT enablement started using
it unconditionally but a CONFIG_X86_KERNEL_IBT=y, CONFIG_BUG=n .config
will trigger a

  arch/x86/kernel/traps.c: In function ‘__exc_control_protection’:
  arch/x86/kernel/traps.c:249:17: error: implicit declaration of function \
  	  ‘__warn’; did you mean ‘pr_warn’? [-Werror=implicit-function-declaration]

Pull up the declarations so that they're unconditionally visible too.

  [ bp: Rewrite commit message. ]

Fixes: 991625f3dd2c ("x86/ibt: Add IBT feature, MSR and #CP handling")
Suggested-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Shida Zhang <zhangshida@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lore.kernel.org/r/20220426032007.510245-1-starzhangzsd@xxxxxxxxx
---
 include/asm-generic/bug.h | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index edb0e2a..ba1f860 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -21,6 +21,12 @@
 #include <linux/panic.h>
 #include <linux/printk.h>
 
+struct warn_args;
+struct pt_regs;
+
+void __warn(const char *file, int line, void *caller, unsigned taint,
+	    struct pt_regs *regs, struct warn_args *args);
+
 #ifdef CONFIG_BUG
 
 #ifdef CONFIG_GENERIC_BUG
@@ -110,11 +116,6 @@ extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
 #endif
 
 /* used internally by panic.c */
-struct warn_args;
-struct pt_regs;
-
-void __warn(const char *file, int line, void *caller, unsigned taint,
-	    struct pt_regs *regs, struct warn_args *args);
 
 #ifndef WARN_ON
 #define WARN_ON(condition) ({						\