kernel.h: split out panic and oops helpers

kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out panic and
oops helpers.

There are several purposes of doing this:
- dropping dependency in bug.h
- dropping a loop by moving out panic_notifier.h
- unload kernel.h from something which has its own domain

At the same time convert users tree-wide to use new headers, although for
the time being include new header back to kernel.h to avoid twisted
indirected includes for existing users.

[akpm@linux-foundation.org: thread_info.h needs limits.h]
[andriy.shevchenko@linux.intel.com: ia64 fix]
  Link: https://lkml.kernel.org/r/20210520130557.55277-1-andriy.shevchenko@linux.intel.com

Link: https://lkml.kernel.org/r/20210511074137.33666-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Co-developed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 112 insertions, 83 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index bf950621febf..baea2eb763d0 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -14,6 +14,7 @@
 #include <linux/math.h>
 #include <linux/minmax.h>
 #include <linux/typecheck.h>
+#include <linux/panic.h>
 #include <linux/printk.h>
 #include <linux/build_bug.h>
 #include <linux/static_call_types.h>
@@ -72,7 +73,6 @@
 #define lower_32_bits(n) ((u32)((n) & 0xffffffff))
 
 struct completion;
-struct pt_regs;
 struct user;
 
 #ifdef CONFIG_PREEMPT_VOLUNTARY
@@ -177,14 +177,6 @@ void __might_fault(const char *file, int line);
 static inline void might_fault(void) { }
 #endif
 
-extern struct atomic_notifier_head panic_notifier_list;
-extern long (*panic_blink)(int state);
-__printf(1, 2)
-void panic(const char *fmt, ...) __noreturn __cold;
-void nmi_panic(struct pt_regs *regs, const char *msg);
-extern void oops_enter(void);
-extern void oops_exit(void);
-extern bool oops_may_print(void);
 void do_exit(long error_code) __noreturn;
 void complete_and_exit(struct completion *, long) __noreturn;
 
@@ -372,52 +364,8 @@ extern int __kernel_text_address(unsigned long addr);
 extern int kernel_text_address(unsigned long addr);
 extern int func_ptr_is_kernel_text(void *ptr);
 
-#ifdef CONFIG_SMP
-extern unsigned int sysctl_oops_all_cpu_backtrace;
-#else
-#define sysctl_oops_all_cpu_backtrace 0
-#endif /* CONFIG_SMP */
-
 extern void bust_spinlocks(int yes);
-extern int panic_timeout;
-extern unsigned long panic_print;
-extern int panic_on_oops;
-extern int panic_on_unrecovered_nmi;
-extern int panic_on_io_nmi;
-extern int panic_on_warn;
-extern unsigned long panic_on_taint;
-extern bool panic_on_taint_nousertaint;
-extern int sysctl_panic_on_rcu_stall;
-extern int sysctl_max_rcu_stall_to_panic;
-extern int sysctl_panic_on_stackoverflow;
-
-extern bool crash_kexec_post_notifiers;
 
-/*
- * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
- * holds a CPU number which is executing panic() currently. A value of
- * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
- */
-extern atomic_t panic_cpu;
-#define PANIC_CPU_INVALID	-1
-
-/*
- * Only to be used by arch init code. If the user over-wrote the default
- * CONFIG_PANIC_TIMEOUT, honor it.
- */
-static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
-{
-	if (panic_timeout == arch_default_timeout)
-		panic_timeout = timeout;
-}
-extern const char *print_tainted(void);
-enum lockdep_ok {
-	LOCKDEP_STILL_OK,
-	LOCKDEP_NOW_UNRELIABLE
-};
-extern void add_taint(unsigned flag, enum lockdep_ok);
-extern int test_taint(unsigned flag);
-extern unsigned long get_taint(void);
 extern int root_mountflags;
 
 extern bool early_boot_irqs_disabled;
@@ -436,36 +384,6 @@ extern enum system_states {
 	SYSTEM_SUSPEND,
 } system_state;
 
-/* This cannot be an enum because some may be used in assembly source. */
-#define TAINT_PROPRIETARY_MODULE	0
-#define TAINT_FORCED_MODULE		1
-#define TAINT_CPU_OUT_OF_SPEC		2
-#define TAINT_FORCED_RMMOD		3
-#define TAINT_MACHINE_CHECK		4
-#define TAINT_BAD_PAGE			5
-#define TAINT_USER			6
-#define TAINT_DIE			7
-#define TAINT_OVERRIDDEN_ACPI_TABLE	8
-#define TAINT_WARN			9
-#define TAINT_CRAP			10
-#define TAINT_FIRMWARE_WORKAROUND	11
-#define TAINT_OOT_MODULE		12
-#define TAINT_UNSIGNED_MODULE		13
-#define TAINT_SOFTLOCKUP		14
-#define TAINT_LIVEPATCH			15
-#define TAINT_AUX			16
-#define TAINT_RANDSTRUCT		17
-#define TAINT_FLAGS_COUNT		18
-#define TAINT_FLAGS_MAX			((1UL << TAINT_FLAGS_COUNT) - 1)
-
-struct taint_flag {
-	char c_true;	/* character printed when tainted */
-	char c_false;	/* character printed when not tainted */
-	bool module;	/* also show as a per-module taint flag */
-};
-
-extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
-
 extern const char hex_asc[];
 #define hex_asc_lo(x)	hex_asc[((x) & 0x0f)]
 #define hex_asc_hi(x)	hex_asc[((x) & 0xf0) >> 4]
diff --git a/include/linux/panic.h b/include/linux/panic.h
new file mode 100644
index 000000000000..f5844908a089
--- /dev/null
+++ b/include/linux/panic.h
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_PANIC_H
+#define _LINUX_PANIC_H
+
+#include <linux/compiler_attributes.h>
+#include <linux/types.h>
+
+struct pt_regs;
+
+extern long (*panic_blink)(int state);
+__printf(1, 2)
+void panic(const char *fmt, ...) __noreturn __cold;
+void nmi_panic(struct pt_regs *regs, const char *msg);
+extern void oops_enter(void);
+extern void oops_exit(void);
+extern bool oops_may_print(void);
+
+#ifdef CONFIG_SMP
+extern unsigned int sysctl_oops_all_cpu_backtrace;
+#else
+#define sysctl_oops_all_cpu_backtrace 0
+#endif /* CONFIG_SMP */
+
+extern int panic_timeout;
+extern unsigned long panic_print;
+extern int panic_on_oops;
+extern int panic_on_unrecovered_nmi;
+extern int panic_on_io_nmi;
+extern int panic_on_warn;
+
+extern unsigned long panic_on_taint;
+extern bool panic_on_taint_nousertaint;
+
+extern int sysctl_panic_on_rcu_stall;
+extern int sysctl_max_rcu_stall_to_panic;
+extern int sysctl_panic_on_stackoverflow;
+
+extern bool crash_kexec_post_notifiers;
+
+/*
+ * panic_cpu is used for synchronizing panic() and crash_kexec() execution. It
+ * holds a CPU number which is executing panic() currently. A value of
+ * PANIC_CPU_INVALID means no CPU has entered panic() or crash_kexec().
+ */
+extern atomic_t panic_cpu;
+#define PANIC_CPU_INVALID	-1
+
+/*
+ * Only to be used by arch init code. If the user over-wrote the default
+ * CONFIG_PANIC_TIMEOUT, honor it.
+ */
+static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
+{
+	if (panic_timeout == arch_default_timeout)
+		panic_timeout = timeout;
+}
+
+/* This cannot be an enum because some may be used in assembly source. */
+#define TAINT_PROPRIETARY_MODULE	0
+#define TAINT_FORCED_MODULE		1
+#define TAINT_CPU_OUT_OF_SPEC		2
+#define TAINT_FORCED_RMMOD		3
+#define TAINT_MACHINE_CHECK		4
+#define TAINT_BAD_PAGE			5
+#define TAINT_USER			6
+#define TAINT_DIE			7
+#define TAINT_OVERRIDDEN_ACPI_TABLE	8
+#define TAINT_WARN			9
+#define TAINT_CRAP			10
+#define TAINT_FIRMWARE_WORKAROUND	11
+#define TAINT_OOT_MODULE		12
+#define TAINT_UNSIGNED_MODULE		13
+#define TAINT_SOFTLOCKUP		14
+#define TAINT_LIVEPATCH			15
+#define TAINT_AUX			16
+#define TAINT_RANDSTRUCT		17
+#define TAINT_FLAGS_COUNT		18
+#define TAINT_FLAGS_MAX			((1UL << TAINT_FLAGS_COUNT) - 1)
+
+struct taint_flag {
+	char c_true;	/* character printed when tainted */
+	char c_false;	/* character printed when not tainted */
+	bool module;	/* also show as a per-module taint flag */
+};
+
+extern const struct taint_flag taint_flags[TAINT_FLAGS_COUNT];
+
+enum lockdep_ok {
+	LOCKDEP_STILL_OK,
+	LOCKDEP_NOW_UNRELIABLE,
+};
+
+extern const char *print_tainted(void);
+extern void add_taint(unsigned flag, enum lockdep_ok);
+extern int test_taint(unsigned flag);
+extern unsigned long get_taint(void);
+
+#endif	/* _LINUX_PANIC_H */
diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h
new file mode 100644
index 000000000000..41e32483d7a7
--- /dev/null
+++ b/include/linux/panic_notifier.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_PANIC_NOTIFIERS_H
+#define _LINUX_PANIC_NOTIFIERS_H
+
+#include <linux/notifier.h>
+#include <linux/types.h>
+
+extern struct atomic_notifier_head panic_notifier_list;
+
+extern bool crash_kexec_post_notifiers;
+
+#endif	/* _LINUX_PANIC_NOTIFIERS_H */
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 157762db9d4b..0999f6317978 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -9,6 +9,7 @@
 #define _LINUX_THREAD_INFO_H
 
 #include <linux/types.h>
+#include <linux/limits.h>
 #include <linux/bug.h>
 #include <linux/restart_block.h>
 #include <linux/errno.h>