Files
Pnina Feder 2e171ab29f panic: add panic_force_cpu= parameter to redirect panic to a specific CPU
Some platforms require panic handling to execute on a specific CPU for
crash dump to work reliably.  This can be due to firmware limitations,
interrupt routing constraints, or platform-specific requirements where
only a single CPU is able to safely enter the crash kernel.

Add the panic_force_cpu= kernel command-line parameter to redirect panic
execution to a designated CPU.  When the parameter is provided, the CPU
that initially triggers panic forwards the panic context to the target CPU
via IPI, which then proceeds with the normal panic and kexec flow.

The IPI delivery is implemented as a weak function
(panic_smp_redirect_cpu) so architectures with NMI support can override it
for more reliable delivery.

If the specified CPU is invalid, offline, or a panic is already in
progress on another CPU, the redirection is skipped and panic continues on
the current CPU.

[pnina.feder@mobileye.com: fix unused variable warning]
  Link: https://lkml.kernel.org/r/20260126122618.2967950-1-pnina.feder@mobileye.com
Link: https://lkml.kernel.org/r/20260122102457.1154599-1-pnina.feder@mobileye.com
Signed-off-by: Pnina Feder <pnina.feder@mobileye.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-02-03 08:21:26 -08:00

114 lines
3.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PANIC_H
#define _LINUX_PANIC_H
#include <linux/compiler_attributes.h>
#include <linux/stdarg.h>
#include <linux/types.h>
struct pt_regs;
extern long (*panic_blink)(int state);
__printf(1, 2)
void panic(const char *fmt, ...) __noreturn __cold;
__printf(1, 0)
void vpanic(const char *fmt, va_list args) __noreturn __cold;
void nmi_panic(struct pt_regs *regs, const char *msg);
void check_panic_on_warn(const char *origin);
extern void oops_enter(void);
extern void oops_exit(void);
extern bool oops_may_print(void);
extern bool panic_triggering_all_cpu_backtrace;
extern int panic_timeout;
extern unsigned long panic_print;
extern int panic_on_oops;
extern int panic_on_warn;
extern unsigned long panic_on_taint;
extern bool panic_on_taint_nousertaint;
extern int sysctl_panic_on_stackoverflow;
extern bool crash_kexec_post_notifiers;
extern void __stack_chk_fail(void);
void abort(void);
/*
* 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;
/*
* panic_redirect_cpu is used when panic is redirected to a specific CPU via
* the panic_force_cpu= boot parameter. It holds the CPU number that originally
* triggered the panic before redirection. A value of PANIC_CPU_INVALID means
* no redirection has occurred.
*/
extern atomic_t panic_redirect_cpu;
#define PANIC_CPU_INVALID -1
bool panic_try_start(void);
void panic_reset(void);
bool panic_in_progress(void);
bool panic_on_this_cpu(void);
bool panic_on_other_cpu(void);
/*
* 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_TEST 18
#define TAINT_FWCTL 19
#define TAINT_FLAGS_COUNT 20
#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 */
const char *desc; /* verbose description of the set 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 const char *print_tainted_verbose(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 */