From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guilherme G. Piccoli Date: Wed, 27 Apr 2022 19:49:16 -0300 Subject: [PATCH 22/30] panic: Introduce the panic post-reboot notifier list In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> Message-ID: <20220427224924.592546-23-gpiccoli@igalia.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org Currently we have 3 notifier lists in the panic path, which will be wired in a way to allow the notifier callbacks to run in different moments at panic time, in a subsequent patch. But there is also an odd set of architecture calls hardcoded in the end of panic path, after the restart machinery. They're responsible for late time tunings / events, like enabling a stop button (Sparc) or effectively stopping the machine (s390). This patch introduces yet another notifier list to offer the architectures a way to add callbacks in such late moment on panic path without the need of ifdefs / hardcoded approaches. Cc: Alexander Gordeev Cc: Christian Borntraeger Cc: "David S. Miller" Cc: Heiko Carstens Cc: Sven Schnelle Cc: Vasily Gorbik Signed-off-by: Guilherme G. Piccoli --- arch/s390/kernel/setup.c | 19 ++++++++++++++++++- arch/sparc/kernel/setup_32.c | 27 +++++++++++++++++++++++---- arch/sparc/kernel/setup_64.c | 29 ++++++++++++++++++++++++----- include/linux/panic_notifier.h | 1 + kernel/panic.c | 19 +++++++------------ 5 files changed, 73 insertions(+), 22 deletions(-) diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index d860ac300919..d816b2045f1e 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -39,7 +39,6 @@ #include #include #include -#include #include #include #include @@ -51,6 +50,7 @@ #include #include #include +#include #include #include @@ -943,6 +943,20 @@ static void __init log_component_list(void) } } +/* + * The following notifier executes as one of the latest things in the panic + * path, only if the restart routines weren't executed (or didn't succeed). + */ +static int panic_event(struct notifier_block *n, unsigned long ev, void *unused) +{ + disabled_wait(); + return NOTIFY_DONE; +} + +static struct notifier_block post_reboot_panic_block = { + .notifier_call = panic_event, +}; + /* * Setup function called from init/main.c just after the banner * was printed. @@ -1058,4 +1072,7 @@ void __init setup_arch(char **cmdline_p) /* Add system specific data to the random pool */ setup_randomness(); + + atomic_notifier_chain_register(&panic_post_reboot_list, + &post_reboot_panic_block); } diff --git a/arch/sparc/kernel/setup_32.c b/arch/sparc/kernel/setup_32.c index c8e0dd99f370..4e2428972f76 100644 --- a/arch/sparc/kernel/setup_32.c +++ b/arch/sparc/kernel/setup_32.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include @@ -51,6 +52,7 @@ #include "kernel.h" +int stop_a_enabled = 1; struct screen_info screen_info = { 0, 0, /* orig-x, orig-y */ 0, /* unused */ @@ -293,6 +295,24 @@ void __init sparc32_start_kernel(struct linux_romvec *rp) start_kernel(); } +/* + * The following notifier executes as one of the latest things in the panic + * path, only if the restart routines weren't executed (or didn't succeed). + */ +static int panic_event(struct notifier_block *n, unsigned long ev, void *unused) +{ + /* Make sure the user can actually press Stop-A (L1-A) */ + stop_a_enabled = 1; + pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" + "twice on console to return to the boot prom\n"); + + return NOTIFY_DONE; +} + +static struct notifier_block post_reboot_panic_block = { + .notifier_call = panic_event, +}; + void __init setup_arch(char **cmdline_p) { int i; @@ -368,9 +388,10 @@ void __init setup_arch(char **cmdline_p) paging_init(); smp_setup_cpu_possible_map(); -} -extern int stop_a_enabled; + atomic_notifier_chain_register(&panic_post_reboot_list, + &post_reboot_panic_block); +} void sun_do_break(void) { @@ -384,8 +405,6 @@ void sun_do_break(void) } EXPORT_SYMBOL(sun_do_break); -int stop_a_enabled = 1; - static int __init topology_init(void) { int i, ncpus, err; diff --git a/arch/sparc/kernel/setup_64.c b/arch/sparc/kernel/setup_64.c index 48abee4eee29..9066c25ecc07 100644 --- a/arch/sparc/kernel/setup_64.c +++ b/arch/sparc/kernel/setup_64.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include @@ -62,6 +63,8 @@ #include "entry.h" #include "kernel.h" +int stop_a_enabled = 1; + /* Used to synchronize accesses to NatSemi SUPER I/O chip configure * operations in asm/ns87303.h */ @@ -632,6 +635,24 @@ void __init alloc_irqstack_bootmem(void) } } +/* + * The following notifier executes as one of the latest things in the panic + * path, only if the restart routines weren't executed (or didn't succeed). + */ +static int panic_event(struct notifier_block *n, unsigned long ev, void *unused) +{ + /* Make sure the user can actually press Stop-A (L1-A) */ + stop_a_enabled = 1; + pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" + "twice on console to return to the boot prom\n"); + + return NOTIFY_DONE; +} + +static struct notifier_block post_reboot_panic_block = { + .notifier_call = panic_event, +}; + void __init setup_arch(char **cmdline_p) { /* Initialize PROM console and command line. */ @@ -691,9 +712,10 @@ void __init setup_arch(char **cmdline_p) * allocate the IRQ stacks. */ alloc_irqstack_bootmem(); -} -extern int stop_a_enabled; + atomic_notifier_chain_register(&panic_post_reboot_list, + &post_reboot_panic_block); +} void sun_do_break(void) { @@ -706,6 +728,3 @@ void sun_do_break(void) prom_cmdline(); } EXPORT_SYMBOL(sun_do_break); - -int stop_a_enabled = 1; -EXPORT_SYMBOL(stop_a_enabled); diff --git a/include/linux/panic_notifier.h b/include/linux/panic_notifier.h index 7912aacbc0e5..bcf6a5ea9d7f 100644 --- a/include/linux/panic_notifier.h +++ b/include/linux/panic_notifier.h @@ -8,6 +8,7 @@ extern struct atomic_notifier_head panic_hypervisor_list; extern struct atomic_notifier_head panic_info_list; extern struct atomic_notifier_head panic_pre_reboot_list; +extern struct atomic_notifier_head panic_post_reboot_list; extern bool crash_kexec_post_notifiers; diff --git a/kernel/panic.c b/kernel/panic.c index a9d43b98b05b..bf792102b43e 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -78,6 +78,9 @@ EXPORT_SYMBOL(panic_info_list); ATOMIC_NOTIFIER_HEAD(panic_pre_reboot_list); EXPORT_SYMBOL(panic_pre_reboot_list); +ATOMIC_NOTIFIER_HEAD(panic_post_reboot_list); +EXPORT_SYMBOL(panic_post_reboot_list); + static long no_blink(int state) { return 0; @@ -359,18 +362,10 @@ void panic(const char *fmt, ...) reboot_mode = panic_reboot_mode; emergency_restart(); } -#ifdef __sparc__ - { - extern int stop_a_enabled; - /* Make sure the user can actually press Stop-A (L1-A) */ - stop_a_enabled = 1; - pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n" - "twice on console to return to the boot prom\n"); - } -#endif -#if defined(CONFIG_S390) - disabled_wait(); -#endif + + atomic_notifier_call_chain(&panic_post_reboot_list, + PANIC_NOTIFIER, buf); + pr_emerg("---[ end Kernel panic - not syncing: %s ]---\n", buf); /* Do not scroll important messages printed above */ -- 2.36.0