From 2332ce1a97963b7769e0c2d40492a10a124efba5 Mon Sep 17 00:00:00 2001 From: Holger Smolinski Date: Fri, 10 Oct 2008 21:33:27 +0200 Subject: [PATCH] [S390] console flush on panic / reboot The s390 console drivers use the unblank callback of the console structure to flush the console buffer. In case of a panic or a reboot the CPU doing the callback can block on the console i/o. The other CPUs in the system continue to work. For panic this is not a good idea. Replace the unblank callback with proper panic/reboot notifier. These get called after all but one CPU have been stopped. Signed-off-by: Holger Smolinski Signed-off-by: Martin Schwidefsky --- drivers/s390/char/con3215.c | 27 +++++++++++++++++++++++---- drivers/s390/char/con3270.c | 27 +++++++++++++++++++++++---- drivers/s390/char/sclp_con.c | 24 ++++++++++++++++++++++-- drivers/s390/char/sclp_vt220.c | 26 ++++++++++++++++++-------- 4 files changed, 86 insertions(+), 18 deletions(-) diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c index d3ec9b55ab35..982cf62ab66d 100644 --- a/drivers/s390/char/con3215.c +++ b/drivers/s390/char/con3215.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include @@ -775,11 +776,11 @@ static struct tty_driver *con3215_device(struct console *c, int *index) } /* - * panic() calls console_unblank before the system enters a - * disabled, endless loop. + * panic() calls con3215_flush through a panic_notifier + * before the system enters a disabled, endless loop. */ static void -con3215_unblank(void) +con3215_flush(void) { struct raw3215_info *raw; unsigned long flags; @@ -790,6 +791,23 @@ con3215_unblank(void) spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags); } +static int con3215_notify(struct notifier_block *self, + unsigned long event, void *data) +{ + con3215_flush(); + return NOTIFY_OK; +} + +static struct notifier_block on_panic_nb = { + .notifier_call = con3215_notify, + .priority = 0, +}; + +static struct notifier_block on_reboot_nb = { + .notifier_call = con3215_notify, + .priority = 0, +}; + /* * The console structure for the 3215 console */ @@ -797,7 +815,6 @@ static struct console con3215 = { .name = "ttyS", .write = con3215_write, .device = con3215_device, - .unblank = con3215_unblank, .flags = CON_PRINTBUFFER, }; @@ -859,6 +876,8 @@ con3215_init(void) raw3215[0] = NULL; return -ENODEV; } + atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + register_reboot_notifier(&on_reboot_nb); register_console(&con3215); return 0; } diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c index 3c07974886ed..d028d2ee83dd 100644 --- a/drivers/s390/char/con3270.c +++ b/drivers/s390/char/con3270.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -528,11 +529,11 @@ con3270_wait_write(struct con3270 *cp) } /* - * panic() calls console_unblank before the system enters a - * disabled, endless loop. + * panic() calls con3270_flush through a panic_notifier + * before the system enters a disabled, endless loop. */ static void -con3270_unblank(void) +con3270_flush(void) { struct con3270 *cp; unsigned long flags; @@ -554,6 +555,23 @@ con3270_unblank(void) spin_unlock_irqrestore(&cp->view.lock, flags); } +static int con3270_notify(struct notifier_block *self, + unsigned long event, void *data) +{ + con3270_flush(); + return NOTIFY_OK; +} + +static struct notifier_block on_panic_nb = { + .notifier_call = con3270_notify, + .priority = 0, +}; + +static struct notifier_block on_reboot_nb = { + .notifier_call = con3270_notify, + .priority = 0, +}; + /* * The console structure for the 3270 console */ @@ -561,7 +579,6 @@ static struct console con3270 = { .name = "tty3270", .write = con3270_write, .device = con3270_device, - .unblank = con3270_unblank, .flags = CON_PRINTBUFFER, }; @@ -623,6 +640,8 @@ con3270_init(void) condev->cline->len = 0; con3270_create_status(condev); condev->input = alloc_string(&condev->freemem, 80); + atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + register_reboot_notifier(&on_reboot_nb); register_console(&con3270); return 0; } diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c index 7e619c534bf4..9a25c4bd1421 100644 --- a/drivers/s390/char/sclp_con.c +++ b/drivers/s390/char/sclp_con.c @@ -16,6 +16,7 @@ #include #include #include +#include #include "sclp.h" #include "sclp_rw.h" @@ -172,7 +173,7 @@ sclp_console_device(struct console *c, int *index) * will be flushed to the SCLP. */ static void -sclp_console_unblank(void) +sclp_console_flush(void) { unsigned long flags; @@ -188,6 +189,24 @@ sclp_console_unblank(void) spin_unlock_irqrestore(&sclp_con_lock, flags); } +static int +sclp_console_notify(struct notifier_block *self, + unsigned long event, void *data) +{ + sclp_console_flush(); + return NOTIFY_OK; +} + +static struct notifier_block on_panic_nb = { + .notifier_call = sclp_console_notify, + .priority = 1, +}; + +static struct notifier_block on_reboot_nb = { + .notifier_call = sclp_console_notify, + .priority = 1, +}; + /* * used to register the SCLP console to the kernel and to * give printk necessary information @@ -197,7 +216,6 @@ static struct console sclp_console = .name = sclp_console_name, .write = sclp_console_write, .device = sclp_console_device, - .unblank = sclp_console_unblank, .flags = CON_PRINTBUFFER, .index = 0 /* ttyS0 */ }; @@ -241,6 +259,8 @@ sclp_console_init(void) sclp_con_width_htab = 8; /* enable printk-access to this driver */ + atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + register_reboot_notifier(&on_reboot_nb); register_console(&sclp_console); return 0; } diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c index ad51738c4261..9854f19f5e62 100644 --- a/drivers/s390/char/sclp_vt220.c +++ b/drivers/s390/char/sclp_vt220.c @@ -24,6 +24,8 @@ #include #include #include +#include + #include #include "sclp.h" @@ -743,24 +745,30 @@ sclp_vt220_con_device(struct console *c, int *index) return sclp_vt220_driver; } -/* - * This routine is called from panic when the kernel is going to give up. - * We have to make sure that all buffers will be flushed to the SCLP. - * Note that this function may be called from within an interrupt context. - */ -static void -sclp_vt220_con_unblank(void) +static int +sclp_vt220_notify(struct notifier_block *self, + unsigned long event, void *data) { __sclp_vt220_flush_buffer(); + return NOTIFY_OK; } +static struct notifier_block on_panic_nb = { + .notifier_call = sclp_vt220_notify, + .priority = 1, +}; + +static struct notifier_block on_reboot_nb = { + .notifier_call = sclp_vt220_notify, + .priority = 1, +}; + /* Structure needed to register with printk */ static struct console sclp_vt220_console = { .name = SCLP_VT220_CONSOLE_NAME, .write = sclp_vt220_con_write, .device = sclp_vt220_con_device, - .unblank = sclp_vt220_con_unblank, .flags = CON_PRINTBUFFER, .index = SCLP_VT220_CONSOLE_INDEX }; @@ -776,6 +784,8 @@ sclp_vt220_con_init(void) if (rc) return rc; /* Attach linux console */ + atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + register_reboot_notifier(&on_reboot_nb); register_console(&sclp_vt220_console); return 0; } -- 2.20.1