A preparation patch for alt_printk work. No functional change. - rename nmi.c to alt_print.c - rename exported functions to have alt_printk prefix.
Signed-off-by: Sergey Senozhatsky <[email protected]> --- include/linux/printk.h | 12 +++---- init/Kconfig | 16 +++++---- init/main.c | 2 +- kernel/kexec_core.c | 2 +- kernel/panic.c | 4 +-- kernel/printk/Makefile | 2 +- kernel/printk/{nmi.c => alt_printk.c} | 61 ++++++++++++++++++----------------- lib/nmi_backtrace.c | 2 +- 8 files changed, 52 insertions(+), 49 deletions(-) rename kernel/printk/{nmi.c => alt_printk.c} (80%) diff --git a/include/linux/printk.h b/include/linux/printk.h index 696a56b..7510613 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -131,17 +131,17 @@ void early_printk(const char *s, ...) { } #endif #ifdef CONFIG_PRINTK_NMI -extern void printk_nmi_init(void); +extern void alt_printk_init(void); extern void printk_nmi_enter(void); extern void printk_nmi_exit(void); -extern void printk_nmi_flush(void); -extern void printk_nmi_flush_on_panic(void); +extern void alt_printk_flush(void); +extern void alt_printk_flush_on_panic(void); #else -static inline void printk_nmi_init(void) { } +static inline void alt_printk_init(void) { } static inline void printk_nmi_enter(void) { } static inline void printk_nmi_exit(void) { } -static inline void printk_nmi_flush(void) { } -static inline void printk_nmi_flush_on_panic(void) { } +static inline void alt_printk_flush(void) { } +static inline void alt_printk_flush_on_panic(void) { } #endif /* PRINTK_NMI */ #ifdef CONFIG_PRINTK diff --git a/init/Kconfig b/init/Kconfig index 34407f1..434807f 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -875,17 +875,19 @@ config LOG_CPU_MAX_BUF_SHIFT 13 => 8 KB for each CPU 12 => 4 KB for each CPU -config NMI_LOG_BUF_SHIFT - int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13 => 8KB)" +config ALT_PRINTK_LOG_BUF_SHIFT + int "Temporary per-CPU printk log buffer size (12 => 4KB, 13 => 8KB)" range 10 21 default 13 - depends on PRINTK_NMI + depends on PRINTK help - Select the size of a per-CPU buffer where NMI messages are temporary - stored. They are copied to the main log buffer in a safe context - to avoid a deadlock. The value defines the size as a power of 2. + Select the size of an alternate printk per-CPU buffer where messages + printed from usafe contexts are temporary stored. One example would + be NMI messages, another one - printk recursion. The messages are + copied to the main log buffer in a safe context to avoid a deadlock. + The value defines the size as a power of 2. - NMI messages are rare and limited. The largest one is when + Those messages are rare and limited. The largest one is when a backtrace is printed. It usually fits into 4KB. Select 8KB if you want to be on the safe side. diff --git a/init/main.c b/init/main.c index 9af9274..3dab03c 100644 --- a/init/main.c +++ b/init/main.c @@ -577,7 +577,7 @@ asmlinkage __visible void __init start_kernel(void) timekeeping_init(); time_init(); sched_clock_postinit(); - printk_nmi_init(); + alt_printk_init(); perf_event_init(); profile_init(); call_function_init(); diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index a865969..a307fa3 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -909,7 +909,7 @@ void crash_kexec(struct pt_regs *regs) old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu); if (old_cpu == PANIC_CPU_INVALID) { /* This is the 1st CPU which comes here, so go ahead. */ - printk_nmi_flush_on_panic(); + alt_printk_flush_on_panic(); __crash_kexec(regs); /* diff --git a/kernel/panic.c b/kernel/panic.c index e6480e2..28f97ce 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -188,7 +188,7 @@ void panic(const char *fmt, ...) * Bypass the panic_cpu check and call __crash_kexec directly. */ if (!_crash_kexec_post_notifiers) { - printk_nmi_flush_on_panic(); + alt_printk_flush_on_panic(); __crash_kexec(NULL); /* @@ -213,7 +213,7 @@ void panic(const char *fmt, ...) atomic_notifier_call_chain(&panic_notifier_list, 0, buf); /* Call flush even twice. It tries harder with a single online CPU */ - printk_nmi_flush_on_panic(); + alt_printk_flush_on_panic(); kmsg_dump(KMSG_DUMP_PANIC); /* diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile index abb0042..3fc5e4e 100644 --- a/kernel/printk/Makefile +++ b/kernel/printk/Makefile @@ -1,3 +1,3 @@ obj-y = printk.o -obj-$(CONFIG_PRINTK_NMI) += nmi.o +obj-$(CONFIG_PRINTK_NMI) += alt_printk.o obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o diff --git a/kernel/printk/nmi.c b/kernel/printk/alt_printk.c similarity index 80% rename from kernel/printk/nmi.c rename to kernel/printk/alt_printk.c index 16bab47..7178661 100644 --- a/kernel/printk/nmi.c +++ b/kernel/printk/alt_printk.c @@ -1,5 +1,5 @@ /* - * nmi.c - Safe printk in NMI context + * alt_printk.c - Safe printk in NMI context * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -39,18 +39,18 @@ * were handled or when IRQs are blocked. */ DEFINE_PER_CPU(printk_func_t, printk_func) = vprintk_default; -static int printk_nmi_irq_ready; +static int alt_printk_irq_ready; atomic_t nmi_message_lost; -#define NMI_LOG_BUF_LEN ((1 << CONFIG_NMI_LOG_BUF_SHIFT) - \ +#define ALT_LOG_BUF_LEN ((1 << CONFIG_ALT_PRINTK_LOG_BUF_SHIFT) - \ sizeof(atomic_t) - sizeof(struct irq_work)) -struct nmi_seq_buf { +struct alt_printk_seq_buf { atomic_t len; /* length of written data */ struct irq_work work; /* IRQ work that flushes the buffer */ - unsigned char buffer[NMI_LOG_BUF_LEN]; + unsigned char buffer[ALT_LOG_BUF_LEN]; }; -static DEFINE_PER_CPU(struct nmi_seq_buf, nmi_print_seq); +static DEFINE_PER_CPU(struct alt_printk_seq_buf, nmi_print_seq); /* * Safe printk() for NMI context. It uses a per-CPU buffer to @@ -60,7 +60,7 @@ static DEFINE_PER_CPU(struct nmi_seq_buf, nmi_print_seq); */ static int vprintk_nmi(const char *fmt, va_list args) { - struct nmi_seq_buf *s = this_cpu_ptr(&nmi_print_seq); + struct alt_printk_seq_buf *s = this_cpu_ptr(&nmi_print_seq); int add = 0; size_t len; @@ -90,7 +90,7 @@ static int vprintk_nmi(const char *fmt, va_list args) goto again; /* Get flushed in a more safe context. */ - if (add && printk_nmi_irq_ready) { + if (add && alt_printk_irq_ready) { /* Make sure that IRQ work is really initialized. */ smp_rmb(); irq_work_queue(&s->work); @@ -99,7 +99,7 @@ static int vprintk_nmi(const char *fmt, va_list args) return add; } -static void printk_nmi_flush_line(const char *text, int len) +static void alt_printk_flush_line(const char *text, int len) { /* * The buffers are flushed in NMI only on panic. The messages must @@ -117,23 +117,24 @@ static void printk_nmi_flush_line(const char *text, int len) * printk one line from the temporary buffer from @start index until * and including the @end index. */ -static void printk_nmi_flush_seq_line(struct nmi_seq_buf *s, +static void alt_printk_flush_seq_line(struct alt_printk_seq_buf *s, int start, int end) { const char *buf = s->buffer + start; - printk_nmi_flush_line(buf, (end - start) + 1); + alt_printk_flush_line(buf, (end - start) + 1); } /* * Flush data from the associated per_CPU buffer. The function * can be called either via IRQ work or independently. */ -static void __printk_nmi_flush(struct irq_work *work) +static void __alt_printk_flush(struct irq_work *work) { static raw_spinlock_t read_lock = __RAW_SPIN_LOCK_INITIALIZER(read_lock); - struct nmi_seq_buf *s = container_of(work, struct nmi_seq_buf, work); + struct alt_printk_seq_buf *s = container_of(work, + struct alt_printk_seq_buf, work); unsigned long flags; size_t len, size; int i, last_i; @@ -157,9 +158,9 @@ static void __printk_nmi_flush(struct irq_work *work) * @len must only increase. */ if (i && i >= len) { - const char *msg = "printk_nmi_flush: internal error\n"; + const char *msg = "alt_printk_flush: internal error\n"; - printk_nmi_flush_line(msg, strlen(msg)); + alt_printk_flush_line(msg, strlen(msg)); } if (!len) @@ -174,14 +175,14 @@ static void __printk_nmi_flush(struct irq_work *work) /* Print line by line. */ for (; i < size; i++) { if (s->buffer[i] == '\n') { - printk_nmi_flush_seq_line(s, last_i, i); + alt_printk_flush_seq_line(s, last_i, i); last_i = i + 1; } } /* Check if there was a partial line. */ if (last_i < size) { - printk_nmi_flush_seq_line(s, last_i, size - 1); - printk_nmi_flush_line("\n", strlen("\n")); + alt_printk_flush_seq_line(s, last_i, size - 1); + alt_printk_flush_line("\n", strlen("\n")); } /* @@ -198,31 +199,31 @@ static void __printk_nmi_flush(struct irq_work *work) } /** - * printk_nmi_flush - flush all per-cpu nmi buffers. + * alt_printk_flush - flush all per-cpu nmi buffers. * * The buffers are flushed automatically via IRQ work. This function * is useful only when someone wants to be sure that all buffers have * been flushed at some point. */ -void printk_nmi_flush(void) +void alt_printk_flush(void) { int cpu; for_each_possible_cpu(cpu) - __printk_nmi_flush(&per_cpu(nmi_print_seq, cpu).work); + __alt_printk_flush(&per_cpu(nmi_print_seq, cpu).work); } /** - * printk_nmi_flush_on_panic - flush all per-cpu nmi buffers when the system + * alt_printk_flush_on_panic - flush all per-cpu nmi buffers when the system * goes down. * - * Similar to printk_nmi_flush() but it can be called even in NMI context when + * Similar to alt_printk_flush() but it can be called even in NMI context when * the system goes down. It does the best effort to get NMI messages into * the main ring buffer. * * Note that it could try harder when there is only one CPU online. */ -void printk_nmi_flush_on_panic(void) +void alt_printk_flush_on_panic(void) { /* * Make sure that we could access the main ring buffer. @@ -236,25 +237,25 @@ void printk_nmi_flush_on_panic(void) raw_spin_lock_init(&logbuf_lock); } - printk_nmi_flush(); + alt_printk_flush(); } -void __init printk_nmi_init(void) +void __init alt_printk_init(void) { int cpu; for_each_possible_cpu(cpu) { - struct nmi_seq_buf *s = &per_cpu(nmi_print_seq, cpu); + struct alt_printk_seq_buf *s = &per_cpu(nmi_print_seq, cpu); - init_irq_work(&s->work, __printk_nmi_flush); + init_irq_work(&s->work, __alt_printk_flush); } /* Make sure that IRQ works are initialized before enabling. */ smp_wmb(); - printk_nmi_irq_ready = 1; + alt_printk_irq_ready = 1; /* Flush pending messages that did not have scheduled IRQ works. */ - printk_nmi_flush(); + alt_printk_flush(); } void printk_nmi_enter(void) diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c index 7555475..257ab1e 100644 --- a/lib/nmi_backtrace.c +++ b/lib/nmi_backtrace.c @@ -77,7 +77,7 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, * Force flush any remote buffers that might be stuck in IRQ context * and therefore could not run their irq_work. */ - printk_nmi_flush(); + alt_printk_flush(); clear_bit_unlock(0, &backtrace_flag); put_cpu(); -- 2.10.0.372.g6fe1b14
