From 8b95d9172be7146c87e7a998310ce2919c851adc Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 14 Jul 2008 23:32:32 +0200 Subject: fix core/stacktrace changes on avr32, mips, sh Fixes this type of problem: CC arch/s390/kernel/stacktrace.o arch/s390/kernel/stacktrace.c:84: warning: data definition has no type or storage class arch/s390/kernel/stacktrace.c:84: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL' arch/s390/kernel/stacktrace.c:84: warning: parameter names (without types) in function declaration arch/s390/kernel/stacktrace.c:97: warning: data definition has no type or storage class arch/s390/kernel/stacktrace.c:97: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL' arch/s390/kernel/stacktrace.c:97: warning: parameter names (without types) in function declaration caused by "stacktrace: export save_stack_trace[_tsk]" Signed-off-by: Heiko Carstens Cc: Stephen Rothwell Cc: Linus Torvalds Cc: Andrew Morton Signed-off-by: Ingo Molnar --- arch/avr32/kernel/stacktrace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/avr32/kernel') diff --git a/arch/avr32/kernel/stacktrace.c b/arch/avr32/kernel/stacktrace.c index f4bdb448049c..c09f0d8dd679 100644 --- a/arch/avr32/kernel/stacktrace.c +++ b/arch/avr32/kernel/stacktrace.c @@ -10,6 +10,7 @@ #include #include #include +#include register unsigned long current_frame_pointer asm("r7"); -- cgit v1.2.1 From b8f8c3cf0a4ac0632ec3f0e15e9dc0c29de917af Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 18 Jul 2008 17:27:28 +0200 Subject: nohz: prevent tick stop outside of the idle loop Jack Ren and Eric Miao tracked down the following long standing problem in the NOHZ code: scheduler switch to idle task enable interrupts Window starts here ----> interrupt happens (does not set NEED_RESCHED) irq_exit() stops the tick ----> interrupt happens (does set NEED_RESCHED) return from schedule() cpu_idle(): preempt_disable(); Window ends here The interrupts can happen at any point inside the race window. The first interrupt stops the tick, the second one causes the scheduler to rerun and switch away from idle again and we end up with the tick disabled. The fact that it needs two interrupts where the first one does not set NEED_RESCHED and the second one does made the bug obscure and extremly hard to reproduce and analyse. Kudos to Jack and Eric. Solution: Limit the NOHZ functionality to the idle loop to make sure that we can not run into such a situation ever again. cpu_idle() { preempt_disable(); while(1) { tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we are in the idle loop while (!need_resched()) halt(); tick_nohz_restart_sched_tick(); <- disables NOHZ mode preempt_enable_no_resched(); schedule(); preempt_disable(); } } In hindsight we should have done this forever, but ... /me grabs a large brown paperbag. Debugged-by: Jack Ren , Debugged-by: eric miao Signed-off-by: Thomas Gleixner --- arch/avr32/kernel/process.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/avr32/kernel') diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c index 6cf9df176274..ff820a9e743a 100644 --- a/arch/avr32/kernel/process.c +++ b/arch/avr32/kernel/process.c @@ -31,7 +31,7 @@ void cpu_idle(void) { /* endless idle loop with no priority at all */ while (1) { - tick_nohz_stop_sched_tick(); + tick_nohz_stop_sched_tick(1); while (!need_resched()) cpu_idle_sleep(); tick_nohz_restart_sched_tick(); -- cgit v1.2.1 From 4a0b2b4dbe1335b8b9886ba3dc85a145d5d938ed Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 1 Jul 2008 18:48:41 +0200 Subject: sysdev: Pass the attribute to the low level sysdev show/store function This allow to dynamically generate attributes and share show/store functions between attributes. Right now most attributes are generated by special macros and lots of duplicated code. With the attribute passed it's instead possible to attach some data to the attribute and then use that in shared low level functions to do different things. I need this for the dynamically generated bank attributes in the x86 machine check code, but it'll allow some further cleanups. I converted all users in tree to the new show/store prototype. It's a single huge patch to avoid unbisectable sections. Runtime tested: x86-32, x86-64 Compiled only: ia64, powerpc Not compile tested/only grep converted: sh, arm, avr32 Signed-off-by: Andi Kleen Signed-off-by: Greg Kroah-Hartman --- arch/avr32/kernel/cpu.c | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-) (limited to 'arch/avr32/kernel') diff --git a/arch/avr32/kernel/cpu.c b/arch/avr32/kernel/cpu.c index b8409caeb23d..e84faffbbeca 100644 --- a/arch/avr32/kernel/cpu.c +++ b/arch/avr32/kernel/cpu.c @@ -26,14 +26,16 @@ static DEFINE_PER_CPU(struct cpu, cpu_devices); * XXX: If/when a SMP-capable implementation of AVR32 will ever be * made, we must make sure that the code executes on the correct CPU. */ -static ssize_t show_pc0event(struct sys_device *dev, char *buf) +static ssize_t show_pc0event(struct sys_device *dev, + struct sysdev_attribute *attr, char *buf) { unsigned long pccr; pccr = sysreg_read(PCCR); return sprintf(buf, "0x%lx\n", (pccr >> 12) & 0x3f); } -static ssize_t store_pc0event(struct sys_device *dev, const char *buf, +static ssize_t store_pc0event(struct sys_device *dev, + struct sysdev_attribute *attr, const char *buf, size_t count) { unsigned long val; @@ -46,15 +48,17 @@ static ssize_t store_pc0event(struct sys_device *dev, const char *buf, sysreg_write(PCCR, val); return count; } -static ssize_t show_pc0count(struct sys_device *dev, char *buf) +static ssize_t show_pc0count(struct sys_device *dev, + struct sysdev_attribute *attr, char *buf) { unsigned long pcnt0; pcnt0 = sysreg_read(PCNT0); return sprintf(buf, "%lu\n", pcnt0); } -static ssize_t store_pc0count(struct sys_device *dev, const char *buf, - size_t count) +static ssize_t store_pc0count(struct sys_device *dev, + struct sysdev_attribute *attr, + const char *buf, size_t count) { unsigned long val; char *endp; @@ -67,14 +71,16 @@ static ssize_t store_pc0count(struct sys_device *dev, const char *buf, return count; } -static ssize_t show_pc1event(struct sys_device *dev, char *buf) +static ssize_t show_pc1event(struct sys_device *dev, + struct sysdev_attribute *attr, char *buf) { unsigned long pccr; pccr = sysreg_read(PCCR); return sprintf(buf, "0x%lx\n", (pccr >> 18) & 0x3f); } -static ssize_t store_pc1event(struct sys_device *dev, const char *buf, +static ssize_t store_pc1event(struct sys_device *dev, + struct sysdev_attribute *attr, const char *buf, size_t count) { unsigned long val; @@ -87,14 +93,16 @@ static ssize_t store_pc1event(struct sys_device *dev, const char *buf, sysreg_write(PCCR, val); return count; } -static ssize_t show_pc1count(struct sys_device *dev, char *buf) +static ssize_t show_pc1count(struct sys_device *dev, + struct sysdev_attribute *attr, char *buf) { unsigned long pcnt1; pcnt1 = sysreg_read(PCNT1); return sprintf(buf, "%lu\n", pcnt1); } -static ssize_t store_pc1count(struct sys_device *dev, const char *buf, +static ssize_t store_pc1count(struct sys_device *dev, + struct sysdev_attribute *attr, const char *buf, size_t count) { unsigned long val; @@ -108,14 +116,16 @@ static ssize_t store_pc1count(struct sys_device *dev, const char *buf, return count; } -static ssize_t show_pccycles(struct sys_device *dev, char *buf) +static ssize_t show_pccycles(struct sys_device *dev, + struct sysdev_attribute *attr, char *buf) { unsigned long pccnt; pccnt = sysreg_read(PCCNT); return sprintf(buf, "%lu\n", pccnt); } -static ssize_t store_pccycles(struct sys_device *dev, const char *buf, +static ssize_t store_pccycles(struct sys_device *dev, + struct sysdev_attribute *attr, const char *buf, size_t count) { unsigned long val; @@ -129,14 +139,16 @@ static ssize_t store_pccycles(struct sys_device *dev, const char *buf, return count; } -static ssize_t show_pcenable(struct sys_device *dev, char *buf) +static ssize_t show_pcenable(struct sys_device *dev, + struct sysdev_attribute *attr, char *buf) { unsigned long pccr; pccr = sysreg_read(PCCR); return sprintf(buf, "%c\n", (pccr & 1)?'1':'0'); } -static ssize_t store_pcenable(struct sys_device *dev, const char *buf, +static ssize_t store_pcenable(struct sys_device *dev, + struct sysdev_attribute *attr, const char *buf, size_t count) { unsigned long pccr, val; -- cgit v1.2.1