diff options
author | Yi Li <yi.li@analog.com> | 2009-12-02 10:58:12 +0300 |
---|---|---|
committer | Mike Frysinger <vapier@gentoo.org> | 2009-12-15 08:16:09 +0300 |
commit | 578d36f5e160208821e8f51037ac1038e065ecaf (patch) | |
tree | 6b1da0d6e7108c0bd217b132e165f2d06007fef8 /arch/blackfin/mach-common | |
parent | ad774b7cb0604d02c3596b79921fcb812df4dc71 (diff) | |
download | linux-578d36f5e160208821e8f51037ac1038e065ecaf.tar.xz |
Blackfin: SMP: don't start up core b until its state has been completely onlined
When testing PREEMPT_RT kernel on BF561-EZKit, the kernel blocks while
booting. When the kernel initializes the ethernet driver, it sleeps and
never wakes up.
The issue happens when the kernel waits for a timer for Core B to timeout
(the timers are per-cpu based: static DEFINE_PER_CPU(struct tvec_base *,
tvec_bases) = &boot_tvec_bases).
However, the ksoftirqd thread for Core B (note, the ksoftirqd thread is
also per-cpu based) cannot work properly, and the timers for Core B never
times out.
When ksoftirqd() for the first time runs on core B, it is possible core A
is still initializing core B (see smp_init() -> cpu_up() -> __cpu_up()).
So the "cpu_is_offline()" check may return true and ksoftirqd moves to
"wait_to_die".
So delay the core b start up until the per-cpu timers have been set up
fully.
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch/blackfin/mach-common')
-rw-r--r-- | arch/blackfin/mach-common/smp.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c index d92b168c8328..369e687582b7 100644 --- a/arch/blackfin/mach-common/smp.c +++ b/arch/blackfin/mach-common/smp.c @@ -336,13 +336,6 @@ int __cpuinit __cpu_up(unsigned int cpu) ret = platform_boot_secondary(cpu, idle); - if (ret) { - cpu_clear(cpu, cpu_present_map); - printk(KERN_CRIT "CPU%u: processor failed to boot (%d)\n", cpu, ret); - free_task(idle); - } else - cpu_set(cpu, cpu_online_map); - secondary_stack = NULL; return ret; @@ -418,9 +411,16 @@ void __cpuinit secondary_start_kernel(void) setup_secondary(cpu); + platform_secondary_init(cpu); + local_irq_enable(); - platform_secondary_init(cpu); + /* + * Calibrate loops per jiffy value. + * IRQs need to be enabled here - D-cache can be invalidated + * in timer irq handler, so core B can read correct jiffies. + */ + calibrate_delay(); cpu_idle(); } |