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| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-02-10 18:45:24 +1100 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-04-01 15:37:09 +1100 |
| commit | fa3f82c8bb7acbe049ea71f258b3ae0a33d9d40b (patch) | |
| tree | 9c5e71195c7948c139ea37d8d0e0287f062910f9 | |
| parent | 963e5d3b76d657f1ebcf3561446d2ba1872bbfa2 (diff) | |
| download | talos-obmc-linux-fa3f82c8bb7acbe049ea71f258b3ae0a33d9d40b.tar.gz talos-obmc-linux-fa3f82c8bb7acbe049ea71f258b3ae0a33d9d40b.zip | |
powerpc/smp: soft-replugged CPUs must go back to start_secondary
Various thing are torn down when a CPU is hot-unplugged. That CPU
is expected to go back to start_secondary when re-plugged to re
initialize everything, such as clock sources, maps, ...
Some implementations just return from cpu_die() callback
in the idle loop when the CPU is "re-plugged". This is not enough.
We fix it using a little asm trampoline which resets the stack
and calls back into start_secondary as if we were all fresh from
boot. The trampoline already existed on ppc64, but we add it for
ppc32
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | arch/powerpc/include/asm/smp.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/kernel/head_32.S | 9 | ||||
| -rw-r--r-- | arch/powerpc/kernel/smp.c | 9 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/offline_states.h | 2 |
4 files changed, 17 insertions, 4 deletions
diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h index 66e237bbe15f..1de0e97a394f 100644 --- a/arch/powerpc/include/asm/smp.h +++ b/arch/powerpc/include/asm/smp.h @@ -36,6 +36,7 @@ extern void cpu_die(void); extern void smp_send_debugger_break(int cpu); extern void smp_message_recv(int); +extern void start_secondary_resume(void); DECLARE_PER_CPU(unsigned int, cpu_pvr); diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S index 98c4b29a56f4..c5c24beb8387 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -890,6 +890,15 @@ __secondary_start: mtspr SPRN_SRR1,r4 SYNC RFI + +_GLOBAL(start_secondary_resume) + /* Reset stack */ + rlwinm r1,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */ + addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD + li r3,0 + std r3,0(r1) /* Zero the stack frame pointer */ + bl start_secondary + b . #endif /* CONFIG_SMP */ #ifdef CONFIG_KVM_BOOK3S_HANDLER diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 981360509172..1c9956c43801 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -502,7 +502,7 @@ static struct device_node *cpu_to_l2cache(int cpu) } /* Activate a secondary processor. */ -int __devinit start_secondary(void *unused) +void __devinit start_secondary(void *unused) { unsigned int cpu = smp_processor_id(); struct device_node *l2_cache; @@ -558,7 +558,8 @@ int __devinit start_secondary(void *unused) local_irq_enable(); cpu_idle(); - return 0; + + BUG(); } int setup_profiling_timer(unsigned int multiplier) @@ -660,5 +661,9 @@ void cpu_die(void) { if (ppc_md.cpu_die) ppc_md.cpu_die(); + + /* If we return, we re-enter start_secondary */ + start_secondary_resume(); } + #endif diff --git a/arch/powerpc/platforms/pseries/offline_states.h b/arch/powerpc/platforms/pseries/offline_states.h index 75a6f480d931..08672d9136ab 100644 --- a/arch/powerpc/platforms/pseries/offline_states.h +++ b/arch/powerpc/platforms/pseries/offline_states.h @@ -34,6 +34,4 @@ static inline void set_default_offline_state(int cpu) #endif extern enum cpu_state_vals get_preferred_offline_state(int cpu); -extern int start_secondary(void); -extern void start_secondary_resume(void); #endif |
