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authorVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>2010-03-01 02:58:09 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2010-03-09 11:57:10 +1100
commit8dbce53cc249a76e9450708d291fce5a7e29c6a1 (patch)
tree8480f0fe8a9aff2a63ef5812adc4c18746b5d846 /arch
parentde0b632ba05bc88949e67d33d1c313fcf922ae2e (diff)
powerpc: Reset kernel stack on cpu online from cede state
Cpu hotplug (offline) without dlpar operation will place cpu in cede state and the extended_cede_processor() function will return when resumed. Kernel stack pointer needs to be reset before start_secondary() is called to continue the online operation. Added new function start_secondary_resume() to do the above steps. Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/head_64.S11
-rw-r--r--arch/powerpc/platforms/pseries/hotplug-cpu.c9
-rw-r--r--arch/powerpc/platforms/pseries/offline_states.h1
3 files changed, 16 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index b24b7001ae1..bed9a29ee38 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -617,6 +617,17 @@ _GLOBAL(start_secondary_prolog)
std r3,0(r1) /* Zero the stack frame pointer */
bl .start_secondary
b .
+/*
+ * Reset stack pointer and call start_secondary
+ * to continue with online operation when woken up
+ * from cede in cpu offline.
+ */
+_GLOBAL(start_secondary_resume)
+ ld r1,PACAKSAVE(r13) /* Reload kernel stack pointer */
+ li r3,0
+ std r3,0(r1) /* Zero the stack frame pointer */
+ bl .start_secondary
+ b .
#endif
/*
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index d1b124e44d7..349e0af9389 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -146,12 +146,11 @@ static void pseries_mach_cpu_die(void)
unregister_slb_shadow(hwcpu, __pa(get_slb_shadow()));
/*
- * NOTE: Calling start_secondary() here for now to
- * start new context.
- * However, need to do it cleanly by resetting the
- * stack pointer.
+ * Call to start_secondary_resume() will not return.
+ * Kernel stack will be reset and start_secondary()
+ * will be called to continue the online operation.
*/
- start_secondary();
+ start_secondary_resume();
} else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) {
diff --git a/arch/powerpc/platforms/pseries/offline_states.h b/arch/powerpc/platforms/pseries/offline_states.h
index 202d8692c6a..75a6f480d93 100644
--- a/arch/powerpc/platforms/pseries/offline_states.h
+++ b/arch/powerpc/platforms/pseries/offline_states.h
@@ -35,4 +35,5 @@ static inline void set_default_offline_state(int cpu)
extern enum cpu_state_vals get_preferred_offline_state(int cpu);
extern int start_secondary(void);
+extern void start_secondary_resume(void);
#endif