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>
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index b24b700..bed9a29 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -617,6 +617,17 @@
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
/*