[PATCH v5 1/2] kprobes/powerpc: Fix arch_deref_entry_point to support ABIv2

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

Since PowerPC64 ABIv2 doesn't have function descriptor
any more, arch_deref_entry_point(), which returns function
entry point from function descriptor, should be updated.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anoop Thomas Mathew <atm@profoundis.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/kernel/kprobes.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 90fab64..72a1034 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -491,7 +491,12 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
 	return ret;
 }
 
-#ifdef CONFIG_PPC64
+#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF == 1)
+/*
+ * On PPC64 ABIv1 the function pointer actually points to the
+ * function's descriptor. The first entry in the descriptor is the
+ * address of the function text.
+ */
 unsigned long arch_deref_entry_point(void *entry)
 {
 	return ((func_descr_t *)entry)->entry;