[RFC PATCH 3/9] powerpc: Introduce a early machine check hook in cpu_spec.

[Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>]

From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>

This patch adds the early machine check function pointer in cputable for
CPU specific early machine check handling. The early machine handle routine
will be called in real mode to handle SLB and TLB errors. This patch just
sets up a mechanism invoke CPU specific handler. The subsequent patches
will populate the function pointer.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/cputable.h |    7 +++++++
 arch/powerpc/kernel/traps.c         |    7 +++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index 6f3887d..d8c098e 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -90,6 +90,13 @@ struct cpu_spec {
 	 * if the error is fatal, 1 if it was fully recovered and 0 to
 	 * pass up (not CPU originated) */
 	int		(*machine_check)(struct pt_regs *regs);
+
+	/*
+	 * Processor specific early machine check handler which is
+	 * called in real mode to handle SLB and TLB errors.
+	 */
+	long		(*machine_check_early)(struct pt_regs *regs);
+
 };
 
 extern struct cpu_spec		*cur_cpu_spec;
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 1720e08..07331b7 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -294,8 +294,11 @@ void system_reset_exception(struct pt_regs *regs)
  */
 long machine_check_early(struct pt_regs *regs)
 {
-	/* TODO: handle/decode machine check reason */
-	return 0;
+	long handled = 0;
+
+	if (cur_cpu_spec && cur_cpu_spec->machine_check_early)
+		handled = cur_cpu_spec->machine_check_early(regs);
+	return handled;
 }
 
 #endif