[Patch 6/8] powerpc: implement crashkernel=auto

[Amerigo Wang <amwang@redhat.com>]

Since in patch 2/8 we already implement the generic part, this will
add the rest part for powerpc.

Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: M. Mohan Kumar <mohan@in.ibm.com>
Cc: Michael Ellerman <michael@ellerman.id.au>

---

Index: linux-2.6/arch/powerpc/include/asm/kexec.h
===================================================================
--- linux-2.6.orig/arch/powerpc/include/asm/kexec.h
+++ linux-2.6/arch/powerpc/include/asm/kexec.h
@@ -39,6 +39,45 @@ typedef void (*crash_shutdown_t)(void);
 
 #ifdef CONFIG_KEXEC
 
+#ifdef CONFIG_KEXEC_AUTO_RESERVE
+
+#ifndef KEXEC_AUTO_THRESHOLD
+#define KEXEC_AUTO_THRESHOLD (1ULL<<31) /* 2G */
+#endif
+
+#ifndef arch_default_crash_base
+static inline
+unsigned long long arch_default_crash_base(void)
+{
+	return KDUMP_KERNELBASE;
+}
+#define arch_default_crash_base arch_default_crash_base
+#endif
+
+#ifndef arch_default_crash_size
+static inline
+unsigned long long arch_default_crash_size(unsigned long long total_size)
+{
+	if (total_size < KEXEC_AUTO_THRESHOLD)
+		return 0;
+	if (total_size < (1ULL<<32))
+		return 1ULL<<27;
+	else {
+#ifdef CONFIG_64BIT
+		if (total_size > (1ULL<<37)) /* 128G */
+			return 1ULL<<32; /* 4G */
+		return 1ULL<<ilog2(roundup(total_size/32, 1ULL<<21));
+#else
+		return 1ULL<<28;
+#endif
+	}
+}
+#define arch_default_crash_size arch_default_crash_size
+#endif
+
+#endif
+#include <asm-generic/kexec.h>
+
 /*
  * This function is responsible for capturing register states if coming
  * via panic or invoking dump using sysrq-trigger.