2 files changed, 7 insertions, 13 deletions

diff --git a/arch/powerpc/include/asm/kdump.h b/arch/powerpc/include/asm/kdump.h
index 6857af58b02e..bffd062adf79 100644
--- a/arch/powerpc/include/asm/kdump.h
+++ b/arch/powerpc/include/asm/kdump.h
@@ -3,17 +3,7 @@
 
 #include <asm/page.h>
 
-/*
- * If CONFIG_RELOCATABLE is enabled we can place the kdump kernel anywhere.
- * To keep enough space in the RMO for the first stage kernel on 64bit, we
- * place it at 64MB. If CONFIG_RELOCATABLE is not enabled we must place
- * the second stage at 32MB.
- */
-#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC64)
-#define KDUMP_KERNELBASE        0x4000000
-#else
 #define KDUMP_KERNELBASE        0x2000000
-#endif
 
 /* How many bytes to reserve at zero for kdump. The reserve limit should
  * be greater or equal to the trampoline's end address.
diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index 6658a1589955..9ce1672afb59 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -136,12 +136,16 @@ void __init reserve_crashkernel(void)
         crashk_res.start = KDUMP_KERNELBASE;
 #else
         if (!crashk_res.start) {
+#ifdef CONFIG_PPC64
                 /*
-                 * unspecified address, choose a region of specified size
-                 * can overlap with initrd (ignoring corruption when retained)
-                 * ppc64 requires kernel and some stacks to be in first segemnt
+                 * On 64bit we split the RMO in half but cap it at half of
+                 * a small SLB (128MB) since the crash kernel needs to place
+                 * itself and some stacks to be in the first segment.
                  */
+                crashk_res.start = min(0x80000000ULL, (ppc64_rma_size / 2));
+#else
                 crashk_res.start = KDUMP_KERNELBASE;
+#endif
         }
 
         crash_base = PAGE_ALIGN(crashk_res.start);