1 files changed, 4 insertions, 1 deletions

diff --git a/arch/ppc64/kernel/prom_init.c b/arch/ppc64/kernel/prom_init.c
index adcf972711fc..122283a1d39a 100644
--- a/arch/ppc64/kernel/prom_init.c
+++ b/arch/ppc64/kernel/prom_init.c
@@ -892,7 +892,10 @@ static void __init prom_init_mem(void)
         if ( RELOC(of_platform) == PLATFORM_PSERIES_LPAR )
                 RELOC(alloc_top) = RELOC(rmo_top);
         else
-                RELOC(alloc_top) = RELOC(rmo_top) = min(0x40000000ul, RELOC(ram_top));
+                /* Some RS64 machines have buggy firmware where claims up at 1GB
+                 * fails. Cap at 768MB as a workaround. Still plenty of room.
+                 */
+                RELOC(alloc_top) = RELOC(rmo_top) = min(0x30000000ul, RELOC(ram_top));
 
         prom_printf("memory layout at init:\n");
         prom_printf("  memory_limit : %x (16 MB aligned)\n", RELOC(prom_memory_limit));