3 files changed, 45 insertions, 3 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 31d5b22c59a2..8a9359ae4718 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -1043,6 +1043,33 @@ static void __init early_reserve_mem(void)
 
 #ifdef CONFIG_PHYP_DUMP
 /**
+ * phyp_dump_calculate_reserve_size() - reserve variable boot area 5% or arg
+ *
+ * Function to find the largest size we need to reserve
+ * during early boot process.
+ *
+ * It either looks for boot param and returns that OR
+ * returns larger of 256 or 5% rounded down to multiples of 256MB.
+ *
+ */
+static inline unsigned long phyp_dump_calculate_reserve_size(void)
+{
+        unsigned long tmp;
+
+        if (phyp_dump_info->reserve_bootvar)
+                return phyp_dump_info->reserve_bootvar;
+
+        /* divide by 20 to get 5% of value */
+        tmp = lmb_end_of_DRAM();
+        do_div(tmp, 20);
+
+        /* round it down in multiples of 256 */
+        tmp = tmp & ~0x0FFFFFFFUL;
+
+        return (tmp > PHYP_DUMP_RMR_END ? tmp : PHYP_DUMP_RMR_END);
+}
+
+/**
  * phyp_dump_reserve_mem() - reserve all not-yet-dumped mmemory
  *
  * This routine may reserve memory regions in the kernel only
@@ -1055,6 +1082,8 @@ static void __init early_reserve_mem(void)
 static void __init phyp_dump_reserve_mem(void)
 {
         unsigned long base, size;
+        unsigned long variable_reserve_size;
+
         if (!phyp_dump_info->phyp_dump_configured) {
                 printk(KERN_ERR "Phyp-dump not supported on this hardware\n");
                 return;
@@ -1065,9 +1094,11 @@ static void __init phyp_dump_reserve_mem(void)
                 return;
         }
 
+        variable_reserve_size = phyp_dump_calculate_reserve_size();
+
         if (phyp_dump_info->phyp_dump_is_active) {
                 /* Reserve *everything* above RMR.Area freed by userland tools*/
-                base = PHYP_DUMP_RMR_END;
+                base = variable_reserve_size;
                 size = lmb_end_of_DRAM() - base;
 
                 /* XXX crashed_ram_end is wrong, since it may be beyond
@@ -1079,7 +1110,7 @@ static void __init phyp_dump_reserve_mem(void)
         } else {
                 size = phyp_dump_info->cpu_state_size +
                         phyp_dump_info->hpte_region_size +
-                        PHYP_DUMP_RMR_END;
+                        variable_reserve_size;
                 base = lmb_end_of_DRAM() - size;
                 lmb_reserve(base, size);
                 phyp_dump_info->init_reserve_start = base;
diff --git a/arch/powerpc/platforms/pseries/phyp_dump.c b/arch/powerpc/platforms/pseries/phyp_dump.c
index 7ddd10526cea..edbc012c2ebc 100644
--- a/arch/powerpc/platforms/pseries/phyp_dump.c
+++ b/arch/powerpc/platforms/pseries/phyp_dump.c
@@ -496,3 +496,12 @@ static int __init early_phyp_dump_enabled(char *p)
 }
 early_param("phyp_dump", early_phyp_dump_enabled);
 
+/* Look for phyp_dump_reserve_size= cmdline option */
+static int __init early_phyp_dump_reserve_size(char *p)
+{
+        if (p)
+                phyp_dump_info->reserve_bootvar = memparse(p, &p);
+
+        return 0;
+}
+early_param("phyp_dump_reserve_size", early_phyp_dump_reserve_size);
diff --git a/include/asm-powerpc/phyp_dump.h b/include/asm-powerpc/phyp_dump.h
index 209a98913d9d..fa74c6c3e106 100644
--- a/include/asm-powerpc/phyp_dump.h
+++ b/include/asm-powerpc/phyp_dump.h
@@ -24,8 +24,10 @@ struct phyp_dump {
         /* Memory that is reserved during very early boot. */
         unsigned long init_reserve_start;
         unsigned long init_reserve_size;
-        /* Check status during boot if dump supported, active & present*/
+        /* cmd line options during boot */
+        unsigned long reserve_bootvar;
         unsigned long phyp_dump_at_boot;
+        /* Check status during boot if dump supported, active & present*/
         unsigned long phyp_dump_configured;
         unsigned long phyp_dump_is_active;
         /* store cpu & hpte size */