5 files changed, 23 insertions, 7 deletions

diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index 270fcd0fbf1a..2765e40d8739 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -46,7 +46,7 @@ extern struct mem_chunk memory_chunk[];
 extern int memory_end_set;
 extern unsigned long memory_end;
 
-void detect_memory_layout(struct mem_chunk chunk[]);
+void detect_memory_layout(struct mem_chunk chunk[], unsigned long maxsize);
 void create_mem_hole(struct mem_chunk memory_chunk[], unsigned long addr,
                      unsigned long size, int type);
 
diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index fb8d8781a011..30b7f63aa4e8 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -88,7 +88,7 @@ static struct mem_chunk *get_memory_layout(void)
         struct mem_chunk *chunk_array;
 
         chunk_array = kzalloc_panic(MEMORY_CHUNKS * sizeof(struct mem_chunk));
-        detect_memory_layout(chunk_array);
+        detect_memory_layout(chunk_array, 0);
         create_mem_hole(chunk_array, OLDMEM_BASE, OLDMEM_SIZE, CHUNK_CRASHK);
         return chunk_array;
 }
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index bda011e2f8ae..dc8770d7173c 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -482,7 +482,6 @@ void __init startup_init(void)
         detect_machine_facilities();
         setup_topology();
         sclp_facilities_detect();
-        detect_memory_layout(memory_chunk);
 #ifdef CONFIG_DYNAMIC_FTRACE
         S390_lowcore.ftrace_func = (unsigned long)ftrace_caller;
 #endif
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 555f1895972e..cdd9ec0a6fc0 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -1066,7 +1066,7 @@ void __init setup_arch(char **cmdline_p)
                 memcpy(&uaccess, &uaccess_std, sizeof(uaccess));
 
         parse_early_param();
-
+        detect_memory_layout(memory_chunk, memory_end);
         os_info_init();
         setup_ipl();
         reserve_oldmem();
diff --git a/arch/s390/mm/mem_detect.c b/arch/s390/mm/mem_detect.c
index 854c08448de1..ec00576bf8d5 100644
--- a/arch/s390/mm/mem_detect.c
+++ b/arch/s390/mm/mem_detect.c
@@ -12,7 +12,7 @@
 
 #define ADDR2G (1ULL << 31)
 
-static void find_memory_chunks(struct mem_chunk chunk[])
+static void find_memory_chunks(struct mem_chunk chunk[], unsigned long maxsize)
 {
         unsigned long long memsize, rnmax, rzm;
         unsigned long addr = 0, size;
@@ -27,6 +27,8 @@ static void find_memory_chunks(struct mem_chunk chunk[])
                 rzm = min(ADDR2G, rzm);
                 memsize = memsize ? min(ADDR2G, memsize) : ADDR2G;
         }
+        if (maxsize)
+                memsize = memsize ? min((unsigned long)memsize, maxsize) : maxsize;
         do {
                 size = 0;
                 type = tprot(addr);
@@ -36,6 +38,8 @@ static void find_memory_chunks(struct mem_chunk chunk[])
                                 break;
                 } while (type == tprot(addr + size));
                 if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
+                        if (memsize && (addr + size > memsize))
+                                size = memsize - addr;
                         chunk[i].addr = addr;
                         chunk[i].size = size;
                         chunk[i].type = type;
@@ -45,7 +49,20 @@ static void find_memory_chunks(struct mem_chunk chunk[])
         } while (addr < memsize && i < MEMORY_CHUNKS);
 }
 
-void detect_memory_layout(struct mem_chunk chunk[])
+/**
+ * detect_memory_layout - fill mem_chunk array with memory layout data
+ * @chunk: mem_chunk array to be filled
+ * @maxsize: maximum address where memory detection should stop
+ *
+ * Fills the passed in memory chunk array with the memory layout of the
+ * machine. The array must have a size of at least MEMORY_CHUNKS and will
+ * be fully initialized afterwards.
+ * If the maxsize paramater has a value > 0 memory detection will stop at
+ * that address. It is guaranteed that all chunks have an ending address
+ * that is smaller than maxsize.
+ * If maxsize is 0 all memory will be detected.
+ */
+void detect_memory_layout(struct mem_chunk chunk[], unsigned long maxsize)
 {
         unsigned long flags, flags_dat, cr0;
 
@@ -69,7 +86,7 @@ void detect_memory_layout(struct mem_chunk chunk[])
         }
         __ctl_store(cr0, 0, 0);
         __ctl_clear_bit(0, 28);
-        find_memory_chunks(chunk);
+        find_memory_chunks(chunk, maxsize);
         __ctl_load(cr0, 0, 0);
 out:
         __arch_local_irq_ssm(flags_dat);