[S390] Memory detection fixes.

VMALLOC_END on 31bit should be 0x8000000UL instead of 0x7fffffffL.
The page mask which is used to make sure memory_end is on 4MB/2MB
boundary is wrong and not needed. Therefore remove it.
Make sure a vmalloc area does also exist and work on (future)
machines with 4TB and more memory.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 32 insertions, 24 deletions

diff --git a/arch/s390/kernel/head31.S b/arch/s390/kernel/head31.S
index 9817c327aab1..4388b3309e0c 100644
--- a/arch/s390/kernel/head31.S
+++ b/arch/s390/kernel/head31.S
@@ -177,8 +177,6 @@ startup_continue:
         st      %r0,4(%r3)              # store size of chunk
         st      %r6,8(%r3)              # store type of chunk
         la      %r3,12(%r3)
-        l       %r4,.Lmemsize-.LPG1(%r13)        # address of variable memory_size
-        st      %r5,0(%r4)              # store last end to memory size
         ahi     %r10,-1                 # update chunk number
 .Lchkloop:
         lr      %r6,%r7                 # set access code to last cc
@@ -293,7 +291,6 @@ startup_continue:
 .Lpcmvpg:.long  0x00080000,0x80000000 + .Lchkmvpg
 .Lpcidte:.long  0x00080000,0x80000000 + .Lchkidte
 .Lpcdiag9c:.long 0x00080000,0x80000000 + .Lchkdiag9c
-.Lmemsize:.long memory_size
 .Lmchunk:.long  memory_chunk
 .Lmflags:.long  machine_flags
 .Lbss_bgn:  .long __bss_start
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index cc6dbc57eb90..c526279e1123 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -81,8 +81,6 @@ startup_continue:
         aghi    %r1,1                   # size is one more than end
         larl    %r2,memory_chunk
         stg     %r1,8(%r2)              # store size of chunk
-        larl    %r2,memory_size
-        stg     %r1,0(%r2)              # set memory size
         j       .Ldonemem
 
 .Lslowmemdetect:
@@ -188,8 +186,6 @@ startup_continue:
         stg     %r0,8(%r3)              # store size of chunk
         st      %r6,20(%r3)             # store type of chunk
         la      %r3,24(%r3)
-        larl    %r8,memory_size
-        stg     %r5,0(%r8)              # store memory size
         ahi     %r10,-1                 # update chunk number
 .Lchkloop:
         lr      %r6,%r7                 # set access code to last cc
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index b1a8ad967f9c..b928fecdc743 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -62,7 +62,6 @@ EXPORT_SYMBOL_GPL(uaccess);
 unsigned int console_mode = 0;
 unsigned int console_devno = -1;
 unsigned int console_irq = -1;
-unsigned long memory_size = 0;
 unsigned long machine_flags = 0;
 
 struct mem_chunk memory_chunk[MEMORY_CHUNKS];
@@ -486,6 +485,37 @@ setup_resources(void)
         }
 }
 
+static void __init setup_memory_end(void)
+{
+        unsigned long real_size, memory_size;
+        unsigned long max_mem, max_phys;
+        int i;
+
+        memory_size = real_size = 0;
+        max_phys = VMALLOC_END - VMALLOC_MIN_SIZE;
+        memory_end &= PAGE_MASK;
+
+        max_mem = memory_end ? min(max_phys, memory_end) : max_phys;
+
+        for (i = 0; i < MEMORY_CHUNKS; i++) {
+                struct mem_chunk *chunk = &memory_chunk[i];
+
+                real_size = max(real_size, chunk->addr + chunk->size);
+                if (chunk->addr >= max_mem) {
+                        memset(chunk, 0, sizeof(*chunk));
+                        continue;
+                }
+                if (chunk->addr + chunk->size > max_mem)
+                        chunk->size = max_mem - chunk->addr;
+                memory_size = max(memory_size, chunk->addr + chunk->size);
+        }
+        if (!memory_end)
+                memory_end = memory_size;
+        if (real_size > memory_end)
+                printk("More memory detected than supported. Unused: %luk\n",
+                       (real_size - memory_end) >> 10);
+}
+
 static void __init
 setup_memory(void)
 {
@@ -642,8 +672,6 @@ setup_arch(char **cmdline_p)
         init_mm.end_data = (unsigned long) &_edata;
         init_mm.brk = (unsigned long) &_end;
 
-        memory_end = memory_size;
-
         if (MACHINE_HAS_MVCOS)
                 memcpy(&uaccess, &uaccess_mvcos, sizeof(uaccess));
         else
@@ -651,20 +679,7 @@ setup_arch(char **cmdline_p)
 
         parse_early_param();
 
-#ifndef CONFIG_64BIT
-        memory_end &= ~0x400000UL;
-
-        /*
-         * We need some free virtual space to be able to do vmalloc.
-         * On a machine with 2GB memory we make sure that we have at
-         * least 128 MB free space for vmalloc.
-         */
-        if (memory_end > 1920*1024*1024)
-                memory_end = 1920*1024*1024;
-#else /* CONFIG_64BIT */
-        memory_end &= ~0x200000UL;
-#endif /* CONFIG_64BIT */
-
+        setup_memory_end();
         setup_memory();
         setup_resources();
         setup_lowcore();