summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/mem_detect.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/s390/kernel/mem_detect.c')
-rw-r--r--arch/s390/kernel/mem_detect.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/arch/s390/kernel/mem_detect.c b/arch/s390/kernel/mem_detect.c
new file mode 100644
index 00000000000..18ed7abe16c
--- /dev/null
+++ b/arch/s390/kernel/mem_detect.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright IBM Corp. 2008
+ * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <asm/ipl.h>
+#include <asm/sclp.h>
+#include <asm/setup.h>
+
+static int memory_fast_detect(struct mem_chunk *chunk)
+{
+ unsigned long val0 = 0;
+ unsigned long val1 = 0xc;
+ int rc = -EOPNOTSUPP;
+
+ if (ipl_flags & IPL_NSS_VALID)
+ return -EOPNOTSUPP;
+ asm volatile(
+ " diag %1,%2,0x260\n"
+ "0: lhi %0,0\n"
+ "1:\n"
+ EX_TABLE(0b,1b)
+ : "+d" (rc), "+d" (val0), "+d" (val1) : : "cc");
+
+ if (rc || val0 != val1)
+ return -EOPNOTSUPP;
+ chunk->size = val0 + 1;
+ return 0;
+}
+
+static inline int tprot(unsigned long addr)
+{
+ int rc = -EFAULT;
+
+ asm volatile(
+ " tprot 0(%1),0\n"
+ "0: ipm %0\n"
+ " srl %0,28\n"
+ "1:\n"
+ EX_TABLE(0b,1b)
+ : "+d" (rc) : "a" (addr) : "cc");
+ return rc;
+}
+
+#define ADDR2G (1ULL << 31)
+
+static void find_memory_chunks(struct mem_chunk chunk[])
+{
+ unsigned long long memsize, rnmax, rzm;
+ unsigned long addr = 0, size;
+ int i = 0, type;
+
+ rzm = sclp_get_rzm();
+ rnmax = sclp_get_rnmax();
+ memsize = rzm * rnmax;
+ if (!rzm)
+ rzm = 1ULL << 17;
+ if (sizeof(long) == 4) {
+ rzm = min(ADDR2G, rzm);
+ memsize = memsize ? min(ADDR2G, memsize) : ADDR2G;
+ }
+ do {
+ size = 0;
+ type = tprot(addr);
+ do {
+ size += rzm;
+ if (memsize && addr + size >= memsize)
+ break;
+ } while (type == tprot(addr + size));
+ if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
+ chunk[i].addr = addr;
+ chunk[i].size = size;
+ chunk[i].type = type;
+ i++;
+ }
+ addr += size;
+ } while (addr < memsize && i < MEMORY_CHUNKS);
+}
+
+void detect_memory_layout(struct mem_chunk chunk[])
+{
+ unsigned long flags, cr0;
+
+ memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));
+ if (memory_fast_detect(&chunk[0]) == 0)
+ return;
+ /* Disable IRQs, DAT and low address protection so tprot does the
+ * right thing and we don't get scheduled away with low address
+ * protection disabled.
+ */
+ flags = __raw_local_irq_stnsm(0xf8);
+ __ctl_store(cr0, 0, 0);
+ __ctl_clear_bit(0, 28);
+ find_memory_chunks(chunk);
+ __ctl_load(cr0, 0, 0);
+ __raw_local_irq_ssm(flags);
+}
+EXPORT_SYMBOL(detect_memory_layout);