Unfortunately, there is no easy way to simply read out the amount
of installed memory. We have to probe (via TEST PROTECTION) for installed
memory in a given range.
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
lib/s390x/asm/arch_def.h | 12 +++++++++++
lib/s390x/io.c | 1 +
lib/s390x/sclp.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
lib/s390x/sclp.h | 1 +
s390x/Makefile | 1 +
5 files changed, 67 insertions(+)
create mode 100644 lib/s390x/sclp.c
diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 72e5c60..ae27ab2 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -151,4 +151,16 @@ struct cpuid {
uint64_t reserved : 15;
};
+static inline int tprot(unsigned long addr)
+{
+ int cc;
+
+ asm volatile(
+ " tprot %1,0\n"
+ " ipm %0\n"
+ " srl %0,28\n"
+ : "=d" (cc) : "Q" (addr) : "cc");
+ return cc;
+}
+
#endif
diff --git a/lib/s390x/io.c b/lib/s390x/io.c
index 3121a78..eb4d171 100644
--- a/lib/s390x/io.c
+++ b/lib/s390x/io.c
@@ -43,6 +43,7 @@ void setup()
setup_args_progname(ipl_args);
setup_facilities();
sclp_ascii_setup();
+ sclp_memory_setup();
}
void exit(int code)
diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c
new file mode 100644
index 0000000..ee56820
--- /dev/null
+++ b/lib/s390x/sclp.c
@@ -0,0 +1,52 @@
+/*
+ * s390x SCLP driver
+ *
+ * Copyright (c) 2017 Red Hat Inc
+ *
+ * Authors:
+ * David Hildenbrand <david@xxxxxxxxxx>
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Library General Public License version 2.
+ */
+
+#include <libcflat.h>
+#include <asm/page.h>
+#include <asm/arch_def.h>
+#include "sclp.h"
+
+static char _sccb[PAGE_SIZE] __attribute__((__aligned__(4096)));
+static uint64_t storage_increment_size;
+static uint64_t max_ram_size;
+static uint64_t ram_size;
+
+void sclp_memory_setup(void)
+{
+ ReadInfo *ri = (void *)_sccb;
+ uint64_t rnmax, rnsize;
+
+ ri->h.length = SCCB_SIZE;
+ sclp_service_call(SCLP_CMDW_READ_SCP_INFO_FORCED, ri);
+
+ /* calculate the storage increment size */
+ rnsize = ri->rnsize;
+ if (!rnsize) {
+ rnsize = ri->rnsize2;
+ }
+ storage_increment_size = rnsize << 20;
+
+ /* calculate the maximum memory size */
+ rnmax = ri->rnmax;
+ if (!rnmax) {
+ rnmax = ri->rnmax2;
+ }
+ max_ram_size = rnmax * storage_increment_size;
+
+ /* lowcore is always accessible, so the first increment is accessible */
+ ram_size = storage_increment_size;
+
+ /* probe for r/w memory up to max memory size */
+ while (ram_size < max_ram_size &&
+ tprot(ram_size + storage_increment_size - 1))
+ ram_size += storage_increment_size;
+}
diff --git a/lib/s390x/sclp.h b/lib/s390x/sclp.h
index ec9dcb1..94ff74b 100644
--- a/lib/s390x/sclp.h
+++ b/lib/s390x/sclp.h
@@ -210,5 +210,6 @@ typedef struct ReadEventData {
void sclp_ascii_setup(void);
void sclp_print(const char *str);
int sclp_service_call(unsigned int command, void *sccb);
+void sclp_memory_setup(void);
#endif /* SCLP_H */
diff --git a/s390x/Makefile b/s390x/Makefile
index f585faf..ce63dd1 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -24,6 +24,7 @@ cflatobjs += lib/util.o
cflatobjs += lib/alloc_phys.o
cflatobjs += lib/s390x/io.o
cflatobjs += lib/s390x/stack.o
+cflatobjs += lib/s390x/sclp.o
cflatobjs += lib/s390x/sclp-ascii.o
cflatobjs += lib/s390x/interrupt.o
--
2.14.3
