[kvm-unit-tests PATCH V5 3/5] lib/powerpc: Add function to start secondary threads

[Suraj Jitindar Singh <sjitindarsingh@gmail.com>]

Add the lib/powerpc/smp.c file and associated header files as a place
to implement generic smp functionality for inclusion in tests.

Add functions start_all_cpus(), start_cpu() and start_thread() to start
all stopped threads of all cpus, all stopped threads of a single cpu or a
single stopped thread of a guest at a given execution location,
respectively.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>

---

Change Log:

V2 -> V3:
	- start_thread now returns int to reflect error, success or failure to
	  start thread
	- start_cpu returns number of threads on cpu and number successfully
	  started
	- start_all_cpus checks if number of threads started == total number of
	  threads - 1
V3 -> V4:
	- Style changes
V4 -> V5:
	- Cosmetic changes
---
 lib/powerpc/asm/smp.h   |  22 +++++++++++
 lib/powerpc/smp.c       | 103 ++++++++++++++++++++++++++++++++++++++++++++++++
 lib/ppc64/asm/smp.h     |   1 +
 powerpc/Makefile.common |   1 +
 4 files changed, 127 insertions(+)
 create mode 100644 lib/powerpc/asm/smp.h
 create mode 100644 lib/powerpc/smp.c
 create mode 100644 lib/ppc64/asm/smp.h

diff --git a/lib/powerpc/asm/smp.h b/lib/powerpc/asm/smp.h
new file mode 100644
index 0000000..21940b4
--- /dev/null
+++ b/lib/powerpc/asm/smp.h
@@ -0,0 +1,22 @@
+#ifndef _ASMPOWERPC_SMP_H_
+#define _ASMPOWERPC_SMP_H_
+
+#include <libcflat.h>
+
+extern int nr_threads;
+
+struct start_threads {
+	int nr_threads;
+	int nr_started;
+};
+
+typedef void (*secondary_entry_fn)(void);
+
+extern void halt(void);
+
+extern int start_thread(int cpu_id, secondary_entry_fn entry, uint32_t r3);
+extern struct start_threads start_cpu(int cpu_node, secondary_entry_fn entry,
+				      uint32_t r3);
+extern bool start_all_cpus(secondary_entry_fn entry, uint32_t r3);
+
+#endif /* _ASMPOWERPC_SMP_H_ */
diff --git a/lib/powerpc/smp.c b/lib/powerpc/smp.c
new file mode 100644
index 0000000..946ad26
--- /dev/null
+++ b/lib/powerpc/smp.c
@@ -0,0 +1,103 @@
+/*
+ * Secondary cpu support
+ *
+ * Copyright 2016 Suraj Jitindar Singh, IBM.
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+
+#include <devicetree.h>
+#include <asm/setup.h>
+#include <asm/rtas.h>
+#include <asm/smp.h>
+
+int nr_threads;
+
+struct secondary_entry_data {
+	secondary_entry_fn entry;
+	uint64_t r3;
+	int nr_started;
+};
+
+/*
+ * Start stopped thread cpu_id at entry
+ * Returns:	<0 on failure to start stopped cpu
+ *		0  on success
+ *		>0 on cpu not in stopped state
+ */
+int start_thread(int cpu_id, secondary_entry_fn entry, uint32_t r3)
+{
+	int query_token, start_token, outputs[1], ret;
+
+	query_token = rtas_token("query-cpu-stopped-state");
+	start_token = rtas_token("start-cpu");
+	assert(query_token != RTAS_UNKNOWN_SERVICE &&
+		start_token != RTAS_UNKNOWN_SERVICE);
+
+	ret = rtas_call(query_token, 1, 2, outputs, cpu_id);
+	if (ret) {
+		printf("query-cpu-stopped-state failed for cpu %d\n", cpu_id);
+	} else if (!outputs[0]) { /* cpu in stopped state */
+		ret = rtas_call(start_token, 3, 1, NULL, cpu_id, entry, r3);
+		if (ret)
+			printf("failed to start cpu %d\n", cpu_id);
+	} else { /* cpu not in stopped state */
+		ret = outputs[0];
+	}
+
+	return ret;
+}
+
+/*
+ * Start all stopped threads (vcpus) on cpu_node
+ * Returns: Number of stopped cpus which were successfully started
+ */
+struct start_threads start_cpu(int cpu_node, secondary_entry_fn entry,
+			       uint32_t r3)
+{
+	int len, i, nr_threads, nr_started = 0;
+	const struct fdt_property *prop;
+	u32 *threads;
+
+	/* Get the id array of threads on this cpu_node */
+	prop = fdt_get_property(dt_fdt(), cpu_node,
+				"ibm,ppc-interrupt-server#s", &len);
+	assert(prop);
+
+	nr_threads = len >> 2; /* Divide by 4 since 4 bytes per thread */
+	threads = (u32 *)prop->data; /* Array of valid ids */
+
+	for (i = 0; i < nr_threads; i++) {
+		if (!start_thread(fdt32_to_cpu(threads[i]), entry, r3))
+			nr_started++;
+	}
+
+	return (struct start_threads) { nr_threads, nr_started };
+}
+
+static void start_each_secondary(int fdtnode, u32 regval __unused, void *info)
+{
+	struct secondary_entry_data *datap = info;
+	struct start_threads ret = start_cpu(fdtnode, datap->entry, datap->r3);
+
+	nr_threads += ret.nr_threads;
+	datap->nr_started += ret.nr_started;
+}
+
+/*
+ * Start all stopped cpus on the guest at entry with register 3 set to r3
+ * We expect that we come in with only one thread currently started
+ * Returns:	TRUE on success
+ *		FALSE on failure
+ */
+bool start_all_cpus(secondary_entry_fn entry, uint32_t r3)
+{
+	struct secondary_entry_data data = { entry, r3,	0 };
+	int ret;
+
+	ret = dt_for_each_cpu_node(start_each_secondary, &data);
+	assert(ret == 0);
+
+	/* We expect that we come in with one thread already started */
+	return data.nr_started == nr_threads - 1;
+}
diff --git a/lib/ppc64/asm/smp.h b/lib/ppc64/asm/smp.h
new file mode 100644
index 0000000..67ced75
--- /dev/null
+++ b/lib/ppc64/asm/smp.h
@@ -0,0 +1 @@
+#include "../../powerpc/asm/smp.h"
diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common
index 404194b..677030a 100644
--- a/powerpc/Makefile.common
+++ b/powerpc/Makefile.common
@@ -37,6 +37,7 @@ cflatobjs += lib/powerpc/setup.o
 cflatobjs += lib/powerpc/rtas.o
 cflatobjs += lib/powerpc/processor.o
 cflatobjs += lib/powerpc/handlers.o
+cflatobjs += lib/powerpc/smp.o
 
 FLATLIBS = $(libcflat) $(LIBFDT_archive)
 %.elf: CFLAGS += $(arch_CFLAGS)
-- 
2.5.5