[kvm-unit-tests PATCH V2 3/4] 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>
---
 lib/powerpc/asm/smp.h   |  15 +++++++
 lib/powerpc/smp.c       | 115 ++++++++++++++++++++++++++++++++++++++++++++++++
 lib/ppc64/asm/smp.h     |   1 +
 powerpc/Makefile.common |   1 +
 4 files changed, 132 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..a4f3e7f
--- /dev/null
+++ b/lib/powerpc/asm/smp.h
@@ -0,0 +1,15 @@
+#ifndef _ASMPOWERPC_SMP_H_
+#define _ASMPOWERPC_SMP_H_
+
+#include <libcflat.h>
+#include <stdint.h>
+
+typedef void (*secondary_entry_fn)(void);
+
+extern void halt(void);
+
+bool start_thread(int cpu_id, secondary_entry_fn entry, uint32_t r3);
+bool start_cpu(int cpu_node, secondary_entry_fn entry, uint32_t r3);
+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..8968907
--- /dev/null
+++ b/lib/powerpc/smp.c
@@ -0,0 +1,115 @@
+/*
+ * Secondary cpu support
+ *
+ * Copyright 2016 Suraj Jitindar Singh, IBM.
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+
+#include <stdint.h>
+#include <libfdt/libfdt.h>
+#include <libfdt/fdt.h>
+#include <devicetree.h>
+#include <libcflat.h>
+#include <string.h>
+#include <asm/rtas.h>
+#include <asm/smp.h>
+
+struct secondary_entry_data {
+	secondary_entry_fn entry;
+	uint64_t r3;
+	bool init_failed;
+};
+
+/*
+ * Start stopped thread cpu_id at entry
+ * Returns:	1 on success or cpu not in stopped state
+ *		0 on failure to start stopped cpu
+ *
+ * Note: This function returns 1 on success in starting a stopped cpu or if the
+ *	 given cpu was not in the stopped state. Thus this can be called on a
+ *	 list of cpus and all the stopped ones will be started while false
+ *	 won't be returned if some cpus in that list were already running. Thus
+ *	 the user should check that cpus passed to this function are already in
+ *	 the stopped state if they want to guarantee that a return value of
+ *	 true corresponds to the given cpu now executing at entry. This
+ *	 function checks again however as calling cpu-start on a not stopped
+ *	 cpu results in undefined behaviour.
+ */
+bool 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);
+		return false;
+	}
+
+	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);
+			return false;
+		}
+	}
+
+	return true;
+}
+
+/*
+ * Start all stopped threads (vcpus) on cpu_node
+ * Returns:	1 on success
+ *		0 on failure
+ */
+bool start_cpu(int cpu_node, secondary_entry_fn entry, uint32_t r3)
+{
+	const struct fdt_property *prop;
+	int len, nr_cpu, cpu;
+	u32 *cpus;
+	bool ret = true;
+
+	/* 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_cpu = len >> 2; /* Divide by 4 since 4 bytes per cpu */
+	cpus = (u32 *)prop->data; /* Array of valid cpu numbers */
+
+	for (cpu = 0; cpu < nr_cpu && ret; cpu++)
+		ret = start_thread(fdt32_to_cpu(cpus[cpu]), entry, r3);
+
+	return ret;
+}
+
+static void start_each_secondary(int fdtnode, u32 regval __unused, void *info)
+{
+	struct secondary_entry_data *datap = info;
+
+	datap->init_failed |= !start_cpu(fdtnode, datap->entry, datap->r3);
+}
+
+/*
+ * Start all stopped cpus on the guest at entry with register 3 set to r3
+ * Returns:	1 on success
+ *		0 on failure
+ */
+bool start_all_cpus(secondary_entry_fn entry, uint32_t r3)
+{
+	struct secondary_entry_data data = {
+		entry,
+		r3,
+		false
+	};
+	int ret;
+
+	ret = dt_for_each_cpu_node(&start_each_secondary, (void *) &data);
+
+	return !(ret || data.init_failed);
+}
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