gpu: nvgpu: unit: fault injection for POSIX build

This adds a fault injection module to the POSIX build that can be added
to modules (for example k*alloc) then exercised in unit tests. The unit
tests can then verify that the driver units handle errors from the
modules.

JIRA NVGPU-1235

Change-Id: I9d9e443608e3d2026e165a62f7a7f011df96fd54
Signed-off-by: Philip Elcan <pelcan@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1927455
GVS: Gerrit_Virtual_Submit
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/Makefile.sources

@@ -44,6 +44,7 @@ srcs :=	os/posix/nvgpu.c \
 	os/posix/nvlink.c \
 	os/posix/lock.c \
 	os/posix/stubs.c \
+	os/posix/posix-fault-injection.c \
 	common/mm/nvgpu_allocator.c \
 	common/mm/bitmap_allocator.c \
 	common/mm/buddy_allocator.c \

drivers/gpu/nvgpu/include/nvgpu/posix/posix-fault-injection.h

@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef NVGPU_POSIX_FAULT_INJECTION_H
+#define NVGPU_POSIX_FAULT_INJECTION_H
+
+struct nvgpu_posix_fault_inj {
+	bool enabled;
+	unsigned int counter;
+};
+
+/**
+ * nvgpu_posix_init_fault_injection - Initialize the fault injection object
+ * to be used by a module that will report errors.
+ *
+ * @fi - pointer to the fault_inj object to initialize
+ */
+void nvgpu_posix_init_fault_injection(struct nvgpu_posix_fault_inj *fi);
+
+
+/**
+ * nvgpu_posix_enable_fault_injection - Enable/Disable fault injection for the
+ *                                      object after @number calls to the
+ *                                      module. This depends on
+ *                                      nvgpu_posix_fault_injection_handle_call
+ *                                      being called by each function in the
+ *                                      module that can fault. Only routines
+ *                                      that can fault will decrement the
+ *                                      delay count.
+ *
+ * @fi - pointer to the fault_inj object.
+ * @enable - true to enable.  false to disable.
+ * @number - After <number> of calls to kmem alloc or cache routines, enable or
+ *           disable fault injection. Use 0 to enable/disable immediately.
+ */
+void nvgpu_posix_enable_fault_injection(struct nvgpu_posix_fault_inj *fi,
+					bool enable, unsigned int number);
+
+
+/**
+ * nvgpu_posix_is_fault_injection_triggered - Query if fault injection is
+ *                                            currently enabled for the @fi
+ *                                            object.
+ *
+ * @fi - pointer to the fault_inj object
+ *
+ * Returns true if fault injections are enabled.
+ */
+bool nvgpu_posix_is_fault_injection_triggered(struct nvgpu_posix_fault_inj *fi);
+
+/**
+ * nvgpu_posix_fault_injection_handle_call - Called by module functions to
+ *                                           track enabling or disabling fault
+ *                                           injections. Returns true if the
+ *                                           module should return an error.
+ *
+ * @fi - pointer to the fault_inj object
+ *
+ * Returns true if the module should return an error.
+ */
+bool nvgpu_posix_fault_injection_handle_call(struct nvgpu_posix_fault_inj *fi);
+
+#endif /* NVGPU_POSIX_FAULT_INJECTION_H */

drivers/gpu/nvgpu/os/posix/posix-fault-injection.c

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <nvgpu/posix/posix-fault-injection.h>
+
+void nvgpu_posix_init_fault_injection(struct nvgpu_posix_fault_inj *fi)
+{
+	fi->enabled = false;
+	fi->counter = 0U;
+}
+
+void nvgpu_posix_enable_fault_injection(struct nvgpu_posix_fault_inj *fi,
+					bool enable, unsigned int number)
+{
+	if (number == 0U) {
+		fi->enabled = enable;
+		fi->counter = 0U;
+	} else {
+		fi->enabled = !enable;
+		fi->counter = number;
+	}
+}
+
+bool nvgpu_posix_is_fault_injection_triggered(struct nvgpu_posix_fault_inj *fi)
+{
+	return fi->enabled;
+}
+
+/*
+ * Return status of fault injection.
+ * Decrement fault injection count for each call.
+ */
+bool nvgpu_posix_fault_injection_handle_call(struct nvgpu_posix_fault_inj *fi)
+{
+	bool current_state = fi->enabled;
+
+	if (fi->counter > 0U) {
+		fi->counter--;
+		if (fi->counter == 0U) {
+			/* for next time */
+			fi->enabled = !fi->enabled;
+		}
+	}
+
+	return current_state;
+}