[PATCH] Fio's initial RTEMS port

[dev.madaari@gmail.com]

From: Udit kumar agarwal <dev.madaari@gmail.com>

- Add rtems-specific config files.
- Constructors/Destructors being not supported by RTEMS, should be
  invoked as normal routines.
- Add documentation for RTEMS
- Update Makefile, os.h for RTEMS
---
 Makefile                  |  11 ++-
 README                    |  29 ++++++
 cgroup.c                  |   7 +-
 client.c                  |   7 +-
 configure                 |   2 +
 crc/xxhash.h              |  15 ++++
 engines/cpu.c             |  14 ++-
 engines/falloc.c          |   7 +-
 engines/filecreate.c      |  14 ++-
 engines/ftruncate.c       |  14 ++-
 engines/glusterfs_async.c |   7 +-
 engines/glusterfs_sync.c  |  14 ++-
 engines/mmap.c            |  14 ++-
 engines/net.c             |  14 ++-
 engines/null.c            |  14 ++-
 engines/sync.c            |  14 ++-
 fio.c                     |   3 +
 fio.h                     |  10 ++-
 fio_sem.c                 |   6 ++
 gettime.c                 |  14 ++-
 init.c                    |  26 +++++-
 ioengines.c               |   2 +
 lib/prio_tree.c           |   7 +-
 options.c                 |   6 +-
 os/os-rtems.h             |  70 +++++++++++++++
 os/os.h                   |   3 +
 os/rtems/rtems-fio-wrap.h |  54 +++++++++++
 os/rtems/rtems-init.c     | 225 ++++++++++++++++++++++++++++++++++++++++++++++
 oslib/inet_aton.c         |   3 +-
 profiles/act.c            |  14 ++-
 profiles/tiobench.c       |  14 ++-
 smalloc.c                 |  11 ++-
 stat.c                    |   6 ++
 t/arch.c                  |   2 +
 34 files changed, 638 insertions(+), 35 deletions(-)
 create mode 100644 os/os-rtems.h
 create mode 100644 os/rtems/rtems-fio-wrap.h
 create mode 100644 os/rtems/rtems-init.c

diff --git a/Makefile b/Makefile
index 20d3ec1..e93f964 100644
--- a/Makefile
+++ b/Makefile
@@ -194,11 +194,20 @@ ifneq (,$(findstring CYGWIN,$(CONFIG_TARGET_OS)))
   LIBS	 += -lpthread -lpsapi -lws2_32
   CFLAGS += -DPSAPI_VERSION=1 -Ios/windows/posix/include -Wno-format -static
 endif
+ifeq ($(CONFIG_TARGET_OS), RTEMS)
+  LDFLAGS += -B $(TOOL_PATH_PREFIX)/arm-rtems5/beagleboneblack/lib -specs bsp_specs -qrtems -Wl,--gc-sections
+  LIBS	  += -Wl,-Bstatic -L. -lbsd -Wl,-Bdynamic -lm -lz
+  CFLAGS  += -I $(TOOL_PATH_PREFIX)/arm-rtems5/beagleboneblack/lib/include -ffunction-sections -fdata-sections -g -mcpu=cortex-a8 -fno-strict-aliasing -ffreestanding -fno-common -w -DHAVE_RTEMS_SCORE_CPUOPTS_H=1 -DHAVE_RTEMS_H=1 -DHAVE_DLFCN_H=1 -DHAVE_RTEMS_PCI_H=1 -DHAVE_RTEMS_RTEMS_DEBUGGER_H=1
+endif
 
 OBJS := $(SOURCE:.c=.o)
 
 FIO_OBJS = $(OBJS) fio.o
 
+ifeq ($(CONFIG_TARGET_OS), RTEMS)
+  FIO_OBJS +=  os/rtems/rtems-init.o
+endif
+
 GFIO_OBJS = $(OBJS) gfio.o graph.o tickmarks.o ghelpers.o goptions.o gerror.o \
 			gclient.o gcompat.o cairo_text_helpers.o printing.o
 
@@ -462,7 +471,7 @@ t/time-test: $(T_TT_OBJS)
 	$(QUIET_LINK)$(CC) $(LDFLAGS) $(CFLAGS) -o $@ $(T_TT_OBJS) $(LIBS)
 
 clean: FORCE
-	@rm -f .depend $(FIO_OBJS) $(GFIO_OBJS) $(OBJS) $(T_OBJS) $(PROGS) $(T_PROGS) $(T_TEST_PROGS) core.* core gfio FIO-VERSION-FILE *.[do] lib/*.d oslib/*.[do] crc/*.d engines/*.[do] profiles/*.[do] t/*.[do] config-host.mak config-host.h y.tab.[ch] lex.yy.c exp/*.[do] lexer.h
+	@rm -f .depend $(FIO_OBJS) $(GFIO_OBJS) $(OBJS) $(T_OBJS) $(PROGS) $(T_PROGS) $(T_TEST_PROGS) core.* core gfio FIO-VERSION-FILE *.[do] lib/*.d oslib/*.[do] crc/*.d engines/*.[do] profiles/*.[do] t/*.[do] config-host.mak config-host.h y.tab.[ch] lex.yy.c exp/*.[do] lexer.h os/rtems/*.[do]
 	@rm -rf  doc/output
 
 distclean: clean FORCE
diff --git a/README b/README
index 38022bb..cbca933 100644
--- a/README
+++ b/README
@@ -192,6 +192,35 @@ https://github.com/mintty/mintty/issues/56 and
 https://github.com/mintty/mintty/wiki/Tips#inputoutput-interaction-with-alien-programs
 for details).
 
+RTEMS
+~~~~~~~
+
+For RTEMS Toolchain generation::
+
+Toolchain, required for cross-compiling fio for desired architecture
+(like arm in this example) can be generated by using RTEMS Source Builder(RSB).
+
+Please note that fio's build for RTEMS has been tested with RSB version 5(commit id:
+25f4db09c85a52fb1640a29f9bdc2de8c2768988), and it may not work with older versions.
+
+Moreover, For enabling POSIX support(required by fio), build the BSP using RTEMS v5 with
+--enable-posix option. After that, if needed(like for using SD card driver for BeagleBone Black)
+one may also need to build rtems-libbsd for the desired BSP.
+
+For Cross-compiling fio for RTEMS::
+
+Variable to be passed for toolchain path is TOOL_PATH_PREFIX, which in this case would be,
+
+ $ export TOOL_PATH_PREFIX=/home/uka_in/development/sandbox/5
+
+After setting up the variable, next step would be to configure and build fio as:
+
+ $ make clean
+ $ ./configure --cc=$TOOL_PATH_PREFIX/bin/arm-rtems5-gcc --disable-optimizations --extra-cflags=-O3
+ $ make CROSS_COMPILE=$TOOL_PATH_PREFIX/bin/arm-rtems5- V=1
+
+Refer to ticket #3429 https://devel.rtems.org/ticket/3429 for updates and
+drawbacks of current implementation.
 
 Documentation
 ~~~~~~~~~~~~~
diff --git a/cgroup.c b/cgroup.c
index 77e31a4..0a3d372 100644
--- a/cgroup.c
+++ b/cgroup.c
@@ -224,7 +224,12 @@ out:
 	sfree(mnt);
 }
 
-static void fio_init cgroup_init(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+cgroup_init(void)
 {
 	lock = fio_sem_init(FIO_SEM_UNLOCKED);
 	if (!lock)
diff --git a/client.c b/client.c
index 2a86ea9..cb4ef56 100644
--- a/client.c
+++ b/client.c
@@ -86,7 +86,12 @@ static void fio_client_remove_hash(struct fio_client *client)
 		flist_del_init(&client->hash_list);
 }
 
-static void fio_init fio_client_hash_init(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_client_hash_init(void)
 {
 	int i;
 
diff --git a/configure b/configure
index 9bdc7a1..53dd857 100755
--- a/configure
+++ b/configure
@@ -262,6 +262,8 @@ elif check_define __sun__ ; then
   CFLAGS="$CFLAGS -D_REENTRANT"
 elif check_define _WIN32 ; then
   targetos='CYGWIN'
+elif check_define __rtems__ ; then
+  targetos='RTEMS'
 else
   targetos=`uname -s`
 fi
diff --git a/crc/xxhash.h b/crc/xxhash.h
index 8850d20..81bf51d 100644
--- a/crc/xxhash.h
+++ b/crc/xxhash.h
@@ -107,9 +107,16 @@ XXH32() :
 // Advanced Hash Functions
 //****************************
 
+/* Unlike most desktop OS, In Newlib unsigned int and uint32_t are different */
+#ifndef __rtems__
 void*         XXH32_init   (unsigned int seed);
 XXH_errorcode XXH32_update (void* state, const void* input, int len);
 unsigned int  XXH32_digest (void* state);
+#else /* __rtems__ */
+void*         XXH32_init   (uint32_t seed);
+XXH_errorcode XXH32_update (void* state, const void* input, int len);
+uint32_t  XXH32_digest (void* state);
+#endif /* __rtems__ */
 
 /*
 These functions calculate the xxhash of an input provided in several small packets,
@@ -135,7 +142,11 @@ Memory will be freed by XXH32_digest().
 
 
 int           XXH32_sizeofState(void);
+#ifndef __rtems__
 XXH_errorcode XXH32_resetState(void* state, unsigned int seed);
+#else /* __rtems__ */
+XXH_errorcode XXH32_resetState(void* state, uint32_t seed);
+#endif /* __rtems__ */
 
 #define       XXH32_SIZEOFSTATE 48
 typedef struct { long long ll[(XXH32_SIZEOFSTATE+(sizeof(long long)-1))/sizeof(long long)]; } XXH32_stateSpace_t;
@@ -151,7 +162,11 @@ use the structure XXH32_stateSpace_t, which will ensure that memory space is lar
 */
 
 
+#ifndef __rtems__
 unsigned int XXH32_intermediateDigest (void* state);
+#else /* __rtems__ */
+uint32_t XXH32_intermediateDigest (void* state);
+#endif /* __rtems__ */
 /*
 This function does the same as XXH32_digest(), generating a 32-bit hash,
 but preserve memory context.
diff --git a/engines/cpu.c b/engines/cpu.c
index 0987250..9838af1 100644
--- a/engines/cpu.c
+++ b/engines/cpu.c
@@ -112,12 +112,22 @@ static struct ioengine_ops ioengine = {
 	.option_struct_size	= sizeof(struct cpu_options),
 };
 
-static void fio_init fio_cpuio_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_cpuio_register(void)
 {
 	register_ioengine(&ioengine);
 }
 
-static void fio_exit fio_cpuio_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+fio_cpuio_unregister(void)
 {
 	unregister_ioengine(&ioengine);
 }
diff --git a/engines/falloc.c b/engines/falloc.c
index 6382569..446638c 100644
--- a/engines/falloc.c
+++ b/engines/falloc.c
@@ -101,7 +101,12 @@ static struct ioengine_ops ioengine = {
 	.flags		= FIO_SYNCIO
 };
 
-static void fio_init fio_syncio_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_syncio_register(void)
 {
 	register_ioengine(&ioengine);
 }
diff --git a/engines/filecreate.c b/engines/filecreate.c
index 39a2950..35dc5d7 100644
--- a/engines/filecreate.c
+++ b/engines/filecreate.c
@@ -107,12 +107,22 @@ static struct ioengine_ops ioengine = {
 				FIO_NOSTATS | FIO_NOFILEHASH,
 };
 
-static void fio_init fio_filecreate_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_filecreate_register(void)
 {
 	register_ioengine(&ioengine);
 }
 
-static void fio_exit fio_filecreate_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+fio_filecreate_unregister(void)
 {
 	unregister_ioengine(&ioengine);
 }
diff --git a/engines/ftruncate.c b/engines/ftruncate.c
index c7ad038..ab616be 100644
--- a/engines/ftruncate.c
+++ b/engines/ftruncate.c
@@ -41,12 +41,22 @@ static struct ioengine_ops ioengine = {
 	.flags		= FIO_SYNCIO | FIO_FAKEIO
 };
 
-static void fio_init fio_syncio_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_syncio_register(void)
 {
 	register_ioengine(&ioengine);
 }
 
-static void fio_exit fio_syncio_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+fio_syncio_unregister(void)
 {
 	unregister_ioengine(&ioengine);
 }
diff --git a/engines/glusterfs_async.c b/engines/glusterfs_async.c
index 9e1c4bf..0f1083b 100644
--- a/engines/glusterfs_async.c
+++ b/engines/glusterfs_async.c
@@ -177,7 +177,12 @@ static struct ioengine_ops ioengine = {
 	.flags = FIO_DISKLESSIO,
 };
 
-static void fio_init fio_gf_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_gf_register(void)
 {
 	register_ioengine(&ioengine);
 }
diff --git a/engines/glusterfs_sync.c b/engines/glusterfs_sync.c
index a10e0ed..b634ce8 100644
--- a/engines/glusterfs_sync.c
+++ b/engines/glusterfs_sync.c
@@ -88,12 +88,22 @@ static struct ioengine_ops ioengine = {
 	.flags = FIO_SYNCIO | FIO_DISKLESSIO,
 };
 
-static void fio_init fio_gf_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_gf_register(void)
 {
 	register_ioengine(&ioengine);
 }
 
-static void fio_exit fio_gf_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+fio_gf_unregister(void)
 {
 	unregister_ioengine(&ioengine);
 }
diff --git a/engines/mmap.c b/engines/mmap.c
index 308b466..7ce6ebf 100644
--- a/engines/mmap.c
+++ b/engines/mmap.c
@@ -277,12 +277,22 @@ static struct ioengine_ops ioengine = {
 	.flags		= FIO_SYNCIO | FIO_NOEXTEND,
 };
 
-static void fio_init fio_mmapio_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_mmapio_register(void)
 {
 	register_ioengine(&ioengine);
 }
 
-static void fio_exit fio_mmapio_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+fio_mmapio_unregister(void)
 {
 	unregister_ioengine(&ioengine);
 }
diff --git a/engines/net.c b/engines/net.c
index ca6fb34..5222601 100644
--- a/engines/net.c
+++ b/engines/net.c
@@ -1451,7 +1451,12 @@ static int str_hostname_cb(void *data, const char *input)
 	return 0;
 }
 
-static void fio_init fio_netio_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_netio_register(void)
 {
 	register_ioengine(&ioengine_rw);
 #ifdef CONFIG_LINUX_SPLICE
@@ -1459,7 +1464,12 @@ static void fio_init fio_netio_register(void)
 #endif
 }
 
-static void fio_exit fio_netio_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+fio_netio_unregister(void)
 {
 	unregister_ioengine(&ioengine_rw);
 #ifdef CONFIG_LINUX_SPLICE
diff --git a/engines/null.c b/engines/null.c
index 4cc0102..da10d69 100644
--- a/engines/null.c
+++ b/engines/null.c
@@ -154,12 +154,22 @@ static struct ioengine_ops ioengine = {
 	.flags		= FIO_DISKLESSIO | FIO_FAKEIO,
 };
 
-static void fio_init fio_null_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_null_register(void)
 {
 	register_ioengine(&ioengine);
 }
 
-static void fio_exit fio_null_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+fio_null_unregister(void)
 {
 	unregister_ioengine(&ioengine);
 }
diff --git a/engines/sync.c b/engines/sync.c
index b3e1c9d..4b98f4d 100644
--- a/engines/sync.c
+++ b/engines/sync.c
@@ -466,7 +466,12 @@ static struct ioengine_ops ioengine_pvrw2 = {
 };
 #endif
 
-static void fio_init fio_syncio_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+fio_syncio_register(void)
 {
 	register_ioengine(&ioengine_rw);
 	register_ioengine(&ioengine_prw);
@@ -479,7 +484,12 @@ static void fio_init fio_syncio_register(void)
 #endif
 }
 
-static void fio_exit fio_syncio_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+fio_syncio_unregister(void)
 {
 	unregister_ioengine(&ioengine_rw);
 	unregister_ioengine(&ioengine_prw);
diff --git a/fio.c b/fio.c
index f19db1b..d4e0821 100644
--- a/fio.c
+++ b/fio.c
@@ -65,3 +65,6 @@ done:
 	deinitialize_fio();
 	return ret;
 }
+#ifdef __rtems__
+#include <os/rtems/rtems-fio-wrap.h>
+#endif /* __rtems__ */
diff --git a/fio.h b/fio.h
index 3ac552b..e382eb7 100644
--- a/fio.h
+++ b/fio.h
@@ -785,7 +785,11 @@ static inline void td_flags_clear(struct thread_data *td, unsigned int *flags,
 	if (!td_async_processing(td))
 		*flags &= ~value;
 	else
+#ifndef __rtems__
 		__sync_fetch_and_and(flags, ~value);
+#else /* __rtems__ */
+		atomic_fetch_and_explicit(flags, ~value, memory_order_relaxed);
+#endif /* __rtems__ */
 }
 
 static inline void td_flags_set(struct thread_data *td, unsigned int *flags,
@@ -794,7 +798,11 @@ static inline void td_flags_set(struct thread_data *td, unsigned int *flags,
 	if (!td_async_processing(td))
 		*flags |= value;
 	else
-		__sync_fetch_and_or(flags, value);
+#ifndef __rtems__
+		__sync_fetch_and_or(flags, ~value);
+#else /*__rtems__ */
+		atomic_fetch_or_explicit(flags, ~value, memory_order_relaxed);
+#endif /* __rtems__ */
 }
 
 extern const char *fio_get_arch_string(int);
diff --git a/fio_sem.c b/fio_sem.c
index 3b48061..b5bc9c2 100644
--- a/fio_sem.c
+++ b/fio_sem.c
@@ -56,9 +56,15 @@ struct fio_sem *fio_sem_init(int value)
 {
 	struct fio_sem *sem = NULL;
 
+#ifndef __rtems__
 	sem = (void *) mmap(NULL, sizeof(struct fio_sem),
 				PROT_READ | PROT_WRITE,
 				OS_MAP_ANON | MAP_SHARED, -1, 0);
+#else /* __rtems__ */
+	sem = (void *) mmap(NULL, sizeof(struct fio_sem),
+				PROT_READ | PROT_WRITE,
+				OS_MAP_ANON | MAP_PRIVATE, -1, 0);
+#endif /* __rtems__ */
 	if (sem == MAP_FAILED) {
 		perror("mmap semaphore");
 		return NULL;
diff --git a/gettime.c b/gettime.c
index c0f2638..03f11eb 100644
--- a/gettime.c
+++ b/gettime.c
@@ -94,7 +94,12 @@ static void gtod_log_caller(void *caller)
 		inc_caller(caller);
 }
 
-static void fio_exit fio_dump_gtod(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+fio_dump_gtod(void)
 {
 	unsigned long total_calls = 0;
 	int i;
@@ -115,7 +120,12 @@ static void fio_exit fio_dump_gtod(void)
 	printf("Total %lu gettimeofday\n", total_calls);
 }
 
-static void fio_init gtod_init(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+gtod_init(void)
 {
 	int i;
 
diff --git a/init.c b/init.c
index af4cc6b..d69b644 100644
--- a/init.c
+++ b/init.c
@@ -7,7 +7,6 @@
 #include <ctype.h>
 #include <string.h>
 #include <errno.h>
-#include <sys/ipc.h>
 #include <sys/types.h>
 #include <dlfcn.h>
 #ifdef CONFIG_VALGRIND_DEV
@@ -21,6 +20,10 @@
 #include <sys/shm.h>
 #endif
 
+#ifndef __rtems__
+#include <sys/ipc.h>
+#endif /* __rtems__ */
+
 #include "parse.h"
 #include "smalloc.h"
 #include "filehash.h"
@@ -31,7 +34,13 @@
 #include "filelock.h"
 #include "steadystate.h"
 
+/* RTEMS uses newlib's getopt_long_only_r() */
+#ifdef __rtems__
+#include <getopt.h>
+#else /* __rtems__ */
 #include "oslib/getopt.h"
+#endif /* __rtems__ */
+
 #include "oslib/strcasestr.h"
 
 #include "crc/test.h"
@@ -87,6 +96,10 @@ unsigned int *fio_warned = NULL;
 static char cmd_optstr[256];
 static bool did_arg;
 
+#ifdef __rtems__
+    struct getopt_data getopt_reent;
+#endif /* __rtems__ */
+
 #define FIO_CLIENT_FLAG		(1 << 16)
 
 /*
@@ -2435,13 +2448,20 @@ int parse_cmd_line(int argc, char *argv[], int client_type)
 	void *cur_client = NULL;
 	int backend = 0;
 
+#ifdef __rtems__
+    memset(&getopt_reent, 0, sizeof(getopt_data));
+#endif /* __rtems__ */
 	/*
 	 * Reset optind handling, since we may call this multiple times
 	 * for the backend.
 	 */
 	optind = 1;
-
-	while ((c = getopt_long_only(argc, argv, ostr, l_opts, &lidx)) != -1) {
+	while ((c =
+#ifdef __rtems__ /* Using Newlib's reentrant version of getopt */
+		getopt_long_only_r(argc, argv, ostr, l_opts, &lidx, &getopt_reent))!= -1) {
+#else /* __rtems__ */
+		getopt_long_only(argc, argv, ostr, l_opts, &lidx))!= -1) {
+#endif /* __rtems__ */
 		if ((c & FIO_CLIENT_FLAG) || client_flag_set(c)) {
 			parse_cmd_client(cur_client, argv[optind - 1]);
 			c &= ~FIO_CLIENT_FLAG;
diff --git a/ioengines.c b/ioengines.c
index d579682..c051ed5 100644
--- a/ioengines.c
+++ b/ioengines.c
@@ -185,6 +185,7 @@ struct ioengine_ops *load_ioengine(struct thread_data *td)
  */
 void free_ioengine(struct thread_data *td)
 {
+#ifndef __rtems__
 	dprint(FD_IO, "free ioengine %s\n", td->io_ops->name);
 
 	if (td->eo && td->io_ops->options) {
@@ -199,6 +200,7 @@ void free_ioengine(struct thread_data *td)
 	}
 
 	td->io_ops = NULL;
+#endif /* __rtems__ */
 }
 
 void close_ioengine(struct thread_data *td)
diff --git a/lib/prio_tree.c b/lib/prio_tree.c
index d8e1b89..95b55a8 100644
--- a/lib/prio_tree.c
+++ b/lib/prio_tree.c
@@ -53,7 +53,12 @@ static void get_index(const struct prio_tree_node *node,
 
 static unsigned long index_bits_to_maxindex[BITS_PER_LONG];
 
-static void fio_init prio_tree_init(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+prio_tree_init(void)
 {
 	unsigned int i;
 
diff --git a/options.c b/options.c
index a174e2c..0abb5b1 100644
--- a/options.c
+++ b/options.c
@@ -4744,7 +4744,7 @@ static char *bc_calc(char *str)
 	if ((!strchr(str, '+') && !strchr(str, '-') && !strchr(str, '*') &&
 	     !strchr(str, '/')) || strchr(str, '\''))
 		return str;
-
+#ifndef __rtems__
 	/*
 	 * Split option from value, we only need to calculate the value
 	 */
@@ -4782,6 +4782,10 @@ static char *bc_calc(char *str)
 	memcpy(buf, str, tmp - str);
 	free(str);
 	return strdup(buf);
+#else /* __rtems__ */
+	log_err("fio: performing math is not supported\n");
+	return NULL;
+#endif /* __rtems__ */
 }
 
 /*
diff --git a/os/os-rtems.h b/os/os-rtems.h
new file mode 100644
index 0000000..4964eb1
--- /dev/null
+++ b/os/os-rtems.h
@@ -0,0 +1,70 @@
+/*-
+ * Copyright (c) 2018 Udit kumar agarwal <dev.madaari@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef FIO_OS_RTEMS_H
+#define FIO_OS_RTEMS_H
+
+#define	FIO_OS	os_rtems
+
+#include <errno.h>
+#include <machine/endian.h>
+#include <sys/socket.h>
+#include <machine/param.h>
+#include <sys/cpuset.h>
+#include <sys/resource.h>
+#include <stdatomic.h>
+#include "../file.h"
+
+#define FIO_HAVE_ODIRECT
+#define FIO_USE_GENERIC_RAND
+#define FIO_USE_GENERIC_INIT_RANDOM_STATE
+#define off64_t _off64_t
+#define OS_MAP_ANON		MAP_ANON
+#define O_DIRECT	0x1000000
+#define FIO_NO_HAVE_SHM_H
+#define CONFIG_NO_SHM
+#define CONFIG_HAVE_MKDIR_TWO
+#define SA_RESTART	0
+#define __need_getopt_newlib
+
+static inline int blockdev_invalidate_cache(struct fio_file *f)
+{
+	return ENOTSUP;
+}
+
+static inline int blockdev_size(struct fio_file *f, unsigned long long *bytes)
+{
+	errno = ENOSYS;
+	return 0;
+}
+
+static inline unsigned long long os_phys_mem(void)
+{
+	errno = ENOSYS;
+	return 0;
+}
+
+#endif
diff --git a/os/os.h b/os/os.h
index becc410..bc230dc 100644
--- a/os/os.h
+++ b/os/os.h
@@ -23,6 +23,7 @@ enum {
 	os_windows,
 	os_android,
 	os_dragonfly,
+	os_rtems,
 
 	os_nr,
 };
@@ -36,6 +37,8 @@ typedef enum {
 #include "os-android.h"
 #elif defined(__linux__)
 #include "os-linux.h"
+#elif defined (__rtems__)
+#include "os-rtems.h"
 #elif defined(__FreeBSD__)
 #include "os-freebsd.h"
 #elif defined(__OpenBSD__)
diff --git a/os/rtems/rtems-fio-wrap.h b/os/rtems/rtems-fio-wrap.h
new file mode 100644
index 0000000..2c639cb
--- /dev/null
+++ b/os/rtems/rtems-fio-wrap.h
@@ -0,0 +1,54 @@
+/* RTEMS specific wrapper for explicitly calling constructors and
+ * destructors */
+
+void act_register(void);
+void tiobench_register(void);
+void fio_syncio_register(void);
+void fio_filecreate_register(void);
+void fio_null_register(void);
+void prio_tree_init(void);
+void fio_syncio_register_ft(void);
+void fio_client_hash_init(void);
+void fio_syncio_unregister(void);
+void tiobench_unregister(void);
+void fio_filecreate_unregister(void);
+void fio_null_unregister(void);
+void act_unregister(void);
+void fio_syncio_unregister_ft(void);
+
+static int
+mainwrapper(int argc, char *argv[])
+{
+	int err=0;
+
+	/* Constructors */
+	act_register();
+	tiobench_register();
+	fio_syncio_register();
+	fio_filecreate_register();
+	fio_null_register();
+	prio_tree_init();
+	fio_syncio_register_ft();
+	fio_client_hash_init();
+
+	err = main(argc, argv, (char *)NULL);
+
+	/* Destructors */
+	fio_syncio_unregister();
+	tiobench_unregister();
+	fio_filecreate_unregister();
+	fio_null_unregister();
+	act_unregister();
+	fio_syncio_unregister_ft();
+
+	return err;
+}
+
+rtems_bsd_command_fio(int argc, char *argv[])
+{
+	int exit_code;
+
+	exit_code = mainwrapper(argc, argv);
+
+	return exit_code;
+}
diff --git a/os/rtems/rtems-init.c b/os/rtems/rtems-init.c
new file mode 100644
index 0000000..a10cfc9
--- /dev/null
+++ b/os/rtems/rtems-init.c
@@ -0,0 +1,225 @@
+/*-
+ * Copyright (c) 2018 Udit kumar agarwal <dev.madaari@gmail.com>
+ * Copyright (c) 2018 Christian Mauderer <christian.mauderer@embedded-brains.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <ifaddrs.h>
+#include <sysexits.h>
+
+#include <machine/rtems-bsd-commands.h>
+
+#include <net/if.h>
+
+#include <rtems/bdbuf.h>
+#include <rtems/console.h>
+#include <rtems/ftpd.h>
+#include <rtems/media.h>
+#include <rtems/shell.h>
+#include <rtems/telnetd.h>
+#include <rtems.h>
+#include <rtems/printer.h>
+#include <rtems/stackchk.h>
+#include <rtems/bsd/bsd.h>
+#include <rtems/bsd/modules.h>
+#include <rtems/dhcpcd.h>
+#include <rtems/console.h>
+#include <rtems/shell.h>
+
+rtems_bsd_command_fio(int argc, char *argv[]);
+
+static rtems_status_code
+media_listener(rtems_media_event event, rtems_media_state state,
+    const char *src, const char *dest, void *arg)
+{
+
+	if (dest != NULL) {
+		printf(", dest = %s", dest);
+	}
+
+	if (arg != NULL) {
+		printf(", arg = %p\n", arg);
+	}
+
+	return RTEMS_SUCCESSFUL;
+}
+
+rtems_shell_cmd_t rtems_shell_fio_Command = {
+	.name = "fio",
+	.usage = "fio testfile.fio",
+	.topic = "user",
+	.command = rtems_bsd_command_fio
+};
+
+int nice(int incr)
+{
+	/* FIXME */
+	return 0;
+}
+
+static void
+early_initialization(void)
+{
+	rtems_status_code sc;
+
+	sc = rtems_bdbuf_init();
+	assert(sc == RTEMS_SUCCESSFUL);
+
+	sc = rtems_media_initialize();
+	assert(sc == RTEMS_SUCCESSFUL);
+
+	sc = rtems_media_listener_add(media_listener, NULL);
+	assert(sc == RTEMS_SUCCESSFUL);
+
+	sc = rtems_media_server_initialize(
+		200,
+		32 * 1024,
+		RTEMS_DEFAULT_MODES,
+		RTEMS_DEFAULT_ATTRIBUTES
+	);
+	assert(sc == RTEMS_SUCCESSFUL);
+}
+
+void
+Init(rtems_task_argument arg)
+{
+	rtems_status_code sc;
+
+	puts("\n*** FIO - Flexible I/O tester ***\n\n");
+
+	early_initialization();
+	rtems_bsd_initialize();
+
+	/* Let the callout timer allocate its resources */
+	sc = rtems_task_wake_after(2);
+	assert(sc == RTEMS_SUCCESSFUL);
+
+	sc = rtems_shell_init("SHLL", 16 * 1024, 1, CONSOLE_DEVICE_NAME,
+		false, true, NULL);
+	assert(sc == RTEMS_SUCCESSFUL);
+
+	assert(0);
+}
+
+
+#define CONFIGURE_MICROSECONDS_PER_TICK 1000
+
+#define CONFIGURE_MAXIMUM_DRIVERS 32
+
+#define CONFIGURE_FILESYSTEM_DOSFS
+
+#define CONFIGURE_MAXIMUM_PROCESSORS 32
+
+/*
+ * Configure LibBSD.
+ */
+
+#define RTEMS_BSD_CONFIG_NET_PF_UNIX
+#define RTEMS_BSD_CONFIG_NET_IP_MROUTE
+#define RTEMS_BSD_CONFIG_NET_IP6_MROUTE
+#define RTEMS_BSD_CONFIG_NET_IF_BRIDGE
+#define RTEMS_BSD_CONFIG_NET_IF_LAGG
+#define RTEMS_BSD_CONFIG_NET_IF_VLAN
+#define RTEMS_BSD_CONFIG_BSP_CONFIG
+#define RTEMS_BSD_CONFIG_INIT
+
+#include <machine/rtems-bsd-config.h>
+
+#define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_STUB_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_ZERO_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_LIBBLOCK
+
+#define CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS 32
+
+#define CONFIGURE_MAXIMUM_USER_EXTENSIONS 1
+
+#define CONFIGURE_UNLIMITED_ALLOCATION_SIZE 32
+#define CONFIGURE_UNLIMITED_OBJECTS
+#define CONFIGURE_UNIFIED_WORK_AREAS
+
+/* Turn cache off */
+#define CONFIGURE_BDBUF_BUFFER_MAX_SIZE (4 * 1024)
+#define CONFIGURE_BDBUF_MAX_READ_AHEAD_BLOCKS 0
+#define CONFIGURE_BDBUF_CACHE_MEMORY_SIZE (1 * 1024 * 1024)
+
+#define CONFIGURE_RTEMS_INIT_TASKS_TABLE
+
+#define CONFIGURE_INIT_TASK_STACK_SIZE (256 * 1024)
+#define CONFIGURE_INIT_TASK_INITIAL_MODES RTEMS_DEFAULT_MODES
+#define CONFIGURE_INIT_TASK_ATTRIBUTES RTEMS_FLOATING_POINT
+
+#define CONFIGURE_INIT
+#define CPU_STACK_MINIMUM_SIZE           (256*1024)
+#include <rtems/confdefs.h>
+
+#define CONFIGURE_SHELL_COMMANDS_INIT
+
+#include <bsp/irq-info.h>
+
+#define CONFIGURE_SHELL_USER_COMMANDS \
+  &rtems_shell_fio_Command
+
+#define CONFIGURE_SHELL_COMMAND_CPUINFO
+#define CONFIGURE_SHELL_COMMAND_PROFREPORT
+#define CONFIGURE_SHELL_COMMAND_MKRFS
+
+#define CONFIGURE_SHELL_COMMAND_CP
+#define CONFIGURE_SHELL_COMMAND_PWD
+#define CONFIGURE_SHELL_COMMAND_LS
+#define CONFIGURE_SHELL_COMMAND_LN
+#define CONFIGURE_SHELL_COMMAND_LSOF
+#define CONFIGURE_SHELL_COMMAND_CHDIR
+#define CONFIGURE_SHELL_COMMAND_CD
+#define CONFIGURE_SHELL_COMMAND_MKDIR
+#define CONFIGURE_SHELL_COMMAND_RMDIR
+#define CONFIGURE_SHELL_COMMAND_CAT
+#define CONFIGURE_SHELL_COMMAND_MV
+#define CONFIGURE_SHELL_COMMAND_RM
+#define CONFIGURE_SHELL_COMMAND_MALLOC_INFO
+#define CONFIGURE_SHELL_COMMAND_SHUTDOWN
+
+#define CONFIGURE_SHELL_COMMAND_FDISK
+#define CONFIGURE_SHELL_COMMAND_BLKSTATS
+#define CONFIGURE_SHELL_COMMAND_BLKSYNC
+#define CONFIGURE_SHELL_COMMAND_MSDOSFMT
+#define CONFIGURE_SHELL_COMMAND_DF
+#define CONFIGURE_SHELL_COMMAND_MOUNT
+#define CONFIGURE_SHELL_COMMAND_UNMOUNT
+#define CONFIGURE_SHELL_COMMAND_MSDOSFMT
+#define CONFIGURE_SHELL_COMMAND_EDIT
+#define CONFIGURE_SHELL_COMMAND_GETENV
+#define CONFIGURE_SHELL_COMMAND_SETENV
+#define CONFIGURE_SHELL_COMMAND_UNSETENV
+#include <rtems/shellconfig.h>
diff --git a/oslib/inet_aton.c b/oslib/inet_aton.c
index 7ae7db7..5bbc05b 100644
--- a/oslib/inet_aton.c
+++ b/oslib/inet_aton.c
@@ -1,6 +1,7 @@
 #include "inet_aton.h"
-
+#ifndef __rtems__
 int inet_aton(const char *cp, struct in_addr *inp)
 {
 	return inet_pton(AF_INET, cp, inp);
 }
+#endif
diff --git a/profiles/act.c b/profiles/act.c
index 5d3bd25..49a321f 100644
--- a/profiles/act.c
+++ b/profiles/act.c
@@ -461,7 +461,12 @@ static struct profile_ops act_profile = {
 	.io_ops		= &act_io_ops,
 };
 
-static void fio_init act_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+act_register(void)
 {
 	act_run_data = calloc(1, sizeof(*act_run_data));
 	act_run_data->sem = fio_sem_init(FIO_SEM_UNLOCKED);
@@ -470,7 +475,12 @@ static void fio_init act_register(void)
 		log_err("fio: failed to register profile 'act'\n");
 }
 
-static void fio_exit act_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+act_unregister(void)
 {
 	while (org_idx && org_idx < opt_idx)
 		free((void *) act_opts[++org_idx]);
diff --git a/profiles/tiobench.c b/profiles/tiobench.c
index f19a085..e36be66 100644
--- a/profiles/tiobench.c
+++ b/profiles/tiobench.c
@@ -121,13 +121,23 @@ static struct profile_ops tiobench_profile = {
 	.opt_data	= &tiobench_options,
 };
 
-static void fio_init tiobench_register(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_init
+#endif /* __rtems__ */
+tiobench_register(void)
 {
 	if (register_profile(&tiobench_profile))
 		log_err("fio: failed to register profile 'tiobench'\n");
 }
 
-static void fio_exit tiobench_unregister(void)
+#ifdef __rtems__
+void
+#else /* __rtems__ */
+static void fio_exit
+#endif /* __rtems__ */
+tiobench_unregister(void)
 {
 	unregister_profile(&tiobench_profile);
 }
diff --git a/smalloc.c b/smalloc.c
index a2ad25a..f42677a 100644
--- a/smalloc.c
+++ b/smalloc.c
@@ -170,12 +170,17 @@ static bool add_pool(struct pool *pool, unsigned int alloc_size)
 	pool->free_blocks = bitmap_blocks * SMALLOC_BPB;
 
 	mmap_flags = OS_MAP_ANON;
-#ifdef CONFIG_ESX
+#if defined(CONFIG_ESX)||defined(__rtems__)
 	mmap_flags |= MAP_PRIVATE;
 #else
 	mmap_flags |= MAP_SHARED;
 #endif
+
+#ifdef __rtems__
+	ptr = (void*)malloc(alloc_size);
+#else
 	ptr = mmap(NULL, alloc_size, PROT_READ|PROT_WRITE, mmap_flags, -1, 0);
+#endif
 
 	if (ptr == MAP_FAILED)
 		goto out_fail;
@@ -193,7 +198,11 @@ static bool add_pool(struct pool *pool, unsigned int alloc_size)
 out_fail:
 	log_err("smalloc: failed adding pool\n");
 	if (pool->map)
+#ifdef __rtems__
+		free(pool->map);
+#else /* __rtems__ */
 		munmap(pool->map, pool->mmap_size);
+#endif /* __rtems__ */
 	return false;
 }
 
diff --git a/stat.c b/stat.c
index a308eb8..093f216 100644
--- a/stat.c
+++ b/stat.c
@@ -38,10 +38,16 @@ void update_rusage_stat(struct thread_data *td)
 					&td->ru_end.ru_utime);
 	ts->sys_time += mtime_since_tv(&td->ru_start.ru_stime,
 					&td->ru_end.ru_stime);
+#ifndef __rtems__ /* Virtual Memory not supported on RTEMS */
 	ts->ctx += td->ru_end.ru_nvcsw + td->ru_end.ru_nivcsw
 			- (td->ru_start.ru_nvcsw + td->ru_start.ru_nivcsw);
 	ts->minf += td->ru_end.ru_minflt - td->ru_start.ru_minflt;
 	ts->majf += td->ru_end.ru_majflt - td->ru_start.ru_majflt;
+#else /* __rtems__ */
+	ts->ctx  = ((uint64_t) -1);
+	ts->minf = ((uint64_t) -1);
+	ts->majf = ((uint64_t) -1);
+#endif /* __rtems__ */
 
 	memcpy(&td->ru_start, &td->ru_end, sizeof(td->ru_end));
 }
diff --git a/t/arch.c b/t/arch.c
index bd28a84..efee2db 100644
--- a/t/arch.c
+++ b/t/arch.c
@@ -1,5 +1,7 @@
 #include "../arch/arch.h"
 
 unsigned long arch_flags = 0;
+#ifndef __rtems__
 bool tsc_reliable;
+#endif /* __rtems__ */
 int arch_random;
-- 
1.9.1