diff --git a/ChangeLog b/ChangeLog
index d64f11e..708555e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -14,6 +14,14 @@
 
 Features
    * Allow comments in test data files.
+   * The selftest program can execute a subset of the tests based on command
+     line arguments.
+   * New unit tests for timing. Improve the self-test to be more robust
+     when run on a heavily-loaded machine.
+
+New deprecations
+   * Deprecate usage of RSA primitives with non-matching key-type
+     (e.g., signing with a public key).
 
 Bugfix
    * Fix ssl_parse_record_header() to silently discard invalid DTLS records
@@ -56,16 +64,14 @@
    * Fix incorrect unit in benchmark output. #850
    * Fix crash when calling mbedtls_ssl_cache_free() twice. Found by
      MilenkoMitrovic, #1104
+   * Fix mbedtls_timing_alarm(0) on Unix.
+   * Fix use of uninitialized memory in mbedtls_timing_get_timer when reset=1.
 
 Changes
    * Extend cert_write example program by options to set the CRT version
      and the message digest. Further, allow enabling/disabling of authority
      identifier, subject identifier and basic constraints extensions.
 
-New deprecations
-   * Deprecate usage of RSA primitives with non-matching key-type
-     (e.g., signing with a public key).
-
 = mbed TLS 2.6.0 branch released 2017-08-10
 
 Security
diff --git a/include/mbedtls/timing.h b/include/mbedtls/timing.h
index ae7a713..bfb8579 100644
--- a/include/mbedtls/timing.h
+++ b/include/mbedtls/timing.h
@@ -1,7 +1,7 @@
 /**
  * \file timing.h
  *
- * \brief Portable interface to the CPU cycle counter
+ * \brief Portable interface to timeouts and to the CPU cycle counter
  *
  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
  *  SPDX-License-Identifier: Apache-2.0
@@ -65,6 +65,9 @@
  * \warning        This is only a best effort! Do not rely on this!
  *                 In particular, it is known to be unreliable on virtual
  *                 machines.
+ *
+ * \note           This value starts at an unspecified origin and
+ *                 may wrap around.
  */
 unsigned long mbedtls_timing_hardclock( void );
 
@@ -72,7 +75,18 @@
  * \brief          Return the elapsed time in milliseconds
  *
  * \param val      points to a timer structure
- * \param reset    if set to 1, the timer is restarted
+ * \param reset    If 0, query the elapsed time. Otherwise (re)start the timer.
+ *
+ * \return         Elapsed time since the previous reset in ms. When
+ *                 restarting, this is always 0.
+ *
+ * \note           To initialize a timer, call this function with reset=1.
+ *
+ *                 Determining the elapsed time and resetting the timer is not
+ *                 atomic on all platforms, so after the sequence
+ *                 `{ get_timer(1); ...; time1 = get_timer(1); ...; time2 =
+ *                 get_timer(0) }` the value time1+time2 is only approximately
+ *                 the delay since the first reset.
  */
 unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset );
 
@@ -80,6 +94,7 @@
  * \brief          Setup an alarm clock
  *
  * \param seconds  delay before the "mbedtls_timing_alarmed" flag is set
+ *                 (must be >=0)
  *
  * \warning        Only one alarm at a time  is supported. In a threaded
  *                 context, this means one for the whole process, not one per
@@ -91,11 +106,15 @@
  * \brief          Set a pair of delays to watch
  *                 (See \c mbedtls_timing_get_delay().)
  *
- * \param data     Pointer to timing data
+ * \param data     Pointer to timing data.
  *                 Must point to a valid \c mbedtls_timing_delay_context struct.
  * \param int_ms   First (intermediate) delay in milliseconds.
+ *                 The effect if int_ms > fin_ms is unspecified.
  * \param fin_ms   Second (final) delay in milliseconds.
  *                 Pass 0 to cancel the current delay.
+ *
+ * \note           To set a single delay, either use \c mbedtls_timing_set_timer
+ *                 directly or use this function with int_ms == fin_ms.
  */
 void mbedtls_timing_set_delay( void *data, uint32_t int_ms, uint32_t fin_ms );
 
@@ -106,7 +125,7 @@
  * \param data     Pointer to timing data
  *                 Must point to a valid \c mbedtls_timing_delay_context struct.
  *
- * \return         -1 if cancelled (fin_ms = 0)
+ * \return         -1 if cancelled (fin_ms = 0),
  *                  0 if none of the delays are passed,
  *                  1 if only the intermediate delay is passed,
  *                  2 if the final delay is passed.
diff --git a/library/timing.c b/library/timing.c
index a7c7ff0..6df137d 100644
--- a/library/timing.c
+++ b/library/timing.c
@@ -244,21 +244,23 @@
 
 unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset )
 {
-    unsigned long delta;
-    LARGE_INTEGER offset, hfreq;
     struct _hr_time *t = (struct _hr_time *) val;
 
-    QueryPerformanceCounter(  &offset );
-    QueryPerformanceFrequency( &hfreq );
-
-    delta = (unsigned long)( ( 1000 *
-        ( offset.QuadPart - t->start.QuadPart ) ) /
-           hfreq.QuadPart );
-
     if( reset )
+    {
         QueryPerformanceCounter( &t->start );
-
-    return( delta );
+        return( 0 );
+    }
+    else
+    {
+        unsigned long delta;
+        LARGE_INTEGER now, hfreq;
+        QueryPerformanceCounter(  &now );
+        QueryPerformanceFrequency( &hfreq );
+        delta = (unsigned long)( ( now.QuadPart - t->start.QuadPart ) * 1000ul
+                                 / hfreq.QuadPart );
+        return( delta );
+    }
 }
 
 /* It's OK to use a global because alarm() is supposed to be global anyway */
@@ -285,23 +287,22 @@
 
 unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset )
 {
-    unsigned long delta;
-    struct timeval offset;
     struct _hr_time *t = (struct _hr_time *) val;
 
-    gettimeofday( &offset, NULL );
-
     if( reset )
     {
-        t->start.tv_sec  = offset.tv_sec;
-        t->start.tv_usec = offset.tv_usec;
+        gettimeofday( &t->start, NULL );
         return( 0 );
     }
-
-    delta = ( offset.tv_sec  - t->start.tv_sec  ) * 1000
-          + ( offset.tv_usec - t->start.tv_usec ) / 1000;
-
-    return( delta );
+    else
+    {
+        unsigned long delta;
+        struct timeval now;
+        gettimeofday( &now, NULL );
+        delta = ( now.tv_sec  - t->start.tv_sec  ) * 1000ul
+              + ( now.tv_usec - t->start.tv_usec ) / 1000;
+        return( delta );
+    }
 }
 
 static void sighandler( int signum )
@@ -315,6 +316,12 @@
     mbedtls_timing_alarmed = 0;
     signal( SIGALRM, sighandler );
     alarm( seconds );
+    if( seconds == 0 )
+    {
+        /* alarm(0) cancelled any previous pending alarm, but the
+           handler won't fire, so raise the flag straight away. */
+        mbedtls_timing_alarmed = 1;
+    }
 }
 
 #endif /* _WIN32 && !EFIX64 && !EFI32 */
@@ -378,13 +385,21 @@
     (void) j;
 }
 
-#define FAIL    do                      \
-{                                       \
-    if( verbose != 0 )                  \
-        mbedtls_printf( "failed\n" );   \
-                                        \
-    return( 1 );                        \
-} while( 0 )
+#define FAIL    do                                                      \
+    {                                                                   \
+        if( verbose != 0 )                                              \
+        {                                                               \
+            mbedtls_printf( "failed at line %d\n", __LINE__ );          \
+            mbedtls_printf( " cycles=%lu ratio=%lu millisecs=%lu secs=%lu hardfail=%d a=%lu b=%lu\n", \
+                            cycles, ratio, millisecs, secs, hardfail,   \
+                            (unsigned long) a, (unsigned long) b );     \
+            mbedtls_printf( " elapsed(hires)=%lu elapsed(ctx)=%lu status(ctx)=%d\n", \
+                            mbedtls_timing_get_timer( &hires, 0 ),      \
+                            mbedtls_timing_get_timer( &ctx.timer, 0 ),  \
+                            mbedtls_timing_get_delay( &ctx ) );         \
+        }                                                               \
+        return( 1 );                                                    \
+    } while( 0 )
 
 /*
  * Checkup routine
@@ -394,22 +409,22 @@
  */
 int mbedtls_timing_self_test( int verbose )
 {
-    unsigned long cycles, ratio;
-    unsigned long millisecs, secs;
-    int hardfail;
+    unsigned long cycles = 0, ratio = 0;
+    unsigned long millisecs = 0, secs = 0;
+    int hardfail = 0;
     struct mbedtls_timing_hr_time hires;
-    uint32_t a, b;
+    uint32_t a = 0, b = 0;
     mbedtls_timing_delay_context ctx;
 
     if( verbose != 0 )
         mbedtls_printf( "  TIMING tests note: will take some time!\n" );
 
-
     if( verbose != 0 )
         mbedtls_printf( "  TIMING test #1 (set_alarm / get_timer): " );
 
-    for( secs = 1; secs <= 3; secs++ )
     {
+        secs = 1;
+
         (void) mbedtls_timing_get_timer( &hires, 1 );
 
         mbedtls_set_alarm( (int) secs );
@@ -421,12 +436,7 @@
         /* For some reason on Windows it looks like alarm has an extra delay
          * (maybe related to creating a new thread). Allow some room here. */
         if( millisecs < 800 * secs || millisecs > 1200 * secs + 300 )
-        {
-            if( verbose != 0 )
-                mbedtls_printf( "failed\n" );
-
-            return( 1 );
-        }
+            FAIL;
     }
 
     if( verbose != 0 )
@@ -435,28 +445,22 @@
     if( verbose != 0 )
         mbedtls_printf( "  TIMING test #2 (set/get_delay        ): " );
 
-    for( a = 200; a <= 400; a += 200 )
     {
-        for( b = 200; b <= 400; b += 200 )
-        {
-            mbedtls_timing_set_delay( &ctx, a, a + b );
+        a = 800;
+        b = 400;
+        mbedtls_timing_set_delay( &ctx, a, a + b );          /* T = 0 */
 
-            busy_msleep( a - a / 8 );
-            if( mbedtls_timing_get_delay( &ctx ) != 0 )
-                FAIL;
+        busy_msleep( a - a / 4 );                      /* T = a - a/4 */
+        if( mbedtls_timing_get_delay( &ctx ) != 0 )
+            FAIL;
 
-            busy_msleep( a / 4 );
-            if( mbedtls_timing_get_delay( &ctx ) != 1 )
-                FAIL;
+        busy_msleep( a / 4 + b / 4 );                  /* T = a + b/4 */
+        if( mbedtls_timing_get_delay( &ctx ) != 1 )
+            FAIL;
 
-            busy_msleep( b - a / 8 - b / 8 );
-            if( mbedtls_timing_get_delay( &ctx ) != 1 )
-                FAIL;
-
-            busy_msleep( b / 4 );
-            if( mbedtls_timing_get_delay( &ctx ) != 2 )
-                FAIL;
-        }
+        busy_msleep( b );                          /* T = a + b + b/4 */
+        if( mbedtls_timing_get_delay( &ctx ) != 2 )
+            FAIL;
     }
 
     mbedtls_timing_set_delay( &ctx, 0, 0 );
@@ -475,7 +479,6 @@
      * On a 4Ghz 32-bit machine the cycle counter wraps about once per second;
      * since the whole test is about 10ms, it shouldn't happen twice in a row.
      */
-    hardfail = 0;
 
 hard_test:
     if( hardfail > 1 )
diff --git a/programs/test/selftest.c b/programs/test/selftest.c
index 1941ad0..72a3734 100644
--- a/programs/test/selftest.c
+++ b/programs/test/selftest.c
@@ -107,8 +107,8 @@
  * self-test. If this fails, we attempt the test anyway, so no error is passed
  * back.
  */
-#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_ENTROPY_C) && \
-    defined(MBEDTLS_ENTROPY_NV_SEED) && !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
+#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_ENTROPY_C)
+#if defined(MBEDTLS_ENTROPY_NV_SEED) && !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
 static void create_entropy_seed_file( void )
 {
     int result;
@@ -136,9 +136,137 @@
 }
 #endif
 
+int mbedtls_entropy_self_test_wrapper( int verbose )
+{
+#if defined(MBEDTLS_ENTROPY_NV_SEED) && !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
+    create_entropy_seed_file( );
+#endif
+    return( mbedtls_entropy_self_test( verbose ) );
+}
+#endif
+
+#if defined(MBEDTLS_SELF_TEST)
+#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
+int mbedtls_memory_buffer_alloc_free_and_self_test( int verbose )
+{
+    if( verbose != 0 )
+    {
+#if defined(MBEDTLS_MEMORY_DEBUG)
+        mbedtls_memory_buffer_alloc_status( );
+#endif
+    }
+    mbedtls_memory_buffer_alloc_free( );
+    return( mbedtls_memory_buffer_alloc_self_test( verbose ) );
+}
+#endif
+
+typedef struct
+{
+    const char *name;
+    int ( *function )( int );
+} selftest_t;
+
+const selftest_t selftests[] =
+{
+#if defined(MBEDTLS_MD2_C)
+    {"md2", mbedtls_md2_self_test},
+#endif
+#if defined(MBEDTLS_MD4_C)
+    {"md4", mbedtls_md4_self_test},
+#endif
+#if defined(MBEDTLS_MD5_C)
+    {"md5", mbedtls_md5_self_test},
+#endif
+#if defined(MBEDTLS_RIPEMD160_C)
+    {"ripemd160", mbedtls_ripemd160_self_test},
+#endif
+#if defined(MBEDTLS_SHA1_C)
+    {"sha1", mbedtls_sha1_self_test},
+#endif
+#if defined(MBEDTLS_SHA256_C)
+    {"sha256", mbedtls_sha256_self_test},
+#endif
+#if defined(MBEDTLS_SHA512_C)
+    {"sha512", mbedtls_sha512_self_test},
+#endif
+#if defined(MBEDTLS_ARC4_C)
+    {"arc4", mbedtls_arc4_self_test},
+#endif
+#if defined(MBEDTLS_DES_C)
+    {"des", mbedtls_des_self_test},
+#endif
+#if defined(MBEDTLS_AES_C)
+    {"aes", mbedtls_aes_self_test},
+#endif
+#if defined(MBEDTLS_GCM_C) && defined(MBEDTLS_AES_C)
+    {"gcm", mbedtls_gcm_self_test},
+#endif
+#if defined(MBEDTLS_CCM_C) && defined(MBEDTLS_AES_C)
+    {"ccm", mbedtls_ccm_self_test},
+#endif
+#if defined(MBEDTLS_CMAC_C)
+    {"cmac", mbedtls_cmac_self_test},
+#endif
+#if defined(MBEDTLS_BASE64_C)
+    {"base64", mbedtls_base64_self_test},
+#endif
+#if defined(MBEDTLS_BIGNUM_C)
+    {"mpi", mbedtls_mpi_self_test},
+#endif
+#if defined(MBEDTLS_RSA_C)
+    {"rsa", mbedtls_rsa_self_test},
+#endif
+#if defined(MBEDTLS_X509_USE_C)
+    {"x509", mbedtls_x509_self_test},
+#endif
+#if defined(MBEDTLS_XTEA_C)
+    {"xtea", mbedtls_xtea_self_test},
+#endif
+#if defined(MBEDTLS_CAMELLIA_C)
+    {"camellia", mbedtls_camellia_self_test},
+#endif
+#if defined(MBEDTLS_CTR_DRBG_C)
+    {"ctr_drbg", mbedtls_ctr_drbg_self_test},
+#endif
+#if defined(MBEDTLS_HMAC_DRBG_C)
+    {"hmac_drbg", mbedtls_hmac_drbg_self_test},
+#endif
+#if defined(MBEDTLS_ECP_C)
+    {"ecp", mbedtls_ecp_self_test},
+#endif
+#if defined(MBEDTLS_ECJPAKE_C)
+    {"ecjpake", mbedtls_ecjpake_self_test},
+#endif
+#if defined(MBEDTLS_DHM_C)
+    {"dhm", mbedtls_dhm_self_test},
+#endif
+#if defined(MBEDTLS_ENTROPY_C)
+    {"entropy", mbedtls_entropy_self_test_wrapper},
+#endif
+#if defined(MBEDTLS_PKCS5_C)
+    {"pkcs5", mbedtls_pkcs5_self_test},
+#endif
+/* Slower test after the faster ones */
+#if defined(MBEDTLS_TIMING_C)
+    {"timing", mbedtls_timing_self_test},
+#endif
+/* Heap test comes last */
+#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
+    {"memory_buffer_alloc", mbedtls_memory_buffer_alloc_free_and_self_test},
+#endif
+    {NULL, NULL}
+};
+#endif /* MBEDTLS_SELF_TEST */
+
 int main( int argc, char *argv[] )
 {
-    int v, suites_tested = 0, suites_failed = 0;
+#if defined(MBEDTLS_SELF_TEST)
+    const selftest_t *test;
+#endif /* MBEDTLS_SELF_TEST */
+    char **argp;
+    int v = 1; /* v=1 for verbose mode */
+    int exclude_mode = 0;
+    int suites_tested = 0, suites_failed = 0;
 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C) && defined(MBEDTLS_SELF_TEST)
     unsigned char buf[1000000];
 #endif
@@ -165,16 +293,24 @@
         mbedtls_exit( MBEDTLS_EXIT_FAILURE );
     }
 
-    if( argc == 2 && ( strcmp( argv[1], "--quiet" ) == 0  ||
-        strcmp( argv[1], "-q" ) == 0 ) )
+    for( argp = argv + ( argc >= 1 ? 1 : argc ); *argp != NULL; ++argp )
     {
-        v = 0;
+        if( strcmp( *argp, "--quiet" ) == 0 ||
+            strcmp( *argp, "-q" ) == 0 )
+        {
+            v = 0;
+        }
+        else if( strcmp( *argp, "--exclude" ) == 0 ||
+                 strcmp( *argp, "-x" ) == 0 )
+        {
+            exclude_mode = 1;
+        }
+        else
+            break;
     }
-    else
-    {
-        v = 1;
+
+    if( v != 0 )
         mbedtls_printf( "\n" );
-    }
 
 #if defined(MBEDTLS_SELF_TEST)
 
@@ -182,246 +318,60 @@
     mbedtls_memory_buffer_alloc_init( buf, sizeof(buf) );
 #endif
 
-#if defined(MBEDTLS_MD2_C)
-    if( mbedtls_md2_self_test( v )  != 0 )
+    if( *argp != NULL && exclude_mode == 0 )
     {
-        suites_failed++;
+        /* Run the specified tests */
+        for( ; *argp != NULL; argp++ )
+        {
+            for( test = selftests; test->name != NULL; test++ )
+            {
+                if( !strcmp( *argp, test->name ) )
+                {
+                    if( test->function( v )  != 0 )
+                    {
+                        suites_failed++;
+                    }
+                    suites_tested++;
+                    break;
+                }
+            }
+            if( test->name == NULL )
+            {
+                mbedtls_printf( "  Test suite %s not available -> failed\n\n", *argp );
+                suites_failed++;
+            }
+        }
     }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_MD4_C)
-    if( mbedtls_md4_self_test( v ) != 0 )
+    else
     {
-        suites_failed++;
+        /* Run all the tests except excluded ones */
+        for( test = selftests; test->name != NULL; test++ )
+        {
+            if( exclude_mode )
+            {
+                char **excluded;
+                for( excluded = argp; *excluded != NULL; ++excluded )
+                {
+                    if( !strcmp( *excluded, test->name ) )
+                        break;
+                }
+                if( *excluded )
+                {
+                    if( v )
+                        mbedtls_printf( "  Skip: %s\n", test->name );
+                    continue;
+                }
+            }
+            if( test->function( v )  != 0 )
+            {
+                suites_failed++;
+            }
+            suites_tested++;
+        }
     }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_MD5_C)
-    if( mbedtls_md5_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_RIPEMD160_C)
-    if( mbedtls_ripemd160_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_SHA1_C)
-    if( mbedtls_sha1_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_SHA256_C)
-    if( mbedtls_sha256_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_SHA512_C)
-    if( mbedtls_sha512_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_ARC4_C)
-    if( mbedtls_arc4_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_DES_C)
-    if( mbedtls_des_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_AES_C)
-    if( mbedtls_aes_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_GCM_C) && defined(MBEDTLS_AES_C)
-    if( mbedtls_gcm_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_CCM_C) && defined(MBEDTLS_AES_C)
-    if( mbedtls_ccm_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_CMAC_C)
-    if( ( mbedtls_cmac_self_test( v ) ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_BASE64_C)
-    if( mbedtls_base64_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_BIGNUM_C)
-    if( mbedtls_mpi_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_RSA_C)
-    if( mbedtls_rsa_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_X509_USE_C)
-    if( mbedtls_x509_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_XTEA_C)
-    if( mbedtls_xtea_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_CAMELLIA_C)
-    if( mbedtls_camellia_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_CTR_DRBG_C)
-    if( mbedtls_ctr_drbg_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_HMAC_DRBG_C)
-    if( mbedtls_hmac_drbg_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_ECP_C)
-    if( mbedtls_ecp_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_ECJPAKE_C)
-    if( mbedtls_ecjpake_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_DHM_C)
-    if( mbedtls_dhm_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_ENTROPY_C)
-
-#if defined(MBEDTLS_ENTROPY_NV_SEED) && !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
-    create_entropy_seed_file();
-#endif
-
-    if( mbedtls_entropy_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-#if defined(MBEDTLS_PKCS5_C)
-    if( mbedtls_pkcs5_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-/* Slow tests last */
-
-#if defined(MBEDTLS_TIMING_C)
-    if( mbedtls_timing_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
-
-    if( v != 0 )
-    {
-#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C) && defined(MBEDTLS_MEMORY_DEBUG)
-        mbedtls_memory_buffer_alloc_status();
-#endif
-    }
-
-#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
-    mbedtls_memory_buffer_alloc_free();
-    if( mbedtls_memory_buffer_alloc_self_test( v ) != 0 )
-    {
-        suites_failed++;
-    }
-    suites_tested++;
-#endif
 
 #else
+    (void) exclude_mode;
     mbedtls_printf( " MBEDTLS_SELF_TEST not defined.\n" );
 #endif
 
diff --git a/tests/suites/test_suite_timing.data b/tests/suites/test_suite_timing.data
index 3ba79a4..4dddcf7 100644
--- a/tests/suites/test_suite_timing.data
+++ b/tests/suites/test_suite_timing.data
@@ -1,2 +1,41 @@
-Timing selftest
-timing_selftest:
+Timing: basic timer operation
+timing_timer_simple:
+
+Timing: timer reset
+timing_timer_reset:
+
+Timing: two parallel timers, delay 0
+timing_two_timers:0:
+
+Timing: two parallel timers, delay 100
+timing_two_timers:100:
+
+Timing: two parallel timers, delay 1000
+timing_two_timers:1000:
+
+Timing: two parallel timers, delay 10000
+timing_two_timers:10000:
+
+Timing: delay 0ms, 0ms
+timing_delay:0:0:
+
+Timing: delay 0ms, 50ms
+timing_delay:0:50:
+
+Timing: delay 50ms, 50ms
+timing_delay:50:50:
+
+Timing: delay 50ms, 100ms
+timing_delay:50:100:
+
+Timing: delay 50ms, 200ms
+timing_delay:50:200:
+
+Timing: alarm in 0 second
+timing_alarm:0:
+
+Timing: alarm in 1 second
+timing_alarm:1:
+
+Timing: hardclock
+timing_hardclock:
diff --git a/tests/suites/test_suite_timing.function b/tests/suites/test_suite_timing.function
index 5882f85..1610155 100644
--- a/tests/suites/test_suite_timing.function
+++ b/tests/suites/test_suite_timing.function
@@ -1,5 +1,51 @@
 /* BEGIN_HEADER */
+
+/* This test module exercises the timing module. One of the expected failure
+   modes is for timers to never expire, which could lead to an infinite loop.
+   The function timing_timer_simple is protected against this failure mode and
+   checks that timers do expire. Other functions will terminate if their
+   timers do expire. Therefore it is recommended to run timing_timer_simple
+   first and run other test functions only if that timing_timer_simple
+   succeeded. */
+
+#include <limits.h>
+
 #include "mbedtls/timing.h"
+
+/* Wait this many milliseconds for a short timing test. This duration
+   should be large enough that, in practice, if you read the timer
+   value twice in a row, it won't have jumped by that much. */
+#define TIMING_SHORT_TEST_MS 100
+
+/* A loop that waits TIMING_SHORT_TEST_MS must not take more than this many
+   iterations. This value needs to be large enough to accommodate fast
+   platforms (e.g. at 4GHz and 10 cycles/iteration a CPU can run through 20
+   million iterations in 50ms). The only motivation to keep this value low is
+   to avoid having an infinite loop if the timer functions are not implemented
+   correctly. Ideally this value should be based on the processor speed but we
+   don't have this information! */
+#define TIMING_SHORT_TEST_ITERATIONS_MAX 1e8
+
+/* alarm(0) must fire in no longer than this amount of time. */
+#define TIMING_ALARM_0_DELAY_MS TIMING_SHORT_TEST_MS
+
+static int expected_delay_status( uint32_t int_ms, uint32_t fin_ms,
+                                  unsigned long actual_ms )
+{
+    return( fin_ms == 0 ? -1 :
+            actual_ms >= fin_ms ? 2 :
+            actual_ms >= int_ms ? 1 :
+            0 );
+}
+
+/* Some conditions in timing_timer_simple suggest that timers are unreliable.
+   Most other test cases rely on timers to terminate, and could loop
+   indefinitely if timers are too broken. So if timing_timer_simple detected a
+   timer that risks not terminating (going backwards, or not reaching the
+   desired count in the alloted clock cycles), set this flag to immediately
+   fail those other tests without running any timers. */
+static int timers_are_badly_broken = 0;
+
 /* END_HEADER */
 
 /* BEGIN_DEPENDENCIES
@@ -7,9 +53,351 @@
  * END_DEPENDENCIES
  */
 
-/* BEGIN_CASE depends_on:MBEDTLS_SELF_TEST */
-void timing_selftest()
+/* BEGIN_CASE */
+void timing_timer_simple( )
 {
-    TEST_ASSERT( mbedtls_timing_self_test( 1 ) == 0 );
+    struct mbedtls_timing_hr_time timer;
+    unsigned long millis = 0;
+    unsigned long new_millis = 0;
+    unsigned long iterations = 0;
+    /* Start the timer. */
+    (void) mbedtls_timing_get_timer( &timer, 1 );
+    /* Busy-wait loop for a few milliseconds. */
+    do
+    {
+        new_millis = mbedtls_timing_get_timer( &timer, 0 );
+        ++iterations;
+        /* Check that the timer didn't go backwards */
+        TEST_ASSERT( new_millis >= millis );
+        millis = new_millis;
+    }
+    while( millis < TIMING_SHORT_TEST_MS &&
+           iterations <= TIMING_SHORT_TEST_ITERATIONS_MAX );
+    /* The wait duration should have been large enough for at least a
+       few runs through the loop, even on the slowest realistic platform. */
+    TEST_ASSERT( iterations >= 2 );
+    /* The wait duration shouldn't have overflowed the iteration count. */
+    TEST_ASSERT( iterations < TIMING_SHORT_TEST_ITERATIONS_MAX );
+    return;
+
+exit:
+    if( iterations >= TIMING_SHORT_TEST_ITERATIONS_MAX ||
+        new_millis < millis )
+    {
+        /* The timer was very unreliable: it didn't increment and the loop ran
+           out, or it went backwards. Other tests that use timers might go
+           into an infinite loop, so we'll skip them. */
+        timers_are_badly_broken = 1;
+    }
+
+    /* No cleanup needed, but show some diagnostic iterations, because timing
+       problems can be hard to reproduce. */
+    mbedtls_fprintf( stdout, "  Finished with millis=%lu new_millis=%lu get(timer)<=%lu iterations=%lu\n",
+                     millis, new_millis, mbedtls_timing_get_timer( &timer, 0 ),
+                     iterations );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void timing_timer_reset( )
+{
+    struct mbedtls_timing_hr_time timer;
+    unsigned long millis = 0;
+    unsigned long iterations = 0;
+
+    /* Skip this test if it looks like timers don't work at all, to avoid an
+       infinite loop below. */
+    TEST_ASSERT( !timers_are_badly_broken );
+
+    /* Start the timer. Timers are always reset to 0. */
+    TEST_ASSERT( mbedtls_timing_get_timer( &timer, 1 ) == 0 );
+    /* Busy-wait loop for a few milliseconds */
+    do
+    {
+        ++iterations;
+        millis = mbedtls_timing_get_timer( &timer, 0 );
+    }
+    while( millis < TIMING_SHORT_TEST_MS );
+
+    /* Reset the timer and check that it has restarted. */
+    TEST_ASSERT( mbedtls_timing_get_timer( &timer, 1 ) == 0 );
+    /* Read the timer immediately after reset. It should be 0 or close
+       to it. */
+    TEST_ASSERT( mbedtls_timing_get_timer( &timer, 0 ) < TIMING_SHORT_TEST_MS );
+    return;
+
+exit:
+    /* No cleanup needed, but show some diagnostic information, because timing
+       problems can be hard to reproduce. */
+    if( !timers_are_badly_broken )
+        mbedtls_fprintf( stdout, "  Finished with millis=%lu get(timer)<=%lu iterations=%lu\n",
+                         millis, mbedtls_timing_get_timer( &timer, 0 ),
+                         iterations );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void timing_two_timers( int delta )
+{
+    struct mbedtls_timing_hr_time timer1, timer2;
+    unsigned long millis1 = 0, millis2 = 0;
+
+    /* Skip this test if it looks like timers don't work at all, to avoid an
+       infinite loop below. */
+    TEST_ASSERT( !timers_are_badly_broken );
+
+    /* Start the first timer and wait for a short time. */
+    (void) mbedtls_timing_get_timer( &timer1, 1 );
+    do
+    {
+        millis1 = mbedtls_timing_get_timer( &timer1, 0 );
+    }
+    while( millis1 < TIMING_SHORT_TEST_MS );
+
+    /* Do a short busy-wait, so that the difference between timer1 and timer2
+       doesn't practically always end up being very close to a whole number of
+       milliseconds. */
+    while( delta > 0 )
+        --delta;
+
+    /* Start the second timer and compare it with the first. */
+    mbedtls_timing_get_timer( &timer2, 1 );
+    do
+    {
+        millis1 = mbedtls_timing_get_timer( &timer1, 0 );
+        millis2 = mbedtls_timing_get_timer( &timer2, 0 );
+        /* The first timer should always be ahead of the first. */
+        TEST_ASSERT( millis1 > millis2 );
+        /* The timers shouldn't drift apart, i.e. millis2-millis1 should stay
+           roughly constant, but this is hard to test reliably, especially in
+           a busy environment such as an overloaded continuous integration
+           system, so we don't test it it. */
+    }
+    while( millis2 < TIMING_SHORT_TEST_MS );
+
+    return;
+
+exit:
+    /* No cleanup needed, but show some diagnostic iterations, because timing
+       problems can be hard to reproduce. */
+    if( !timers_are_badly_broken )
+        mbedtls_fprintf( stdout, "  Finished with millis1=%lu get(timer1)<=%lu millis2=%lu get(timer2)<=%lu\n",
+                         millis1, mbedtls_timing_get_timer( &timer1, 0 ),
+                         millis2, mbedtls_timing_get_timer( &timer2, 0 ) );
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void timing_alarm( int seconds )
+{
+    struct mbedtls_timing_hr_time timer;
+    unsigned long millis = 0;
+    /* We check that about the desired number of seconds has elapsed. Be
+       slightly liberal with the lower bound, so as to allow platforms where
+       the alarm (with second resolution) and the timer (with millisecond
+       resolution) are based on different clocks. Be very liberal with the
+       upper bound, because the platform might be busy. */
+    unsigned long millis_min = ( seconds > 0 ?
+                                 seconds * 900 :
+                                 0 );
+    unsigned long millis_max = ( seconds > 0 ?
+                                 seconds * 1100 + 400 :
+                                 TIMING_ALARM_0_DELAY_MS );
+    unsigned long iterations = 0;
+
+    /* Skip this test if it looks like timers don't work at all, to avoid an
+       infinite loop below. */
+    TEST_ASSERT( !timers_are_badly_broken );
+
+    /* Set an alarm and count how long it takes with a timer. */
+    (void) mbedtls_timing_get_timer( &timer, 1 );
+    mbedtls_set_alarm( seconds );
+
+    if( seconds > 0 )
+    {
+        /* We set the alarm for at least 1 second. It should not have fired
+           immediately, even on a slow and busy platform. */
+        TEST_ASSERT( !mbedtls_timing_alarmed );
+    }
+    /* A 0-second alarm should fire quickly, but we don't guarantee that it
+       fires immediately, so mbedtls_timing_alarmed may or may not be set at
+       this point. */
+
+    /* Busy-wait until the alarm rings */
+    do
+    {
+        ++iterations;
+        millis = mbedtls_timing_get_timer( &timer, 0 );
+    }
+    while( !mbedtls_timing_alarmed && millis <= millis_max );
+
+    TEST_ASSERT( mbedtls_timing_alarmed );
+    TEST_ASSERT( millis >= millis_min );
+    TEST_ASSERT( millis <= millis_max );
+
+    mbedtls_timing_alarmed = 0;
+    return;
+
+exit:
+    /* Show some diagnostic iterations, because timing
+       problems can be hard to reproduce. */
+    if( !timers_are_badly_broken )
+        mbedtls_fprintf( stdout, "  Finished with alarmed=%d millis=%lu get(timer)<=%lu iterations=%lu\n",
+                         mbedtls_timing_alarmed,
+                         millis, mbedtls_timing_get_timer( &timer, 0 ),
+                         iterations );
+    /* Cleanup */
+    mbedtls_timing_alarmed = 0;
+}
+/* END_CASE */
+
+/* BEGIN_CASE */
+void timing_delay( int int_ms, int fin_ms )
+{
+    /* This function assumes that if int_ms is nonzero then it is large
+       enough that we have time to read all timers at least once in an
+       interval of time lasting int_ms milliseconds, and likewise for (fin_ms
+       - int_ms). So don't call it with arguments that are too small. */
+
+    mbedtls_timing_delay_context delay;
+    struct mbedtls_timing_hr_time timer;
+    unsigned long delta = 0; /* delay started between timer=0 and timer=delta */
+    unsigned long before = 0, after = 0;
+    unsigned long iterations = 0;
+    int status = -2;
+    int saw_status_1 = 0;
+    int warn_inconclusive = 0;
+
+    assert( int_ms >= 0 );
+    assert( fin_ms >= 0 );
+
+    /* Skip this test if it looks like timers don't work at all, to avoid an
+       infinite loop below. */
+    TEST_ASSERT( !timers_are_badly_broken );
+
+    /* Start a reference timer. Program a delay, and verify that the status of
+       the delay is consistent with the time given by the reference timer. */
+    (void) mbedtls_timing_get_timer( &timer, 1 );
+    mbedtls_timing_set_delay( &delay, int_ms, fin_ms );
+    /* Set delta to an upper bound for the interval between the start of timer
+       and the start of delay. Reading timer after starting delay gives us an
+       upper bound for the interval, rounded to a 1ms precision. Since this
+       might have been rounded down, but we need an upper bound, we add 1. */
+    delta = mbedtls_timing_get_timer( &timer, 0 ) + 1;
+
+    status = mbedtls_timing_get_delay( &delay );
+    if( fin_ms == 0 )
+    {
+        /* Cancelled timer. Just check the correct status for this case. */
+        TEST_ASSERT( status == -1 );
+        return;
+    }
+
+    /* Initially, none of the delays must be passed yet if they're nonzero.
+       This could fail for very small values of int_ms and fin_ms, where "very
+       small" depends how fast and how busy the platform is. */
+    if( int_ms > 0 )
+    {
+        TEST_ASSERT( status == 0 );
+    }
+    else
+    {
+        TEST_ASSERT( status == 1 );
+    }
+
+    do
+    {
+        unsigned long delay_min, delay_max;
+        int status_min, status_max;
+        ++iterations;
+        before = mbedtls_timing_get_timer( &timer, 0 );
+        status = mbedtls_timing_get_delay( &delay );
+        after = mbedtls_timing_get_timer( &timer, 0 );
+        /* At a time between before and after, the delay's status was status.
+           Check that this is consistent given that the delay was started
+           between times 0 and delta. */
+        delay_min = ( before > delta ? before - delta : 0 );
+        status_min = expected_delay_status( int_ms, fin_ms, delay_min );
+        delay_max = after;
+        status_max = expected_delay_status( int_ms, fin_ms, delay_max );
+        TEST_ASSERT( status >= status_min );
+        TEST_ASSERT( status <= status_max );
+        if( status == 1 )
+            saw_status_1 = 1;
+    }
+    while ( before <= fin_ms + delta && status != 2 );
+
+    /* Since we've waited at least fin_ms, the delay must have fully
+       expired. */
+    TEST_ASSERT( status == 2 );
+
+    /* If the second delay is more than the first, then there must have been a
+       point in time when the first delay was passed but not the second delay.
+       This could fail for very small values of (fin_ms - int_ms), where "very
+       small" depends how fast and how busy the platform is. In practice, this
+       is the test that's most likely to fail on a heavily loaded machine. */
+    if( fin_ms > int_ms )
+    {
+        warn_inconclusive = 1;
+        TEST_ASSERT( saw_status_1 );
+    }
+
+    return;
+
+exit:
+    /* No cleanup needed, but show some diagnostic iterations, because timing
+       problems can be hard to reproduce. */
+    if( !timers_are_badly_broken )
+        mbedtls_fprintf( stdout, "  Finished with delta=%lu before=%lu after=%lu status=%d iterations=%lu\n",
+                         delta, before, after, status, iterations );
+    if( warn_inconclusive )
+        mbedtls_fprintf( stdout, "  Inconclusive test, try running it on a less heavily loaded machine.\n" );
+ }
+/* END_CASE */
+
+/* BEGIN_CASE */
+void timing_hardclock( )
+{
+    /* We make very few guarantees about mbedtls_timing_hardclock: its rate is
+       platform-dependent, it can wrap around. So there isn't much we can
+       test. But we do at least test that it doesn't crash, stall or return
+       completely nonsensical values. */
+
+    struct mbedtls_timing_hr_time timer;
+    unsigned long hardclock0 = -1, hardclock1 = -1, delta1 = -1;
+
+    /* Skip this test if it looks like timers don't work at all, to avoid an
+       infinite loop below. */
+    TEST_ASSERT( !timers_are_badly_broken );
+
+    hardclock0 = mbedtls_timing_hardclock( );
+    /* Wait 2ms to ensure a nonzero delay. Since the timer interface has 1ms
+       resolution and unspecified precision, waiting 1ms might be a very small
+       delay that's rounded up. */
+    (void) mbedtls_timing_get_timer( &timer, 1 );
+    while( mbedtls_timing_get_timer( &timer, 0 ) < 2 )
+        /*busy-wait loop*/;
+    hardclock1 = mbedtls_timing_hardclock( );
+
+    /* Although the hardclock counter can wrap around, the difference
+       (hardclock1 - hardclock0) is taken modulo the type size, so it is
+       correct as long as the counter only wrapped around at most once. We
+       further require the difference to be nonzero (after a wait of more than
+       1ms, the counter must have changed), and not to be overly large (after
+       a wait of less than 3ms, plus time lost because other processes were
+       scheduled on the CPU). If the hardclock counter runs at 4GHz, then
+       1000000000 (which is 1/4 of the counter wraparound on a 32-bit machine)
+       allows 250ms. */
+    delta1 = hardclock1 - hardclock0;
+    TEST_ASSERT( delta1 > 0 );
+    TEST_ASSERT( delta1 < 1000000000 );
+    return;
+
+exit:
+    /* No cleanup needed, but show some diagnostic iterations, because timing
+       problems can be hard to reproduce. */
+    if( !timers_are_badly_broken )
+        mbedtls_fprintf( stdout, "  Finished with hardclock=%lu,%lu\n",
+                         hardclock0, hardclock1 );
 }
 /* END_CASE */