semihosting: Implement SYS_ELAPSED and SYS_TICKFREQ

These are part of Semihosting for AArch32 and AArch64 Release 2.0

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210107170717.2098982-8-keithp@keithp.com>
Message-Id: <20210108224256.2321-19-alex.bennee@linaro.org>

hw/semihosting/arm-compat-semi.c

@@ -38,6 +38,7 @@
 #include "hw/semihosting/console.h"
 #include "hw/semihosting/common-semi.h"
 #include "qemu/log.h"
+#include "qemu/timer.h"
 #ifdef CONFIG_USER_ONLY
 #include "qemu.h"
 
@@ -73,6 +74,8 @@
 #define TARGET_SYS_EXIT        0x18
 #define TARGET_SYS_SYNCCACHE   0x19
 #define TARGET_SYS_EXIT_EXTENDED 0x20
+#define TARGET_SYS_ELAPSED     0x30
+#define TARGET_SYS_TICKFREQ    0x31
 
 /* ADP_Stopped_ApplicationExit is used for exit(0),
  * anything else is implemented as exit(1) */
@@ -837,6 +840,7 @@ target_ulong do_common_semihosting(CPUState *cs)
     uint32_t ret;
     uint32_t len;
     GuestFD *gf;
+    int64_t elapsed;
 
     (void) env; /* Used implicitly by arm lock_user macro */
     nr = common_semi_arg(cs, 0) & 0xffffffffU;
@@ -1246,6 +1250,18 @@ target_ulong do_common_semihosting(CPUState *cs)
         }
         gdb_exit(ret);
         exit(ret);
+    case TARGET_SYS_ELAPSED:
+        elapsed = get_clock() - clock_start;
+        if (sizeof(target_ulong) == 8) {
+            SET_ARG(0, elapsed);
+        } else {
+            SET_ARG(0, (uint32_t) elapsed);
+            SET_ARG(1, (uint32_t) (elapsed >> 32));
+        }
+        return 0;
+    case TARGET_SYS_TICKFREQ:
+        /* qemu always uses nsec */
+        return 1000000000;
     case TARGET_SYS_SYNCCACHE:
         /*
          * Clean the D-cache and invalidate the I-cache for the specified

include/qemu/timer.h

@@ -808,6 +808,8 @@ static inline int64_t get_clock_realtime(void)
     return tv.tv_sec * 1000000000LL + (tv.tv_usec * 1000);
 }
 
+extern int64_t clock_start;
+
 /* Warning: don't insert tracepoints into these functions, they are
    also used by simpletrace backend and tracepoints would cause
    an infinite recursion! */

util/qemu-timer-common.c

@@ -27,6 +27,8 @@
 /***********************************************************/
 /* real time host monotonic timer */
 
+int64_t clock_start;
+
 #ifdef _WIN32
 
 int64_t clock_freq;
@@ -41,6 +43,7 @@ static void __attribute__((constructor)) init_get_clock(void)
         exit(1);
     }
     clock_freq = freq.QuadPart;
+    clock_start = get_clock();
 }
 
 #else
@@ -55,5 +58,6 @@ static void __attribute__((constructor)) init_get_clock(void)
     if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
         use_rt_clock = 1;
     }
+    clock_start = get_clock();
 }
 #endif