linux-user: Add support for adjtimex() syscall

This patch implements Qemu user mode adjtimex() syscall support.

Syscall adjtimex() reads and optionally sets parameters for a clock
adjustment algorithm used in network synchonization or similar scenarios.

Its declaration is:

int adjtimex(struct timex *buf);

The correspondent source code in the Linux kernel is at kernel/time.c,
line 206.

The Qemu implementation is based on invocation of host's adjtimex(), and
its key part is in the "TARGET_NR_adjtimex" case segment of the the main
switch statement of the function do_syscall(), in linux-user/syscalls.c. All
necessary conversions of the data structures from target to host and from
host to target are covered. Two new functions, target_to_host_timex() and
host_to_target_timex(), are provided for the purpose of such conversions.
For that purpose, the support for related structure "timex" had tp be added
to the file linux-user/syscall_defs.h, based on its definition in Linux
kernel. Also, the relevant support for "-strace" Qemu option is included
in files linux-user/strace.c and linux-user/strace.list.

This patch also fixes failures of LTP tests adjtimex01 and adjtimex02, if
executed in Qemu user mode.

Signed-off-by: Aleksandar Rikalo <aleksandar.rikalo@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 9fdbe865dc..ca8fa6ee91 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -207,6 +207,34 @@ struct target_itimerspec {
     struct target_timespec it_value;
 };
 
+struct target_timex {
+    abi_uint modes;              /* Mode selector */
+    abi_long offset;             /* Time offset */
+    abi_long freq;               /* Frequency offset */
+    abi_long maxerror;           /* Maximum error (microseconds) */
+    abi_long esterror;           /* Estimated error (microseconds) */
+    abi_int status;              /* Clock command/status */
+    abi_long constant;           /* PLL (phase-locked loop) time constant */
+    abi_long precision;          /* Clock precision (microseconds, ro) */
+    abi_long tolerance;          /* Clock freq. tolerance (ppm, ro) */
+    struct target_timeval time;  /* Current time */
+    abi_long tick;               /* Microseconds between clock ticks */
+    abi_long ppsfreq;            /* PPS (pulse per second) frequency */
+    abi_long jitter;             /* PPS jitter (ro); nanoseconds */
+    abi_int shift;               /* PPS interval duration (seconds) */
+    abi_long stabil;             /* PPS stability */
+    abi_long jitcnt;             /* PPS jitter limit exceeded (ro) */
+    abi_long calcnt;             /* PPS calibration intervals */
+    abi_long errcnt;             /* PPS calibration errors */
+    abi_long stbcnt;             /* PPS stability limit exceeded */
+    abi_int tai;                 /* TAI offset */
+
+    /* Further padding bytes to allow for future expansion */
+    abi_int:32; abi_int:32; abi_int:32; abi_int:32;
+    abi_int:32; abi_int:32; abi_int:32; abi_int:32;
+    abi_int:32; abi_int:32; abi_int:32;
+};
+
 typedef abi_long target_clock_t;
 
 #define TARGET_HZ 100