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linux-user: Add support for adjtimex() syscall

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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>
This commit is contained in:
Aleksandar Markovic 2016-09-22 18:56:50 +02:00 • committed by Riku Voipio
parent da158a86c4
commit 19f59bcef9
4 changed files with 162 additions and 2 deletions
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28
linux-user/syscall_defs.h
View file

@ -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