Dear Qemu Community, I would like to ask you for some advice regarding the usage of arm-linux-user/qemu-arm user space program simulation.
Background: ----------- I'm looking for a way to efficiently test y2038 in-glibc solution for 32 bit architectures (e.g. ARM). For now I do use qemu-system-arm (part of Yocto/OE), which I'm using to run Linux kernel 5.1, glibc under test and Y2038 tests. It works [1]. Problem: -------- I would like to test cross-compiled tests (which are built from glibc sources) without the need to run the emulated system with qemu-system-arm. I've come across the "QEMU user mode", which would execute the cross-compiled test (with already cross-compiled glibc via -L switch) and just return exit status code. This sounds appealing. As fair as I've read - QEMU user mode emulates ARM syscalls. During test execution (single qemu user mode process) I would need to adjust date with clock_settime64 syscall and then execute other syscalls if needed. Please correct me if I'm wrong: - It looks like qemu-arm doesn't have switch which would allow it to set time offset (to e.g. year 2039 - something similar to qemu-system-arm -rtc=). - As of 5.1 qemu version there is no support for syscalls supporting 64 bit time on 32 bit architectures (e.g. clock_settime64 and friends from [2]). For my example program [3] statically build for testing (it works with qemu-system-arm): ~/work/qemu-arm-tests-program$ ../qemu-5.1.0-arm/arm-linux-user/qemu-arm -L ~/work/yocto/y2038/build/tmp/armv7at2hf-neon-poky-linux-gnueabi/y2038-glibc/2.30+git999-r0/image/opt -strace ./cst 17746 brk(NULL) = 0x00074000 17746 brk(0x000748a8) = 0x000748a8 17746 uname(0x40800370) = 0 17746 readlink("/proc/self/exe",0x407ff488,4096) = 43 17746 brk(0x000958a8) = 0x000958a8 17746 brk(0x00096000) = 0x00096000 17746 mprotect(0x00070000,8192,PROT_READ) = 0 17746statx(1,"",AT_EMPTY_PATH|AT_NO_AUTOMOUNT,STATX_BASIC_STATS,0x407ffd70) = 0 17746 Unknown syscall 404 --> is the syscall number of clock_settime64 17746 dup(2) = 3 17746 fcntl64(3,F_GETFL) = 2 17746statx(3,"",AT_EMPTY_PATH|AT_NO_AUTOMOUNT,STATX_BASIC_STATS,0x407ff8e8) = 0 ERR Questions: ---------- 1. Is there any plan to add support for emulating syscalls supporting 64 bit time on 32 bit architectures [2]? 2. Provide QEMU user space switch to adjust its time (i.e. add some offset to in-fly emulated time syscalls - like clock_settime64) when it is started? Thanks in advance for your help and reply. Links: [1] - https://github.com/lmajewski/meta-y2038/ [2] - https://elixir.bootlin.com/linux/latest/source/arch/arm/tools/syscall.tbl#L419 [3]: Example program: cat <<- EOF >> clock_settime_test.c #include <stdio.h> #include <time.h> int main (int argc, char **argv) { struct timespec tv; int ret; tv.tv_sec = 0x7FFFFFFF; tv.tv_sec += 61; tv.tv_nsec = 0; printf("clock_settime test program: "); ret = clock_settime(CLOCK_REALTIME, &tv); if (!ret) printf("OK\n"); else perror("ERR\n"); return 0; } EOF Build the test program: gcc -Wall -ggdb -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64 -I/opt/include -I/opt/usr/include -L/opt/usr/lib \ -Wl,-rpath=/opt/lib -Wl,--dynamic-linker=/opt/lib/ld-linux.so.2 clock_settime_test.c -o cst -static Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lu...@denx.de
pgpj3Hdt62hNP.pgp
Description: OpenPGP digital signature