Le 11/07/2018 à 15:04, Laurent Vivier a écrit : > Le 11/07/2018 à 12:55, Shivaprasad G Bhat a écrit : >> Qemu includes the glibc headers for the host defines and target headers are >> part of the qemu source themselves. The glibc has the F_GETLK64, F_SETLK64 >> and F_SETLKW64 defined to 12, 13 and 14 for all archs(generic) in >> sysdeps/unix/sysv/linux/bits/fcntl-linux.h. The linux kernel generic >> definition for F_*LK is 5, 6 & 7 and F_*LK64* is 12,13, and 14 as seen in >> include/uapi/asm-generic/fcntl.h. On 64bit machine, by default the kernel >> assumes all F_*LK to 64bit calls and doesnt support use of F_*LK64* as >> can be seen in include/linux/fcntl.h in linux source. >> >> On x86_64 host, the values for F_*LK64* are set to 5, 6 and 7 >> explicitly in /usr/include/x86_64-linux-gnu/bits/fcntl.h by the glibc. >> Whereas, a PPC64 host doesn't have such a definition in >> /usr/include/powerpc64le-linux-gnu/bits/fcntl.h by the glibc. So, >> the sources on PPC64 host sees the default value of F_*LK64* >> as 12, 13 & 14(fcntl-linux.h). >> >> Since the 64bit kernel doesnt support 12, 13 & 14; the glibc fcntl syscall >> implementation(__libc_fcntl*(), __fcntl64_nocancel) does the F_*LK64* value >> convertion back to F_*LK* values on PPC64 as seen in >> sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h with FCNTL_ADJUST_CMD() >> macro. Whereas on x86_64 host the values for F_*LK64* are set to 5, 6 and 7 >> and no adjustments are needed. >> >> Since qemu doesnt use the glibc fcntl, but makes the safe_syscall* on its >> own, the PPC64 qemu is calling the syscall with 12, 13, and 14(without >> adjustment) and they all fail. The fcntl calls to F_GETLK/F_SETLK|W all >> fail by all pplications run on PPC64 host user emulation. >> >> The fix here could be to see why on PPC64 the glibc is still keeping >> F_*LK64* different from F_*LK and why adjusting them to 5, 6 and 7 before >> the syscall for PPC only. See if we can make the >> /usr/include/powerpc64le-linux-gnu/bits/fcntl.h to have the values >> 5, 6 & 7 just like x86_64 and remove the adjustment code in glibc. That way, >> qemu sources see the kernel supported values in glibc headers. >> >> OR >> >> On PPC64 host, qemu sources see both F_LK* & F_LK64* as same and set to >> 12, 13 and 14 because __USE_FILE_OFFSET64 is defined in qemu >> sources(also refer sysdeps/unix/sysv/linux/bits/fcntl-linux.h). >> Since F_*LK and F_*LK64 are same, the value adjument like done by glibc in >> qemu sources is difficult. So, Overwrite the glibc defaults with the actual >> supported values in Qemu. The current patch is doing this. >> >> Signed-off-by: Shivaprasad G Bhat <sb...@linux.vnet.ibm.com> >> --- >> linux-user/syscall.c | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/linux-user/syscall.c b/linux-user/syscall.c >> index 7b9ac3b408..1693e69ce0 100644 >> --- a/linux-user/syscall.c >> +++ b/linux-user/syscall.c >> @@ -250,6 +250,20 @@ static type name (type1 arg1,type2 arg2,type3 >> arg3,type4 arg4,type5 arg5, \ >> #define TARGET_NR__llseek TARGET_NR_llseek >> #endif >> >> +/* glibc headers has these defined to 12, 13 and 14 and is not supported >> + * by kernel. The glibc fcntl call actually adjusts them back to 5, 6 and 7 >> + * before making the syscall(). Since we make the syscall directly, >> + * overwite/adjust to what is supported by the kernel. >> + */ >> +#if defined(__linux__) && defined(__powerpc64__) >> +#undef F_GETLK64 >> +#define F_GETLK64 5 /* Get record locking info. */ >> +#undef F_SETLK64 >> +#define F_SETLK64 6 /* Set record locking info (non-blocking). >> */ >> +#undef F_SETLKW64 >> +#define F_SETLKW64 7 /* Set record locking info (blocking). */ >> +#endif >> + >> #ifdef __NR_gettid >> _syscall0(int, gettid) >> #else >> > > These macros are used in target_to_host_fcntl_cmd(), and this function > is used with safe_fcntl() and fcntl(). > > So I think it would be cleaner to do the change after > target_to_host_fcntl_cmd() in do_fcntl() as it is done in glibc instead > of redefining system values. Something like: > > --- a/linux-user/syscall.c > +++ b/linux-user/syscall.c > @@ -6782,6 +6782,12 @@ static abi_long do_fcntl(int fd, int cmd, > abi_ulong arg) > if (host_cmd == -TARGET_EINVAL) > return host_cmd; > > +#if defined(__linux__) && defined(__powerpc64__)
Moreover, I think the "defined(__linux__)" is not needed as linux-user/syscall.c is compiled only on linux. Thanks, Laurent