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__) + if (host_cmd >= F_GETLK64 && host_cmd <= F_SETLKW64) { + host_cmd -= F_GETLK64 - F_GETLK; + } +#endif + switch(cmd) { case TARGET_F_GETLK: ret = copy_from_user_flock(&fl64, arg); Thanks, Laurent