Hi, any news/comment about this?
thx Waldemar Waldemar Brodkorb wrote, > fork() is broken for MIPS64 N64 ABI. You can check it with a simple > C program statically linked with qemu-mips64 user emulation. > Internally fork() is using the clone system call (at least with NPTL) > with 5 arguments. See ./libpthread/nptl/sysdeps/unix/sysv/linux/i386/fork.c. > The calling conventions for MIPS N32 and N64 allow to use up to 8 registers > for that. See http://en.wikipedia.org/wiki/Calling_convention#MIPS > This is correctly implemented in libc/sysdeps/linux/mips/bits/syscalls.h, > but not in libc/sysdeps/linux/mips/sysdep.h. fork.c uses the later one. > It seems that fork() works fine for MIPS64 N32 with just using the stack like > with the O32 case. There is a user of INLINE_SYSCALL with 7 arguments in > libc/sysdeps/linux/common/sync_file_range.c for MIPS64 N32, so I decided to > only use the macros for the MIPS64 N64 case. With this patch my uClibc based > Linux system boots up fine in qemu-system-mips64. > > Signed-off-by: Waldemar Brodkorb <w...@openadk.org> > --- > libc/sysdeps/linux/mips/sysdep.h | 63 > ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 63 insertions(+) > > diff --git a/libc/sysdeps/linux/mips/sysdep.h > b/libc/sysdeps/linux/mips/sysdep.h > index 6dba1fb..46b6c53 100644 > --- a/libc/sysdeps/linux/mips/sysdep.h > +++ b/libc/sysdeps/linux/mips/sysdep.h > @@ -279,6 +279,8 @@ L(syse1): > _sys_result; \ > }) > > +#if _MIPS_SIM == _ABIO32 || _MIPS_SIM == _ABIN32 > + > /* We need to use a frame pointer for the functions in which we > adjust $sp around the syscall, or debug information and unwind > information will be $sp relative and thus wrong during the syscall. As > @@ -382,6 +384,67 @@ L(syse1): > #define __SYSCALL_CLOBBERS "$1", "$3", "$8", "$9", "$10", "$11", "$12", > "$13", \ > "$14", "$15", "$24", "$25", "memory" > > +#else /* N64 */ > + > +#undef internal_syscall5 > +#define internal_syscall5(ncs_init, cs_init, input, err, arg1, arg2, arg3, > arg4, arg5) \ > +({ \ > + long _sys_result; \ > + \ > + { \ > + register long __v0 __asm__("$2") ncs_init; \ > + register long __a0 __asm__("$4") = (long) arg1; \ > + register long __a1 __asm__("$5") = (long) arg2; \ > + register long __a2 __asm__("$6") = (long) arg3; \ > + register long __a3 __asm__("$7") = (long) arg4; \ > + register long __a4 __asm__("$8") = (long) arg5; \ > + __asm__ __volatile__ ( \ > + ".set\tnoreorder\n\t" \ > + cs_init \ > + "syscall\n\t" \ > + ".set\treorder" \ > + : "=r" (__v0), "+r" (__a3) \ > + : input, "r" (__a0), "r" (__a1), "r" (__a2), "r" (__a4) \ > + : __SYSCALL_CLOBBERS); \ > + err = __a3; \ > + _sys_result = __v0; \ > + } \ > + _sys_result; \ > +}) > + > +#undef internal_syscall6 > +#define internal_syscall6(ncs_init, cs_init, input, err, arg1, arg2, arg3, > arg4, arg5, arg6) \ > +({ \ > + long _sys_result; \ > + \ > + { \ > + register long __v0 __asm__("$2") ncs_init; \ > + register long __a0 __asm__("$4") = (long) arg1; \ > + register long __a1 __asm__("$5") = (long) arg2; \ > + register long __a2 __asm__("$6") = (long) arg3; \ > + register long __a3 __asm__("$7") = (long) arg4; \ > + register long __a4 __asm__("$8") = (long) arg5; \ > + register long __a5 __asm__("$9") = (long) arg6; \ > + __asm__ __volatile__ ( \ > + ".set\tnoreorder\n\t" \ > + cs_init \ > + "syscall\n\t" \ > + ".set\treorder" \ > + : "=r" (__v0), "+r" (__a3) \ > + : input, "r" (__a0), "r" (__a1), "r" (__a2), "r" (__a4), \ > + "r" (__a5) \ > + : __SYSCALL_CLOBBERS); \ > + err = __a3; \ > + _sys_result = __v0; \ > + } \ > + _sys_result; \ > +}) > + > +#define __SYSCALL_CLOBBERS "$1", "$3", "$10", "$11", "$12", "$13", \ > + "$14", "$15", "$24", "$25", "hi", "lo", "memory" > + > +#endif > + > /* Pointer mangling is not yet supported for MIPS. */ > #define PTR_MANGLE(var) (void) (var) > #define PTR_DEMANGLE(var) (void) (var) > -- > 1.7.10.4 > > _______________________________________________ > uClibc mailing list > uClibc@uclibc.org > http://lists.busybox.net/mailman/listinfo/uclibc > _______________________________________________ uClibc mailing list uClibc@uclibc.org http://lists.busybox.net/mailman/listinfo/uclibc
