On Mon, 2024-06-24 at 18:37 +0200, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@xxxxxxxx> > > The unusual function calling conventions on SuperH ended up causing > sync_file_range to have the wrong argument order, with the 'flags' > argument getting sorted before 'nbytes' by the compiler. > > In userspace, I found that musl, glibc, uclibc and strace all expect the > normal calling conventions with 'nbytes' last, so changing the kernel > to match them should make all of those work. > > In order to be able to also fix libc implementations to work with existing > kernels, they need to be able to tell which ABI is used. An easy way > to do this is to add yet another system call using the sync_file_range2 > ABI that works the same on all architectures. > > Old user binaries can now work on new kernels, and new binaries can > try the new sync_file_range2() to work with new kernels or fall back > to the old sync_file_range() version if that doesn't exist. > > Cc: stable@xxxxxxxxxxxxxxx > Fixes: 75c92acdd5b1 ("sh: Wire up new syscalls.") > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- > arch/sh/kernel/sys_sh32.c | 11 +++++++++++ > arch/sh/kernel/syscalls/syscall.tbl | 3 ++- > 2 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/arch/sh/kernel/sys_sh32.c b/arch/sh/kernel/sys_sh32.c > index 9dca568509a5..d6f4afcb0e87 100644 > --- a/arch/sh/kernel/sys_sh32.c > +++ b/arch/sh/kernel/sys_sh32.c > @@ -59,3 +59,14 @@ asmlinkage int sys_fadvise64_64_wrapper(int fd, u32 offset0, u32 offset1, > (u64)len0 << 32 | len1, advice); > #endif > } > + > +/* > + * swap the arguments the way that libc wants them instead of > + * moving flags ahead of the 64-bit nbytes argument > + */ > +SYSCALL_DEFINE6(sh_sync_file_range6, int, fd, SC_ARG64(offset), > + SC_ARG64(nbytes), unsigned int, flags) > +{ > + return ksys_sync_file_range(fd, SC_VAL64(loff_t, offset), > + SC_VAL64(loff_t, nbytes), flags); > +} > diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl > index bbf83a2db986..c55fd7696d40 100644 > --- a/arch/sh/kernel/syscalls/syscall.tbl > +++ b/arch/sh/kernel/syscalls/syscall.tbl > @@ -321,7 +321,7 @@ > 311 common set_robust_list sys_set_robust_list > 312 common get_robust_list sys_get_robust_list > 313 common splice sys_splice > -314 common sync_file_range sys_sync_file_range > +314 common sync_file_range sys_sh_sync_file_range6 > 315 common tee sys_tee > 316 common vmsplice sys_vmsplice > 317 common move_pages sys_move_pages > @@ -395,6 +395,7 @@ > 385 common pkey_alloc sys_pkey_alloc > 386 common pkey_free sys_pkey_free > 387 common rseq sys_rseq > +388 common sync_file_range2 sys_sync_file_range2 > # room for arch specific syscalls > 393 common semget sys_semget > 394 common semctl sys_semctl Acked-by: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx> Adrian -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer `. `' Physicist `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913