kevin/linux
1
Fork 0
Code

sh: rework sync_file_range ABI

Browse Source 
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@vger.kernel.org
Fixes: 75c92acdd5 ("sh: Wire up new syscalls.")
Acked-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann 2024-06-11 22:12:43 +02:00
parent b1e31c134a
commit 30766f1105
2 changed files with 13 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/sh/kernel/sys_sh32.c
View File

@ -59,3 +59,14 @@ asmlinkage int sys_fadvise64_64_wrapper(int fd, u32 offset0, u32 offset1,
(u64)len0 << 32 | len1, advice); (u64)len0 << 32 | len1, advice);
#endif #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);
}

3
arch/sh/kernel/syscalls/syscall.tbl
View File

@ -321,7 +321,7 @@
311 common set_robust_list sys_set_robust_list 311 common set_robust_list sys_set_robust_list
312 common get_robust_list sys_get_robust_list 312 common get_robust_list sys_get_robust_list
313 common splice sys_splice 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 315 common tee sys_tee
316 common vmsplice sys_vmsplice 316 common vmsplice sys_vmsplice
317 common move_pages sys_move_pages 317 common move_pages sys_move_pages
@ -395,6 +395,7 @@
385 common pkey_alloc sys_pkey_alloc 385 common pkey_alloc sys_pkey_alloc
386 common pkey_free sys_pkey_free 386 common pkey_free sys_pkey_free
387 common rseq sys_rseq 387 common rseq sys_rseq
388 common sync_file_range2 sys_sync_file_range2
# room for arch specific syscalls # room for arch specific syscalls
393 common semget sys_semget 393 common semget sys_semget
394 common semctl sys_semctl 394 common semctl sys_semctl