On Thu, Jan 20, 2022 at 10:43 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:
>
> On Thu, Jan 20, 2022 at 8:39 AM <guoren@xxxxxxxxxx> wrote:
> >
> > /* The array of function pointers for syscalls. */
> > extern void * const sys_call_table[];
> > +#ifdef CONFIG_COMPAT
> > +extern void * const compat_sys_call_table[];
> > +#endif
>
> No need for the #ifdef, the normal convention is to just define the
> extern declaration unconditionally for symbols that may or may not be defined.
Okay
>
> > +COMPAT_SYSCALL_DEFINE3(truncate64, const char __user *, pathname,
> > + arg_u32p(length))
> > +{
> > + return ksys_truncate(pathname, arg_u64(length));
> > +}
>
> Are you sure these are the right calling conventions? According to [1],
> I think the 64-bit argument should be in an aligned pair of registers,
> which means you need an extra pad argument as in the arm64 version
> of these functions. Same for ftruncate64, pread64, pwrite64, and
> readahead.
[1] has abandoned.
See:
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc
Ltp test results:
ftruncate01 PASS 0
ftruncate01_64 PASS 0
ftruncate03 PASS 0
ftruncate03_64 PASS 0
ftruncate04 CONF 32
ftruncate04_64 CONF 32
truncate02 PASS 0
truncate02_64 PASS 0
truncate03 PASS 0
truncate03_64 PASS 0
pread01 PASS 0
pread01_64 PASS 0
pread02 PASS 0
pread02_64 PASS 0
pread03 PASS 0
pread03_64 PASS 0
pwrite01_64 PASS 0
pwrite02_64 PASS 0
pwrite03_64 PASS 0
pwrite04_64 PASS 0
readahead01 PASS 0
readahead02 CONF 32
>
> > +COMPAT_SYSCALL_DEFINE3(ftruncate64, unsigned int, fd, arg_u32p(length))
> > +{
> > + return ksys_ftruncate(fd, arg_u64(length));
> > +}
> > +
> > +COMPAT_SYSCALL_DEFINE6(fallocate, int, fd, int, mode,
> > + arg_u32p(offset), arg_u32p(len))
> > +{
> > + return ksys_fallocate(fd, mode, arg_u64(offset), arg_u64(len));
> > +}
> > +
> > +COMPAT_SYSCALL_DEFINE5(pread64, unsigned int, fd, char __user *, buf,
> > + size_t, count, arg_u32p(pos))
> > +{
> > + return ksys_pread64(fd, buf, count, arg_u64(pos));
> > +}
> > +
> > +COMPAT_SYSCALL_DEFINE5(pwrite64, unsigned int, fd,
> > + const char __user *, buf, size_t, count, arg_u32p(pos))
> > +{
> > + return ksys_pwrite64(fd, buf, count, arg_u64(pos));
> > +}
> > +
> > +COMPAT_SYSCALL_DEFINE6(sync_file_range, int, fd, arg_u32p(offset),
> > + arg_u32p(nbytes), unsigned int, flags)
> > +{
> > + return ksys_sync_file_range(fd, arg_u64(offset), arg_u64(nbytes),
> > + flags);
> > +}
> > +
> > +COMPAT_SYSCALL_DEFINE4(readahead, int, fd, arg_u32p(offset),
> > + size_t, count)
> > +{
> > + return ksys_readahead(fd, arg_u64(offset), count);
> > +}
> > +
> > +COMPAT_SYSCALL_DEFINE6(fadvise64_64, int, fd, int, advice, arg_u32p(offset),
> > + arg_u32p(len))
> > +{
> > + return ksys_fadvise64_64(fd, arg_u64(offset), arg_u64(len), advice);
> > +}
>
> I still feel like these should be the common implementations next to the
> native handlers inside of an #ifdef CONFIG_COMPAT.
>
> The names clash with the custom versions defined for powerpc and sparc,
> but the duplicates look compatible if you can account for the padded
> argument and the lo/hi order of the pairs, so could just be removed here
> (all other architectures use custom function names instead).
I would try it later.
>
> Arnd
>
> [1] https://riscv.org/wp-content/uploads/2015/01/riscv-calling.pdf
--
Best Regards
Guo Ren
ML: https://lore.kernel.org/linux-csky/
