[01/19] compat ABI: use non-compat openat and open_by_handle_at variants

Commit Message

Andreas Schwab June 27, 2016, 7:47 a.m. UTC

Yury Norov <[e-mail]> writes:

> The only difference is that non-compat version forces O_LARGEFILE,
> and it should be the default behaviour for all architectures, as
> we don't support 32-bit off_t. The only exception is tile32, that
> continues with compat version of syscalls.
>
> Signed-off-by: Yury Norov <[e-mail]>
> Acked-by: Arnd Bergmann <[e-mail]>
> Acked-by: Chris Metcalf <[e-mail]> [for tile]
> ---
>  arch/tile/kernel/compat.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c
> index 4912084..489ae19 100644
> --- a/arch/tile/kernel/compat.c
> +++ b/arch/tile/kernel/compat.c
> @@ -94,6 +94,9 @@ COMPAT_SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned int, offset_high,
>  #define compat_sys_readahead sys32_readahead
>  #define sys_llseek compat_sys_llseek
>  
> +#define sys_openat		compat_sys_openat
> +#define sys_open_by_handle_at	compat_sys_open_by_handle_at
> +
>  /* Call the assembly trampolines where necessary. */
>  #define compat_sys_rt_sigreturn _compat_sys_rt_sigreturn
>  #define sys_clone _sys_clone

This is a no-op.  Did you mean to add this?  Without that the testsuite
of tar fails on ILP32.

Comments

Yury Norov Aug. 15, 2016, 2:30 p.m. UTC | #1

On Mon, Jun 27, 2016 at 09:47:38AM +0200, Andreas Schwab wrote:
> Yury Norov <[e-mail]> writes:
> 
> > The only difference is that non-compat version forces O_LARGEFILE,
> > and it should be the default behaviour for all architectures, as
> > we don't support 32-bit off_t. The only exception is tile32, that
> > continues with compat version of syscalls.
> >
> > Signed-off-by: Yury Norov <[e-mail]>
> > Acked-by: Arnd Bergmann <[e-mail]>
> > Acked-by: Chris Metcalf <[e-mail]> [for tile]
> > ---
> >  arch/tile/kernel/compat.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c
> > index 4912084..489ae19 100644
> > --- a/arch/tile/kernel/compat.c
> > +++ b/arch/tile/kernel/compat.c
> > @@ -94,6 +94,9 @@ COMPAT_SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned int, offset_high,
> >  #define compat_sys_readahead sys32_readahead
> >  #define sys_llseek compat_sys_llseek
> >  
> > +#define sys_openat		compat_sys_openat
> > +#define sys_open_by_handle_at	compat_sys_open_by_handle_at
> > +
> >  /* Call the assembly trampolines where necessary. */
> >  #define compat_sys_rt_sigreturn _compat_sys_rt_sigreturn
> >  #define sys_clone _sys_clone
> 
> This is a no-op.  Did you mean to add this?  Without that the testsuite
> of tar fails on ILP32.

The change you suggest below is what I originally sent at the end of
December, but that chunk was lost after one of numerous rebases probably.

http://lkml.iu.edu/hypermail/linux/kernel/1512.3/00510.html

IIRC, the only difference between this couple of syscalls and their
compat versions is that non-compat syscalls set O_LARGEFILE depending
on (BITS_PER_LONG != 32). Next patch of this series introduces
ARCH_32BIT_OFF_T config option to force O_LARGEFILE for 64-bit arches,
and all new 32-bit arches, as ARCH_32BIT_OFF_T is enabled for existing
32-bit arches explicitly.

O_LARGEFILE is controlled like this:
        -#define force_o_largefile() (BITS_PER_LONG != 32)
        +#define force_o_largefile() (!IS_ENABLED(CONFIG_ARCH_32BIT_OFF_T))

So if I restore original patch, everything will work. But my question
is: if ARCH_32BIT_OFF_T disables O_LARGEFILE for tile32 anyway, what
for we redirect native syscall handlers to compat ones? They are
looking identical...

If my understanding is correct, we can drop the change in
arch/tile/kernel/compat.c and join this patch with next one in this
series.

Chris, Arnd?

> 
> diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> index a26415b..4dcc38d 100644
> --- a/include/uapi/asm-generic/unistd.h
> +++ b/include/uapi/asm-generic/unistd.h
> @@ -178,7 +178,7 @@ __SYSCALL(__NR_fchownat, sys_fchownat)
>  #define __NR_fchown 55
>  __SYSCALL(__NR_fchown, sys_fchown)
>  #define __NR_openat 56
> -__SC_COMP(__NR_openat, sys_openat, compat_sys_openat)
> +__SYSCALL(__NR_openat, sys_openat)
>  #define __NR_close 57
>  __SYSCALL(__NR_close, sys_close)
>  #define __NR_vhangup 58
> @@ -676,8 +676,7 @@ __SYSCALL(__NR_fanotify_mark, sys_fanotify_mark)
>  #define __NR_name_to_handle_at         264
>  __SYSCALL(__NR_name_to_handle_at, sys_name_to_handle_at)
>  #define __NR_open_by_handle_at         265
> -__SC_COMP(__NR_open_by_handle_at, sys_open_by_handle_at, \
> -	  compat_sys_open_by_handle_at)
> +__SYSCALL(__NR_open_by_handle_at, sys_open_by_handle_at)
>  #define __NR_clock_adjtime 266
>  __SC_COMP(__NR_clock_adjtime, sys_clock_adjtime, compat_sys_clock_adjtime)
>  #define __NR_syncfs 267
> -- 
> 2.9.0
> 
> 
> Andreas.
> 
> -- 
> Andreas Schwab, SUSE Labs, [e-mail]
> GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
> "And now for something completely different."

Arnd Bergmann Aug. 25, 2016, 3:52 p.m. UTC | #2

On Monday, August 15, 2016 5:30:28 PM CEST Yury Norov wrote:
> On Mon, Jun 27, 2016 at 09:47:38AM +0200, Andreas Schwab wrote:
> > Yury Norov <[e-mail]> writes:
> > 
> > > The only difference is that non-compat version forces O_LARGEFILE,
> > > and it should be the default behaviour for all architectures, as
> > > we don't support 32-bit off_t. The only exception is tile32, that
> > > continues with compat version of syscalls.
> > >
> > > Signed-off-by: Yury Norov <[e-mail]>
> > > Acked-by: Arnd Bergmann <[e-mail]>
> > > Acked-by: Chris Metcalf <[e-mail]> [for tile]
> > > ---
> > >  arch/tile/kernel/compat.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c
> > > index 4912084..489ae19 100644
> > > --- a/arch/tile/kernel/compat.c
> > > +++ b/arch/tile/kernel/compat.c
> > > @@ -94,6 +94,9 @@ COMPAT_SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned int, offset_high,
> > >  #define compat_sys_readahead sys32_readahead
> > >  #define sys_llseek compat_sys_llseek
> > >  
> > > +#define sys_openat		compat_sys_openat
> > > +#define sys_open_by_handle_at	compat_sys_open_by_handle_at
> > > +
> > >  /* Call the assembly trampolines where necessary. */
> > >  #define compat_sys_rt_sigreturn _compat_sys_rt_sigreturn
> > >  #define sys_clone _sys_clone
> > 
> > This is a no-op.  Did you mean to add this?  Without that the testsuite
> > of tar fails on ILP32.
> 
> The change you suggest below is what I originally sent at the end of
> December, but that chunk was lost after one of numerous rebases probably.
> 
> http://lkml.iu.edu/hypermail/linux/kernel/1512.3/00510.html
> 
> IIRC, the only difference between this couple of syscalls and their
> compat versions is that non-compat syscalls set O_LARGEFILE depending
> on (BITS_PER_LONG != 32). Next patch of this series introduces
> ARCH_32BIT_OFF_T config option to force O_LARGEFILE for 64-bit arches,
> and all new 32-bit arches, as ARCH_32BIT_OFF_T is enabled for existing
> 32-bit arches explicitly.
> 
> O_LARGEFILE is controlled like this:
>         -#define force_o_largefile() (BITS_PER_LONG != 32)
>         +#define force_o_largefile() (!IS_ENABLED(CONFIG_ARCH_32BIT_OFF_T))
> 
> So if I restore original patch, everything will work. But my question
> is: if ARCH_32BIT_OFF_T disables O_LARGEFILE for tile32 anyway, what
> for we redirect native syscall handlers to compat ones? They are
> looking identical...

I've lost context here, but let me try to recall what we had
discussed in the past:

- native 32-bit architectures are handled using CONFIG_ARCH_32BIT_OFF_T
- native 64-bit architectures keep setting the flag.
- compat 32-bit architectures need special cases, but the only one
  that exists is tile, which has to keep not setting O_LARGEFILE
  while new compat architectures (ilp32) should set it.
 
> If my understanding is correct, we can drop the change in
> arch/tile/kernel/compat.c and join this patch with next one in this
> series.
> 
> Chris, Arnd?

The change in arch/tile/kernel/compat.c can either come before the
below change, or in the same patch, but not later.

	Arnd

> > diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> > index a26415b..4dcc38d 100644
> > --- a/include/uapi/asm-generic/unistd.h
> > +++ b/include/uapi/asm-generic/unistd.h
> > @@ -178,7 +178,7 @@ __SYSCALL(__NR_fchownat, sys_fchownat)
> >  #define __NR_fchown 55
> >  __SYSCALL(__NR_fchown, sys_fchown)
> >  #define __NR_openat 56
> > -__SC_COMP(__NR_openat, sys_openat, compat_sys_openat)
> > +__SYSCALL(__NR_openat, sys_openat)
> >  #define __NR_close 57
> >  __SYSCALL(__NR_close, sys_close)
> >  #define __NR_vhangup 58
> > @@ -676,8 +676,7 @@ __SYSCALL(__NR_fanotify_mark, sys_fanotify_mark)
> >  #define __NR_name_to_handle_at         264
> >  __SYSCALL(__NR_name_to_handle_at, sys_name_to_handle_at)
> >  #define __NR_open_by_handle_at         265
> > -__SC_COMP(__NR_open_by_handle_at, sys_open_by_handle_at, \
> > -	  compat_sys_open_by_handle_at)
> > +__SYSCALL(__NR_open_by_handle_at, sys_open_by_handle_at)
> >  #define __NR_clock_adjtime 266
> >  __SC_COMP(__NR_clock_adjtime, sys_clock_adjtime, compat_sys_clock_adjtime)
> >  #define __NR_syncfs 267
>

Yury Norov Aug. 29, 2016, 8:43 a.m. UTC | #3

On Thu, Aug 25, 2016 at 05:52:11PM +0200, Arnd Bergmann wrote:
> On Monday, August 15, 2016 5:30:28 PM CEST Yury Norov wrote:
> > On Mon, Jun 27, 2016 at 09:47:38AM +0200, Andreas Schwab wrote:
> > > Yury Norov <[e-mail]> writes:
> > > 
> > > > The only difference is that non-compat version forces O_LARGEFILE,
> > > > and it should be the default behaviour for all architectures, as
> > > > we don't support 32-bit off_t. The only exception is tile32, that
> > > > continues with compat version of syscalls.
> > > >
> > > > Signed-off-by: Yury Norov <[e-mail]>
> > > > Acked-by: Arnd Bergmann <[e-mail]>
> > > > Acked-by: Chris Metcalf <[e-mail]> [for tile]
> > > > ---
> > > >  arch/tile/kernel/compat.c | 3 +++
> > > >  1 file changed, 3 insertions(+)
> > > >
> > > > diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c
> > > > index 4912084..489ae19 100644
> > > > --- a/arch/tile/kernel/compat.c
> > > > +++ b/arch/tile/kernel/compat.c
> > > > @@ -94,6 +94,9 @@ COMPAT_SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned int, offset_high,
> > > >  #define compat_sys_readahead sys32_readahead
> > > >  #define sys_llseek compat_sys_llseek
> > > >  
> > > > +#define sys_openat		compat_sys_openat
> > > > +#define sys_open_by_handle_at	compat_sys_open_by_handle_at
> > > > +
> > > >  /* Call the assembly trampolines where necessary. */
> > > >  #define compat_sys_rt_sigreturn _compat_sys_rt_sigreturn
> > > >  #define sys_clone _sys_clone
> > > 
> > > This is a no-op.  Did you mean to add this?  Without that the testsuite
> > > of tar fails on ILP32.
> > 
> > The change you suggest below is what I originally sent at the end of
> > December, but that chunk was lost after one of numerous rebases probably.
> > 
> > http://lkml.iu.edu/hypermail/linux/kernel/1512.3/00510.html
> > 
> > IIRC, the only difference between this couple of syscalls and their
> > compat versions is that non-compat syscalls set O_LARGEFILE depending
> > on (BITS_PER_LONG != 32). Next patch of this series introduces
> > ARCH_32BIT_OFF_T config option to force O_LARGEFILE for 64-bit arches,
> > and all new 32-bit arches, as ARCH_32BIT_OFF_T is enabled for existing
> > 32-bit arches explicitly.
> > 
> > O_LARGEFILE is controlled like this:
> >         -#define force_o_largefile() (BITS_PER_LONG != 32)
> >         +#define force_o_largefile() (!IS_ENABLED(CONFIG_ARCH_32BIT_OFF_T))
> > 
> > So if I restore original patch, everything will work. But my question
> > is: if ARCH_32BIT_OFF_T disables O_LARGEFILE for tile32 anyway, what
> > for we redirect native syscall handlers to compat ones? They are
> > looking identical...
> 
> I've lost context here, but let me try to recall what we had
> discussed in the past:
> 
> - native 32-bit architectures are handled using CONFIG_ARCH_32BIT_OFF_T
> - native 64-bit architectures keep setting the flag.
> - compat 32-bit architectures need special cases, but the only one
>   that exists is tile, which has to keep not setting O_LARGEFILE
>   while new compat architectures (ilp32) should set it.
>  
> > If my understanding is correct, we can drop the change in
> > arch/tile/kernel/compat.c and join this patch with next one in this
> > series.
> > 
> > Chris, Arnd?
> 
> The change in arch/tile/kernel/compat.c can either come before the
> below change, or in the same patch, but not later.
> 
> 	Arnd

Correct, I'll add it to this patch

> 
> > > diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> > > index a26415b..4dcc38d 100644
> > > --- a/include/uapi/asm-generic/unistd.h
> > > +++ b/include/uapi/asm-generic/unistd.h
> > > @@ -178,7 +178,7 @@ __SYSCALL(__NR_fchownat, sys_fchownat)
> > >  #define __NR_fchown 55
> > >  __SYSCALL(__NR_fchown, sys_fchown)
> > >  #define __NR_openat 56
> > > -__SC_COMP(__NR_openat, sys_openat, compat_sys_openat)
> > > +__SYSCALL(__NR_openat, sys_openat)
> > >  #define __NR_close 57
> > >  __SYSCALL(__NR_close, sys_close)
> > >  #define __NR_vhangup 58
> > > @@ -676,8 +676,7 @@ __SYSCALL(__NR_fanotify_mark, sys_fanotify_mark)
> > >  #define __NR_name_to_handle_at         264
> > >  __SYSCALL(__NR_name_to_handle_at, sys_name_to_handle_at)
> > >  #define __NR_open_by_handle_at         265
> > > -__SC_COMP(__NR_open_by_handle_at, sys_open_by_handle_at, \
> > > -	  compat_sys_open_by_handle_at)
> > > +__SYSCALL(__NR_open_by_handle_at, sys_open_by_handle_at)
> > >  #define __NR_clock_adjtime 266
> > >  __SC_COMP(__NR_clock_adjtime, sys_clock_adjtime, compat_sys_clock_adjtime)
> > >  #define __NR_syncfs 267
> > 
>

Patch

diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index a26415b..4dcc38d 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -178,7 +178,7 @@  __SYSCALL(__NR_fchownat, sys_fchownat)
 #define __NR_fchown 55
 __SYSCALL(__NR_fchown, sys_fchown)
 #define __NR_openat 56
-__SC_COMP(__NR_openat, sys_openat, compat_sys_openat)
+__SYSCALL(__NR_openat, sys_openat)
 #define __NR_close 57
 __SYSCALL(__NR_close, sys_close)
 #define __NR_vhangup 58
@@ -676,8 +676,7 @@  __SYSCALL(__NR_fanotify_mark, sys_fanotify_mark)
 #define __NR_name_to_handle_at         264
 __SYSCALL(__NR_name_to_handle_at, sys_name_to_handle_at)
 #define __NR_open_by_handle_at         265
-__SC_COMP(__NR_open_by_handle_at, sys_open_by_handle_at, \
-	  compat_sys_open_by_handle_at)
+__SYSCALL(__NR_open_by_handle_at, sys_open_by_handle_at)
 #define __NR_clock_adjtime 266
 __SC_COMP(__NR_clock_adjtime, sys_clock_adjtime, compat_sys_clock_adjtime)
 #define __NR_syncfs 267