ARM port missing pivot_root syscall

ARM port missing pivot_root syscall

[Jamie Lokier]

A few months ago a colleague was frustrated to find pivot_root missing
from the ARM port.  Semi-standard C programs that use this call would
not compile for the ARM.  Perhaps you ARM folks would like to add it?

It's probably an oversight.  Perhaps the person who added
__NR_pivot_root to the other architectures and updated the syscall table
did so before the ARM port was integrated, or perhaps the change was
lost or something like that.

On this general theme, there are other constants, whose names are not
arch-specific but whose _values_ are arch-specific.  E.g. look in
<asm/fcntl.h>.  In most cases, some of the values are required for
historical compatibility, sometimes with other operating systems.

I wonder if there are other constants missing from some ports in the
same way that __NR_pivot_root was left out of the ARM point.

Just something to think about.  Perhaps someone enthusiastic would like
to audit.

have a nice day,
-- Jamie

Re: ARM port missing pivot_root syscall

[Russell King]

_Please_ don't reply to this address - just substitute 'rmk@arm.linux.org.uk'
or 'linux@arm.linux.org.uk' please.

> A few months ago a colleague was frustrated to find pivot_root missing
> from the ARM port.  Semi-standard C programs that use this call would
> not compile for the ARM.  Perhaps you ARM folks would like to add it?

The missing system calls got added in the latest kernel.

> On this general theme, there are other constants, whose names are not
> arch-specific but whose _values_ are arch-specific.  E.g. look in
> <asm/fcntl.h>.  In most cases, some of the values are required for
> historical compatibility, sometimes with other operating systems.

I don't see any missing constants in fcntl.h, compared with x86.  Which
kernel version are you using?

Re: ARM port missing pivot_root syscall

[Jamie Lokier]

Russell King wrote:
> > A few months ago a colleague was frustrated to find pivot_root missing
> > from the ARM port.  Semi-standard C programs that use this call would
> > not compile for the ARM.  Perhaps you ARM folks would like to add it?
> 
> The missing system calls got added in the latest kernel.

Ok, good.

> > On this general theme, there are other constants, whose names are not
> > arch-specific but whose _values_ are arch-specific.  E.g. look in
> > <asm/fcntl.h>.  In most cases, some of the values are required for
> > historical compatibility, sometimes with other operating systems.
> 
> I don't see any missing constants in fcntl.h, compared with x86.  Which
> kernel version are you using?

I'm not aware of any other missing constants.

Just, having seen the missing syscalls which were presumably accidental,
I put forward that someone might wish to audit the other architectures
for missing definitions from other arch-specific header files.  Not just
asm/fcntl.h, but also e.g. asm/termios.h and others.  The idea is not
specific to the ARM port.

-- Jamie