RE: pread() and pwrite() system calls

2012-05-30 Thread David Laight
> > We have a system with linux 2.6.32 and the somewhat archaic > > uClibc 0.9.27 (but I'm not sure the current version is > > any better, and I think there are binary compatibility > > if we update). > > > > I've just discovered that pread() is 'implemented' > > by using 3 lseek() system calls an

RE: pread() and pwrite() system calls

2012-05-29 Thread Michael Ellerman
On Tue, 2012-05-29 at 09:28 +0100, David Laight wrote: > > > A special pread/pwrite asm stub that just copies > > > r7 to r0 could be used. > > > > > > Would it be enough to do: > > > syscall_pread_pwrite: > > > mov 0,7 > > > sc > > > blr > > > and handle the -ve -> errno in C? > > > > Huh?

RE: pread() and pwrite() system calls

2012-05-29 Thread David Laight
> > A special pread/pwrite asm stub that just copies > > r7 to r0 could be used. > > > > Would it be enough to do: > > syscall_pread_pwrite: > > mov 0,7 > > sc > > blr > > and handle the -ve -> errno in C? > > Huh? Won't fly, r0 is used for the system call number! I was copying that

Re: pread() and pwrite() system calls

2012-05-25 Thread Gabriel Paubert
On Fri, May 25, 2012 at 02:29:06PM +0100, David Laight wrote: > We have a system with linux 2.6.32 and the somewhat archaic > uClibc 0.9.27 (but I'm not sure the current version is > any better, and I think there are binary compatibility > if we update). > > I've just discovered that pread() is 'i