I have started to look a little bit at the LTP tests. And one of the testcases that fails (actually it doesn't fail as it supposed to do) is the syscall getsockopt. I think the failure is due to the copy_to_user(0, from, 4) call returns 0, which I wouldn't expect when the destination pointer is NULL. I think the problem is in the __copy_user function in arch/mips/lib/memcpy. It tries to handle the exception, which we get because the destination pointer is NULL, by returning the number of uncopied bytes in $a2 to the caller. But in this case the length is only 4 bytes, and the copying is done by a single 'sw'. The problem is the length ($a2) is decreased by 4 before the 'sw' is executed. The 'sw' fails and __copy_user terminates, but returns with $a2 = 0 (instead 4). I thing the following patch will solve the problem. /Carsten -- _ _ ____ ___ Carsten Langgaard Mailto:carstenl@mips.com |\ /|||___)(___ MIPS Denmark Direct: +45 4486 5527 | \/ ||| ____) Lautrupvang 4B Switch: +45 4486 5555 TECHNOLOGIES 2750 Ballerup Fax...: +45 4486 5556 Denmark http://www.mips.com
Index: arch/mips/lib/memcpy.S =================================================================== RCS file: /home/repository/sw/linux-2.4.18/arch/mips/lib/memcpy.S,v retrieving revision 1.1.1.1 diff -u -r1.1.1.1 memcpy.S --- arch/mips/lib/memcpy.S 4 Mar 2002 11:12:21 -0000 1.1.1.1 +++ arch/mips/lib/memcpy.S 24 Jun 2002 13:46:07 -0000 @@ -248,8 +248,8 @@ 1: EXC( LOAD t0, 0(src), l_exc) ADD src, src, NBYTES - SUB len, len, NBYTES EXC( STORE t0, 0(dst), s_exc) + SUB len, len, NBYTES bne rem, len, 1b ADD dst, dst, NBYTES
