"H . J . Lu" wrote:
>
> On Wed, Jun 13, 2001 at 05:39:08PM +0200, Maciej W. Rozycki wrote:
> > On Wed, 13 Jun 2001, H . J . Lu wrote:
> >
> > > I don't have problem with 2.4.0-test11. It is the change in 2.4.3
> > > which breaks glibc.
> >
> > You mean someone changed sysmips() in an incompatible way? Aaarghh...
>
> I don't remeber the detail, it is eithet kernel crash or glibc crash.
> I switched to mips II for glibc as the result.
>
> H.J.
The latest CVS tree removed MIPS_ATOMIC_SET for CPUs without ll/sc. See the
diff below.
RCS file: /cvs/linux/arch/mips/kernel/sysmips.c,v
retrieving revision 1.17
retrieving revision 1.18
diff -r1.17 -r1.18
77a78
> #ifdef CONFIG_CPU_HAS_LLSC
120a122,124
> #else
> printk("sys_sysmips(MIPS_ATOMIC_SET, ...) not ready for !CONFIG_CPU_HAS_LLSC\n");
> #endif
However the log says:
date: 2001/04/08 13:24:27; author: ralf; state: Exp; lines: +4 -0
Fix ll/sc emulation. Extracted from Linux-VR tree by Harald.
It seems that the checkin is a mistake because apparently it is not what
linux-vr is doing. They used to have a piece of code for CPUs without ll/sc.
And recently they moved to ll/sc instruction emulation.
Ralf, the following patch includes the original vr code for MIPS_ATOMIC_SET,
no ll/sc case. Although we all know it is buggy (for small negative set
values), it is still better than nothing.
Jun
diff -Nru sysmips.c.orig sysmips.c
--- sysmips.c.orig Wed Jun 13 11:32:09 2001
+++ sysmips.c Wed Jun 13 11:46:06 2001
@@ -120,7 +120,23 @@
: "r" (&cmd));
/* Unreached */
#else
- printk("sys_sysmips(MIPS_ATOMIC_SET, ...) not ready for !CONFIG_CPU_HAS_LLSC\n");
+ /* this is handled in assembly now */
+ panic("Unexpected MIPS_ATOMIC_SET call in sys_sysmips()");
+#else
+ int flags;
+
+ /* without ll/sc, we have a broken code that kind of works */
+ /* This is broken in case of page faults and SMP ...
+ Risc/OS fauls after maximum 20 tries with EAGAIN. */
+ p = (int *) arg1;
+ retval = verify_area(VERIFY_WRITE, p, sizeof(*p));
+ if (retval)
+ goto out;
+ save_and_cli(flags);
+ retval = *p;
+ *p = arg2;
+ restore_flags(flags);
+ goto out;
#endif
}
