Re: 2.2.{9,10} strangeness (random SEGV/ILL in kernel compilation)

Alexander V. Lukyanov (lav@yars.free.net)
Tue, 22 Jun 1999 21:37:32 +0400


On Tue, Jun 22, 1999 at 11:13:53AM +0400, Alexander V. Lukyanov wrote:
> Looks like I have found the problem. 2.2.10 with
> arch/alpha/kernel/entry.S from 2.2.7 works flawlessly for me.
> Can anybody confirm that?
>
> One suspicious change in 2.2.8 was removing `call_pal PAL_tbi' after
> PAL_swpctx. What could that mean... I have not tried to back-out that
> part of patch yet, maybe someone will figure out what was wrong with 2.2.8
> patch.

Ok, I have verified that this patch against 2.2.10-ac2 (re-adding two lines)
solves my problem:
--- entry.S-ac2 Mon Jun 21 21:18:50 1999
+++ entry.S Tue Jun 22 20:28:04 1999
@@ -525,7 +525,8 @@
.prologue 0
bsr $1,do_switch_stack
call_pal PAL_swpctx
- unop
+ lda $16,-2($31)
+ call_pal PAL_tbi
bsr $1,undo_switch_stack
lda $8,0x3fff
bic $30,$8,$8

PAL_tbi is "Translation Buffer Invalidate" and -2 argument means "Flush
all TB entries (tbia)", so I guess it is really needed for context switch.

Alexander.