RTAS should never cause an exception but if it does (for example accessing
outside our RMO) then we might go a long way through the kernel before
oopsing. If we unset MSR_RI we should at least stop things on exception
exit.
Signed-off-by: Anton Blanchard <an...@samba.org>
---
The setting of MSR_RI during RTAS calls went in ages ago (2003), and I'm
not sure why. Clearly an exception inside RTAS is fatal since we most likely
have a bad r13.
Index: powerpc.git/arch/powerpc/kernel/entry_64.S
===================================================================
--- powerpc.git.orig/arch/powerpc/kernel/entry_64.S 2010-02-08
12:25:51.543072119 +1100
+++ powerpc.git/arch/powerpc/kernel/entry_64.S 2010-02-08 12:26:56.043513290
+1100
@@ -791,9 +791,8 @@ _GLOBAL(enter_rtas)
li r9,1
rldicr r9,r9,MSR_SF_LG,(63-MSR_SF_LG)
- ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP
+ ori r9,r9,MSR_IR|MSR_DR|MSR_FE0|MSR_FE1|MSR_FP|MSR_RI
andc r6,r0,r9
- ori r6,r6,MSR_RI
sync /* disable interrupts so SRR0/1 */
mtmsrd r0 /* don't get trashed */
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