On 03/30/2016 12:44 PM, Hari Bathini wrote:
On 03/30/2016 05:55 AM, Michael Ellerman wrote:
On Tue, 2016-29-03 at 18:34:37 UTC, Hari Bathini wrote:
diff --git a/arch/powerpc/kernel/exceptions-64s.S
b/arch/powerpc/kernel/exceptions-64s.S
index 7716ceb..e598580 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -764,8 +764,8 @@ kvmppc_skip_Hinterrupt:
#endif
/*
- * Code from here down to __end_handlers is invoked from the
- * exception prologs above. Because the prologs assemble the
+ * Code from here down to end of out of line handlers is invoked from
+ * the exception prologs above. Because the prologs assemble the
I think it would be better to just replace __end_handlers with
__end_interrupts,
that way it's entirely clear what location you're talking about.
@@ -953,11 +953,6 @@ hv_facility_unavailable_relon_trampoline:
#endif
STD_RELON_EXCEPTION_PSERIES(0x5700, 0x1700, altivec_assist)
- /* Other future vectors */
- .align 7
- .globl __end_interrupts
-__end_interrupts:
-
.align 7
system_call_entry:
b system_call_common
@@ -1230,10 +1225,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
STD_EXCEPTION_COMMON(0xf60, facility_unavailable,
facility_unavailable_exception)
STD_EXCEPTION_COMMON(0xf80, hv_facility_unavailable,
facility_unavailable_exception)
- .align 7
- .globl __end_handlers
-__end_handlers:
-
Sorry I wasn't clear in my last mail, please do this as a separate
cleanup patch
after this patch.
ok..
@@ -1244,6 +1235,16 @@ __end_handlers:
STD_RELON_EXCEPTION_PSERIES_OOL(0xf60, facility_unavailable)
STD_RELON_EXCEPTION_HV_OOL(0xf80, hv_facility_unavailable)
+ /* FIXME: For now, let us move the __end_interrupts marker
down past
Why is it FIXME?
In general I don't want to merge code that adds a FIXME unless there
is some
very good reason.
AFAICS this is a permanent solution isn't it?
Except for a few short interrupt vectors like 0x4f00, 04f20, etc., all
other
vectors defined till __end_interrupts marker ensure that
LOAD_HANDLER() is
used for branching to labels like system_call_entry,
data_access_common, etc.
that are currently not copied to real 0 in relocation case.
So, we are forced to move the __end_interrupts marker down only to handle
space constraint in the short vectors. So, I added the FIXME to remind
the
scope for improvement in the code. But after thinking over again now,
moving
the marker down makes us copy an additional 1~2 KB along with the
21~22 KB
that we are copying already. So, not much of an improvement to lose
sleep over
or to add a FIXME, I guess. Your thoughts?
Alternatively, how about moving the OOLs handlers that can't be branched
with LOAD_HANDLER
under __end_interrupts. This way we won't be copying more than a few
absolutely needed handlers.
STD_RELON_EXCEPTION_HV_OOL(0xe40, emulation_assist)
.
.
STD_RELON_EXCEPTION_HV_OOL(0xf80, hv_facility_unavailable)
We can leave __end_handlers marker to indicate code that should be part
of the
first 64K of kernel image.
Thanks
Hari
Also, FIXME is the reason, why I did not replace __end_handlers with
__end_interrupts in the comment earlier.
+ * the out-of-line handlers, to make sure we also copy OOL
handlers
+ * to real adress 0x100 when running a relocatable kernel. This
helps
It doesn't "help" it's 100% required.
Yep. Will change the wording.
Thanks for the review!
- Hari
+ * in cases where interrupt vectors are not long enough (like
0x4f00,
+ * 0x4f20, etc.) to branch out to OOL handlers with
LOAD_HANDLER().
+ */
+ .align 7
+ .globl __end_interrupts
+__end_interrupts:
+
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
/*
* Data area reserved for FWNMI option.
cheers
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