Re: head -r365932 on PowerMac G5 (2 dual-core sockets): Crashes before login prompt if powerd is enabled in /etc/rc.conf
Mark Millard via freebsd-ppc <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.ppc |
|---|---|
| Message-ID | <[email protected]> |
On 2020-Sep-22, at 12:45, Brandon Bergren <bdragon at FreeBSD.org> wrote:
>
> On Tue, Sep 22, 2020, at 2:35 PM, Mark Millard wrote:
>>
>> Seems to target 32 bit powerpc but the context I'm reporting is
>> for powerpc64 overall. May be the mis-compiles are not limited
>> to 32-bit powerpc variants?
>
> DOH! You're right,
>
> Try a build with _MINUS_O forced to -O2 and see if that fixes things.
>
> FWIW, there is a differential to change the default across the board @ https://reviews.freebsd.org/D26471 because the whole "inlines are not inlining" problem affects everything.
>
> The change boils down to LLVM 11 changing their default of what -O "means" to be -O1 instead of -O2, which breaks a bunch of kernel assumptions regarding inlining.
>
On the 2 dual-core socket G5:
# sysctl dev.cpu.0.freq
dev.cpu.0.freq: 2500
based on using:
# svnlite diff /usr/src/sys/conf/kern.pre.mk
Index: /usr/src/sys/conf/kern.pre.mk
===================================================================
--- /usr/src/sys/conf/kern.pre.mk (revision 365932)
+++ /usr/src/sys/conf/kern.pre.mk (working copy)
@@ -51,15 +51,7 @@
SIZE?= size
.if defined(DEBUG)
-.if ${MACHINE_ARCH} == "powerpc" || ${MACHINE_ARCH} == "powerpcspe"
-# Work around clang 11 miscompile on 32 bit powerpc.
-_MINUS_O= -O2
-.else
-_MINUS_O= -O
-.endif
CTFFLAGS+= -g
-.else
-_MINUS_O= -O2
.endif
.if ${MACHINE_CPUARCH} == "amd64"
.if ${COMPILER_TYPE} == "clang"
@@ -68,7 +60,7 @@
COPTFLAGS?=-O2 -frename-registers -pipe
.endif
.else
-COPTFLAGS?=${_MINUS_O} -pipe
+COPTFLAGS?=-O2 -pipe
.endif
.if !empty(COPTFLAGS:M-O[23s]) && empty(COPTFLAGS:M-fno-strict-aliasing)
COPTFLAGS+= -fno-strict-aliasing
[I doubt that this had anything to do with the extremely
early 2-socket G4 boot failure, given what you had for
"powerpc": it should have been -O2 already.]
===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
_______________________________________________
[email protected] mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-ppc
To unsubscribe, send any mail to "[email protected]"