svn commit: r352832 - head/sys/powerpc/booke

[Justin Hibbits]

Author: jhibbits
Date: Sat Sep 28 03:33:07 2019
New Revision: 352832
URL: https://svnweb.freebsd.org/changeset/base/352832

Log:
  powerpc/booke64: Align initial stack setting to match that of aim64's
  
  Clang9/LLD9 appears to get quite confused with the instruction stream used
  to obtain the tmpstack pointer, almost as though it thinks this is a C
  function, so tries to optimize it.  Since the AIM64 method doesn't use the
  TOC to obtain the tmpstack, just follow that model, and lld won't get
  confused.
  
  Reported by:	bdragon
  MFC after:	2 weeks

Modified:
  head/sys/powerpc/booke/locore.S

Modified: head/sys/powerpc/booke/locore.S
==============================================================================
--- head/sys/powerpc/booke/locore.S	Sat Sep 28 02:49:46 2019	(r352831)
+++ head/sys/powerpc/booke/locore.S	Sat Sep 28 03:33:07 2019	(r352832)
@@ -298,16 +298,18 @@ done_mapping:
 	ld	%r1,0(%r2)
 	add	%r2,%r1,%r2
 	mtspr	SPR_SPRG8, %r2
+	nop
 
 	/* Get load offset */
 	ld	%r31,-0x8000(%r2) /* First TOC entry is TOC base */
 	subf    %r31,%r31,%r2	/* Subtract from real TOC base to get base */
 
 	/* Set up the stack pointer */
-	addis	%r1,%r2,TOC_REF(tmpstack)@ha
-	ld	%r1,TOC_REF(tmpstack)@l(%r1)
-	addi	%r1,%r1,TMPSTACKSZ-96
-	add	%r1,%r1,%r31
+	bl	1f
+	.llong	tmpstack + TMPSTACKSZ - 96 - .
+1:	mflr	%r3
+	ld	%r1,0(%r3)
+	add	%r1,%r1,%r3
 	bl	1f
 	.llong _DYNAMIC-.
 1:	mflr	%r3