Subject: Re: linux-next: build failure after merge of most trees

From: David Miller <[email-masked]>
Date: Thu, 22 Jun 2017 10:13:06 -0400 (EDT)

From: Nicholas Piggin <[email-masked]>
Date: Thu, 22 Jun 2017 18:41:16 +1000

> Is there any way for the linker to place the inputs to avoid unresolvable
> relocations where possible?

I don't think so.

> A way to work around this is to make arch/sparc/lib/hweight.o an obj-y
> rather than lib-y. That's a hack because it just serves to move the
> input location, but not really any more of a hack than the current code
> that also only works because of input locations...

I could adjust those branches in the sparc code into indirect calls
but it's going to perform a bit poorly on older cpus.

Something like this:

diff --git a/arch/sparc/lib/hweight.S b/arch/sparc/lib/hweight.S
index f9985f1..d21cf20 100644
--- a/arch/sparc/lib/hweight.S
+++ b/arch/sparc/lib/hweight.S
@@ -4,9 +4,9 @@
 	.text
 	.align	32
 ENTRY(__arch_hweight8)
-	ba,pt	%xcc, __sw_hweight8
+	sethi	%hi(__sw_hweight8), %g1
+	jmpl	%g1 + %lo(__sw_hweight8), %g0
 	 nop
-	nop
 ENDPROC(__arch_hweight8)
 EXPORT_SYMBOL(__arch_hweight8)
 	.section	.popc_3insn_patch, "ax"
@@ -17,9 +17,9 @@ EXPORT_SYMBOL(__arch_hweight8)
 	.previous
 
 ENTRY(__arch_hweight16)
-	ba,pt	%xcc, __sw_hweight16
+	sethi	%hi(__sw_hweight16), %g1
+	jmpl	%g1 + %lo(__sw_hweight16), %g0
 	 nop
-	nop
 ENDPROC(__arch_hweight16)
 EXPORT_SYMBOL(__arch_hweight16)
 	.section	.popc_3insn_patch, "ax"
@@ -30,9 +30,9 @@ EXPORT_SYMBOL(__arch_hweight16)
 	.previous
 
 ENTRY(__arch_hweight32)
-	ba,pt	%xcc, __sw_hweight32
+	sethi	%hi(__sw_hweight32), %g1
+	jmpl	%g1 + %lo(__sw_hweight32), %g0
 	 nop
-	nop
 ENDPROC(__arch_hweight32)
 EXPORT_SYMBOL(__arch_hweight32)
 	.section	.popc_3insn_patch, "ax"
@@ -43,9 +43,9 @@ EXPORT_SYMBOL(__arch_hweight32)
 	.previous
 
 ENTRY(__arch_hweight64)
-	ba,pt	%xcc, __sw_hweight64
+	sethi	%hi(__sw_hweight16), %g1
+	jmpl	%g1 + %lo(__sw_hweight16), %g0
 	 nop
-	nop
 ENDPROC(__arch_hweight64)
 EXPORT_SYMBOL(__arch_hweight64)
 	.section	.popc_3insn_patch, "ax"