[PATCH 3.2 043/125] powerpc: Fix 64 bit builds with binutils 2.24

Ben Hutchings
2014-07-08T19:19:27Z

From: Guenter Roeck <linux@roeck-us.net>

commit 7998eb3dc700aaf499f93f50b3d77da834ef9e1d upstream.

With binutils 2.24, various 64 bit builds fail with relocation errors
such as

arch/powerpc/kernel/built-in.o: In function `exc_debug_crit_book3e':
(.text+0x165ee): relocation truncated to fit: R_PPC64_ADDR16_HI
against symbol `interrupt_base_book3e' defined in .text section
in arch/powerpc/kernel/built-in.o
arch/powerpc/kernel/built-in.o: In function `exc_debug_crit_book3e':
(.text+0x16602): relocation truncated to fit: R_PPC64_ADDR16_HI
against symbol `interrupt_end_book3e' defined in .text section
in arch/powerpc/kernel/built-in.o

The assembler maintainer says:

I changed the ABI, something that had to be done but unfortunately
happens to break the booke kernel code. When building up a 64-bit
value with lis, ori, shl, oris, ori or similar sequences, you now
should use @high and @higha in place of @h and @ha. @h and @ha
(and their associated relocs R_PPC64_ADDR16_HI and R_PPC64_ADDR16_HA)
now report overflow if the value is out of 32-bit signed range.
ie. @h and @ha assume you're building a 32-bit value. This is needed
to report out-of-range -mcmodel=medium toc pointer offsets in @toc@h
and @toc@ha expressions, and for consistency I did the same for all
other @h and @ha relocs.

Replacing @h with @high in one strategic location fixes the relocation
errors. This has to be done conditionally since the assembler either
supports @h or @high but not both.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/powerpc/Makefile | 4 +++-
arch/powerpc/include/asm/ppc_asm.h | 7 ++++++-
2 files changed, 9 insertions(+), 2 deletions(-)

--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -69,7 +69,9 @@ LDFLAGS_vmlinux := $(LDFLAGS_vmlinux-yy)

CFLAGS-$(CONFIG_PPC64) := -mminimal-toc -mtraceback=no -mcall-aixdesc
CFLAGS-$(CONFIG_PPC32) := -ffixed-r2 -mmultiple
-KBUILD_CPPFLAGS += -Iarch/$(ARCH)
+asinstr := $(call as-instr,lis 9$(comma)foo@high,-DHAVE_AS_ATHIGH=1)
+
+KBUILD_CPPFLAGS += -Iarch/$(ARCH) $(asinstr)
KBUILD_AFLAGS += -Iarch/$(ARCH)
KBUILD_CFLAGS += -msoft-float -pipe -Iarch/$(ARCH) $(CFLAGS-y)
CPP = $(CC) -E $(KBUILD_CFLAGS)
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -292,11 +292,16 @@ n:
* ld rY,ADDROFF(name)(rX)
*/
#ifdef __powerpc64__
+#ifdef HAVE_AS_ATHIGH
+#define __AS_ATHIGH high
+#else
+#define __AS_ATHIGH h
+#endif
#define LOAD_REG_IMMEDIATE(reg,expr) \
lis (reg),(expr)@highest; \
ori (reg),(reg),(expr)@higher; \
rldicr (reg),(reg),32,31; \
- oris (reg),(reg),(expr)@h; \
+ oris reg,reg,(expr)@__AS_ATHIGH; \
ori (reg),(reg),(expr)@l;

#define LOAD_REG_ADDR(reg,name) \