[ZESTY] [PATCH 24/33] powerpc/64: CONFIG_RELOCATABLE support for hmi interrupts

[Breno Leitao]

From: Nicholas Piggin <npiggin at gmail.com>

BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1675806

The branch from hmi_exception_early to hmi_exception_realmode must use
a "relocatable-style" branch, because it is branching from unrelocated
exception code to beyond __end_interrupts.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
(cherry picked from commit 2337d207288f163e10bd8d4d7eeb0c1c75046a0c)
Signed-off-by: Breno Leitao <breno.leitao at gmail.com>
---
 arch/powerpc/include/asm/exception-64s.h | 8 ++++++++
 arch/powerpc/kernel/exceptions-64s.S     | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 8fa09fa500f0..14752eee3d0c 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -236,6 +236,11 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 	mtctr	reg;							\
 	bctr
 
+#define BRANCH_LINK_TO_FAR(reg, label)					\
+	__LOAD_FAR_HANDLER(reg, label);					\
+	mtctr	reg;							\
+	bctrl
+
 /*
  * KVM requires __LOAD_FAR_HANDLER.
  *
@@ -260,6 +265,9 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 #define BRANCH_TO_COMMON(reg, label)					\
 	b	label
 
+#define BRANCH_LINK_TO_FAR(reg, label)					\
+	bl	label
+
 #define BRANCH_TO_KVM(reg, label)					\
 	b	label
 
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index f86eb236324e..f2a18432253c 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -982,7 +982,7 @@ TRAMP_REAL_BEGIN(hmi_exception_early)
 	EXCEPTION_PROLOG_COMMON_2(PACA_EXGEN)
 	EXCEPTION_PROLOG_COMMON_3(0xe60)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-	bl	hmi_exception_realmode
+	BRANCH_LINK_TO_FAR(r4, hmi_exception_realmode)
 	/* Windup the stack. */
 	/* Move original HSRR0 and HSRR1 into the respective regs */
 	ld	r9,_MSR(r1)
-- 
2.11.0