powerpc fixes for 4.11 #8

Just two fixes. The first fixes kprobing a stdu, and is marked for stable as
 it's been broken for ~ever. In hindsight this could have gone in next.
 
 The other is a fix for a change we merged this cycle, where if we take a certain
 exception when the kernel is running relocated (currently only used for kdump),
 we checkstop the box.
 
 Thanks to:
   Ravi Bangoria.
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Merge tag 'powerpc-4.11-8' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "Just two fixes.

  The first fixes kprobing a stdu, and is marked for stable as it's been
  broken for ~ever. In hindsight this could have gone in next.

  The other is a fix for a change we merged this cycle, where if we take
  a certain exception when the kernel is running relocated (currently
  only used for kdump), we checkstop the box.

  Thanks to Ravi Bangoria"

* tag 'powerpc-4.11-8' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64: Fix HMI exception on LE with CONFIG_RELOCATABLE=y
  powerpc/kprobe: Fix oops when kprobed on 'stdu' instruction

arch/powerpc/include/asm/exception-64s.h

@@ -236,9 +236,9 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 	mtctr	reg;							\
 	bctr
 
-#define BRANCH_LINK_TO_FAR(reg, label)					\
-	__LOAD_FAR_HANDLER(reg, label);					\
-	mtctr	reg;							\
+#define BRANCH_LINK_TO_FAR(label)					\
+	__LOAD_FAR_HANDLER(r12, label);					\
+	mtctr	r12;							\
 	bctrl
 
 /*
@@ -265,7 +265,7 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 #define BRANCH_TO_COMMON(reg, label)					\
 	b	label
 
-#define BRANCH_LINK_TO_FAR(reg, label)					\
+#define BRANCH_LINK_TO_FAR(label)					\
 	bl	label
 
 #define BRANCH_TO_KVM(reg, label)					\

arch/powerpc/kernel/entry_64.S

@@ -689,7 +689,7 @@ resume_kernel:
 
 	addi	r8,r1,INT_FRAME_SIZE	/* Get the kprobed function entry */
 
-	lwz	r3,GPR1(r1)
+	ld	r3,GPR1(r1)
 	subi	r3,r3,INT_FRAME_SIZE	/* dst: Allocate a trampoline exception frame */
 	mr	r4,r1			/* src:  current exception frame */
 	mr	r1,r3			/* Reroute the trampoline frame to r1 */
@@ -703,8 +703,8 @@ resume_kernel:
 	addi	r6,r6,8
 	bdnz	2b
 
-	/* Do real store operation to complete stwu */
-	lwz	r5,GPR1(r1)
+	/* Do real store operation to complete stdu */
+	ld	r5,GPR1(r1)
 	std	r8,0(r5)
 
 	/* Clear _TIF_EMULATE_STACK_STORE flag */

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
-	BRANCH_LINK_TO_FAR(r4, hmi_exception_realmode)
+	BRANCH_LINK_TO_FAR(hmi_exception_realmode) /* Function call ABI */
 	/* Windup the stack. */
 	/* Move original HSRR0 and HSRR1 into the respective regs */
 	ld	r9,_MSR(r1)