Merge tag 'powerpc-4.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "A handful of fixes, mostly for new code:

   - some reworking of the new STRICT_KERNEL_RWX support to make sure we
     also remove executable permission from __init memory before it's
     freed.

   - a fix to some recent optimisations to the hypercall entry where we
     were clobbering r12, this was breaking nested guests (PR KVM).

   - a fix for the recent patch to opal_configure_cores(). This could
     break booting on bare metal Power8 boxes if the kernel was built
     without CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG.

   - .. and finally a workaround for spurious PMU interrupts on Power9
     DD2.

  Thanks to: Nicholas Piggin, Anton Blanchard, Balbir Singh"

* tag 'powerpc-4.13-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/mm: Mark __init memory no-execute when STRICT_KERNEL_RWX=y
  powerpc/mm/hash: Refactor hash__mark_rodata_ro()
  powerpc/mm/radix: Refactor radix__mark_rodata_ro()
  powerpc/64s: Fix hypercall entry clobbering r12 input
  powerpc/perf: Avoid spurious PMU interrupts after idle
  powerpc/powernv: Fix boot on Power8 bare metal due to opal_configure_cores()

arch/powerpc/kernel/exceptions-64s.S

@@ -824,7 +824,7 @@ EXC_COMMON(trap_0b_common, 0xb00, unknown_exception)
  * r3 volatile parameter and return value for status
  * r4-r10 volatile input and output value
  * r11 volatile hypercall number and output value
- * r12 volatile
+ * r12 volatile input and output value
  * r13-r31 nonvolatile
  * LR nonvolatile
  * CTR volatile
@@ -834,25 +834,26 @@ EXC_COMMON(trap_0b_common, 0xb00, unknown_exception)
  * Other registers nonvolatile
  *
  * The intersection of volatile registers that don't contain possible
- * inputs is: r12, cr0, xer, ctr. We may use these as scratch regs
- * upon entry without saving.
+ * inputs is: cr0, xer, ctr. We may use these as scratch regs upon entry
+ * without saving, though xer is not a good idea to use, as hardware may
+ * interpret some bits so it may be costly to change them.
  */
 #ifdef CONFIG_KVM_BOOK3S_64_HANDLER
 	/*
 	 * There is a little bit of juggling to get syscall and hcall
-	 * working well. Save r10 in ctr to be restored in case it is a
-	 * hcall.
+	 * working well. Save r13 in ctr to avoid using SPRG scratch
+	 * register.
 	 *
 	 * Userspace syscalls have already saved the PPR, hcalls must save
 	 * it before setting HMT_MEDIUM.
 	 */
 #define SYSCALL_KVMTEST							\
-	mr	r12,r13;						\
+	mtctr	r13;							\
 	GET_PACA(r13);							\
-	mtctr	r10;							\
+	std	r10,PACA_EXGEN+EX_R10(r13);				\
 	KVMTEST_PR(0xc00); /* uses r10, branch to do_kvm_0xc00_system_call */ \
 	HMT_MEDIUM;							\
-	mr	r9,r12;							\
+	mfctr	r9;
 
 #else
 #define SYSCALL_KVMTEST							\
@@ -935,8 +936,8 @@ EXC_VIRT_END(system_call, 0x4c00, 0x100)
 	 * This is a hcall, so register convention is as above, with these
 	 * differences:
 	 * r13 = PACA
-	 * r12 = orig r13
-	 * ctr = orig r10
+	 * ctr = orig r13
+	 * orig r10 saved in PACA
 	 */
 TRAMP_KVM_BEGIN(do_kvm_0xc00)
 	 /*
@@ -944,14 +945,13 @@ TRAMP_KVM_BEGIN(do_kvm_0xc00)
 	  * HMT_MEDIUM. That allows the KVM code to save that value into the
 	  * guest state (it is the guest's PPR value).
 	  */
-	OPT_GET_SPR(r0, SPRN_PPR, CPU_FTR_HAS_PPR)
+	OPT_GET_SPR(r10, SPRN_PPR, CPU_FTR_HAS_PPR)
 	HMT_MEDIUM
-	OPT_SAVE_REG_TO_PACA(PACA_EXGEN+EX_PPR, r0, CPU_FTR_HAS_PPR)
+	OPT_SAVE_REG_TO_PACA(PACA_EXGEN+EX_PPR, r10, CPU_FTR_HAS_PPR)
 	mfctr	r10
-	SET_SCRATCH0(r12)
+	SET_SCRATCH0(r10)
 	std	r9,PACA_EXGEN+EX_R9(r13)
 	mfcr	r9
-	std	r10,PACA_EXGEN+EX_R10(r13)
 	KVM_HANDLER(PACA_EXGEN, EXC_STD, 0xc00)
 #endif