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()

4 files changed, 63 insertions, 18 deletions

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 8541f18694a4..46b4e67d2372 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -402,6 +402,7 @@ void __init mem_init(void)
 void free_initmem(void)
 {
 	ppc_md.progress = ppc_printk_progress;
+	mark_initmem_nx();
 	free_initmem_default(POISON_FREE_INITMEM);
 }
 
diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c
index 188b4107584d..443a2c66a304 100644
--- a/arch/powerpc/mm/pgtable-hash64.c
+++ b/arch/powerpc/mm/pgtable-hash64.c
@@ -425,33 +425,51 @@ int hash__has_transparent_hugepage(void)
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
-void hash__mark_rodata_ro(void)
+static bool hash__change_memory_range(unsigned long start, unsigned long end,
+				      unsigned long newpp)
 {
-	unsigned long start = (unsigned long)_stext;
-	unsigned long end = (unsigned long)__init_begin;
 	unsigned long idx;
 	unsigned int step, shift;
-	unsigned long newpp = PP_RXXX;
 
 	shift = mmu_psize_defs[mmu_linear_psize].shift;
 	step = 1 << shift;
 
-	start = ((start + step - 1) >> shift) << shift;
-	end = (end >> shift) << shift;
+	start = ALIGN_DOWN(start, step);
+	end = ALIGN(end, step); // aligns up
 
-	pr_devel("marking ro start %lx, end %lx, step %x\n",
-			start, end, step);
+	if (start >= end)
+		return false;
 
-	if (start == end) {
-		pr_warn("could not set rodata ro, relocate the start"
-			" of the kernel to a 0x%x boundary\n", step);
-		return;
-	}
+	pr_debug("Changing page protection on range 0x%lx-0x%lx, to 0x%lx, step 0x%x\n",
+		 start, end, newpp, step);
 
 	for (idx = start; idx < end; idx += step)
 		/* Not sure if we can do much with the return value */
 		mmu_hash_ops.hpte_updateboltedpp(newpp, idx, mmu_linear_psize,
 							mmu_kernel_ssize);
 
+	return true;
+}
+
+void hash__mark_rodata_ro(void)
+{
+	unsigned long start, end;
+
+	start = (unsigned long)_stext;
+	end = (unsigned long)__init_begin;
+
+	WARN_ON(!hash__change_memory_range(start, end, PP_RXXX));
+}
+
+void hash__mark_initmem_nx(void)
+{
+	unsigned long start, end, pp;
+
+	start = (unsigned long)__init_begin;
+	end = (unsigned long)__init_end;
+
+	pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL));
+
+	WARN_ON(!hash__change_memory_range(start, end, pp));
 }
 #endif
diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 8c13e4282308..5cc50d47ce3f 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -112,10 +112,9 @@ set_the_pte:
 }
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
-void radix__mark_rodata_ro(void)
+void radix__change_memory_range(unsigned long start, unsigned long end,
+				unsigned long clear)
 {
-	unsigned long start = (unsigned long)_stext;
-	unsigned long end = (unsigned long)__init_begin;
 	unsigned long idx;
 	pgd_t *pgdp;
 	pud_t *pudp;
@@ -125,7 +124,8 @@ void radix__mark_rodata_ro(void)
 	start = ALIGN_DOWN(start, PAGE_SIZE);
 	end = PAGE_ALIGN(end); // aligns up
 
-	pr_devel("marking ro start %lx, end %lx\n", start, end);
+	pr_debug("Changing flags on range %lx-%lx removing 0x%lx\n",
+		 start, end, clear);
 
 	for (idx = start; idx < end; idx += PAGE_SIZE) {
 		pgdp = pgd_offset_k(idx);
@@ -147,11 +147,29 @@ void radix__mark_rodata_ro(void)
 		if (!ptep)
 			continue;
 update_the_pte:
-		radix__pte_update(&init_mm, idx, ptep, _PAGE_WRITE, 0, 0);
+		radix__pte_update(&init_mm, idx, ptep, clear, 0, 0);
 	}
 
 	radix__flush_tlb_kernel_range(start, end);
 }
+
+void radix__mark_rodata_ro(void)
+{
+	unsigned long start, end;
+
+	start = (unsigned long)_stext;
+	end = (unsigned long)__init_begin;
+
+	radix__change_memory_range(start, end, _PAGE_WRITE);
+}
+
+void radix__mark_initmem_nx(void)
+{
+	unsigned long start = (unsigned long)__init_begin;
+	unsigned long end = (unsigned long)__init_end;
+
+	radix__change_memory_range(start, end, _PAGE_EXEC);
+}
 #endif /* CONFIG_STRICT_KERNEL_RWX */
 
 static inline void __meminit print_mapping(unsigned long start,
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 5c0b795d656c..0736e94c7615 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -505,4 +505,12 @@ void mark_rodata_ro(void)
 	else
 		hash__mark_rodata_ro();
 }
+
+void mark_initmem_nx(void)
+{
+	if (radix_enabled())
+		radix__mark_initmem_nx();
+	else
+		hash__mark_initmem_nx();
+}
 #endif