Merge tag 'powerpc-4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:

 - An implementation for the newly added hv_ops->flush() for the OPAL
   hvc console driver backends, I forgot to apply this after merging the
   hvc driver changes before the merge window.

 - Enable all PCI bridges at boot on powernv, to avoid races when
   multiple children of a bridge try to enable it simultaneously. This
   is a workaround until the PCI core can be enhanced to fix the races.

 - A fix to query PowerVM for the correct system topology at boot before
   initialising sched domains, seen in some configurations to cause
   broken scheduling etc.

 - A fix for pte_access_permitted() on "nohash" platforms.

 - Two commits to fix SIGBUS when using remap_pfn_range() seen on Power9
   due to a workaround when using the nest MMU (GPUs, accelerators).

 - Another fix to the VFIO code used by KVM, the previous fix had some
   bugs which caused guests to not start in some configurations.

 - A handful of other minor fixes.

Thanks to: Aneesh Kumar K.V, Benjamin Herrenschmidt, Christophe Leroy,
Hari Bathini, Luke Dashjr, Mahesh Salgaonkar, Nicholas Piggin, Paul
Mackerras, Srikar Dronamraju.

* tag 'powerpc-4.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/mce: Fix SLB rebolting during MCE recovery path.
  KVM: PPC: Book3S: Fix guest DMA when guest partially backed by THP pages
  powerpc/mm/radix: Only need the Nest MMU workaround for R -> RW transition
  powerpc/mm/books3s: Add new pte bit to mark pte temporarily invalid.
  powerpc/nohash: fix pte_access_permitted()
  powerpc/topology: Get topology for shared processors at boot
  powerpc64/ftrace: Include ftrace.h needed for enable/disable calls
  powerpc/powernv/pci: Work around races in PCI bridge enabling
  powerpc/fadump: cleanup crash memory ranges support
  powerpc/powernv: provide a console flush operation for opal hvc driver
  powerpc/traps: Avoid rate limit messages from show unhandled signals
  powerpc/64s: Fix PACA_IRQ_HARD_DIS accounting in idle_power4()

arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -44,6 +44,16 @@
 
 #define _PAGE_PTE		0x4000000000000000UL	/* distinguishes PTEs from pointers */
 #define _PAGE_PRESENT		0x8000000000000000UL	/* pte contains a translation */
+/*
+ * We need to mark a pmd pte invalid while splitting. We can do that by clearing
+ * the _PAGE_PRESENT bit. But then that will be taken as a swap pte. In order to
+ * differentiate between two use a SW field when invalidating.
+ *
+ * We do that temporary invalidate for regular pte entry in ptep_set_access_flags
+ *
+ * This is used only when _PAGE_PRESENT is cleared.
+ */
+#define _PAGE_INVALID		_RPAGE_SW0
 
 /*
  * Top and bottom bits of RPN which can be used by hash
@@ -568,7 +578,13 @@ static inline pte_t pte_clear_savedwrite(pte_t pte)
 
 static inline int pte_present(pte_t pte)
 {
-	return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT));
+	/*
+	 * A pte is considerent present if _PAGE_PRESENT is set.
+	 * We also need to consider the pte present which is marked
+	 * invalid during ptep_set_access_flags. Hence we look for _PAGE_INVALID
+	 * if we find _PAGE_PRESENT cleared.
+	 */
+	return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_INVALID));
 }
 
 #ifdef CONFIG_PPC_MEM_KEYS

arch/powerpc/include/asm/nohash/pgtable.h

@@ -51,17 +51,14 @@ static inline int pte_present(pte_t pte)
 #define pte_access_permitted pte_access_permitted
 static inline bool pte_access_permitted(pte_t pte, bool write)
 {
-	unsigned long pteval = pte_val(pte);
 	/*
 	 * A read-only access is controlled by _PAGE_USER bit.
 	 * We have _PAGE_READ set for WRITE and EXECUTE
 	 */
-	unsigned long need_pte_bits = _PAGE_PRESENT | _PAGE_USER;
+	if (!pte_present(pte) || !pte_user(pte) || !pte_read(pte))
+		return false;
 
-	if (write)
-		need_pte_bits |= _PAGE_WRITE;
-
-	if ((pteval & need_pte_bits) != need_pte_bits)
+	if (write && !pte_write(pte))
 		return false;
 
 	return true;

arch/powerpc/include/asm/opal.h

@@ -308,6 +308,7 @@ extern void opal_configure_cores(void);
 extern int opal_get_chars(uint32_t vtermno, char *buf, int count);
 extern int opal_put_chars(uint32_t vtermno, const char *buf, int total_len);
 extern int opal_put_chars_atomic(uint32_t vtermno, const char *buf, int total_len);
+extern int opal_flush_chars(uint32_t vtermno, bool wait);
 extern int opal_flush_console(uint32_t vtermno);
 
 extern void hvc_opal_init_early(void);

arch/powerpc/include/asm/topology.h

@@ -92,6 +92,7 @@ extern int stop_topology_update(void);
 extern int prrn_is_enabled(void);
 extern int find_and_online_cpu_nid(int cpu);
 extern int timed_topology_update(int nsecs);
+extern void __init shared_proc_topology_init(void);
 #else
 static inline int start_topology_update(void)
 {
@@ -113,6 +114,10 @@ static inline int timed_topology_update(int nsecs)
 {
 	return 0;
 }
+
+#ifdef CONFIG_SMP
+static inline void shared_proc_topology_init(void) {}
+#endif
 #endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
 
 #include <asm-generic/topology.h>