Merge tag 'powerpc-4.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Highlights include:

   - Support for direct mapped LPC on POWER9, giving Linux direct access
     to devices that may be on there such as a UART.

   - Memory hotplug support for the Power9 Radix MMU.

   - Add new AUX vectors describing the processor's cache geometry, to
     be used by glibc.

   - The ability for a guest to ask the hypervisor to resize the guest's
     hash table, and in addition support for doing so automatically when
     memory is hotplugged into/out-of the guest. This allows the hash
     table to be sized based on the current memory usage of the guest,
     rather than the maximum possible memory usage.

   - Implementation of optprobes (kprobe optimisation) for powerpc.

  In addition there's the topic branch shared with the KVM tree, which
  includes support for guests to use the Radix MMU on Power9.

  Thanks to:
    Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju T, Anton
    Blanchard, Benjamin Herrenschmidt, Chris Packham, Daniel Axtens,
    Daniel Borkmann, David Gibson, Finn Thain, Gautham R. Shenoy, Gavin
    Shan, Greg Kurz, Joel Stanley, John Allen, Madhavan Srinivasan,
    Mahesh Salgaonkar, Markus Elfring, Michael Neuling, Nathan Fontenot,
    Naveen N. Rao, Nicholas Piggin, Paul Mackerras, Ravi Bangoria, Reza
    Arbab, Shailendra Singh, Vaibhav Jain, Wei Yongjun"

* tag 'powerpc-4.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (129 commits)
  powerpc/mm/radix: Skip ptesync in pte update helpers
  powerpc/mm/radix: Use ptep_get_and_clear_full when clearing pte for full mm
  powerpc/mm/radix: Update pte update sequence for pte clear case
  powerpc/mm: Update PROTFAULT handling in the page fault path
  powerpc/xmon: Fix data-breakpoint
  powerpc/mm: Fix build break with BOOK3S_64=n and MEMORY_HOTPLUG=y
  powerpc/mm: Fix build break when CMA=n && SPAPR_TCE_IOMMU=y
  powerpc/mm: Fix build break with RADIX=y & HUGETLBFS=n
  powerpc/pseries: Fix typo in parameter description
  powerpc/kprobes: Remove kprobe_exceptions_notify()
  kprobes: Introduce weak variant of kprobe_exceptions_notify()
  powerpc/ftrace: Fix confusing help text for DISABLE_MPROFILE_KERNEL
  powerpc/powernv: Fix opal_exit tracepoint opcode
  powerpc: Add a prototype for mcount() so it can be versioned
  powerpc: Drop GPL from of_node_to_nid() export to match other arches
  powerpc/kprobes: Optimize kprobe in kretprobe_trampoline()
  powerpc/kprobes: Implement Optprobes
  powerpc/kprobes: Fixes for kprobe_lookup_name() on BE
  powerpc: Add helper to check if offset is within relative branch range
  powerpc/bpf: Introduce __PPC_SH64()
  ...

1 files changed, 33 insertions, 10 deletions

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 62a50d6d1053..8dc758658972 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -407,15 +407,6 @@ good_area:
 		    (cpu_has_feature(CPU_FTR_NOEXECUTE) ||
 		     !(vma->vm_flags & (VM_READ | VM_WRITE))))
 			goto bad_area;
-
-#ifdef CONFIG_PPC_STD_MMU
-		/*
-		 * protfault should only happen due to us
-		 * mapping a region readonly temporarily. PROT_NONE
-		 * is also covered by the VMA check above.
-		 */
-		WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
-#endif /* CONFIG_PPC_STD_MMU */
 	/* a write */
 	} else if (is_write) {
 		if (!(vma->vm_flags & VM_WRITE))
@@ -425,8 +416,40 @@ good_area:
 	} else {
 		if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
 			goto bad_area;
-		WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
 	}
+#ifdef CONFIG_PPC_STD_MMU
+	/*
+	 * For hash translation mode, we should never get a
+	 * PROTFAULT. Any update to pte to reduce access will result in us
+	 * removing the hash page table entry, thus resulting in a DSISR_NOHPTE
+	 * fault instead of DSISR_PROTFAULT.
+	 *
+	 * A pte update to relax the access will not result in a hash page table
+	 * entry invalidate and hence can result in DSISR_PROTFAULT.
+	 * ptep_set_access_flags() doesn't do a hpte flush. This is why we have
+	 * the special !is_write in the below conditional.
+	 *
+	 * For platforms that doesn't supports coherent icache and do support
+	 * per page noexec bit, we do setup things such that we do the
+	 * sync between D/I cache via fault. But that is handled via low level
+	 * hash fault code (hash_page_do_lazy_icache()) and we should not reach
+	 * here in such case.
+	 *
+	 * For wrong access that can result in PROTFAULT, the above vma->vm_flags
+	 * check should handle those and hence we should fall to the bad_area
+	 * handling correctly.
+	 *
+	 * For embedded with per page exec support that doesn't support coherent
+	 * icache we do get PROTFAULT and we handle that D/I cache sync in
+	 * set_pte_at while taking the noexec/prot fault. Hence this is WARN_ON
+	 * is conditional for server MMU.
+	 *
+	 * For radix, we can get prot fault for autonuma case, because radix
+	 * page table will have them marked noaccess for user.
+	 */
+	if (!radix_enabled() && !is_write)
+		WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
+#endif /* CONFIG_PPC_STD_MMU */
 
 	/*
 	 * If for any reason at all we couldn't handle the fault,