Merge branch 'fixes' into next

Merge our fixes branch into next, this brings in a number of commits
that fix bugs we don't want to hit in next, in particular the fix for
CVE-2019-12817.

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

@@ -884,6 +884,23 @@ static inline int pmd_present(pmd_t pmd)
 	return false;
 }
 
+static inline int pmd_is_serializing(pmd_t pmd)
+{
+	/*
+	 * If the pmd is undergoing a split, the _PAGE_PRESENT bit is clear
+	 * and _PAGE_INVALID is set (see pmd_present, pmdp_invalidate).
+	 *
+	 * This condition may also occur when flushing a pmd while flushing
+	 * it (see ptep_modify_prot_start), so callers must ensure this
+	 * case is fine as well.
+	 */
+	if ((pmd_raw(pmd) & cpu_to_be64(_PAGE_PRESENT | _PAGE_INVALID)) ==
+						cpu_to_be64(_PAGE_INVALID))
+		return true;
+
+	return false;
+}
+
 static inline int pmd_bad(pmd_t pmd)
 {
 	if (radix_enabled())
@@ -1100,6 +1117,19 @@ static inline int pmd_protnone(pmd_t pmd)
 #define pmd_access_permitted pmd_access_permitted
 static inline bool pmd_access_permitted(pmd_t pmd, bool write)
 {
+	/*
+	 * pmdp_invalidate sets this combination (which is not caught by
+	 * !pte_present() check in pte_access_permitted), to prevent
+	 * lock-free lookups, as part of the serialize_against_pte_lookup()
+	 * synchronisation.
+	 *
+	 * This also catches the case where the PTE's hardware PRESENT bit is
+	 * cleared while TLB is flushed, which is suboptimal but should not
+	 * be frequent.
+	 */
+	if (pmd_is_serializing(pmd))
+		return false;
+
 	return pte_access_permitted(pmd_pte(pmd), write);
 }
 

arch/powerpc/include/asm/btext.h

@@ -13,7 +13,11 @@ extern void btext_update_display(unsigned long phys, int width, int height,
 				 int depth, int pitch);
 extern void btext_setup_display(int width, int height, int depth, int pitch,
 				unsigned long address);
+#ifdef CONFIG_PPC32
 extern void btext_prepare_BAT(void);
+#else
+static inline void btext_prepare_BAT(void) { }
+#endif
 extern void btext_map(void);
 extern void btext_unmap(void);
 

arch/powerpc/include/asm/kexec.h

@@ -94,6 +94,9 @@ static inline bool kdump_in_progress(void)
 	return crashing_cpu >= 0;
 }
 
+void relocate_new_kernel(unsigned long indirection_page, unsigned long reboot_code_buffer,
+			 unsigned long start_address) __noreturn;
+
 #ifdef CONFIG_KEXEC_FILE
 extern const struct kexec_file_ops kexec_elf64_ops;
 

arch/powerpc/include/asm/page.h

@@ -323,6 +323,13 @@ struct vm_area_struct;
 #endif /* __ASSEMBLY__ */
 #include <asm/slice.h>
 
+/*
+ * Allow 30-bit DMA for very limited Broadcom wifi chips on many powerbooks.
+ */
+#ifdef CONFIG_PPC32
+#define ARCH_ZONE_DMA_BITS 30
+#else
 #define ARCH_ZONE_DMA_BITS 31
+#endif
 
 #endif /* _ASM_POWERPC_PAGE_H */