Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a2adf95..a7d626b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -694,7 +694,13 @@
 }
 
 extern void kvfree(const void *addr);
+extern void kvfree_sensitive(const void *addr, size_t len);
 
+/*
+ * Mapcount of compound page as a whole, does not include mapped sub-pages.
+ *
+ * Must be called only for compound pages or any their tail sub-pages.
+ */
 static inline int compound_mapcount(struct page *page)
 {
 	VM_BUG_ON_PAGE(!PageCompound(page), page);
@@ -714,10 +720,16 @@
 
 int __page_mapcount(struct page *page);
 
+/*
+ * Mapcount of 0-order page; when compound sub-page, includes
+ * compound_mapcount().
+ *
+ * Result is undefined for pages which cannot be mapped into userspace.
+ * For example SLAB or special types of pages. See function page_has_type().
+ * They use this place in struct page differently.
+ */
 static inline int page_mapcount(struct page *page)
 {
-	VM_BUG_ON_PAGE(PageSlab(page), page);
-
 	if (unlikely(PageCompound(page)))
 		return __page_mapcount(page);
 	return atomic_read(&page->_mapcount) + 1;
@@ -1214,13 +1226,26 @@
 #endif /* CONFIG_NUMA_BALANCING */
 
 #ifdef CONFIG_KASAN_SW_TAGS
+
+/*
+ * KASAN per-page tags are stored xor'ed with 0xff. This allows to avoid
+ * setting tags for all pages to native kernel tag value 0xff, as the default
+ * value 0x00 maps to 0xff.
+ */
+
 static inline u8 page_kasan_tag(const struct page *page)
 {
-	return (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK;
+	u8 tag;
+
+	tag = (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK;
+	tag ^= 0xff;
+
+	return tag;
 }
 
 static inline void page_kasan_tag_set(struct page *page, u8 tag)
 {
+	tag ^= 0xff;
 	page->flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT);
 	page->flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT;
 }
@@ -1434,6 +1459,7 @@
 	struct address_space *check_mapping;	/* Check page->mapping if set */
 	pgoff_t	first_index;			/* Lowest page->index to unmap */
 	pgoff_t last_index;			/* Highest page->index to unmap */
+	struct page *single_page;		/* Locked page to be unmapped */
 };
 
 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
@@ -1454,9 +1480,11 @@
 		unsigned long end, unsigned long floor, unsigned long ceiling);
 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
 			struct vm_area_struct *vma);
-int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
-		   struct mmu_notifier_range *range,
-		   pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp);
+int follow_invalidate_pte(struct mm_struct *mm, unsigned long address,
+			  struct mmu_notifier_range *range, pte_t **ptepp,
+			  pmd_t **pmdpp, spinlock_t **ptlp);
+int follow_pte(struct mm_struct *mm, unsigned long address,
+	       pte_t **ptepp, spinlock_t **ptlp);
 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
 	unsigned long *pfn);
 int follow_phys(struct vm_area_struct *vma, unsigned long address,
@@ -1478,6 +1506,7 @@
 extern int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
 			    unsigned long address, unsigned int fault_flags,
 			    bool *unlocked);
+void unmap_mapping_page(struct page *page);
 void unmap_mapping_pages(struct address_space *mapping,
 		pgoff_t start, pgoff_t nr, bool even_cows);
 void unmap_mapping_range(struct address_space *mapping,
@@ -1498,6 +1527,7 @@
 	BUG();
 	return -EFAULT;
 }
+static inline void unmap_mapping_page(struct page *page) { }
 static inline void unmap_mapping_pages(struct address_space *mapping,
 		pgoff_t start, pgoff_t nr, bool even_cows) { }
 static inline void unmap_mapping_range(struct address_space *mapping,
@@ -2196,7 +2226,7 @@
 
 extern void set_dma_reserve(unsigned long new_dma_reserve);
 extern void memmap_init_zone(unsigned long, int, unsigned long, unsigned long,
-		enum memmap_context, struct vmem_altmap *);
+		enum meminit_context, struct vmem_altmap *);
 extern void setup_per_zone_wmarks(void);
 extern int __meminit init_per_zone_wmark_min(void);
 extern void mem_init(void);
@@ -2560,6 +2590,15 @@
 	return VM_FAULT_NOPAGE;
 }
 
+#ifndef io_remap_pfn_range
+static inline int io_remap_pfn_range(struct vm_area_struct *vma,
+				     unsigned long addr, unsigned long pfn,
+				     unsigned long size, pgprot_t prot)
+{
+	return remap_pfn_range(vma, addr, pfn, size, pgprot_decrypted(prot));
+}
+#endif
+
 static inline vm_fault_t vmf_error(int err)
 {
 	if (err == -ENOMEM)
@@ -2666,14 +2705,26 @@
 	       !page_poisoning_enabled();
 }
 
-#ifdef CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT
-DECLARE_STATIC_KEY_TRUE(_debug_pagealloc_enabled);
+#ifdef CONFIG_DEBUG_PAGEALLOC
+extern void init_debug_pagealloc(void);
 #else
-DECLARE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
+static inline void init_debug_pagealloc(void) {}
 #endif
+extern bool _debug_pagealloc_enabled_early;
+DECLARE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
 
 static inline bool debug_pagealloc_enabled(void)
 {
+	return IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) &&
+		_debug_pagealloc_enabled_early;
+}
+
+/*
+ * For use in fast paths after init_debug_pagealloc() has run, or when a
+ * false negative result is not harmful when called too early.
+ */
+static inline bool debug_pagealloc_enabled_static(void)
+{
 	if (!IS_ENABLED(CONFIG_DEBUG_PAGEALLOC))
 		return false;
 
@@ -2683,6 +2734,10 @@
 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP)
 extern void __kernel_map_pages(struct page *page, int numpages, int enable);
 
+/*
+ * When called in DEBUG_PAGEALLOC context, the call should most likely be
+ * guarded by debug_pagealloc_enabled() or debug_pagealloc_enabled_static()
+ */
 static inline void
 kernel_map_pages(struct page *page, int numpages, int enable)
 {
@@ -2873,5 +2928,37 @@
 	return !memcmp_pages(page1, page2);
 }
 
+/**
+ * seal_check_future_write - Check for F_SEAL_FUTURE_WRITE flag and handle it
+ * @seals: the seals to check
+ * @vma: the vma to operate on
+ *
+ * Check whether F_SEAL_FUTURE_WRITE is set; if so, do proper check/handling on
+ * the vma flags.  Return 0 if check pass, or <0 for errors.
+ */
+static inline int seal_check_future_write(int seals, struct vm_area_struct *vma)
+{
+	if (seals & F_SEAL_FUTURE_WRITE) {
+		/*
+		 * New PROT_WRITE and MAP_SHARED mmaps are not allowed when
+		 * "future write" seal active.
+		 */
+		if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
+			return -EPERM;
+
+		/*
+		 * Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as
+		 * MAP_SHARED and read-only, take care to not allow mprotect to
+		 * revert protections on such mappings. Do this only for shared
+		 * mappings. For private mappings, don't need to mask
+		 * VM_MAYWRITE as we still want them to be COW-writable.
+		 */
+		if (vma->vm_flags & VM_SHARED)
+			vma->vm_flags &= ~(VM_MAYWRITE);
+	}
+
+	return 0;
+}
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */