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/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 0bc530c..ea85f23 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -253,6 +253,7 @@
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/* NOTE: when predicate huge page, consider also pmd_devmap, or use pmd_large */
 static inline int pmd_trans_huge(pmd_t pmd)
 {
 	return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE;
@@ -624,12 +625,15 @@
 	return __pmd(val);
 }
 
-/* mprotect needs to preserve PAT bits when updating vm_page_prot */
+/*
+ * mprotect needs to preserve PAT and encryption bits when updating
+ * vm_page_prot
+ */
 #define pgprot_modify pgprot_modify
 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 {
 	pgprotval_t preservebits = pgprot_val(oldprot) & _PAGE_CHG_MASK;
-	pgprotval_t addbits = pgprot_val(newprot);
+	pgprotval_t addbits = pgprot_val(newprot) & ~_PAGE_CHG_MASK;
 	return __pgprot(preservebits | addbits);
 }