Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index ddee1f0..206a4b6 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -184,24 +184,25 @@
 	pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
 
 	if (la57) {
-		p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
+		p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++],
+				    physaddr);
 
 		i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
 		pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
 		pgd[i + 1] = (pgdval_t)p4d + pgtable_flags;
 
-		i = (physaddr >> P4D_SHIFT) % PTRS_PER_P4D;
-		p4d[i + 0] = (pgdval_t)pud + pgtable_flags;
-		p4d[i + 1] = (pgdval_t)pud + pgtable_flags;
+		i = physaddr >> P4D_SHIFT;
+		p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
+		p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
 	} else {
 		i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
 		pgd[i + 0] = (pgdval_t)pud + pgtable_flags;
 		pgd[i + 1] = (pgdval_t)pud + pgtable_flags;
 	}
 
-	i = (physaddr >> PUD_SHIFT) % PTRS_PER_PUD;
-	pud[i + 0] = (pudval_t)pmd + pgtable_flags;
-	pud[i + 1] = (pudval_t)pmd + pgtable_flags;
+	i = physaddr >> PUD_SHIFT;
+	pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
+	pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
 
 	pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
 	/* Filter out unsupported __PAGE_KERNEL_* bits: */
@@ -211,8 +212,9 @@
 	pmd_entry +=  physaddr;
 
 	for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
-		int idx = i + (physaddr >> PMD_SHIFT) % PTRS_PER_PMD;
-		pmd[idx] = pmd_entry + i * PMD_SIZE;
+		int idx = i + (physaddr >> PMD_SHIFT);
+
+		pmd[idx % PTRS_PER_PMD] = pmd_entry + i * PMD_SIZE;
 	}
 
 	/*
@@ -220,13 +222,31 @@
 	 * we might write invalid pmds, when the kernel is relocated
 	 * cleanup_highmap() fixes this up along with the mappings
 	 * beyond _end.
+	 *
+	 * Only the region occupied by the kernel image has so far
+	 * been checked against the table of usable memory regions
+	 * provided by the firmware, so invalidate pages outside that
+	 * region. A page table entry that maps to a reserved area of
+	 * memory would allow processor speculation into that area,
+	 * and on some hardware (particularly the UV platform) even
+	 * speculative access to some reserved areas is caught as an
+	 * error, causing the BIOS to halt the system.
 	 */
 
 	pmd = fixup_pointer(level2_kernel_pgt, physaddr);
-	for (i = 0; i < PTRS_PER_PMD; i++) {
+
+	/* invalidate pages before the kernel image */
+	for (i = 0; i < pmd_index((unsigned long)_text); i++)
+		pmd[i] &= ~_PAGE_PRESENT;
+
+	/* fixup pages that are part of the kernel image */
+	for (; i <= pmd_index((unsigned long)_end); i++)
 		if (pmd[i] & _PAGE_PRESENT)
 			pmd[i] += load_delta;
-	}
+
+	/* invalidate pages after the kernel image */
+	for (; i < PTRS_PER_PMD; i++)
+		pmd[i] &= ~_PAGE_PRESENT;
 
 	/*
 	 * Fixup phys_base - remove the memory encryption mask to obtain
@@ -385,7 +405,7 @@
 	 */
 	sme_map_bootdata(real_mode_data);
 
-	memcpy(&boot_params, real_mode_data, sizeof boot_params);
+	memcpy(&boot_params, real_mode_data, sizeof(boot_params));
 	sanitize_boot_params(&boot_params);
 	cmd_line_ptr = get_cmd_line_ptr();
 	if (cmd_line_ptr) {