From: Joerg Roedel <jroedel@suse.de>
Date: Mon, 7 Sep 2020 15:15:22 +0200
Subject: x86/boot/compressed/64: Check return value of
 kernel_ident_mapping_init()
Git-commit: 4b3fdca64a7e8ad90c87cad1fbc6991471f48dc7
Patch-mainline: v5.10-rc1
References: jsc#SLE-14337

The function can fail to create an identity mapping, check for that
and bail out if it happens.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-22-joro@8bytes.org
---
 arch/x86/boot/compressed/ident_map_64.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -94,6 +94,8 @@ static struct x86_mapping_info mapping_i
  */
 static void add_identity_map(unsigned long start, unsigned long end)
 {
+	int ret;
+
 	/* Align boundary to 2M. */
 	start = round_down(start, PMD_SIZE);
 	end = round_up(end, PMD_SIZE);
@@ -101,8 +103,9 @@ static void add_identity_map(unsigned lo
 		return;
 
 	/* Build the mapping. */
-	kernel_ident_mapping_init(&mapping_info, (pgd_t *)top_level_pgt,
-				  start, end);
+	ret = kernel_ident_mapping_init(&mapping_info, (pgd_t *)top_level_pgt, start, end);
+	if (ret)
+		error("Error: kernel_ident_mapping_init() failed\n");
 }
 
 /* Locates and clears a region for a new top level page table. */