From: Vasily Gorbik <gor@linux.ibm.com>
Date: Wed, 17 Jan 2024 10:50:46 +0000 (+0100)
Subject: s390/nospec: Correct modules thunk offset calculation
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ea84f14d2a6b1a4fde17d2713dbdfdef7b84da87;p=linux.git

s390/nospec: Correct modules thunk offset calculation

Fix offset calculation when branch target is more then 2Gb away.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
---

diff --git a/arch/s390/kernel/nospec-branch.c b/arch/s390/kernel/nospec-branch.c
index d1b16d83e49ad..9b8c24ebb0085 100644
--- a/arch/s390/kernel/nospec-branch.c
+++ b/arch/s390/kernel/nospec-branch.c
@@ -114,10 +114,10 @@ static void __init_or_module __nospec_revert(s32 *start, s32 *end)
 			type = BRASL_EXPOLINE;	/* brasl instruction */
 		else
 			continue;
-		thunk = instr + (*(int *)(instr + 2)) * 2;
+		thunk = instr + (long)(*(int *)(instr + 2)) * 2;
 		if (thunk[0] == 0xc6 && thunk[1] == 0x00)
 			/* exrl %r0,<target-br> */
-			br = thunk + (*(int *)(thunk + 2)) * 2;
+			br = thunk + (long)(*(int *)(thunk + 2)) * 2;
 		else
 			continue;
 		if (br[0] != 0x07 || (br[1] & 0xf0) != 0xf0)