From 1a66bd51ca21f341281d8e3157d3d3f4a94fd26c Mon Sep 17 00:00:00 2001
From: Leif Lindholm <quic_llindhol@quicinc.com>
Date: Thu, 1 Oct 2020 19:37:12 +0100
Subject: [PATCH] MdePkg/BaseLib: ensure ARM LongJump never returns 0

The ARM implementation of InternalLongJump always returned the value
Value - but it is not supposed to ever return 0. Add the test to prevent
that, and return 1 if Value is 0 - as is already present in AArch64.

Signed-off-by: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
---
 MdePkg/Library/BaseLib/Arm/SetJumpLongJump.S   | 2 ++
 MdePkg/Library/BaseLib/Arm/SetJumpLongJump.asm | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/MdePkg/Library/BaseLib/Arm/SetJumpLongJump.S b/MdePkg/Library/BaseLib/Arm/SetJumpLongJump.S
index e91320252255..14006c6123e3 100644
--- a/MdePkg/Library/BaseLib/Arm/SetJumpLongJump.S
+++ b/MdePkg/Library/BaseLib/Arm/SetJumpLongJump.S
@@ -57,6 +57,8 @@ ASM_PFX(SetJump):
 ASM_PFX(InternalLongJump):
   ldmia  r0, {r3-r12,r14}
   mov    r13, r3
+  cmp    r1, #0
+  moveq  r1, #1
   mov    r0, r1
   bx     lr
 
diff --git a/MdePkg/Library/BaseLib/Arm/SetJumpLongJump.asm b/MdePkg/Library/BaseLib/Arm/SetJumpLongJump.asm
index ef02d85e0e66..15eb3dc28fb7 100644
--- a/MdePkg/Library/BaseLib/Arm/SetJumpLongJump.asm
+++ b/MdePkg/Library/BaseLib/Arm/SetJumpLongJump.asm
@@ -57,6 +57,8 @@ SetJump
 InternalLongJump
   LDM   R0, {R3-R12,R14}
   MOV   R13, R3
+  CMP   R1, #0
+  MOVEQ R1, #1
   MOV   R0, R1
   BX    LR