X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=ArmPlatformPkg%2FSec%2FArm%2FHelper.asm;h=0a2baaf19e36c65afa4a3078e43e612098dcdf04;hp=8aa7d7840d56459bab93c7b9a8a149237efe77a2;hb=949973b6c033918489e935869a5d2391e4feacb0;hpb=aaa0820553db9da8dee3ea562942dce89873886d

diff --git a/ArmPlatformPkg/Sec/Arm/Helper.asm b/ArmPlatformPkg/Sec/Arm/Helper.asm
index 8aa7d7840d..0a2baaf19e 100644
--- a/ArmPlatformPkg/Sec/Arm/Helper.asm
+++ b/ArmPlatformPkg/Sec/Arm/Helper.asm
@@ -45,10 +45,8 @@ enter_monitor_mode FUNCTION
     bx      r4
     ENDFUNC
 
-// We cannot use the instruction 'movs pc, lr' because the caller can be written either in ARM or Thumb2 assembler.
-// When we will jump into this function, we will set the CPSR flag to ARM assembler. By copying directly 'lr' into
-// 'pc'; we will not change the CPSR flag and it will crash.
-// The way to fix this limitation is to do the movs into the ARM assmbler code and then do a 'bx'.
+// Return-from-exception is not an interworking return, so we must do it
+// in two steps, in case r0 has the Thumb bit set.
 return_from_exception
     adr     lr, returned_exception
     movs    pc, lr