UefiCpuPkg/PiSmmCpuDxeSmm: Add volatile to mNumberToFinish

Add volatile qualifier to mNumberToFinish to prevent GCC 5.4
compiler from optimizing away required logic in ACPI S3 resume.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c
index 4af86b70f2aa34d8eac0dacd38d0211dcff45282..532b7c44bd17a5b0213f68f90eeec11496521e5a 100644 (file)
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c
@@ -55,7 +55,7 @@ AsmGetAddressMap (
 #define LEGACY_REGION_BASE    (0xA0000 - LEGACY_REGION_SIZE)\r
 \r
 ACPI_CPU_DATA                mAcpiCpuData;\r
-UINT32                       mNumberToFinish;\r
+volatile UINT32              mNumberToFinish;\r
 MP_CPU_EXCHANGE_INFO         *mExchangeInfo;\r
 BOOLEAN                      mRestoreSmmConfigurationInS3 = FALSE;\r
 VOID                         *mGdtForAp = NULL;\r