[edk2-devel] [PATCH V8 32/47] OvmfPkg/Sec: Declare local variable as volatile in SecCoreStartupWithStack
Min Xu
min.m.xu at intel.com
Sat Mar 12 01:53:57 UTC 2022
RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
Declare the local variables in SecCoreStartupWithStack that actually
move the data elements as volatile to prevent the optimizer from
replacing this function with the intrinsic memcpy().
Cc: Ard Biesheuvel <ardb+tianocore at kernel.org>
Cc: Jordan Justen <jordan.l.justen at intel.com>
Cc: Brijesh Singh <brijesh.singh at amd.com>
Cc: Erdem Aktas <erdemaktas at google.com>
Cc: James Bottomley <jejb at linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao at intel.com>
Cc: Tom Lendacky <thomas.lendacky at amd.com>
Cc: Gerd Hoffmann <kraxel at redhat.com>
Signed-off-by: Min Xu <min.m.xu at intel.com>
---
OvmfPkg/Sec/SecMain.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c
index 2c5561661ef3..02520e25ab9a 100644
--- a/OvmfPkg/Sec/SecMain.c
+++ b/OvmfPkg/Sec/SecMain.c
@@ -757,12 +757,17 @@ SecCoreStartupWithStack (
//
IdtTableInStack.PeiService = NULL;
for (Index = 0; Index < SEC_IDT_ENTRY_COUNT; Index++) {
- UINT8 *Src;
- UINT8 *Dst;
- UINTN Byte;
+ //
+ // Declare the local variables that actually move the data elements as
+ // volatile to prevent the optimizer from replacing this function with
+ // the intrinsic memcpy()
+ //
+ CONST UINT8 *Src;
+ volatile UINT8 *Dst;
+ UINTN Byte;
- Src = (UINT8 *)&mIdtEntryTemplate;
- Dst = (UINT8 *)&IdtTableInStack.IdtTable[Index];
+ Src = (CONST UINT8 *)&mIdtEntryTemplate;
+ Dst = (volatile UINT8 *)&IdtTableInStack.IdtTable[Index];
for (Byte = 0; Byte < sizeof (mIdtEntryTemplate); Byte++) {
Dst[Byte] = Src[Byte];
}
--
2.29.2.windows.2
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