diff options
Diffstat (limited to 'UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c')
| -rw-r--r-- | UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c | 61 |
1 files changed, 42 insertions, 19 deletions
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c index 67ad9a4c07..2b2e1a5390 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c @@ -861,35 +861,58 @@ PiCpuSmmEntry ( mSmmStackSize = EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (PcdGet32 (PcdCpuSmmStackSize)));
if (FeaturePcdGet (PcdCpuSmmStackGuard)) {
//
- // 2 more pages is allocated for each processor.
- // one is guard page and the other is known good stack.
+ // SMM Stack Guard Enabled
+ // 2 more pages is allocated for each processor, one is guard page and the other is known good stack.
//
- // +-------------------------------------------+-----+-------------------------------------------+
- // | Known Good Stack | Guard Page | SMM Stack | ... | Known Good Stack | Guard Page | SMM Stack |
- // +-------------------------------------------+-----+-------------------------------------------+
- // | | | |
- // |<-------------- Processor 0 -------------->| |<-------------- Processor n -------------->|
+ // +--------------------------------------------------+-----+--------------------------------------------------+
+ // | Known Good Stack | Guard Page | SMM Stack | ... | Known Good Stack | Guard Page | SMM Stack |
+ // +--------------------------------------------------+-----+--------------------------------------------------+
+ // | 4K | 4K PcdCpuSmmStackSize| | 4K | 4K PcdCpuSmmStackSize|
+ // |<---------------- mSmmStackSize ----------------->| |<---------------- mSmmStackSize ----------------->|
+ // | | | |
+ // |<------------------ Processor 0 ----------------->| |<------------------ Processor n ----------------->|
//
mSmmStackSize += EFI_PAGES_TO_SIZE (2);
}
mSmmShadowStackSize = 0;
if ((PcdGet32 (PcdControlFlowEnforcementPropertyMask) != 0) && mCetSupported) {
- //
- // Append Shadow Stack after normal stack
- //
- // |= Stacks
- // +--------------------------------------------------+---------------------------------------------------------------+
- // | Known Good Stack | Guard Page | SMM Stack | Known Good Shadow Stack | Guard Page | SMM Shadow Stack |
- // +--------------------------------------------------+---------------------------------------------------------------+
- // | |PcdCpuSmmStackSize| |PcdCpuSmmShadowStackSize|
- // |<---------------- mSmmStackSize ----------------->|<--------------------- mSmmShadowStackSize ------------------->|
- // | |
- // |<-------------------------------------------- Processor N ------------------------------------------------------->|
- //
mSmmShadowStackSize = EFI_PAGES_TO_SIZE (EFI_SIZE_TO_PAGES (PcdGet32 (PcdCpuSmmShadowStackSize)));
+
if (FeaturePcdGet (PcdCpuSmmStackGuard)) {
+ //
+ // SMM Stack Guard Enabled
+ // Append Shadow Stack after normal stack
+ // 2 more pages is allocated for each processor, one is guard page and the other is known good shadow stack.
+ //
+ // |= Stacks
+ // +--------------------------------------------------+---------------------------------------------------------------+
+ // | Known Good Stack | Guard Page | SMM Stack | Known Good Shadow Stack | Guard Page | SMM Shadow Stack |
+ // +--------------------------------------------------+---------------------------------------------------------------+
+ // | 4K | 4K |PcdCpuSmmStackSize| 4K | 4K |PcdCpuSmmShadowStackSize|
+ // |<---------------- mSmmStackSize ----------------->|<--------------------- mSmmShadowStackSize ------------------->|
+ // | |
+ // |<-------------------------------------------- Processor N ------------------------------------------------------->|
+ //
mSmmShadowStackSize += EFI_PAGES_TO_SIZE (2);
+ } else {
+ //
+ // SMM Stack Guard Disabled (Known Good Stack is still required for potential stack switch.)
+ // Append Shadow Stack after normal stack with 1 more page as known good shadow stack.
+ // 1 more pages is allocated for each processor, it is known good stack.
+ //
+ //
+ // |= Stacks
+ // +-------------------------------------+--------------------------------------------------+
+ // | Known Good Stack | SMM Stack | Known Good Shadow Stack | SMM Shadow Stack |
+ // +-------------------------------------+--------------------------------------------------+
+ // | 4K |PcdCpuSmmStackSize| 4K |PcdCpuSmmShadowStackSize|
+ // |<---------- mSmmStackSize ---------->|<--------------- mSmmShadowStackSize ------------>|
+ // | |
+ // |<-------------------------------- Processor N ----------------------------------------->|
+ //
+ mSmmShadowStackSize += EFI_PAGES_TO_SIZE (1);
+ mSmmStackSize += EFI_PAGES_TO_SIZE (1);
}
}
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