zbrid created this revision.
zbrid added reviewers: sconstab, craig.topper, mattdr.
Herald added subscribers: llvm-commits, cfe-commits, hiraditya.
Herald added projects: clang, LLVM.
This patch creates a clang flag to enable SESES. This flag also ensures that
lvi-cfi is on when using seses via clang.
SESES should use lvi-cfi to mitigate returns and indirect branches.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D79910
Files:
clang/docs/ClangCommandLineReference.rst
clang/include/clang/Driver/Options.td
clang/lib/Driver/ToolChains/Arch/X86.cpp
clang/test/Driver/x86-target-features.c
llvm/lib/Target/X86/X86.td
llvm/lib/Target/X86/X86SpeculativeExecutionSideEffectSuppression.cpp
llvm/lib/Target/X86/X86Subtarget.h
Index: llvm/lib/Target/X86/X86Subtarget.h
===================================================================
--- llvm/lib/Target/X86/X86Subtarget.h
+++ llvm/lib/Target/X86/X86Subtarget.h
@@ -437,6 +437,9 @@
/// POP+LFENCE+JMP sequence.
bool UseLVIControlFlowIntegrity = false;
+ /// Enable Speculative Execution Side Effect Suppression
+ bool UseSpeculativeExecutionSideEffectSuppression = false;
+
/// Insert LFENCE instructions to prevent data speculatively injected into
/// loads from being used maliciously.
bool UseLVILoadHardening = false;
@@ -744,6 +747,9 @@
bool useGLMDivSqrtCosts() const { return UseGLMDivSqrtCosts; }
bool useLVIControlFlowIntegrity() const { return UseLVIControlFlowIntegrity; }
bool useLVILoadHardening() const { return UseLVILoadHardening; }
+ bool useSpeculativeExecutionSideEffectSuppression() const {
+ return UseSpeculativeExecutionSideEffectSuppression;
+ }
unsigned getPreferVectorWidth() const { return PreferVectorWidth; }
unsigned getRequiredVectorWidth() const { return RequiredVectorWidth; }
Index: llvm/lib/Target/X86/X86SpeculativeExecutionSideEffectSuppression.cpp
===================================================================
--- llvm/lib/Target/X86/X86SpeculativeExecutionSideEffectSuppression.cpp
+++ llvm/lib/Target/X86/X86SpeculativeExecutionSideEffectSuppression.cpp
@@ -86,13 +86,14 @@
bool X86SpeculativeExecutionSideEffectSuppression::runOnMachineFunction(
MachineFunction &MF) {
- if (!EnableSpeculativeExecutionSideEffectSuppression)
+ const X86Subtarget &Subtarget = MF.getSubtarget<X86Subtarget>();
+ if (!Subtarget.useSpeculativeExecutionSideEffectSuppression() &&
+ !EnableSpeculativeExecutionSideEffectSuppression)
return false;
LLVM_DEBUG(dbgs() << "********** " << getPassName() << " : " << MF.getName()
<< " **********\n");
bool Modified = false;
- const X86Subtarget &Subtarget = MF.getSubtarget<X86Subtarget>();
const X86InstrInfo *TII = Subtarget.getInstrInfo();
for (MachineBasicBlock &MBB : MF) {
MachineInstr *FirstTerminator = nullptr;
Index: llvm/lib/Target/X86/X86.td
===================================================================
--- llvm/lib/Target/X86/X86.td
+++ llvm/lib/Target/X86/X86.td
@@ -435,6 +435,13 @@
"ourselves. Only has effect when combined with some other retpoline "
"feature", [FeatureRetpolineIndirectCalls]>;
+// Enable SESES to mitigate speculative execution attacks
+def FeatureSpeculativeExecutionSideEffectSuppression
+ : SubtargetFeature<
+ "seses", "UseSpeculativeExecutionSideEffectSuppression", "true",
+ "Prevent speculative execution side channel timing attacks by "
+ "inserting a speculation barrier before memory reads, memory writes, "
+ "and conditional branches.">;
// Mitigate LVI attacks against indirect calls/branches and call returns
def FeatureLVIControlFlowIntegrity
: SubtargetFeature<
Index: clang/test/Driver/x86-target-features.c
===================================================================
--- clang/test/Driver/x86-target-features.c
+++ clang/test/Driver/x86-target-features.c
@@ -178,6 +178,27 @@
// RUN: %clang -target i386-linux-gnu -mlvi-hardening -mretpoline-external-thunk %s -### -o %t.o 2>&1 | FileCheck -check-prefix=LVIHARDENING-RETPOLINE-EXTERNAL-THUNK %s
// LVIHARDENING-RETPOLINE-EXTERNAL-THUNK: error: invalid argument 'mretpoline-external-thunk' not allowed with 'mlvi-hardening'
+// RUN: %clang -target i386-linux-gnu -mseses %s -### -o %t.o 2>&1 | FileCheck -check-prefix=SESES %s
+// RUN: %clang -target i386-linux-gnu -mno-seses %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-SESES %s
+// SESES: "-target-feature" "+seses"
+// SESES: "-target-feature" "+lvi-cfi"
+// NO-SESES-NOT: seses
+// NO-SESES-NOT: lvi-cfi
+
+// RUN: %clang -target i386-linux-gnu -mseses -mno-lvi-cfi %s -### -o %t.o 2>&1 | FileCheck -check-prefix=SESES-NOLVICFI %s
+// SESES-NOLVICFI: "-target-feature" "+seses"
+// SESES-NOLVICFI-NOT: lvi-cfi
+
+// RUN: %clang -target i386-linux-gnu -mseses -mspeculative-load-hardening %s -### -o %t.o 2>&1 | FileCheck -check-prefix=SESES-SLH %s
+// SESES-SLH: error: invalid argument 'mspeculative-load-hardening' not allowed with 'mseses'
+// RUN: %clang -target i386-linux-gnu -mseses -mretpoline %s -### -o %t.o 2>&1 | FileCheck -check-prefix=SESES-RETPOLINE %s
+// SESES-RETPOLINE: error: invalid argument 'mretpoline' not allowed with 'mseses'
+// RUN: %clang -target i386-linux-gnu -mseses -mretpoline-external-thunk %s -### -o %t.o 2>&1 | FileCheck -check-prefix=SESES-RETPOLINE-EXTERNAL-THUNK %s
+// SESES-RETPOLINE-EXTERNAL-THUNK: error: invalid argument 'mretpoline-external-thunk' not allowed with 'mseses'
+
+// RUN: %clang -target i386-linux-gnu -mseses -mlvi-hardening %s -### -o %t.o 2>&1 | FileCheck -check-prefix=SESES-LVIHARDENING %s
+// SESES-LVIHARDENING: error: invalid argument 'mlvi-hardening' not allowed with 'mseses'
+
// RUN: %clang -target i386-linux-gnu -mwaitpkg %s -### -o %t.o 2>&1 | FileCheck -check-prefix=WAITPKG %s
// RUN: %clang -target i386-linux-gnu -mno-waitpkg %s -### -o %t.o 2>&1 | FileCheck -check-prefix=NO-WAITPKG %s
// WAITPKG: "-target-feature" "+waitpkg"
Index: clang/lib/Driver/ToolChains/Arch/X86.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Arch/X86.cpp
+++ clang/lib/Driver/ToolChains/Arch/X86.cpp
@@ -184,6 +184,24 @@
LVIOpt = options::OPT_mlvi_cfi;
}
+ if (Args.hasFlag(options::OPT_m_seses, options::OPT_mno_seses, false)) {
+ if (LVIOpt == options::OPT_mlvi_hardening)
+ D.Diag(diag::err_drv_argument_not_allowed_with)
+ << D.getOpts().getOptionName(options::OPT_mlvi_hardening)
+ << D.getOpts().getOptionName(options::OPT_m_seses);
+
+ if (SpectreOpt != clang::driver::options::ID::OPT_INVALID)
+ D.Diag(diag::err_drv_argument_not_allowed_with)
+ << D.getOpts().getOptionName(SpectreOpt)
+ << D.getOpts().getOptionName(options::OPT_m_seses);
+
+ Features.push_back("+seses");
+ if (!Args.hasArg(options::OPT_mno_lvi_cfi)) {
+ Features.push_back("+lvi-cfi");
+ LVIOpt = options::OPT_mlvi_cfi;
+ }
+ }
+
if (SpectreOpt != clang::driver::options::ID::OPT_INVALID &&
LVIOpt != clang::driver::options::ID::OPT_INVALID) {
D.Diag(diag::err_drv_argument_not_allowed_with)
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -2342,6 +2342,11 @@
HelpText<"Enable only control-flow mitigations for Load Value Injection (LVI)">;
def mno_lvi_cfi : Flag<["-"], "mno-lvi-cfi">, Group<m_Group>, Flags<[CoreOption,DriverOption]>,
HelpText<"Disable control-flow mitigations for Load Value Injection (LVI)">;
+def m_seses : Flag<["-"], "mseses">, Group<m_Group>, Flags<[CoreOption, DriverOption]>,
+ HelpText<"Enable speculative execution side effect suppression (SESES). "
+ "Includes LVI control flow integrity mitigations">;
+def mno_seses : Flag<["-"], "mno-seses">, Group<m_Group>, Flags<[CoreOption, DriverOption]>,
+ HelpText<"Disable speculative execution side effect suppression (SESES)">;
def mrelax : Flag<["-"], "mrelax">, Group<m_riscv_Features_Group>,
HelpText<"Enable linker relaxation">;
Index: clang/docs/ClangCommandLineReference.rst
===================================================================
--- clang/docs/ClangCommandLineReference.rst
+++ clang/docs/ClangCommandLineReference.rst
@@ -2629,6 +2629,11 @@
Enable only control-flow mitigations for Load Value Injection (LVI)
+.. option:: -mseses, -mno-seses
+
+Enable speculative execution side effect suppression along with the LVI control-
+flow mitigations.
+
.. option:: -mmacosx-version-min=<arg>, -mmacos-version-min=<arg>
Set Mac OS X deployment target
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