Patchwork x86: Add IBT/SHSTK bits to cpu-features

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Submitter H.J. Lu
Date Aug. 8, 2017, 7:24 p.m.
Message ID <20170808192454.GA32301@gmail.com>
Download mbox | patch
Permalink /patch/21998/
State New
Headers show

Comments

H.J. Lu - Aug. 8, 2017, 7:24 p.m.
Add IBT/SHSTK bits to cpu-features for Shadow Stack in Intel Control-flow
Enforcement Technology (CET) instructions:

https://software.intel.com/sites/default/files/managed/4d/2a/control-flow-enforcement-technology-preview.pdf

Any comments or objections?

H.J.
---
	* sysdeps/x86/cpu-features.h (bit_cpu_BIT): New.
	(bit_cpu_SHSTK): Likewise.
	(index_cpu_IBT): Likewise.
	(index_cpu_SHSTK): Likewise.
	(reg_IBT): Likewise.
	(reg_SHSTK): Likewise.
	* sysdeps/x86/cpu-tunables.c (TUNABLE_CALLBACK (set_hwcaps)):
	Handle index_cpu_IBT and index_cpu_SHSTK.
---
 sysdeps/x86/cpu-features.h | 8 ++++++++
 sysdeps/x86/cpu-tunables.c | 2 ++
 2 files changed, 10 insertions(+)

Patch

diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h
index af52689123..9733e6ee66 100644
--- a/sysdeps/x86/cpu-features.h
+++ b/sysdeps/x86/cpu-features.h
@@ -74,6 +74,8 @@ 
 #define bit_cpu_AVX512CD	(1 << 28)
 #define bit_cpu_AVX512BW	(1 << 30)
 #define bit_cpu_AVX512VL	(1u << 31)
+#define bit_cpu_IBT		(1u << 20)
+#define bit_cpu_SHSTK		(1u << 7)
 
 /* XCR0 Feature flags.  */
 #define bit_XMM_state		(1 << 1)
@@ -103,6 +105,8 @@ 
 # define index_cpu_AVX2	COMMON_CPUID_INDEX_7*CPUID_SIZE+CPUID_EBX_OFFSET
 # define index_cpu_ERMS	COMMON_CPUID_INDEX_7*CPUID_SIZE+CPUID_EBX_OFFSET
 # define index_cpu_MOVBE COMMON_CPUID_INDEX_1*CPUID_SIZE+CPUID_ECX_OFFSET
+# define index_cpu_IBT	COMMON_CPUID_INDEX_7*CPUID_SIZE+CPUID_EDX_OFFSET
+# define index_cpu_SHSTK COMMON_CPUID_INDEX_7*CPUID_SIZE+CPUID_ECX_OFFSET
 
 # define index_arch_Fast_Rep_String	FEATURE_INDEX_1*FEATURE_SIZE
 # define index_arch_Fast_Copy_Backward	FEATURE_INDEX_1*FEATURE_SIZE
@@ -220,6 +224,8 @@  extern const struct cpu_features *__get_cpu_features (void)
 # define index_cpu_LZCNT	COMMON_CPUID_INDEX_1
 # define index_cpu_MOVBE	COMMON_CPUID_INDEX_1
 # define index_cpu_POPCNT	COMMON_CPUID_INDEX_1
+# define index_cpu_IBT		COMMON_CPUID_INDEX_7
+# define index_cpu_SHSTK	COMMON_CPUID_INDEX_7
 
 # define reg_CX8		edx
 # define reg_CMOV		edx
@@ -249,6 +255,8 @@  extern const struct cpu_features *__get_cpu_features (void)
 # define reg_LZCNT		ecx
 # define reg_MOVBE		ecx
 # define reg_POPCNT		ecx
+# define reg_IBT		edx
+# define reg_SHSTK		ecx
 
 # define index_arch_Fast_Rep_String	FEATURE_INDEX_1
 # define index_arch_Fast_Copy_Backward	FEATURE_INDEX_1
diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c
index 872dd1267f..0ab708cca8 100644
--- a/sysdeps/x86/cpu-tunables.c
+++ b/sysdeps/x86/cpu-tunables.c
@@ -164,6 +164,7 @@  TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
 	      CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, CX8, 3);
 	      CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, FMA, 3);
 	      CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, HTT, 3);
+	      CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, IBT, 3);
 	      CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, RTM, 3);
 	    }
 	  break;
@@ -186,6 +187,7 @@  TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp)
 	    {
 	      CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, LZCNT, 5);
 	      CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, MOVBE, 5);
+	      CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SHSTK, 5);
 	      CHECK_GLIBC_IFUNC_CPU_OFF (n, cpu_features, SSSE3, 5);
 	    }
 	  break;