x86_64: add pseudo-features for 32-bit compat syscall

Add pseudo-feature bits to describe whether the CPU supports sysenter
and/or syscall from ia32-compat userspace.  This removes a hardcoded
test in vdso32-setup.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 9 insertions, 2 deletions

diff --git a/arch/x86/kernel/cpu/centaur_64.c b/arch/x86/kernel/cpu/centaur_64.c
index 13526fd5cce1..2026d2119cdb 100644
--- a/arch/x86/kernel/cpu/centaur_64.c
+++ b/arch/x86/kernel/cpu/centaur_64.c
@@ -10,6 +10,8 @@ static void __cpuinit early_init_centaur(struct cpuinfo_x86 *c)
 {
         if (c->x86 == 0x6 && c->x86_model >= 0xf)
                 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
+
+        set_cpu_cap(c, X86_FEATURE_SYSENTER32);
 }
 
 static void __cpuinit init_centaur(struct cpuinfo_x86 *c)
diff --git a/arch/x86/kernel/cpu/common_64.c b/arch/x86/kernel/cpu/common_64.c
index 751850235291..36537ab9e56a 100644
--- a/arch/x86/kernel/cpu/common_64.c
+++ b/arch/x86/kernel/cpu/common_64.c
@@ -314,6 +314,9 @@ static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c)
         if (c->extended_cpuid_level >= 0x80000007)
                 c->x86_power = cpuid_edx(0x80000007);
 
+        /* Assume all 64-bit CPUs support 32-bit syscall */
+        set_cpu_cap(c, X86_FEATURE_SYSCALL32);
+
         if (c->x86_vendor != X86_VENDOR_UNKNOWN &&
             cpu_devs[c->x86_vendor]->c_early_init)
                 cpu_devs[c->x86_vendor]->c_early_init(c);
diff --git a/arch/x86/kernel/cpu/intel_64.c b/arch/x86/kernel/cpu/intel_64.c
index fcb1cc9d75ca..02f773399e39 100644
--- a/arch/x86/kernel/cpu/intel_64.c
+++ b/arch/x86/kernel/cpu/intel_64.c
@@ -12,6 +12,8 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
         if ((c->x86 == 0xf && c->x86_model >= 0x03) ||
             (c->x86 == 0x6 && c->x86_model >= 0x0e))
                 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
+
+        set_cpu_cap(c, X86_FEATURE_SYSENTER32);
 }
 
 /*
diff --git a/include/asm-x86/cpufeature.h b/include/asm-x86/cpufeature.h
index 84a56da397b1..75ef959db329 100644
--- a/include/asm-x86/cpufeature.h
+++ b/include/asm-x86/cpufeature.h
@@ -74,8 +74,8 @@
 #define X86_FEATURE_ARCH_PERFMON (3*32+11) /* Intel Architectural PerfMon */
 #define X86_FEATURE_PEBS        (3*32+12)  /* Precise-Event Based Sampling */
 #define X86_FEATURE_BTS         (3*32+13)  /* Branch Trace Store */
-/* 14 free */
-/* 15 free */
+#define X86_FEATURE_SYSCALL32   (3*32+14)  /* syscall in ia32 userspace */
+#define X86_FEATURE_SYSENTER32  (3*32+15)  /* sysenter in ia32 userspace */
 #define X86_FEATURE_REP_GOOD    (3*32+16) /* rep microcode works well on this CPU */
 #define X86_FEATURE_MFENCE_RDTSC (3*32+17) /* Mfence synchronizes RDTSC */
 #define X86_FEATURE_LFENCE_RDTSC (3*32+18) /* Lfence synchronizes RDTSC */