As vsyscall emulation is now supported during #GP, remove the
restriction on LASS when vsyscall emulation is compiled in.
As a result, there is no need for setup_lass() anymore. LASS is enabled
by default through a late_initcall().
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
---
arch/x86/kernel/cpu/common.c | 15 ---------------
1 file changed, 15 deletions(-)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 3557f0e6b3aa..02472fc763d9 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -406,20 +406,6 @@ static __always_inline void setup_umip(struct cpuinfo_x86 *c)
cr4_clear_bits(X86_CR4_UMIP);
}
-static __always_inline void setup_lass(struct cpuinfo_x86 *c)
-{
- if (!cpu_feature_enabled(X86_FEATURE_LASS))
- return;
-
- /*
- * Legacy vsyscall page access causes a #GP when LASS is active.
- * Disable LASS because the #GP handler doesn't support vsyscall
- * emulation.
- */
- if (IS_ENABLED(CONFIG_X86_VSYSCALL_EMULATION))
- setup_clear_cpu_cap(X86_FEATURE_LASS);
-}
-
static int enable_lass(unsigned int cpu)
{
cr4_set_bits(X86_CR4_LASS);
@@ -2061,7 +2047,6 @@ static void identify_cpu(struct cpuinfo_x86 *c)
setup_smep(c);
setup_smap(c);
setup_umip(c);
- setup_lass(c);
/* Enable FSGSBASE instructions if available. */
if (cpu_has(c, X86_FEATURE_FSGSBASE)) {
--
2.43.0