x86, vdso: Move syscall and sysenter setup into kernel/cpu/common.c
This code is used during CPU setup, and it isn't strictly speaking
related to the 32-bit vdso. It's easier to understand how this
works when the code is closer to its callers.
This also lets syscall32_cpu_init be static, which might save some
trivial amount of kernel text.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/4e466987204e232d7b55a53ff6b9739f12237461.1399317206.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a135239..7c65b46 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -953,6 +953,38 @@
else
vgetcpu_mode = VGETCPU_LSL;
}
+
+/* May not be __init: called during resume */
+static void syscall32_cpu_init(void)
+{
+ /* Load these always in case some future AMD CPU supports
+ SYSENTER from compat mode too. */
+ wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
+ wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
+ wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
+
+ wrmsrl(MSR_CSTAR, ia32_cstar_target);
+}
+#endif
+
+#ifdef CONFIG_X86_32
+void enable_sep_cpu(void)
+{
+ int cpu = get_cpu();
+ struct tss_struct *tss = &per_cpu(init_tss, cpu);
+
+ if (!boot_cpu_has(X86_FEATURE_SEP)) {
+ put_cpu();
+ return;
+ }
+
+ tss->x86_tss.ss1 = __KERNEL_CS;
+ tss->x86_tss.sp1 = sizeof(struct tss_struct) + (unsigned long) tss;
+ wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
+ wrmsr(MSR_IA32_SYSENTER_ESP, tss->x86_tss.sp1, 0);
+ wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long) ia32_sysenter_target, 0);
+ put_cpu();
+}
#endif
void __init identify_boot_cpu(void)