diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
index 57e1eb221e..6141b7eb9c 100644
--- a/xen/arch/x86/cpu/mcheck/mce.c
+++ b/xen/arch/x86/cpu/mcheck/mce.c
@@ -599,7 +599,7 @@ unsigned int mce_firstbank(struct cpuinfo_x86 *c)
            c->x86_vendor == X86_VENDOR_INTEL && c->x86_model < 0x1a;
 }
 
-int show_mca_info(int inited, struct cpuinfo_x86 *c)
+static int show_mca_info(int inited, struct cpuinfo_x86 *c)
 {
     static enum mcheck_type g_type = mcheck_unset;
 
diff --git a/xen/arch/x86/cpu/mcheck/mce_amd.c b/xen/arch/x86/cpu/mcheck/mce_amd.c
index adc36522cc..72f3feeaee 100644
--- a/xen/arch/x86/cpu/mcheck/mce_amd.c
+++ b/xen/arch/x86/cpu/mcheck/mce_amd.c
@@ -87,7 +87,7 @@ enum mc_ec_type {
     MC_EC_BUS_TYPE = 0x0800,
 };
 
-enum mc_ec_type
+static enum mc_ec_type
 mc_ec2type(uint16_t errorcode)
 {
     if ( errorcode & MC_EC_BUS_TYPE )
diff --git a/xen/arch/x86/cpu/microcode/core.c b/xen/arch/x86/cpu/microcode/core.c
index bec8b55db2..9fcb9c1c3a 100644
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -149,7 +149,7 @@ static int __init cf_check parse_ucode(const char *s)
 }
 custom_param("ucode", parse_ucode);
 
-void __init microcode_scan_module(
+static void __init microcode_scan_module(
     unsigned long *module_map,
     const multiboot_info_t *mbi)
 {
diff --git a/xen/arch/x86/nmi.c b/xen/arch/x86/nmi.c
index c5c28300b0..104e366bd3 100644
--- a/xen/arch/x86/nmi.c
+++ b/xen/arch/x86/nmi.c
@@ -108,7 +108,7 @@ static unsigned int lapic_nmi_owner;
  *     be enabled
  * -1: the lapic NMI watchdog is disabled, but can be enabled
  */
-int nmi_active;
+static int nmi_active;
 
 #define K7_EVNTSEL_ENABLE	(1 << 22)
 #define K7_EVNTSEL_INT		(1 << 20)
diff --git a/xen/arch/x86/spec_ctrl.c b/xen/arch/x86/spec_ctrl.c
index ebe56a96cd..9b8fdb5303 100644
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -43,9 +43,9 @@ static enum ind_thunk {
 } opt_thunk __initdata = THUNK_DEFAULT;
 
 static int8_t __initdata opt_ibrs = -1;
-int8_t __initdata opt_stibp = -1;
+static int8_t __initdata opt_stibp = -1;
 bool __ro_after_init opt_ssbd;
-int8_t __initdata opt_psfd = -1;
+static int8_t __initdata opt_psfd = -1;
 
 int8_t __ro_after_init opt_ibpb_ctxt_switch = -1;
 int8_t __read_mostly opt_eager_fpu = -1;