x86/traps: More use of nocall

sysenter_eflags_saved() and int80_direct_trap() are now only used by a single
translation unit.  Move the declarations into the respective traps.c, renaming
int80_direct_trap() to entry_int80() to match the style elsewhere.

Annotate all 3 with nocall like all other entry paths.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

xen/arch/x86/include/asm/processor.h

@@ -457,9 +457,7 @@ static inline void enable_nmis(void)
                      [cs] "r" (__HYPERVISOR_CS) );
 }
 
-void sysenter_entry(void);
-void sysenter_eflags_saved(void);
-void int80_direct_trap(void);
+void nocall sysenter_entry(void);
 
 struct stubs {
     union {

xen/arch/x86/pv/traps.c

@@ -132,6 +132,7 @@ static void cf_check nmi_softirq(void)
     *v_ptr = NULL;
 }
 
+void nocall entry_int80(void);
 void nocall entry_int82(void);
 
 void __init pv_trap_init(void)
@@ -144,7 +145,7 @@ void __init pv_trap_init(void)
 
     /* Fast trap for int80 (faster than taking the #GP-fixup path). */
     _set_gate(idt_table + LEGACY_SYSCALL_VECTOR, SYS_DESC_irq_gate, 3,
-              &int80_direct_trap);
+              &entry_int80);
 
     open_softirq(NMI_SOFTIRQ, nmi_softirq);
 }

xen/arch/x86/traps.c

@@ -1884,6 +1884,8 @@ void do_device_not_available(struct cpu_user_regs *regs)
 #endif
 }
 
+void nocall sysenter_eflags_saved(void);
+
 /* SAF-1-safe */
 void do_debug(struct cpu_user_regs *regs)
 {

xen/arch/x86/x86_64/entry.S

@@ -385,7 +385,7 @@ UNLIKELY_END(sysenter_gpf)
 #endif
         jmp   .Lbounce_exception
 
-ENTRY(int80_direct_trap)
+ENTRY(entry_int80)
         ENDBR64
         ALTERNATIVE "", clac, X86_FEATURE_XEN_SMAP
         pushq $0