[PATCH] x86/traps: More use of nocall

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>

Followup from XSA-446
---
 xen/arch/x86/include/asm/processor.h | 4 +---
 xen/arch/x86/pv/traps.c              | 3 ++-
 xen/arch/x86/traps.c                 | 2 ++
 xen/arch/x86/x86_64/entry.S          | 2 +-
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/include/asm/processor.h 
b/xen/arch/x86/include/asm/processor.h
index b0d2a62c075f..ff62b080afbf 100644
--- a/xen/arch/x86/include/asm/processor.h
+++ b/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 {
diff --git a/xen/arch/x86/pv/traps.c b/xen/arch/x86/pv/traps.c
index 240d1a2db7a3..83e84e276233 100644
--- a/xen/arch/x86/pv/traps.c
+++ b/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);
 }
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index e1356f696aba..9a6d29f24ae1 100644
--- a/xen/arch/x86/traps.c
+++ b/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)
 {
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index 9a7b129aa7e4..bf654fe27ec3 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/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
-- 
2.30.2