make all (native) hypercalls consistently have "long" return type

for common and x86 ones at least, to address the problem of storing
zero-extended values into the multicall result field otherwise.

Reported-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -2973,7 +2973,7 @@ static inline void fixunmap_domain_page(
 #define fixunmap_domain_page(ptr) ((void)(ptr))
 #endif
 
-int do_mmuext_op(
+long do_mmuext_op(
     XEN_GUEST_HANDLE(mmuext_op_t) uops,
     unsigned int count,
     XEN_GUEST_HANDLE(uint) pdone,
@@ -3437,7 +3437,7 @@ int do_mmuext_op(
     return rc;
 }
 
-int do_mmu_update(
+long do_mmu_update(
     XEN_GUEST_HANDLE(mmu_update_t) ureqs,
     unsigned int count,
     XEN_GUEST_HANDLE(uint) pdone,
@@ -4285,15 +4285,15 @@ static int __do_update_va_mapping(
     return rc;
 }
 
-int do_update_va_mapping(unsigned long va, u64 val64,
-                         unsigned long flags)
+long do_update_va_mapping(unsigned long va, u64 val64,
+                          unsigned long flags)
 {
     return __do_update_va_mapping(va, val64, flags, current->domain);
 }
 
-int do_update_va_mapping_otherdomain(unsigned long va, u64 val64,
-                                     unsigned long flags,
-                                     domid_t domid)
+long do_update_va_mapping_otherdomain(unsigned long va, u64 val64,
+                                      unsigned long flags,
+                                      domid_t domid)
 {
     struct domain *pg_owner;
     int rc;
--- a/xen/common/compat/xenoprof.c
+++ b/xen/common/compat/xenoprof.c
@@ -5,6 +5,7 @@
 #include <compat/xenoprof.h>
 
 #define COMPAT
+#define ret_t int
 
 #define do_xenoprof_op compat_xenoprof_op
 
--- a/xen/common/kexec.c
+++ b/xen/common/kexec.c
@@ -845,8 +845,8 @@ static int kexec_exec(XEN_GUEST_HANDLE(v
     return -EINVAL; /* never reached */
 }
 
-int do_kexec_op_internal(unsigned long op, XEN_GUEST_HANDLE(void) uarg,
-                           int compat)
+static int do_kexec_op_internal(unsigned long op, XEN_GUEST_HANDLE(void) uarg,
+                                bool_t compat)
 {
     unsigned long flags;
     int ret = -EINVAL;
--- a/xen/common/xenoprof.c
+++ b/xen/common/xenoprof.c
@@ -607,6 +607,8 @@ static int xenoprof_op_init(XEN_GUEST_HA
     return (copy_to_guest(arg, &xenoprof_init, 1) ? -EFAULT : 0);
 }
 
+#define ret_t long
+
 #endif /* !COMPAT */
 
 static int xenoprof_op_get_buffer(XEN_GUEST_HANDLE(void) arg)
@@ -660,7 +662,7 @@ static int xenoprof_op_get_buffer(XEN_GU
                       || (op == XENOPROF_disable_virq)  \
                       || (op == XENOPROF_get_buffer))
  
-int do_xenoprof_op(int op, XEN_GUEST_HANDLE(void) arg)
+ret_t do_xenoprof_op(int op, XEN_GUEST_HANDLE(void) arg)
 {
     int ret = 0;
     
@@ -904,6 +906,7 @@ int do_xenoprof_op(int op, XEN_GUEST_HAN
 }
 
 #if defined(CONFIG_COMPAT) && !defined(COMPAT)
+#undef ret_t
 #include "compat/xenoprof.c"
 #endif
 
--- a/xen/include/asm-x86/hypercall.h
+++ b/xen/include/asm-x86/hypercall.h
@@ -24,7 +24,7 @@ extern long
 do_set_trap_table(
     XEN_GUEST_HANDLE(const_trap_info_t) traps);
 
-extern int
+extern long
 do_mmu_update(
     XEN_GUEST_HANDLE(mmu_update_t) ureqs,
     unsigned int count,
@@ -62,7 +62,7 @@ do_update_descriptor(
 extern long
 do_mca(XEN_GUEST_HANDLE(xen_mc_t) u_xen_mc);
 
-extern int
+extern long
 do_update_va_mapping(
     unsigned long va,
     u64 val64,
@@ -72,14 +72,14 @@ extern long
 do_physdev_op(
     int cmd, XEN_GUEST_HANDLE(void) arg);
 
-extern int
+extern long
 do_update_va_mapping_otherdomain(
     unsigned long va,
     u64 val64,
     unsigned long flags,
     domid_t domid);
 
-extern int
+extern long
 do_mmuext_op(
     XEN_GUEST_HANDLE(mmuext_op_t) uops,
     unsigned int count,
@@ -90,10 +90,6 @@ extern unsigned long
 do_iret(
     void);
 
-extern int
-do_kexec(
-    unsigned long op, unsigned arg1, XEN_GUEST_HANDLE(void) uarg);
-
 #ifdef __x86_64__
 
 extern long
--- a/xen/include/xen/hypercall.h
+++ b/xen/include/xen/hypercall.h
@@ -137,7 +137,7 @@ extern long
 do_tmem_op(
     XEN_GUEST_HANDLE(tmem_op_t) uops);
 
-extern int
+extern long
 do_xenoprof_op(int op, XEN_GUEST_HANDLE(void) arg);
 
 #ifdef CONFIG_COMPAT