[xen staging] x86/pv: fix clang build without CONFIG_PV32

[patchbot@xxxxxxx]

commit fc5d0c98076b4c84fa978259eae0f521e95962c7
Author:     Roger Pau Monné <roger.pau@xxxxxxxxxx>
AuthorDate: Fri Apr 23 15:58:37 2021 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Apr 23 15:58:37 2021 +0200

    x86/pv: fix clang build without CONFIG_PV32
    
    Clang reports the following build error without CONFIG_PV32:
    
    hypercall.c:253:10: error: variable 'op' is used uninitialized whenever 
'if' condition is false [-Werror,-Wsometimes-uninitialized]
        if ( !is_pv_32bit_vcpu(curr) )
             ^~~~~~~~~~~~~~~~~~~~~~~
    hypercall.c:282:21: note: uninitialized use occurs here
        return unlikely(op == __HYPERVISOR_iret)
                        ^~
    /root/src/xen/xen/include/xen/compiler.h:21:43: note: expanded from macro 
'unlikely'
    #define unlikely(x)   __builtin_expect(!!(x),0)
                                              ^
    hypercall.c:253:5: note: remove the 'if' if its condition is always true
        if ( !is_pv_32bit_vcpu(curr) )
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    hypercall.c:251:21: note: initialize the variable 'op' to silence this 
warning
        unsigned long op;
                        ^
                         = 0
    
    Rearrange the code in arch_do_multicall_call so that the if guards the
    32bit branch and when CONFIG_PV32 is not set there's no conditional at
    all.
    
    Fixes: 527922008bc ('x86: slim down hypercall handling when !PV32')
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/pv/hypercall.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/pv/hypercall.c b/xen/arch/x86/pv/hypercall.c
index e30c59b628..d573f74aa1 100644
--- a/xen/arch/x86/pv/hypercall.c
+++ b/xen/arch/x86/pv/hypercall.c
@@ -250,34 +250,34 @@ enum mc_disposition arch_do_multicall_call(struct 
mc_state *state)
     struct vcpu *curr = current;
     unsigned long op;
 
-    if ( !is_pv_32bit_vcpu(curr) )
+#ifdef CONFIG_PV32
+    if ( is_pv_32bit_vcpu(curr) )
     {
-        struct multicall_entry *call = &state->call;
+        struct compat_multicall_entry *call = &state->compat_call;
 
         op = call->op;
         if ( (op < ARRAY_SIZE(pv_hypercall_table)) &&
-             pv_hypercall_table[op].native )
-            call->result = pv_hypercall_table[op].native(
+             pv_hypercall_table[op].compat )
+            call->result = pv_hypercall_table[op].compat(
                 call->args[0], call->args[1], call->args[2],
                 call->args[3], call->args[4], call->args[5]);
         else
             call->result = -ENOSYS;
     }
-#ifdef CONFIG_PV32
     else
+#endif
     {
-        struct compat_multicall_entry *call = &state->compat_call;
+        struct multicall_entry *call = &state->call;
 
         op = call->op;
         if ( (op < ARRAY_SIZE(pv_hypercall_table)) &&
-             pv_hypercall_table[op].compat )
-            call->result = pv_hypercall_table[op].compat(
+             pv_hypercall_table[op].native )
+            call->result = pv_hypercall_table[op].native(
                 call->args[0], call->args[1], call->args[2],
                 call->args[3], call->args[4], call->args[5]);
         else
             call->result = -ENOSYS;
     }
-#endif
 
     return unlikely(op == __HYPERVISOR_iret)
            ? mc_exit
--
generated by git-patchbot for /home/xen/git/xen.git#staging