[Xen-changelog] [xen stable-4.8] x86: fix build with gcc 7

[patchbot@xxxxxxx]

commit d721af1f6e7cbdf33f7357c00d7580afd863eb39
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Jun 9 13:40:28 2017 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Jun 9 13:40:28 2017 +0200

    x86: fix build with gcc 7
    
    -Wint-in-bool-context, enabled by default in gcc 7, doesn't like
    multiplication in conditional operators. "Hide" them, at the risk of
    the next compiler version becoming smarter and recognizing even those.
    (The hope is that added smartness then would also better deal with
    legitimate cases like the ones here.)
    
    The change could have been done in access_ok(), but I think we better
    keep it at the places the compiler is actually unhappy about.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: f32400e90c046a9fd76c8917a60d34ade9c02ea2
    master date: 2017-05-19 10:11:36 +0200
---
 xen/arch/x86/traps.c                 | 4 ++--
 xen/include/asm-x86/x86_64/uaccess.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index b464211..19ac652 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -3565,7 +3565,7 @@ static void emulate_gate_op(struct cpu_user_regs *regs)
                 return;
             }
             stkp = (unsigned int *)(unsigned long)((unsigned int)base + esp);
-            if ( !compat_access_ok(stkp - 4 - nparm, (4 + nparm) * 4) )
+            if ( !compat_access_ok(stkp - 4 - nparm, 16 + nparm * 4) )
             {
                 do_guest_trap(TRAP_gp_fault, regs);
                 return;
@@ -3584,7 +3584,7 @@ static void emulate_gate_op(struct cpu_user_regs *regs)
                      !check_stack_limit(ar, limit, esp + nparm * 4, nparm * 4) 
)
                     return do_guest_trap(TRAP_gp_fault, regs);
                 ustkp = (unsigned int *)(unsigned long)((unsigned int)base + 
regs->_esp + nparm * 4);
-                if ( !compat_access_ok(ustkp - nparm, nparm * 4) )
+                if ( !compat_access_ok(ustkp - nparm, 0 + nparm * 4) )
                 {
                     do_guest_trap(TRAP_gp_fault, regs);
                     return;
diff --git a/xen/include/asm-x86/x86_64/uaccess.h 
b/xen/include/asm-x86/x86_64/uaccess.h
index 4275e66..d7dad4f 100644
--- a/xen/include/asm-x86/x86_64/uaccess.h
+++ b/xen/include/asm-x86/x86_64/uaccess.h
@@ -55,7 +55,7 @@ extern void *xlat_malloc(unsigned long *xlat_page_current, 
size_t size);
 
 #define compat_array_access_ok(addr,count,size) \
     (likely((count) < (~0U / (size))) && \
-     compat_access_ok(addr, (count) * (size)))
+     compat_access_ok(addr, 0 + (count) * (size)))
 
 #define __put_user_size(x,ptr,size,retval,errret)                      \
 do {                                                                   \
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.8

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