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@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Julien Grall <julien.grall@arm.com>

diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index dfca0a5bf8d5e98d2a0c4c0368141ad9a2591feb..e66245aa7c78c781f6376606e2d980dce06e45d1 100644 (file)
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -3318,7 +3318,7 @@ 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;
@@ -3338,7 +3338,7 @@ static void emulate_gate_op(struct cpu_user_regs *regs)
                     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 4275e66f401f587848268023bd5732f77232de4a..083ea9d0c39f615370d0ecc398b0ef1cdaa3d6f1 100644 (file)
--- a/xen/include/asm-x86/x86_64/uaccess.h
+++ b/xen/include/asm-x86/x86_64/uaccess.h
@@ -42,7 +42,7 @@ extern void *xlat_malloc(unsigned long *xlat_page_current, size_t size);
 
 #define array_access_ok(addr, count, size) \
     (likely(((count) ?: 0UL) < (~0UL / (size))) && \
-     access_ok(addr, (count) * (size)))
+     access_ok(addr, 0 + (count) * (size)))
 
 #define __compat_addr_ok(d, addr) \
     ((unsigned long)(addr) < HYPERVISOR_COMPAT_VIRT_START(d))
@@ -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 {                                                                   \