-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 <[email protected]> --- a/xen/arch/x86/traps.c +++ b/xen/arch/x86/traps.c @@ -3318,7 +3318,7 @@ static void emulate_gate_op(struct cpu_u 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_u 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; --- 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 * #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 * #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 { \
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 <[email protected]> --- a/xen/arch/x86/traps.c +++ b/xen/arch/x86/traps.c @@ -3318,7 +3318,7 @@ static void emulate_gate_op(struct cpu_u 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_u 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; --- 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 * #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 * #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 { \
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