Re: [Xen-devel] [PATCH] xen/x86: Fix compilation issue with clang 3.2

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 01.05.13 at 15:20, Julien Grall <julien.grall@xxxxxxxxxx> wrote:
> HYPERVISOR_VIRT_START is an unsigned long constant. In shadow code, Xen
> compares this value with a int which is wrong.
> 
> multi.c:1981:5: error: comparison of constant 8796025913344 with expression 
> of
> type 'int' is always true 
> [-Werror,-Wtautological-constant-out-of-range-compare]
>     SHADOW_FOREACH_L2E(sl2mfn, sl2e, 0, 0, v->domain, {
>                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> multi.c:1320:18: note: expanded from macro 'SHADOW_FOREACH_L2E'
>                      < (HYPERVISOR_VIRT_START >> SHADOW_L2_PAGETABLE_SHIFT) ) 
> \
>                        ^ 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Which makes relatively obvious that these checks are there only
for 32-bit Xen, which we don't have anymore. So rather than
fixing dead code, why don't we simply drop it?

Jan

> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
> ---
>  xen/arch/x86/mm/shadow/multi.c |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
> index a8ef75e..f2e70d2 100644
> --- a/xen/arch/x86/mm/shadow/multi.c
> +++ b/xen/arch/x86/mm/shadow/multi.c
> @@ -1308,7 +1308,8 @@ do {                                                    
>                 \
>  /* 32-bit l2 on PAE/64: four pages, touch every second entry, and avoid Xen 
> */
>  #define SHADOW_FOREACH_L2E(_sl2mfn, _sl2e, _gl2p, _done, _dom, _code)     \
>  do {                                                                      \
> -    int _i, _j, __done = 0;                                               \
> +    unsigned long _i, _j;                                                 \
> +    int __done = 0;                                                       \
>      int _xen = !shadow_mode_external(_dom);                               \
>      ASSERT(mfn_to_page(_sl2mfn)->u.sh.type == SH_type_l2_32_shadow);\
>      for ( _j = 0; _j < 4 && !__done; _j++ )                               \
> @@ -1335,7 +1336,7 @@ do {                                                    
>                   \
>  /* PAE: if it's an l2h, don't touch Xen mappings */
>  #define SHADOW_FOREACH_L2E(_sl2mfn, _sl2e, _gl2p, _done, _dom, _code)      
> \
>  do {                                                                       
> \
> -    int _i;                                                                \
> +    unsigned long _i;                                                      
> \
>      int _xen = !shadow_mode_external(_dom);                                
> \
>      shadow_l2e_t *_sp = sh_map_domain_page((_sl2mfn));                     
> \
>      ASSERT(mfn_to_page(_sl2mfn)->u.sh.type == SH_type_l2_pae_shadow \
> -- 
> 1.7.10.4
> 
> 
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> http://lists.xen.org/xen-devel 




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