Re: multiboot_mmap_entry.zero isn't zero

[Andrei Borzenkov]

14.02.2016 14:24, Wink Saville пишет:
> I'm using multiboot2 and I see a zero field in grub/include/multiboot2.h:
> 
> struct multiboot_mmap_entry
> {
>   multiboot_uint64_t addr;
>   multiboot_uint64_t len;
> #define MULTIBOOT_MEMORY_AVAILABLE 1
> #define MULTIBOOT_MEMORY_RESERVED 2
> #define MULTIBOOT_MEMORY_ACPI_RECLAIMABLE       3
> #define MULTIBOOT_MEMORY_NVS                    4
> #define MULTIBOOT_MEMORY_BADRAM                 5
>   multiboot_uint32_t type;
>   multiboot_uint32_t zero;
> } GRUB_PACKED;
> typedef struct multiboot_mmap_entry multiboot_memory_map_t;
> 

OK, I pushed fix (although documentation also says OS should ignore this
field :) )

> 
> Although in grub/include/multiboot.h it does not exist:
> 
> struct multiboot_mmap_entry
> {
>   multiboot_uint32_t size;
>   multiboot_uint64_t addr;
>   multiboot_uint64_t len;
> #define MULTIBOOT_MEMORY_AVAILABLE 1
> #define MULTIBOOT_MEMORY_RESERVED 2
> #define MULTIBOOT_MEMORY_ACPI_RECLAIMABLE       3
> #define MULTIBOOT_MEMORY_NVS                    4
> #define MULTIBOOT_MEMORY_BADRAM                 5
>   multiboot_uint32_t type;
> } GRUB_PACKED;
> typedef struct multiboot_mmap_entry multiboot_memory_map_t;
> 
> 
> On Sat, Feb 13, 2016 at 11:12 PM, Andrei Borzenkov <address@hidden> wrote:
>> 14.02.2016 00:20, Wink Saville пишет:
>>> I'm processing multiboot_tag_mmap and the multiboot_mmap_entry.zero
>>> isn't zero. As best as I can tell grub isn't initializing it. Here is
>>> the code from grub-core/loader/i386/multiboot_mbi.c:
>>>
>>> /* Helper for grub_fill_multiboot_mmap.  */
>>> static int
>>> grub_fill_multiboot_mmap_iter (grub_uint64_t addr, grub_uint64_t size,
>>>        grub_memory_type_t type, void *data)
>>> {
>>>   struct multiboot_mmap_entry **mmap_entry = data;
>>>
>>>   (*mmap_entry)->addr = addr;
>>>   (*mmap_entry)->len = size;
>>>   (*mmap_entry)->type = type;
>>>   (*mmap_entry)->size = sizeof (struct multiboot_mmap_entry) - sizeof
>>> ((*mmap_entry)->size);
>>>   (*mmap_entry)++;
>>>
>>>   return 0;
>>> }
>>>
>>> And similar code in grub-core/loader/multiboot_mbi2.c:
>>>
>>> /* Helper for grub_fill_multiboot_mmap.  */
>>> static int
>>> grub_fill_multiboot_mmap_iter (grub_uint64_t addr, grub_uint64_t size,
>>>        grub_memory_type_t type, void *data)
>>> {
>>>   struct multiboot_mmap_entry **mmap_entry = data;
>>>
>>>   (*mmap_entry)->addr = addr;
>>>   (*mmap_entry)->len = size;
>>>   (*mmap_entry)->type = type;
>>>   (*mmap_entry)++;
>>>
>>>   return 0;
>>> }
>>>
>>> And I'd expect to see:
>>>
>>> (*mmap_entry)->zero = 0;
>>>
>>> Is there a reason its not being zeroed?
>>>
>>
>> Because it does not exist?
>>
>>
>> _______________________________________________
>> Grub-devel mailing list
>> address@hidden
>> https://lists.gnu.org/mailman/listinfo/grub-devel