Re: [PATCH 2/6] efi/libstub: Allocate headspace in efi_get_memory_map()

From: Ingo Molnar
Date: Mon Aug 22 2016 - 12:37:35 EST



* Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> wrote:

> + efi_boottime_memory_map_t map;
>
> nr_desc = 0;
> e820ext = NULL;
> e820ext_size = 0;
> + map.map = &mem_map;
> + map.map_size = &map_sz;
> + map.desc_size = &desc_size;
> + map.desc_ver = &desc_version;
> + map.key_ptr = &key;
> + map.buff_size = &buff_size;

> + *map->desc_size = sizeof(*m);
> + *map->map_size = *map->desc_size * 32;
> + *map->buff_size = *map->map_size;

> + boot_map.map = (efi_memory_desc_t **)&map.map;
> + boot_map.map_size = &map_size;
> + boot_map.desc_size = &map.desc_size;
> + boot_map.desc_ver = NULL;
> + boot_map.key_ptr = NULL;
> + boot_map.buff_size = &buff_size;

> + boot_map.map = &map;
> + boot_map.map_size = &map_size;
> + boot_map.desc_size = &desc_size;
> + boot_map.desc_ver = NULL;
> + boot_map.key_ptr = NULL;
> + boot_map.buff_size = &buff_size;

> + efi_boottime_memory_map_t boot_map;
> +
> + boot_map.map = &map;
> + boot_map.map_size = &map_size;
> + boot_map.desc_size = &desc_size;
> + boot_map.desc_ver = NULL;
> + boot_map.key_ptr = NULL;
> + boot_map.buff_size = &buff_size;

> + efi_boottime_memory_map_t map;
> +
> + map.map = &runtime_map;
> + map.map_size = &map_size;
> + map.desc_size = &desc_size;
> + map.desc_ver = &desc_ver;
> + map.key_ptr = &mmap_key;
> + map.buff_size = &buff_size;

> + efi_boottime_memory_map_t map;
>
> - status = efi_get_memory_map(sys_table_arg, &memory_map, &map_size,
> - &desc_size, NULL, NULL);
> + map.map = &memory_map;
> + map.map_size = &map_size;
> + map.desc_size = &desc_size;
> + map.desc_ver = NULL;
> + map.key_ptr = NULL;
> + map.buff_size = &buff_size;

That's really ugly - if we do such initializations then at minimum they should be
aligned vertically.

> u32 imagesize;
> } efi_capsule_header_t;
>
> +typedef struct {
> + efi_memory_desc_t **map;
> + unsigned long *map_size;
> + unsigned long *desc_size;
> + u32 *desc_ver;
> + unsigned long *key_ptr;
> + unsigned long *buff_size;
> +} efi_boottime_memory_map_t;

Ditto for structure definitions:

typedef struct {
efi_memory_desc_t **map;
unsigned long *map_size;
unsigned long *desc_size;
u32 *desc_ver;
unsigned long *key_ptr;
unsigned long *buff_size;
} efi_boottime_memory_map_t;

Plus it would be nice to just use a proper structure name instead of a typedef -
such as:

struct efi_boot_memmap {
...
};

(Note that this name is also shorter)

... in the kernel we generally only use typedefs for short, synthetic types -
bigger objects like this should be explicit structs - unless there's some strong
reason to do it via a typedef.

Thanks,

Ingo