Re: [PATCH v2 2/3] efi_loader: carve out efi_get_memory_map_alloc()

9 Jan 2023

      Hi Heinrich
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+/**

efi_get_memory_map_alloc() - allocate map describing memory usage

The caller is responsible for calling FreePool() if the call succeeds.

@memory_map              buffer to which the memory map is written

@map_size                size of the memory map

Return:          status code

*/

+efi_status_t efi_get_memory_map_alloc(efi_uintn_t *map_size,

                             struct efi_mem_desc **memory_map)

+{

efi_status_t ret;

*memory_map = NULL;
*map_size = 0;
ret = efi_get_memory_map(map_size, *memory_map, NULL, NULL, NULL);

Although this is correct and efi_get_memory_map() will only return
EFI_BUFFER_TOO_SMALL, since we initialize the map_size to 0,  I don't know
if code analysis tools are smart enough to understand this.  Perhaps we
should initialize ret?
After an assignment ret cannot be uninitialized.
Did you find a path through efi_get_memory_map() returning an undefined
value?
Nop, just misread the patch!
Regards
/Ilias
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Best regards
Heinrich
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if (ret == EFI_BUFFER_TOO_SMALL) {
       *map_size += sizeof(struct efi_mem_desc); /* for the map */

       ret = efi_allocate_pool(EFI_BOOT_SERVICES_DATA, *map_size,

                               (void **)memory_map);

       if (ret != EFI_SUCCESS)

               return ret;

       ret = efi_get_memory_map(map_size, *memory_map,

                                NULL, NULL, NULL);

       if (ret != EFI_SUCCESS) {

               efi_free_pool(*memory_map);

               *memory_map = NULL;

       }

}

return ret;

+}

/**
efi_add_conventional_memory_map() - add a RAM memory area to the map

--
2.37.2
Reviewed-by: Ilias Apalodimas ilias.apalodimas@linaro.org