[U-Boot] [PATCH v5 7/7] efi_loader: Declare secure memory as reserved

[york sun]

On 10/17/2016 02:11 AM, Alexander Graf wrote:
>
>
> On 15.10.16 18:58, york sun wrote:
>> On 10/15/2016 03:03 AM, Alexander Graf wrote:
>>> Some systems may implemente TrustZone (EL3) in U-Boot. Those systems
>>> reserve some memory that U-Boot is aware of as secure.
>>>
>>> For those systems, mask out that secure memory in the EFI memory map,
>>> as it's not usable from EL2 or EL1.
>>>
>>> Signed-off-by: Alexander Graf <agraf at suse.de>
>>>
>>> ---
>>>
>>> v4 -> v5:
>>>
>>>   - Use gd->arch.secure_ram
>>> ---
>>>  lib/efi_loader/efi_memory.c | 15 +++++++++++++++
>>>  1 file changed, 15 insertions(+)
>>>
>>> diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
>>> index 95aa590..4966e48 100644
>>> --- a/lib/efi_loader/efi_memory.c
>>> +++ b/lib/efi_loader/efi_memory.c
>>> @@ -474,5 +474,20 @@ int efi_memory_init(void)
>>>  	efi_bounce_buffer = (void*)(uintptr_t)efi_bounce_buffer_addr;
>>>  #endif
>>>
>>> +#ifdef CONFIG_SYS_MEM_RESERVE_SECURE
>>> +	/* Declare secure ram as reserved */
>>> +        if (gd->arch.secure_ram & MEM_RESERVE_SECURE_SECURED) {
>>> +		uint64_t secure_start = gd->arch.secure_ram;
>>> +		uint64_t secure_pages = CONFIG_SYS_MEM_RESERVE_SECURE;
>>> +
>>> +		secure_start &= MEM_RESERVE_SECURE_ADDR_MASK;
>>> +		secure_start &= ~EFI_PAGE_MASK;
>>> +		secure_pages = (secure_pages + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT;
>>> +
>>> +		efi_add_memory_map(secure_start, secure_pages,
>>> +				   EFI_RESERVED_MEMORY_TYPE, false);
>>> +        }
>>> +#endif
>>> +
>>>  	return 0;
>>>  }
>>>
>>
>> Alex,
>>
>> Do you see any issue without this patch? The secure memory is not
>> visible to OS. gd->ram_size is reduced to hide the secure memory.
>
> We're building the memory map out of gd->bd->bi_dram rather than
> ram_size, because it's perfectly reasonable for systems to have memory
> holes.
>
> So even if we're adjusting gd->ram_size, the OS will still see secure
> memory. In fact, doesn't bootm do that as well?
>
> arch/arm/lib/bootm-fdt.c:       ret = fdt_fixup_memory_banks(blob,
> start, size, CONFIG_NR_DRAM_BANKS);
>
> On armv7, arch_fixup_fdt() removes the secure memory region from the
> edge of a memory bank. But on armv8 I don't see anything like it?
>

Alex,

For ARMv8, our SoCs have several regions. Depends on the board 
implementation, the memory may end up in different banks. See 
board/freescale/ls2080ardb/ddr.c for example. The secure ram is already 
carved out.

York