On 15.01.16 14:02, Leif Lindholm wrote:
> On Fri, Jan 15, 2016 at 01:13:15AM +0100, Alexander Graf wrote:
>> On 26.12.15 19:09, Leif Lindholm wrote:
>>>> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
>>>> new file mode 100644
>>>> index 0000000..ed95962
>>>> --- /dev/null
>>>> +++ b/lib/efi_loader/efi_boottime.c
>>>> @@ -0,0 +1,838 @@
>>>> +/*
>>>> + * EFI application boot time services
>>>> + *
> ...
>>>> +
>>>> +static unsigned long efi_raise_tpl(unsigned long new_tpl)
>>>> +{
>>>> + EFI_ENTRY("0x%lx", new_tpl);
>>>> + return EFI_EXIT(efi_unsupported(__func__));
>>>
>>> "Unlike other UEFI interface functions, EFI_BOOT_SERVICES.RaiseTPL()
>>> does not return a status code. Instead, it returns the previous task
>>> priority level, which is to be restored later with a matching call to
>>> RestoreTPL()."
>>
>> Since we don't do TPLs (or IRQs for that matter), I'll just return 0 here.
>
> Sure.
>
>>>> +}
>>>> +
>>>> +static void efi_restore_tpl(unsigned long old_tpl)
>>>> +{
>>>> + EFI_ENTRY("0x%lx", old_tpl);
>>>> + EFI_EXIT(efi_unsupported(__func__));
>>>
>>> (void function, nothing to return)
>>
>> Yes, hence no return. EFI_EXIT deals with the gd swapping and
>> efi_unsupported() gives me a nice debug message :).
>
> Ah, ok.
>
>>>> +static efi_status_t efi_allocate_pages(int type, int memory_type,
>>>> + unsigned long pages, uint64_t *memory)
>>>> +{
>>>> + u64 len = pages << 12;
>>>> + efi_status_t r = EFI_SUCCESS;
>>>> +
>>>> + EFI_ENTRY("%d, %d, 0x%lx, %p", type, memory_type, pages, memory);
>>>> +
>>>> + switch (type) {
>>>> + case 0:
>>>> + /* Any page means we can go to efi_alloc */
>>>> + *memory = (unsigned long)efi_alloc(len, memory_type);
>>>> + break;
>>>> + case 1:
>>>> + /* Max address */
>>>> + if (gd->relocaddr < *memory) {
>>>> + *memory = (unsigned long)efi_alloc(len, memory_type);
>>>> + break;
>>>> + }
>>>> + r = EFI_UNSUPPORTED;
>>>
>>> EFI_OUT_OF_RESOURCES/EFI_NOT_FOUND?
>>>
>>>> + break;
>>>> + case 2:
>>>> + /* Exact address, grant it. The addr is already in *memory. */
>>>
>>> As far as I can tell, this is why GRUB works. Because it filters
>>> through the memory map manually, requesting to allocate its heap at an
>>> exact address in a region of free memory in the UEFI memory map.
>>
>> Yes.
>>
>>> The key is that EFI_LOADER_MEMORY will be used by applications loaded
>>> as well as by U-Boot to load applications into. A simple example where
>>> this could be problematic would be a large(ish) initrd loaded via initrd=
>>> on kernel (stub loader) command line rather than via GRUB.
>>
>> Ah, so here the 128MB limit on the LOADER_DATA section might bite us?
>
> Yeah, I think so.
>
>>>> + runtime_start = (ulong)&__efi_runtime_start & ~0xfffULL;
>>>> + runtime_end = ((ulong)&__efi_runtime_stop + 0xfff) & ~0xfffULL;
>>>> + runtime_len_pages = (runtime_end - runtime_start) >> 12;
>>>> + runtime_len = runtime_len_pages << 12;
>>>> +
>>>> + /* Fill in where normal RAM is (up to U-Boot) */
>>>> + efi_memory_map[0].num_pages = gd->relocaddr >> 12;
>>>
>>> U-Boot question: is gd->relocaddr always the offset from start of RAM?
>>> How does this work with gaps in memory map?
>>
>> U-Boot always relocates itself at TOM (or at least what we consider TOM
>> here). gd->relocaddr is the physical address of the start of U-Boot
>> which is right below TOM.
>
> Still ... would need additional handling if memory has holes (like,
> fitted with multiple DIMMs smaller than the individual memory window
> reserved for them). Or even on something like Juno, which has 2GB of
> RAM at 0x00_8000_0000, and a further 6GB at 0x08_8000_0000 (I think).
Yes. I think we'll have to just implement that when we hit the first
board that does this (and has awareness in U-Boot for it).
With the UEFI entry path, Linux will ignore memory nodes in dt, right?
>
>>>> +#ifdef CONFIG_SYS_SDRAM_BASE
>>>> + efi_memory_map[0].physical_start = CONFIG_SYS_SDRAM_BASE;
>>>> + efi_memory_map[0].virtual_start = CONFIG_SYS_SDRAM_BASE;
>>>> + efi_memory_map[0].num_pages -= CONFIG_SYS_SDRAM_BASE >> 12;
>>> #else
>>> #error "..."
>>> ?
>>
>> If it's not defined, it's 0 :).
>
> Make it
> #if CONFIG_SYS_SDRAM_BASE != 0
> for clarity?
I really don't think we'll make it more readable with more #iffery here :).
Alex
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