Hi Ilias,
Ok, I will change that in a v2. As a question: in here it is a U-Boot
routine the one that is doing the memcpy of the initrd, the one implemented
in the load_file2 protocol, the OS never knows about this dp explicitly,
could we technically use reserved data in here then?
Il mer 19 mar 2025, 09:37 Ilias Apalodimas <ilias.apalodi...@linaro.org> ha
scritto:
> On Wed, 19 Mar 2025 at 14:07, Adriano Córdova <adria...@gmail.com> wrote:
> >
> > Hi Ilias,
> >
> > El mié, 19 mar 2025 a las 6:32, Ilias Apalodimas (<
> ilias.apalodi...@linaro.org>) escribió:
> >>
> >> Hi Adriano,
> >>
> >> [...]
> >>
> >> > */
> >> > static efi_status_t efi_binary_run_dp(void *image, size_t size, void
> *fdt,
> >> > + void *initrd, size_t initd_sz,
> >> > struct efi_device_path *dp_dev,
> >> > struct efi_device_path *dp_img)
> >> > {
> >> > efi_status_t ret;
> >> > + struct efi_device_path *dp_initrd;
> >> >
> >> > /* Initialize EFI drivers */
> >> > ret = efi_init_obj_list();
> >> > @@ -230,6 +234,14 @@ static efi_status_t efi_binary_run_dp(void
> *image, size_t size, void *fdt,
> >> > if (ret != EFI_SUCCESS)
> >> > return ret;
> >> >
> >> > + dp_initrd = efi_dp_from_mem(EFI_RESERVED_MEMORY_TYPE,
> (uintptr_t)initrd, initd_sz);
> >>
> >> Why do we need reserved memory? What the EFI stub does, is allocate a
> >> new memory buffer which you later copy the initrd to.
> >> I think Boot Services Data is enough.
>
> I meant to write loader data*
>
> >
> >
> > dp_initrd is freed when the efi application returns in
> efi_initrd_deregister. Do you suggest to change it to
> > Boot Sevices Data and when the efi application returns just assume that
> it is freed?
>
> You will still have to free it on failures which is what
> efi_initrd_deregister() will do once we return from efi boot manager.
> But if you define it as reserved memory, it won't be usable by the OS.
> Since linux will eventually copy that memory in a buffer it allocated,
> you don't have to preserve it. So you can just define it as
> EFI_LOADER_DATA
>
> > I took the usage from:
> >
> https://github.com/u-boot/u-boot/blob/8bc3542384e3a1219e5ffb62b79d16dddc1b1fb9/lib/efi_loader/efi_bootmgr.c#L514
>
> This is a different use-case. In this we download and run an EFI
> application from memory and I guess the assumption is that the EFI
> application will return so the type doesn't matter that much as it
> will eventually be freed. This obviously is not the case if the EFI
> application is a kernel.
> That being said, I think we can switch this to LOADER_CODE as well.
> Heinrich any ideas?
>
> Thanks
> /Ilias
>
> >
> >>
> >>
> >> [...]
> >>
> >> Thanks
> >> /Ilias
>
