On Fri, Jul 06, 2018 at 09:42:28AM +0900, AKASHI Takahiro wrote: > On Fri, Jul 06, 2018 at 12:31:49AM +0200, Ard Biesheuvel wrote: > > On 5 July 2018 at 18:48, Will Deacon <will.deacon@xxxxxxx> wrote: > > > On Thu, Jul 05, 2018 at 12:02:15PM +0100, James Morse wrote: > > >> On 05/07/18 10:43, AKASHI Takahiro wrote: > > >> > On Wed, Jul 04, 2018 at 08:49:32PM +0200, Ard Biesheuvel wrote: > > >> >> On 4 July 2018 at 19:06, Will Deacon <will.deacon@xxxxxxx> wrote: > > >> >>> On Tue, Jun 19, 2018 at 03:44:23PM +0900, AKASHI Takahiro wrote: > > >> >>>> Since arm_enter_runtime_services() was modified to always create a virtual > > >> >>>> mapping of UEFI memory map in the previous patch, it is now renamed to > > >> >>>> efi_enter_virtual_mode() and called earlier before acpi_load_tables() > > >> >>>> in acpi_early_init(). > > >> >>>> > > >> >>>> This will allow us to use UEFI memory map in acpi_os_ioremap() to create > > >> >>>> mappings of ACPI tables using memory attributes described in UEFI memory > > >> >>>> map. > > >> > > >> >>> Hmm, this is ugly as hell. Is there nothing else we can piggy-back off? > > >> >>> It's also fairly jarring that, on x86, efi_enter_virtual_mode() is called > > >> >>> a few lines later, *after* acpi_early_init() has been called. > > >> > > >> >> Currently, there is a gap where we have already torn down the early > > >> >> mapping and haven't created the definitive mapping of the UEFI memory > > >> >> map. There are other reasons why this is an issue, and I recently > > >> >> proposed [0] myself to address one of them > > >> > > >> >> Akashi-san, could you please confirm whether the patch below would be > > >> >> sufficient for you? Apologies for going back and forth on this, but I > > >> >> agree with Will that we should try to avoid warts like the one above > > >> >> in generic code. > > >> >> > > >> >> [0] https://marc.info/?l=linux-efi&m=152930773507524&w=2 > > >> > > > >> > I think that this patch will also work. > > >> > Please drop my patch#2 and #3 if you want to pick up my patchset, Will. > > >> > > >> Patch 2 is what changes arm_enable_runtime_services() to map the efi memory map > > >> before bailing out due to efi=noruntime. > > >> > > >> Without it, 'efi=noruntime' means no-acpi-tables. > > > > > > So it sounds like we want patch 2. Akashi, given that this series is only > > > four patches, please can you send out a v3 with the stuff that should be > > > reviewed and merged? Otherwise, there's a real risk we end up with breakage > > > that goes unnoticed initially. > > > > > > > Yes, we want patches #1, #2 and #4, and this one can be replaced with > > my patch above. Everything can be taken via the arm64 tree as far as I > > am concerned. > > I almost believed that my patch#2 was just a preparatory one for patch#3 > where arm_enable_runtime_services() is moved aggressively forward. > But acpi_os_ioremap() is not a __init function and I can now agree to > keeping patch#2. > > Meanwhile, the consequent code with Ard's patch would look like: > ---8<--- > static int __init arm_enable_runtime_services(void) > { > ... > efi_memmap_unmap(); > > mapsize = efi.memmap.desc_size * efi.memmap.nr_map; > > if (efi_memmap_init_late(efi.memmap.phys_map, mapsize)) { > pr_err("Failed to remap EFI memory map\n"); > return 0; > } > ... > } > --->8--- > It seems to me that it makes no sense. Oops, it does. Comments at efi_memmap_init_late() say: ---8<--- * The reason there are two EFI memmap initialisation * (efi_memmap_init_early() and this late version) is because the * early EFI memmap should be explicitly unmapped once EFI * initialisation is complete as the fixmap space used to map the EFI * memmap (via early_memremap()) is a scarce resource. --->8--- > Is it okay to take them out? Never mind. > > -Takahiro AKASHI _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
