On 22 October 2014 19:06, Mark Salter <msalter@xxxxxxxxxx> wrote:
> On Wed, 2014-10-22 at 16:21 +0200, Ard Biesheuvel wrote:
>> On systems that boot via UEFI, all memory nodes are deleted from the
>> device tree, and instead, the size and location of system RAM is derived
>> from the UEFI memory map. This is handled by reserve_regions, which not only
>> reserves parts of memory that UEFI declares as reserved, but also installs
>> the memblocks that cover the remaining usable memory.
>>
>> Currently, reserve_regions() is only called if uefi_init() succeeds.
>> However, it does not actually depend on anything that uefi_init() does,
>> and not calling reserve_regions() results in a broken boot, so it is
>> better to just call it unconditionally.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>> ---
>> arch/arm64/kernel/efi.c | 11 ++++-------
>> 1 file changed, 4 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
>> index 51522ab0c6da..4cec21b1ecdd 100644
>> --- a/arch/arm64/kernel/efi.c
>> +++ b/arch/arm64/kernel/efi.c
>> @@ -313,8 +313,7 @@ void __init efi_init(void)
>> memmap.desc_size = params.desc_size;
>> memmap.desc_version = params.desc_ver;
>>
>> - if (uefi_init() < 0)
>> - return;
>> + WARN_ON(uefi_init() < 0);
>>
>> reserve_regions();
>> }
>
> It also looks like EFI_BOOT flag will be set even if uefi_init fails.
> If uefi_init fails, we only need reserve_regions() for the purpose
> of adding memblocks. Otherwise, we end up wasting a lot of memory.
Indeed. But perhaps it would be cleaner to add the memblocks in a
separate function that gets called before uefi_init(), let
reserve_regions() do just what it name implies, and retain the above
hunk so that the reserve_regions() call is only performed if UEFI
initialized correctly.
--
Ard.
> So, something like this would also be needed:
>
> diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
> index 03aaa99..5a6e189 100644
> --- a/arch/arm64/kernel/efi.c
> +++ b/arch/arm64/kernel/efi.c
> @@ -81,9 +81,6 @@ static int __init uefi_init(void)
> return -ENOMEM;
> }
>
> - set_bit(EFI_BOOT, &efi.flags);
> - set_bit(EFI_64BIT, &efi.flags);
> -
> /*
> * Verify the EFI Table
> */
> @@ -109,6 +106,9 @@ static int __init uefi_init(void)
> efi.systab->hdr.revision >> 16,
> efi.systab->hdr.revision & 0xffff, vendor);
>
> + set_bit(EFI_BOOT, &efi.flags);
> + set_bit(EFI_64BIT, &efi.flags);
> +
> retval = efi_config_init(NULL);
> if (retval == 0)
> set_bit(EFI_CONFIG_TABLES, &efi.flags);
> @@ -177,9 +177,10 @@ static __init void reserve_regions(void)
> if (is_normal_ram(md))
> early_init_dt_add_memory_arch(paddr, size);
>
> - if (is_reserve_region(md) ||
> - md->type == EFI_BOOT_SERVICES_CODE ||
> - md->type == EFI_BOOT_SERVICES_DATA) {
> + if (efi_enabled(EFI_BOOT) &&
> + (is_reserve_region(md) ||
> + md->type == EFI_BOOT_SERVICES_CODE ||
> + md->type == EFI_BOOT_SERVICES_DATA)) {
> memblock_reserve(paddr, size);
> if (uefi_debug)
> pr_cont("*");
>
>> @@ -374,15 +373,13 @@ static int __init arm64_enter_virtual_mode(void)
>> int count = 0;
>> unsigned long flags;
>>
>> - if (!efi_enabled(EFI_BOOT)) {
>> - pr_info("EFI services will not be available.\n");
>> - return -1;
>> - }
>> + if (!efi_enabled(EFI_MEMMAP))
>> + return 0;
>>
>> mapsize = memmap.map_end - memmap.map;
>> early_memunmap(memmap.map, mapsize);
>>
>> - if (efi_runtime_disabled()) {
>> + if (!efi_enabled(EFI_BOOT) || efi_runtime_disabled()) {
>> pr_info("EFI runtime services will be disabled.\n");
>> return -1;
>> }
>
>
--
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