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.
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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