[PATCH 5.15 064/128] x86/boot: Move EFI range reservation after cmdline parsing

Greg Kroah-Hartman
2021-12-27T15:51:40Z

From: Mike Rapoport <rppt@kernel.org>

commit 2f5b3514c33fecad4003ce0f22ca9691492d310b upstream.

The memory reservation in arch/x86/platform/efi/efi.c depends on at
least two command line parameters. Put it back later in the boot process
and move efi_memblock_x86_reserve_range() out of early_memory_reserve().

An attempt to fix this was done in

8d48bf8206f7 ("x86/boot: Pull up cmdline preparation and early param parsing")

but that caused other troubles so it got reverted.

The bug this is addressing is:

Dan reports that Anjaneya Chagam can no longer use the efi=nosoftreserve
kernel command line parameter to suppress "soft reservation" behavior.

This is due to the fact that the following call-chain happens at boot:

early_reserve_memory
|-> efi_memblock_x86_reserve_range
|-> efi_fake_memmap_early

which does

if (!efi_soft_reserve_enabled())
return;

and that would have set EFI_MEM_NO_SOFT_RESERVE after having parsed
"nosoftreserve".

However, parse_early_param() gets called *after* it, leading to the boot
cmdline not being taken into account.

See also https://lore.kernel.org/r/e8dd8993c38702ee6dd73b3c11f158617e665607.camel@intel.com

[ bp: Turn into a proper patch. ]

Signed-off-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211213112757.2612-4-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/setup.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -713,9 +713,6 @@ static void __init early_reserve_memory(

early_reserve_initrd();

- if (efi_enabled(EFI_BOOT))
- efi_memblock_x86_reserve_range();
-
memblock_x86_reserve_range_setup_data();

reserve_ibft_region();
@@ -890,6 +887,9 @@ void __init setup_arch(char **cmdline_p)

parse_early_param();

+ if (efi_enabled(EFI_BOOT))
+ efi_memblock_x86_reserve_range();
+
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* Memory used by the kernel cannot be hot-removed because Linux