Commit 9de49990 authored by Joerg Roedel's avatar Joerg Roedel Committed by Borislav Petkov
Browse files

x86/realmode: Add comment for Global bit usage in trampoline_pgd 



Document the fact that using the trampoline_pgd will result in the
creation of global TLB entries in the user range of the address
space.

Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211202153226.22946-2-joro@8bytes.org
parent e1cd82a3

arch/x86/mm/init.c

+5 −0
Original line number Diff line number Diff line
@@ -714,6 +714,11 @@ static void __init memory_map_bottom_up(unsigned long map_start, 
static void __init init_trampoline(void)

{

#ifdef CONFIG_X86_64

	/*

	 * The code below will alias kernel page-tables in the user-range of the

	 * address space, including the Global bit. So global TLB entries will

	 * be created when using the trampoline page-table.

	 */

	if (!kaslr_memory_enabled())

		trampoline_pgd_entry = init_top_pgt[pgd_index(__PAGE_OFFSET)];

	else