[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20211202153226.22946-2-joro@8bytes.org>
Date: Thu, 2 Dec 2021 16:32:23 +0100
From: Joerg Roedel <joro@...tes.org>
To: x86@...nel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
hpa@...or.com, Dave Hansen <dave.hansen@...ux.intel.com>,
Andy Lutomirski <luto@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Mike Rapoport <rppt@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Brijesh Singh <brijesh.singh@....com>,
linux-kernel@...r.kernel.org, Joerg Roedel <jroedel@...e.de>,
Joerg Roedel <joro@...tes.org>
Subject: [PATCH v4 1/4] x86/realmode: Add comment for Global bit usage in trampline_pgd
From: Joerg Roedel <jroedel@...e.de>
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: Joerg Roedel <jroedel@...e.de>
---
arch/x86/mm/init.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 1895986842b9..4ba024d5b63a 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -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
--
2.34.0
Powered by blists - more mailing lists