pve-kernel-lowlatency-qoup/patches/kernel/0028-x86-fpu-Move-FPU-initialization-into-arch_cpu_finali.patch
Stoiko Ivanov 9dd7462461 add fixes for downfall
by cherry-picking the relevant commits from launchpad/lunar [0].
(relevant commits are based on k.o/stable commits for this)

minimally tested by booting my (ryzen) machine with this kernel and
skimming through dmesg after boot.

[0] git://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/lunar

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
2023-08-16 09:56:23 +02:00

81 lines
2.4 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 14 Jun 2023 01:39:46 +0200
Subject: [PATCH] x86/fpu: Move FPU initialization into
arch_cpu_finalize_init()
Initializing the FPU during the early boot process is a pointless
exercise. Early boot is convoluted and fragile enough.
Nothing requires that the FPU is set up early. It has to be initialized
before fork_init() because the task_struct size depends on the FPU register
buffer size.
Move the initialization to arch_cpu_finalize_init() which is the perfect
place to do so.
No functional change.
This allows to remove quite some of the custom early command line parsing,
but that's subject to the next installment.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.902376621@linutronix.de
(cherry picked from commit b81fac906a8f9e682e513ddd95697ec7a20878d4)
CVE-2022-40982
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
(cherry picked from commit 010f3814ec351195c9d0a9a408798f9c66fdb906)
Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
---
arch/x86/kernel/cpu/common.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 794eb851cb0d..9b53d1cb424d 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1596,8 +1596,6 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
sld_setup(c);
- fpu__init_system();
-
#ifdef CONFIG_X86_32
/*
* Regardless of whether PCID is enumerated, the SDM says
@@ -2283,8 +2281,6 @@ void cpu_init(void)
doublefault_init_cpu_tss();
- fpu__init_cpu();
-
if (is_uv_system())
uv_cpu_init();
@@ -2300,6 +2296,7 @@ void cpu_init_secondary(void)
*/
cpu_init_exception_handling();
cpu_init();
+ fpu__init_cpu();
}
#endif
@@ -2394,6 +2391,13 @@ void __init arch_cpu_finalize_init(void)
'0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
}
+ /*
+ * Must be before alternatives because it might set or clear
+ * feature bits.
+ */
+ fpu__init_system();
+ fpu__init_cpu();
+
alternative_instructions();
if (IS_ENABLED(CONFIG_X86_64)) {