diff options
author | Borislav Petkov <bp@suse.de> | 2022-05-25 18:12:31 +0200 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2022-05-31 09:31:19 +0200 |
commit | d23d33ea0fcdc4bbb484990bf53867f99c63ccab (patch) | |
tree | 4f3eac2da6ba21bd0528e3245d10913495430546 /arch | |
parent | a77a94f86273ce42a39cb479217dd8d68acfe0ff (diff) | |
download | linux-stable-d23d33ea0fcdc4bbb484990bf53867f99c63ccab.tar.gz linux-stable-d23d33ea0fcdc4bbb484990bf53867f99c63ccab.tar.bz2 linux-stable-d23d33ea0fcdc4bbb484990bf53867f99c63ccab.zip |
x86/microcode: Taint and warn on late loading
Warn before it is attempted and taint the kernel. Late loading microcode
can lead to malfunction of the kernel when the microcode update changes
behaviour. There is no way for the kernel to determine whether its safe or
not.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220525161232.14924-4-bp@alien8.de
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/kernel/cpu/microcode/core.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index c717db6b6856..801b44ac3851 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -493,6 +493,9 @@ static int microcode_reload_late(void) { int ret; + pr_err("Attempting late microcode loading - it is dangerous and taints the kernel.\n"); + pr_err("You should switch to early loading, if possible.\n"); + atomic_set(&late_cpus_in, 0); atomic_set(&late_cpus_out, 0); @@ -541,6 +544,8 @@ put: if (ret == 0) ret = size; + add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); + return ret; } |