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Subject[PATCH 3/4] x86/microcode: Taint and warn on late loading
Date
From: Borislav Petkov <bp@suse.de>

Warn before it is attempted and taint the kernel.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
arch/x86/kernel/cpu/microcode/core.c | 5 +++++
1 file changed, 5 insertions(+)

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 @@ static ssize_t reload_store(struct device *dev,
if (ret == 0)
ret = size;

+ add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
+
return ret;
}

--
2.35.1
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