Messages in this thread Patch in this message | | | Date | Wed, 25 May 2022 14:52:20 +0200 | From | Borislav Petkov <> | Subject | [RFC PATCH -v2] x86/microcode: Taint and warn on late loading |
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On Wed, May 25, 2022 at 12:03:52PM +0200, Peter Zijlstra wrote: > Should we not warn *before* attempting the ucode update? Should the > whole thing come unstuck, you at least have some clue.
Sure.
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 -- Regards/Gruss, Boris.
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