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authorBorislav Petkov <bp@suse.de>2022-05-25 19:12:30 +0300
committerThomas Gleixner <tglx@linutronix.de>2022-05-31 10:31:19 +0300
commita77a94f86273ce42a39cb479217dd8d68acfe0ff (patch)
treec54dd66607fa015e227baa7f9b05cfabc84c7896 /arch/x86/Kconfig
parent181b6f40e9ea80c76756d4d0cdeed396016c487e (diff)
downloadlinux-a77a94f86273ce42a39cb479217dd8d68acfe0ff.tar.xz
x86/microcode: Default-disable late loading
It is dangerous and it should not be used anyway - there's a nice early loading already. Requested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20220525161232.14924-3-bp@alien8.de
Diffstat (limited to 'arch/x86/Kconfig')
-rw-r--r--arch/x86/Kconfig11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f423a2d87b15..976309d57a58 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1350,6 +1350,17 @@ config MICROCODE_AMD
If you select this option, microcode patch loading support for AMD
processors will be enabled.
+config MICROCODE_LATE_LOADING
+ bool "Late microcode loading (DANGEROUS)"
+ default n
+ depends on MICROCODE
+ help
+ Loading microcode late, when the system is up and executing instructions
+ is a tricky business and should be avoided if possible. Just the sequence
+ of synchronizing all cores and SMT threads is one fragile dance which does
+ not guarantee that cores might not softlock after the loading. Therefore,
+ use this at your own risk. Late loading taints the kernel too.
+
config X86_MSR
tristate "/dev/cpu/*/msr - Model-specific register support"
help