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authorBorislav Petkov <bp@suse.de>2022-05-25 18:12:30 +0200
committerThomas Gleixner <tglx@linutronix.de>2022-05-31 09:31:19 +0200
commita77a94f86273ce42a39cb479217dd8d68acfe0ff (patch)
treec54dd66607fa015e227baa7f9b05cfabc84c7896 /arch/x86/kernel/cpu/microcode
parent181b6f40e9ea80c76756d4d0cdeed396016c487e (diff)
downloadlinux-a77a94f86273ce42a39cb479217dd8d68acfe0ff.tar.gz
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/kernel/cpu/microcode')
-rw-r--r--arch/x86/kernel/cpu/microcode/core.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index b72c4134f289..c717db6b6856 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -376,6 +376,7 @@ static int apply_microcode_on_target(int cpu)
 /* fake device for request_firmware */
 static struct platform_device	*microcode_pdev;
 
+#ifdef CONFIG_MICROCODE_LATE_LOADING
 /*
  * Late loading dance. Why the heavy-handed stomp_machine effort?
  *
@@ -543,6 +544,9 @@ put:
 	return ret;
 }
 
+static DEVICE_ATTR_WO(reload);
+#endif
+
 static ssize_t version_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
@@ -559,7 +563,6 @@ static ssize_t pf_show(struct device *dev,
 	return sprintf(buf, "0x%x\n", uci->cpu_sig.pf);
 }
 
-static DEVICE_ATTR_WO(reload);
 static DEVICE_ATTR(version, 0444, version_show, NULL);
 static DEVICE_ATTR(processor_flags, 0444, pf_show, NULL);
 
@@ -712,7 +715,9 @@ static int mc_cpu_down_prep(unsigned int cpu)
 }
 
 static struct attribute *cpu_root_microcode_attrs[] = {
+#ifdef CONFIG_MICROCODE_LATE_LOADING
 	&dev_attr_reload.attr,
+#endif
 	NULL
 };