kernel-rt/SOURCES/1018-x86-microcode-Rip-out-the-OLD_INTERFACE.patch

From c11a8e91d637901133fad441470d2240cc9d05e7 Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@suse.de>
Date: Wed, 25 May 2022 18:12:29 +0200
Subject: [PATCH 04/36] x86/microcode: Rip out the OLD_INTERFACE

Everything should be using the early initrd loading by now.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220525161232.14924-2-bp@alien8.de

(cherry picked from commit 181b6f40e9ea80c76756d4d0cdeed396016c487e)
Signed-off-by: Mridula Shastry <mridula.c.shastry@oracle.com>
Reviewed-by: Todd Vierling <todd.vierling@oracle.com>
---
 arch/x86/Kconfig                     |  12 ----
 arch/x86/kernel/cpu/microcode/core.c | 100 ---------------------------
 2 files changed, 112 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 4f762b807bd4..b9bcde5c538f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1360,18 +1360,6 @@ config MICROCODE_AMD
 	  If you select this option, microcode patch loading support for AMD
 	  processors will be enabled.
 
-config MICROCODE_OLD_INTERFACE
-	bool "Ancient loading interface (DEPRECATED)"
-	default n
-	depends on MICROCODE
-	---help---
-	  DO NOT USE THIS! This is the ancient /dev/cpu/microcode interface
-	  which was used by userspace tools like iucode_tool and microcode.ctl.
-	  It is inadequate because it runs too late to be able to properly
-	  load microcode on a machine and it needs special tools. Instead, you
-	  should've switched to the early loading method with the initrd or
-	  builtin microcode by now: Documentation/x86/microcode.txt
-
 config X86_MSR
 	tristate "/dev/cpu/*/msr - Model-specific register support"
 	---help---
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index f0946658f885..bbc262a5fc0d 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -392,98 +392,6 @@ static int apply_microcode_on_target(int cpu)
 	return ret;
 }
 
-#ifdef CONFIG_MICROCODE_OLD_INTERFACE
-static int do_microcode_update(const void __user *buf, size_t size)
-{
-	int error = 0;
-	int cpu;
-
-	for_each_online_cpu(cpu) {
-		struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-		enum ucode_state ustate;
-
-		if (!uci->valid)
-			continue;
-
-		ustate = microcode_ops->request_microcode_user(cpu, buf, size);
-		if (ustate == UCODE_ERROR) {
-			error = -1;
-			break;
-		} else if (ustate == UCODE_NEW) {
-			apply_microcode_on_target(cpu);
-		}
-	}
-
-	return error;
-}
-
-static int microcode_open(struct inode *inode, struct file *file)
-{
-	return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
-}
-
-static ssize_t microcode_write(struct file *file, const char __user *buf,
-			       size_t len, loff_t *ppos)
-{
-	ssize_t ret = -EINVAL;
-	unsigned long nr_pages = totalram_pages();
-
-	if ((len >> PAGE_SHIFT) > nr_pages) {
-		pr_err("too much data (max %ld pages)\n", nr_pages);
-		return ret;
-	}
-
-	get_online_cpus();
-	mutex_lock(&microcode_mutex);
-
-	if (do_microcode_update(buf, len) == 0)
-		ret = (ssize_t)len;
-
-	if (ret > 0)
-		perf_check_microcode();
-
-	mutex_unlock(&microcode_mutex);
-	put_online_cpus();
-
-	return ret;
-}
-
-static const struct file_operations microcode_fops = {
-	.owner			= THIS_MODULE,
-	.write			= microcode_write,
-	.open			= microcode_open,
-	.llseek		= no_llseek,
-};
-
-static struct miscdevice microcode_dev = {
-	.minor			= MICROCODE_MINOR,
-	.name			= "microcode",
-	.nodename		= "cpu/microcode",
-	.fops			= &microcode_fops,
-};
-
-static int __init microcode_dev_init(void)
-{
-	int error;
-
-	error = misc_register(&microcode_dev);
-	if (error) {
-		pr_err("can't misc_register on minor=%d\n", MICROCODE_MINOR);
-		return error;
-	}
-
-	return 0;
-}
-
-static void __exit microcode_dev_exit(void)
-{
-	misc_deregister(&microcode_dev);
-}
-#else
-#define microcode_dev_init()	0
-#define microcode_dev_exit()	do { } while (0)
-#endif
-
 /* fake device for request_firmware */
 static struct platform_device	*microcode_pdev;
 
@@ -876,10 +784,6 @@ int __init microcode_init(void)
 		goto out_driver;
 	}
 
-	error = microcode_dev_init();
-	if (error)
-		goto out_ucode_group;
-
 	register_syscore_ops(&mc_syscore_ops);
 	cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
 				  mc_cpu_starting, NULL);
@@ -890,10 +794,6 @@ int __init microcode_init(void)
 
 	return 0;
 
- out_ucode_group:
-	sysfs_remove_group(&cpu_subsys.dev_root->kobj,
-			   &cpu_root_microcode_group);
-
  out_driver:
 	get_online_cpus();
 	mutex_lock(&microcode_mutex);
-- 
2.39.3