x86/mtrr: Add a stop_machine() handler calling only cache_cpu_init()

Instead of having a stop_machine() handler for either a specific
MTRR register or all state at once, add a handler just for calling
cache_cpu_init() if appropriate.

Add functions for calling stop_machine() with this handler as well.

Add a generic replacement for mtrr_bp_restore() and a wrapper for
mtrr_bp_init().

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221102074713.21493-13-jgross@suse.com
Signed-off-by: Borislav Petkov <bp@suse.de>

5 files changed, 66 insertions, 91 deletions

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 063d556d5759..4e155bd2574f 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -15,6 +15,7 @@
 #include <linux/capability.h>
 #include <linux/sysfs.h>
 #include <linux/pci.h>
+#include <linux/stop_machine.h>
 
 #include <asm/cpufeature.h>
 #include <asm/cacheinfo.h>
@@ -1121,7 +1122,7 @@ void cache_enable(void) __releases(cache_disable_lock)
 	raw_spin_unlock(&cache_disable_lock);
 }
 
-void cache_cpu_init(void)
+static void cache_cpu_init(void)
 {
 	unsigned long flags;
 
@@ -1149,3 +1150,59 @@ bool get_cache_aps_delayed_init(void)
 {
 	return cache_aps_delayed_init;
 }
+
+static int cache_rendezvous_handler(void *unused)
+{
+	if (get_cache_aps_delayed_init() || !cpu_online(smp_processor_id()))
+		cache_cpu_init();
+
+	return 0;
+}
+
+void __init cache_bp_init(void)
+{
+	mtrr_bp_init();
+
+	if (memory_caching_control)
+		cache_cpu_init();
+}
+
+void cache_bp_restore(void)
+{
+	if (memory_caching_control)
+		cache_cpu_init();
+}
+
+void cache_ap_init(void)
+{
+	if (!memory_caching_control || get_cache_aps_delayed_init())
+		return;
+
+	/*
+	 * Ideally we should hold mtrr_mutex here to avoid MTRR entries
+	 * changed, but this routine will be called in CPU boot time,
+	 * holding the lock breaks it.
+	 *
+	 * This routine is called in two cases:
+	 *
+	 *   1. very early time of software resume, when there absolutely
+	 *      isn't MTRR entry changes;
+	 *
+	 *   2. CPU hotadd time. We let mtrr_add/del_page hold cpuhotplug
+	 *      lock to prevent MTRR entry changes
+	 */
+	stop_machine_from_inactive_cpu(cache_rendezvous_handler, NULL,
+				       cpu_callout_mask);
+}
+
+/*
+ * Delayed cache initialization for all AP's
+ */
+void cache_aps_init(void)
+{
+	if (!memory_caching_control || !get_cache_aps_delayed_init())
+		return;
+
+	stop_machine(cache_rendezvous_handler, NULL, cpu_online_mask);
+	set_cache_aps_delayed_init(false);
+}
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 3e508f239098..fd058b547f8d 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -52,6 +52,7 @@
 #include <asm/cpu.h>
 #include <asm/mce.h>
 #include <asm/msr.h>
+#include <asm/cacheinfo.h>
 #include <asm/memtype.h>
 #include <asm/microcode.h>
 #include <asm/microcode_intel.h>
@@ -1948,7 +1949,7 @@ void identify_secondary_cpu(struct cpuinfo_x86 *c)
 #ifdef CONFIG_X86_32
 	enable_sep_cpu();
 #endif
-	mtrr_ap_init();
+	cache_ap_init();
 	validate_apic_and_package_id(c);
 	x86_spec_ctrl_setup_ap();
 	update_srbds_msr();
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 15ee6d72fb1f..99b6973a69b4 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -73,9 +73,6 @@ static const struct mtrr_ops *mtrr_ops[X86_VENDOR_NUM] __ro_after_init;
 
 const struct mtrr_ops *mtrr_if;
 
-static void set_mtrr(unsigned int reg, unsigned long base,
-		     unsigned long size, mtrr_type type);
-
 void __init set_mtrr_ops(const struct mtrr_ops *ops)
 {
 	if (ops->vendor && ops->vendor < X86_VENDOR_NUM)
@@ -158,26 +155,8 @@ static int mtrr_rendezvous_handler(void *info)
 {
 	struct set_mtrr_data *data = info;
 
-	/*
-	 * We use this same function to initialize the mtrrs during boot,
-	 * resume, runtime cpu online and on an explicit request to set a
-	 * specific MTRR.
-	 *
-	 * During boot or suspend, the state of the boot cpu's mtrrs has been
-	 * saved, and we want to replicate that across all the cpus that come
-	 * online (either at the end of boot or resume or during a runtime cpu
-	 * online). If we're doing that, @reg is set to something special and on
-	 * all the CPUs we do cache_cpu_init() (On the logical CPU that
-	 * started the boot/resume sequence, this might be a duplicate
-	 * cache_cpu_init()).
-	 */
-	if (data->smp_reg != ~0U) {
-		mtrr_if->set(data->smp_reg, data->smp_base,
-			     data->smp_size, data->smp_type);
-	} else if (get_cache_aps_delayed_init() ||
-		   !cpu_online(smp_processor_id())) {
-		cache_cpu_init();
-	}
+	mtrr_if->set(data->smp_reg, data->smp_base,
+		     data->smp_size, data->smp_type);
 	return 0;
 }
 
@@ -247,19 +226,6 @@ static void set_mtrr_cpuslocked(unsigned int reg, unsigned long base,
 	stop_machine_cpuslocked(mtrr_rendezvous_handler, &data, cpu_online_mask);
 }
 
-static void set_mtrr_from_inactive_cpu(unsigned int reg, unsigned long base,
-				      unsigned long size, mtrr_type type)
-{
-	struct set_mtrr_data data = { .smp_reg = reg,
-				      .smp_base = base,
-				      .smp_size = size,
-				      .smp_type = type
-				    };
-
-	stop_machine_from_inactive_cpu(mtrr_rendezvous_handler, &data,
-				       cpu_callout_mask);
-}
-
 /**
  * mtrr_add_page - Add a memory type region
  * @base: Physical base address of region in pages (in units of 4 kB!)
@@ -761,7 +727,6 @@ void __init mtrr_bp_init(void)
 			if (get_mtrr_state()) {
 				memory_caching_control |= CACHE_MTRR | CACHE_PAT;
 				changed_by_mtrr_cleanup = mtrr_cleanup(phys_addr);
-				cache_cpu_init();
 			} else {
 				mtrr_if = NULL;
 			}
@@ -780,27 +745,6 @@ void __init mtrr_bp_init(void)
 	}
 }
 
-void mtrr_ap_init(void)
-{
-	if (!memory_caching_control || get_cache_aps_delayed_init())
-		return;
-
-	/*
-	 * Ideally we should hold mtrr_mutex here to avoid mtrr entries
-	 * changed, but this routine will be called in cpu boot time,
-	 * holding the lock breaks it.
-	 *
-	 * This routine is called in two cases:
-	 *
-	 *   1. very early time of software resume, when there absolutely
-	 *      isn't mtrr entry changes;
-	 *
-	 *   2. cpu hotadd time. We let mtrr_add/del_page hold cpuhotplug
-	 *      lock to prevent mtrr entry changes
-	 */
-	set_mtrr_from_inactive_cpu(~0U, 0, 0, 0);
-}
-
 /**
  * mtrr_save_state - Save current fixed-range MTRR state of the first
  *	cpu in cpu_online_mask.
@@ -816,34 +760,6 @@ void mtrr_save_state(void)
 	smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1);
 }
 
-/*
- * Delayed MTRR initialization for all AP's
- */
-void mtrr_aps_init(void)
-{
-	if (!memory_caching_control)
-		return;
-
-	/*
-	 * Check if someone has requested the delay of AP MTRR initialization,
-	 * by doing set_mtrr_aps_delayed_init(), prior to this point. If not,
-	 * then we are done.
-	 */
-	if (!get_cache_aps_delayed_init())
-		return;
-
-	set_mtrr(~0U, 0, 0, 0);
-	set_cache_aps_delayed_init(false);
-}
-
-void mtrr_bp_restore(void)
-{
-	if (!memory_caching_control)
-		return;
-
-	cache_cpu_init();
-}
-
 static int __init mtrr_init_finialize(void)
 {
 	if (!mtrr_enabled())
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 216fee7144ee..e0e185ee0229 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -34,6 +34,7 @@
 #include <asm/numa.h>
 #include <asm/bios_ebda.h>
 #include <asm/bugs.h>
+#include <asm/cacheinfo.h>
 #include <asm/cpu.h>
 #include <asm/efi.h>
 #include <asm/gart.h>
@@ -1075,7 +1076,7 @@ void __init setup_arch(char **cmdline_p)
 
 	/* update e820 for memory not covered by WB MTRRs */
 	if (IS_ENABLED(CONFIG_MTRR))
-		mtrr_bp_init();
+		cache_bp_init();
 	else
 		pat_disable("PAT support disabled because CONFIG_MTRR is disabled in the kernel.");
 
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 13c71ab29d84..1b61a480c966 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1445,7 +1445,7 @@ void arch_thaw_secondary_cpus_begin(void)
 
 void arch_thaw_secondary_cpus_end(void)
 {
-	mtrr_aps_init();
+	cache_aps_init();
 }
 
 /*
@@ -1488,7 +1488,7 @@ void __init native_smp_cpus_done(unsigned int max_cpus)
 
 	nmi_selftest();
 	impress_friends();
-	mtrr_aps_init();
+	cache_aps_init();
 }
 
 static int __initdata setup_possible_cpus = -1;