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 <[e-mail]>
Signed-off-by: Borislav Petkov <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Borislav Petkov <[e-mail]>

arch/x86/include/asm/cacheinfo.h

···
 
 void cache_disable(void);
 void cache_enable(void);
-void cache_cpu_init(void);
 void set_cache_aps_delayed_init(bool val);
 bool get_cache_aps_delayed_init(void);
+void cache_bp_init(void);
+void cache_bp_restore(void);
+void cache_ap_init(void);
+void cache_aps_init(void);
 
 #endif /* _ASM_X86_CACHEINFO_H */

arch/x86/include/asm/mtrr.h

···
 
 #include <uapi/asm/mtrr.h>
 
-void mtrr_bp_init(void);
-
 /*
  * The following functions are for use by other drivers that cannot use
  * arch_phys_wc_add and arch_phys_wc_del.
  */
 # ifdef CONFIG_MTRR
+void mtrr_bp_init(void);
 extern u8 mtrr_type_lookup(u64 addr, u64 end, u8 *uniform);
 extern void mtrr_save_fixed_ranges(void *);
 extern void mtrr_save_state(void);
···
 extern int mtrr_del(int reg, unsigned long base, unsigned long size);
 extern int mtrr_del_page(int reg, unsigned long base, unsigned long size);
 extern void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi);
-extern void mtrr_ap_init(void);
-extern void mtrr_aps_init(void);
 extern void mtrr_bp_restore(void);
 extern int mtrr_trim_uncached_memory(unsigned long end_pfn);
 extern int amd_special_default_mtrr(void);
···
 static inline void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
 {
 }
-#define mtrr_ap_init() do {} while (0)
-#define mtrr_aps_init() do {} while (0)
+#define mtrr_bp_init() do {} while (0)
 #define mtrr_bp_restore() do {} while (0)
 #define mtrr_disable() do {} while (0)
 #define mtrr_enable() do {} while (0)

arch/x86/kernel/cpu/cacheinfo.c

···
 #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>
···
 	raw_spin_unlock(&cache_disable_lock);
 }
 
-void cache_cpu_init(void)
+static void cache_cpu_init(void)
 {
 	unsigned long flags;
 
···
 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);
 }

arch/x86/kernel/cpu/common.c

···
 #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>
···
 #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();

arch/x86/kernel/cpu/mtrr/mtrr.c

···
 
 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)
···
 {
 	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;
 }
 
···
 				    };
 
 	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);
 }
 
 /**
···
 			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;
 			}
···
 	}
 }
 
-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.
···
 
 	first_cpu = cpumask_first(cpu_online_mask);
 	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)

arch/x86/kernel/setup.c

···
 #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>
···
 
 	/* 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.");
 

arch/x86/kernel/smpboot.c

···
 
 void arch_thaw_secondary_cpus_end(void)
 {
-	mtrr_aps_init();
+	cache_aps_init();
 }
 
 /*
···
 
 	nmi_selftest();
 	impress_friends();
-	mtrr_aps_init();
+	cache_aps_init();
 }
 
 static int __initdata setup_possible_cpus = -1;

arch/x86/power/cpu.c

···
 #include <asm/fpu/api.h>
 #include <asm/debugreg.h>
 #include <asm/cpu.h>
+#include <asm/cacheinfo.h>
 #include <asm/mmu_context.h>
 #include <asm/cpu_device_id.h>
 #include <asm/microcode.h>
···
 	do_fpu_end();
 	tsc_verify_tsc_adjust(true);
 	x86_platform.restore_sched_clock_state();
-	mtrr_bp_restore();
+	cache_bp_restore();
 	perf_restore_debug_store();
 
 	c = &cpu_data(smp_processor_id());