powerpc fixes for 4.15 #8

More than we'd like after rc8, but nothing very alarming either, just tying up
 loose ends before the release:
 
 Since we changed powernv to use cpufreq_get() from show_cpuinfo(), we see
 warnings with PREEMPT enabled. But the preempt_disable() in show_cpuinfo()
 doesn't actually prevent CPU hotplug as it suggests, so remove it.
 
 Two updates to the recently merged RFI flush code. Wire up the generic sysfs
 file to report the status, and add a debugfs file to allow enabling/disabling it
 at runtime.
 
 Two updates to xmon, one to add the RFI flush related fields to the paca dump,
 and another to not use hashed pointers in the paca dump.
 
 And one minor fix to add a missing include of linux/types.h in asm/hvcall.h, not
 seen to break the build in upstream, but correct anyway.
 
 Thanks to:
   Benjamin Herrenschmidt, Michal Suchanek, Nicholas Piggin.
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Merge tag 'powerpc-4.15-8' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "More than we'd like after rc8, but nothing very alarming either, just
  tying up loose ends before the release:

  Since we changed powernv to use cpufreq_get() from show_cpuinfo(), we
  see warnings with PREEMPT enabled. But the preempt_disable() in
  show_cpuinfo() doesn't actually prevent CPU hotplug as it suggests, so
  remove it.

  Two updates to the recently merged RFI flush code. Wire up the generic
  sysfs file to report the status, and add a debugfs file to allow
  enabling/disabling it at runtime.

  Two updates to xmon, one to add the RFI flush related fields to the
  paca dump, and another to not use hashed pointers in the paca dump.

  And one minor fix to add a missing include of linux/types.h in
  asm/hvcall.h, not seen to break the build in upstream, but correct
  anyway.

  Thanks to: Benjamin Herrenschmidt, Michal Suchanek, Nicholas Piggin"

* tag 'powerpc-4.15-8' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/pseries: include linux/types.h in asm/hvcall.h
  powerpc/64s: Allow control of RFI flush via debugfs
  powerpc/64s: Wire up cpu_show_meltdown()
  powerpc: Don't preempt_disable() in show_cpuinfo()
  powerpc/xmon: Don't print hashed pointers in paca dump
  powerpc/xmon: Add RFI flush related fields to paca dump

arch/powerpc/Kconfig

@@ -166,6 +166,7 @@ config PPC
 	select GENERIC_CLOCKEVENTS_BROADCAST	if SMP
 	select GENERIC_CMOS_UPDATE
 	select GENERIC_CPU_AUTOPROBE
+	select GENERIC_CPU_VULNERABILITIES	if PPC_BOOK3S_64
 	select GENERIC_IRQ_SHOW
 	select GENERIC_IRQ_SHOW_LEVEL
 	select GENERIC_SMP_IDLE_THREAD

arch/powerpc/include/asm/hvcall.h

@@ -353,6 +353,7 @@
 #define PROC_TABLE_GTSE		0x01
 
 #ifndef __ASSEMBLY__
+#include <linux/types.h>
 
 /**
  * plpar_hcall_norets: - Make a pseries hypervisor call with no return arguments

arch/powerpc/kernel/setup-common.c

@@ -242,14 +242,6 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 	unsigned short maj;
 	unsigned short min;
 
-	/* We only show online cpus: disable preempt (overzealous, I
-	 * knew) to prevent cpu going down. */
-	preempt_disable();
-	if (!cpu_online(cpu_id)) {
-		preempt_enable();
-		return 0;
-	}
-
 #ifdef CONFIG_SMP
 	pvr = per_cpu(cpu_pvr, cpu_id);
 #else
@@ -358,9 +350,6 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 #ifdef CONFIG_SMP
 	seq_printf(m, "\n");
 #endif
-
-	preempt_enable();
-
 	/* If this is the last cpu, print the summary */
 	if (cpumask_next(cpu_id, cpu_online_mask) >= nr_cpu_ids)
 		show_cpuinfo_summary(m);

arch/powerpc/kernel/setup_64.c

@@ -38,6 +38,7 @@
 #include <linux/memory.h>
 #include <linux/nmi.h>
 
+#include <asm/debugfs.h>
 #include <asm/io.h>
 #include <asm/kdump.h>
 #include <asm/prom.h>
@@ -901,4 +902,41 @@ void __init setup_rfi_flush(enum l1d_flush_type types, bool enable)
 	if (!no_rfi_flush)
 		rfi_flush_enable(enable);
 }
+
+#ifdef CONFIG_DEBUG_FS
+static int rfi_flush_set(void *data, u64 val)
+{
+	if (val == 1)
+		rfi_flush_enable(true);
+	else if (val == 0)
+		rfi_flush_enable(false);
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static int rfi_flush_get(void *data, u64 *val)
+{
+	*val = rfi_flush ? 1 : 0;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_rfi_flush, rfi_flush_get, rfi_flush_set, "%llu\n");
+
+static __init int rfi_flush_debugfs_init(void)
+{
+	debugfs_create_file("rfi_flush", 0600, powerpc_debugfs_root, NULL, &fops_rfi_flush);
+	return 0;
+}
+device_initcall(rfi_flush_debugfs_init);
+#endif
+
+ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	if (rfi_flush)
+		return sprintf(buf, "Mitigation: RFI Flush\n");
+
+	return sprintf(buf, "Vulnerable\n");
+}
 #endif /* CONFIG_PPC_BOOK3S_64 */

arch/powerpc/xmon/xmon.c

@@ -2344,10 +2344,10 @@ static void dump_one_paca(int cpu)
 	DUMP(p, kernel_toc, "lx");
 	DUMP(p, kernelbase, "lx");
 	DUMP(p, kernel_msr, "lx");
-	DUMP(p, emergency_sp, "p");
+	DUMP(p, emergency_sp, "px");
 #ifdef CONFIG_PPC_BOOK3S_64
-	DUMP(p, nmi_emergency_sp, "p");
+	DUMP(p, nmi_emergency_sp, "px");
-	DUMP(p, mc_emergency_sp, "p");
+	DUMP(p, mc_emergency_sp, "px");
 	DUMP(p, in_nmi, "x");
 	DUMP(p, in_mce, "x");
 	DUMP(p, hmi_event_available, "x");
@@ -2375,17 +2375,21 @@ static void dump_one_paca(int cpu)
 	DUMP(p, slb_cache_ptr, "x");
 	for (i = 0; i < SLB_CACHE_ENTRIES; i++)
 		printf(" slb_cache[%d]:        = 0x%016lx\n", i, p->slb_cache[i]);
+
+	DUMP(p, rfi_flush_fallback_area, "px");
+	DUMP(p, l1d_flush_congruence, "llx");
+	DUMP(p, l1d_flush_sets, "llx");
 #endif
 	DUMP(p, dscr_default, "llx");
 #ifdef CONFIG_PPC_BOOK3E
-	DUMP(p, pgd, "p");
+	DUMP(p, pgd, "px");
-	DUMP(p, kernel_pgd, "p");
+	DUMP(p, kernel_pgd, "px");
-	DUMP(p, tcd_ptr, "p");
+	DUMP(p, tcd_ptr, "px");
-	DUMP(p, mc_kstack, "p");
+	DUMP(p, mc_kstack, "px");
-	DUMP(p, crit_kstack, "p");
+	DUMP(p, crit_kstack, "px");
-	DUMP(p, dbg_kstack, "p");
+	DUMP(p, dbg_kstack, "px");
 #endif
-	DUMP(p, __current, "p");
+	DUMP(p, __current, "px");
 	DUMP(p, kstack, "lx");
 	printf(" kstack_base          = 0x%016lx\n", p->kstack & ~(THREAD_SIZE - 1));
 	DUMP(p, stab_rr, "lx");
@@ -2403,7 +2407,7 @@ static void dump_one_paca(int cpu)
 #endif
 
 #ifdef CONFIG_PPC_POWERNV
-	DUMP(p, core_idle_state_ptr, "p");
+	DUMP(p, core_idle_state_ptr, "px");
 	DUMP(p, thread_idle_state, "x");
 	DUMP(p, thread_mask, "x");
 	DUMP(p, subcore_sibling_mask, "x");