Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 476 insertions, 0 deletions

diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
new file mode 100644
index 000000000..8c867b43c
--- /dev/null
+++ b/arch/s390/kernel/nmi.c
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *   Machine check handler
+ *
+ *    Copyright IBM Corp. 2000, 2009
+ *    Author(s): Ingo Adlung <adlung@de.ibm.com>,
+ *		 Martin Schwidefsky <schwidefsky@de.ibm.com>,
+ *		 Cornelia Huck <cornelia.huck@de.ibm.com>,
+ *		 Heiko Carstens <heiko.carstens@de.ibm.com>,
+ */
+
+#include <linux/kernel_stat.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/hardirq.h>
+#include <linux/log2.h>
+#include <linux/kprobes.h>
+#include <linux/kmemleak.h>
+#include <linux/time.h>
+#include <linux/module.h>
+#include <linux/sched/signal.h>
+
+#include <linux/export.h>
+#include <asm/lowcore.h>
+#include <asm/smp.h>
+#include <asm/stp.h>
+#include <asm/cputime.h>
+#include <asm/nmi.h>
+#include <asm/crw.h>
+#include <asm/switch_to.h>
+#include <asm/ctl_reg.h>
+#include <asm/asm-offsets.h>
+#include <linux/kvm_host.h>
+
+struct mcck_struct {
+	unsigned int kill_task : 1;
+	unsigned int channel_report : 1;
+	unsigned int warning : 1;
+	unsigned int stp_queue : 1;
+	unsigned long mcck_code;
+};
+
+static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
+static struct kmem_cache *mcesa_cache;
+static unsigned long mcesa_origin_lc;
+
+static inline int nmi_needs_mcesa(void)
+{
+	return MACHINE_HAS_VX || MACHINE_HAS_GS;
+}
+
+static inline unsigned long nmi_get_mcesa_size(void)
+{
+	if (MACHINE_HAS_GS)
+		return MCESA_MAX_SIZE;
+	return MCESA_MIN_SIZE;
+}
+
+/*
+ * The initial machine check extended save area for the boot CPU.
+ * It will be replaced by nmi_init() with an allocated structure.
+ * The structure is required for machine check happening early in
+ * the boot process.
+ */
+static struct mcesa boot_mcesa __initdata __aligned(MCESA_MAX_SIZE);
+
+void __init nmi_alloc_boot_cpu(struct lowcore *lc)
+{
+	if (!nmi_needs_mcesa())
+		return;
+	lc->mcesad = (unsigned long) &boot_mcesa;
+	if (MACHINE_HAS_GS)
+		lc->mcesad |= ilog2(MCESA_MAX_SIZE);
+}
+
+static int __init nmi_init(void)
+{
+	unsigned long origin, cr0, size;
+
+	if (!nmi_needs_mcesa())
+		return 0;
+	size = nmi_get_mcesa_size();
+	if (size > MCESA_MIN_SIZE)
+		mcesa_origin_lc = ilog2(size);
+	/* create slab cache for the machine-check-extended-save-areas */
+	mcesa_cache = kmem_cache_create("nmi_save_areas", size, size, 0, NULL);
+	if (!mcesa_cache)
+		panic("Couldn't create nmi save area cache");
+	origin = (unsigned long) kmem_cache_alloc(mcesa_cache, GFP_KERNEL);
+	if (!origin)
+		panic("Couldn't allocate nmi save area");
+	/* The pointer is stored with mcesa_bits ORed in */
+	kmemleak_not_leak((void *) origin);
+	__ctl_store(cr0, 0, 0);
+	__ctl_clear_bit(0, 28); /* disable lowcore protection */
+	/* Replace boot_mcesa on the boot CPU */
+	S390_lowcore.mcesad = origin | mcesa_origin_lc;
+	__ctl_load(cr0, 0, 0);
+	return 0;
+}
+early_initcall(nmi_init);
+
+int nmi_alloc_per_cpu(struct lowcore *lc)
+{
+	unsigned long origin;
+
+	if (!nmi_needs_mcesa())
+		return 0;
+	origin = (unsigned long) kmem_cache_alloc(mcesa_cache, GFP_KERNEL);
+	if (!origin)
+		return -ENOMEM;
+	/* The pointer is stored with mcesa_bits ORed in */
+	kmemleak_not_leak((void *) origin);
+	lc->mcesad = origin | mcesa_origin_lc;
+	return 0;
+}
+
+void nmi_free_per_cpu(struct lowcore *lc)
+{
+	if (!nmi_needs_mcesa())
+		return;
+	kmem_cache_free(mcesa_cache, (void *)(lc->mcesad & MCESA_ORIGIN_MASK));
+}
+
+static notrace void s390_handle_damage(void)
+{
+	smp_emergency_stop();
+	disabled_wait((unsigned long) __builtin_return_address(0));
+	while (1);
+}
+NOKPROBE_SYMBOL(s390_handle_damage);
+
+/*
+ * Main machine check handler function. Will be called with interrupts enabled
+ * or disabled and machine checks enabled or disabled.
+ */
+void s390_handle_mcck(void)
+{
+	unsigned long flags;
+	struct mcck_struct mcck;
+
+	/*
+	 * Disable machine checks and get the current state of accumulated
+	 * machine checks. Afterwards delete the old state and enable machine
+	 * checks again.
+	 */
+	local_irq_save(flags);
+	local_mcck_disable();
+	mcck = *this_cpu_ptr(&cpu_mcck);
+	memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));
+	clear_cpu_flag(CIF_MCCK_PENDING);
+	local_mcck_enable();
+	local_irq_restore(flags);
+
+	if (mcck.channel_report)
+		crw_handle_channel_report();
+	/*
+	 * A warning may remain for a prolonged period on the bare iron.
+	 * (actually until the machine is powered off, or the problem is gone)
+	 * So we just stop listening for the WARNING MCH and avoid continuously
+	 * being interrupted.  One caveat is however, that we must do this per
+	 * processor and cannot use the smp version of ctl_clear_bit().
+	 * On VM we only get one interrupt per virtally presented machinecheck.
+	 * Though one suffices, we may get one interrupt per (virtual) cpu.
+	 */
+	if (mcck.warning) {	/* WARNING pending ? */
+		static int mchchk_wng_posted = 0;
+
+		/* Use single cpu clear, as we cannot handle smp here. */
+		__ctl_clear_bit(14, 24);	/* Disable WARNING MCH */
+		if (xchg(&mchchk_wng_posted, 1) == 0)
+			kill_cad_pid(SIGPWR, 1);
+	}
+	if (mcck.stp_queue)
+		stp_queue_work();
+	if (mcck.kill_task) {
+		local_irq_enable();
+		printk(KERN_EMERG "mcck: Terminating task because of machine "
+		       "malfunction (code 0x%016lx).\n", mcck.mcck_code);
+		printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
+		       current->comm, current->pid);
+		do_exit(SIGSEGV);
+	}
+}
+EXPORT_SYMBOL_GPL(s390_handle_mcck);
+
+/*
+ * returns 0 if all required registers are available
+ * returns 1 otherwise
+ */
+static int notrace s390_check_registers(union mci mci, int umode)
+{
+	union ctlreg2 cr2;
+	int kill_task;
+
+	kill_task = 0;
+
+	if (!mci.gr) {
+		/*
+		 * General purpose registers couldn't be restored and have
+		 * unknown contents. Stop system or terminate process.
+		 */
+		if (!umode)
+			s390_handle_damage();
+		kill_task = 1;
+	}
+	/* Check control registers */
+	if (!mci.cr) {
+		/*
+		 * Control registers have unknown contents.
+		 * Can't recover and therefore stopping machine.
+		 */
+		s390_handle_damage();
+	}
+	if (!mci.fp) {
+		/*
+		 * Floating point registers can't be restored. If the
+		 * kernel currently uses floating point registers the
+		 * system is stopped. If the process has its floating
+		 * pointer registers loaded it is terminated.
+		 */
+		if (S390_lowcore.fpu_flags & KERNEL_VXR_V0V7)
+			s390_handle_damage();
+		if (!test_cpu_flag(CIF_FPU))
+			kill_task = 1;
+	}
+	if (!mci.fc) {
+		/*
+		 * Floating point control register can't be restored.
+		 * If the kernel currently uses the floating pointer
+		 * registers and needs the FPC register the system is
+		 * stopped. If the process has its floating pointer
+		 * registers loaded it is terminated.
+		 */
+		if (S390_lowcore.fpu_flags & KERNEL_FPC)
+			s390_handle_damage();
+		if (!test_cpu_flag(CIF_FPU))
+			kill_task = 1;
+	}
+
+	if (MACHINE_HAS_VX) {
+		if (!mci.vr) {
+			/*
+			 * Vector registers can't be restored. If the kernel
+			 * currently uses vector registers the system is
+			 * stopped. If the process has its vector registers
+			 * loaded it is terminated.
+			 */
+			if (S390_lowcore.fpu_flags & KERNEL_VXR)
+				s390_handle_damage();
+			if (!test_cpu_flag(CIF_FPU))
+				kill_task = 1;
+		}
+	}
+	/* Check if access registers are valid */
+	if (!mci.ar) {
+		/*
+		 * Access registers have unknown contents.
+		 * Terminating task.
+		 */
+		kill_task = 1;
+	}
+	/* Check guarded storage registers */
+	cr2.val = S390_lowcore.cregs_save_area[2];
+	if (cr2.gse) {
+		if (!mci.gs) {
+			/*
+			 * Guarded storage register can't be restored and
+			 * the current processes uses guarded storage.
+			 * It has to be terminated.
+			 */
+			kill_task = 1;
+		}
+	}
+	/* Check if old PSW is valid */
+	if (!mci.wp) {
+		/*
+		 * Can't tell if we come from user or kernel mode
+		 * -> stopping machine.
+		 */
+		s390_handle_damage();
+	}
+	/* Check for invalid kernel instruction address */
+	if (!mci.ia && !umode) {
+		/*
+		 * The instruction address got lost while running
+		 * in the kernel -> stopping machine.
+		 */
+		s390_handle_damage();
+	}
+
+	if (!mci.ms || !mci.pm || !mci.ia)
+		kill_task = 1;
+
+	return kill_task;
+}
+NOKPROBE_SYMBOL(s390_check_registers);
+
+/*
+ * Backup the guest's machine check info to its description block
+ */
+static void notrace s390_backup_mcck_info(struct pt_regs *regs)
+{
+	struct mcck_volatile_info *mcck_backup;
+	struct sie_page *sie_page;
+
+	/* r14 contains the sie block, which was set in sie64a */
+	struct kvm_s390_sie_block *sie_block =
+			(struct kvm_s390_sie_block *) regs->gprs[14];
+
+	if (sie_block == NULL)
+		/* Something's seriously wrong, stop system. */
+		s390_handle_damage();
+
+	sie_page = container_of(sie_block, struct sie_page, sie_block);
+	mcck_backup = &sie_page->mcck_info;
+	mcck_backup->mcic = S390_lowcore.mcck_interruption_code &
+				~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE);
+	mcck_backup->ext_damage_code = S390_lowcore.external_damage_code;
+	mcck_backup->failing_storage_address
+			= S390_lowcore.failing_storage_address;
+}
+NOKPROBE_SYMBOL(s390_backup_mcck_info);
+
+#define MAX_IPD_COUNT	29
+#define MAX_IPD_TIME	(5 * 60 * USEC_PER_SEC) /* 5 minutes */
+
+#define ED_STP_ISLAND	6	/* External damage STP island check */
+#define ED_STP_SYNC	7	/* External damage STP sync check */
+
+#define MCCK_CODE_NO_GUEST	(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE)
+
+/*
+ * machine check handler.
+ */
+void notrace s390_do_machine_check(struct pt_regs *regs)
+{
+	static int ipd_count;
+	static DEFINE_SPINLOCK(ipd_lock);
+	static unsigned long long last_ipd;
+	struct mcck_struct *mcck;
+	unsigned long long tmp;
+	union mci mci;
+	unsigned long mcck_dam_code;
+
+	nmi_enter();
+	inc_irq_stat(NMI_NMI);
+	mci.val = S390_lowcore.mcck_interruption_code;
+	mcck = this_cpu_ptr(&cpu_mcck);
+
+	if (mci.sd) {
+		/* System damage -> stopping machine */
+		s390_handle_damage();
+	}
+
+	/*
+	 * Reinject the instruction processing damages' machine checks
+	 * including Delayed Access Exception into the guest
+	 * instead of damaging the host if they happen in the guest.
+	 */
+	if (mci.pd && !test_cpu_flag(CIF_MCCK_GUEST)) {
+		if (mci.b) {
+			/* Processing backup -> verify if we can survive this */
+			u64 z_mcic, o_mcic, t_mcic;
+			z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
+			o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
+				  1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
+				  1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
+				  1ULL<<16);
+			t_mcic = mci.val;
+
+			if (((t_mcic & z_mcic) != 0) ||
+			    ((t_mcic & o_mcic) != o_mcic)) {
+				s390_handle_damage();
+			}
+
+			/*
+			 * Nullifying exigent condition, therefore we might
+			 * retry this instruction.
+			 */
+			spin_lock(&ipd_lock);
+			tmp = get_tod_clock();
+			if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
+				ipd_count++;
+			else
+				ipd_count = 1;
+			last_ipd = tmp;
+			if (ipd_count == MAX_IPD_COUNT)
+				s390_handle_damage();
+			spin_unlock(&ipd_lock);
+		} else {
+			/* Processing damage -> stopping machine */
+			s390_handle_damage();
+		}
+	}
+	if (s390_check_registers(mci, user_mode(regs))) {
+		/*
+		 * Couldn't restore all register contents for the
+		 * user space process -> mark task for termination.
+		 */
+		mcck->kill_task = 1;
+		mcck->mcck_code = mci.val;
+		set_cpu_flag(CIF_MCCK_PENDING);
+	}
+
+	/*
+	 * Backup the machine check's info if it happens when the guest
+	 * is running.
+	 */
+	if (test_cpu_flag(CIF_MCCK_GUEST))
+		s390_backup_mcck_info(regs);
+
+	if (mci.cd) {
+		/* Timing facility damage */
+		s390_handle_damage();
+	}
+	if (mci.ed && mci.ec) {
+		/* External damage */
+		if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
+			mcck->stp_queue |= stp_sync_check();
+		if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
+			mcck->stp_queue |= stp_island_check();
+		if (mcck->stp_queue)
+			set_cpu_flag(CIF_MCCK_PENDING);
+	}
+
+	/*
+	 * Reinject storage related machine checks into the guest if they
+	 * happen when the guest is running.
+	 */
+	if (!test_cpu_flag(CIF_MCCK_GUEST)) {
+		if (mci.se)
+			/* Storage error uncorrected */
+			s390_handle_damage();
+		if (mci.ke)
+			/* Storage key-error uncorrected */
+			s390_handle_damage();
+		if (mci.ds && mci.fa)
+			/* Storage degradation */
+			s390_handle_damage();
+	}
+	if (mci.cp) {
+		/* Channel report word pending */
+		mcck->channel_report = 1;
+		set_cpu_flag(CIF_MCCK_PENDING);
+	}
+	if (mci.w) {
+		/* Warning pending */
+		mcck->warning = 1;
+		set_cpu_flag(CIF_MCCK_PENDING);
+	}
+
+	/*
+	 * If there are only Channel Report Pending and External Damage
+	 * machine checks, they will not be reinjected into the guest
+	 * because they refer to host conditions only.
+	 */
+	mcck_dam_code = (mci.val & MCIC_SUBCLASS_MASK);
+	if (test_cpu_flag(CIF_MCCK_GUEST) &&
+	(mcck_dam_code & MCCK_CODE_NO_GUEST) != mcck_dam_code) {
+		/* Set exit reason code for host's later handling */
+		*((long *)(regs->gprs[15] + __SF_SIE_REASON)) = -EINTR;
+	}
+	clear_cpu_flag(CIF_MCCK_GUEST);
+	nmi_exit();
+}
+NOKPROBE_SYMBOL(s390_do_machine_check);
+
+static int __init machine_check_init(void)
+{
+	ctl_set_bit(14, 25);	/* enable external damage MCH */
+	ctl_set_bit(14, 27);	/* enable system recovery MCH */
+	ctl_set_bit(14, 24);	/* enable warning MCH */
+	return 0;
+}
+early_initcall(machine_check_init);