aboutsummaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/nmi.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/s390/kernel/nmi.c')
-rw-r--r--arch/s390/kernel/nmi.c89
1 files changed, 51 insertions, 38 deletions
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 20f8e1868853..31cb9b00a36b 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -6,12 +6,12 @@
* 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/entry-common.h>
#include <linux/hardirq.h>
#include <linux/log2.h>
#include <linux/kprobes.h>
@@ -30,6 +30,8 @@
#include <asm/switch_to.h>
#include <asm/ctl_reg.h>
#include <asm/asm-offsets.h>
+#include <asm/pai.h>
+
#include <linux/kvm_host.h>
struct mcck_struct {
@@ -58,27 +60,27 @@ static inline unsigned long nmi_get_mcesa_size(void)
/*
* 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.
+ * It will be replaced on the boot CPU reinit 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);
+static struct mcesa boot_mcesa __aligned(MCESA_MAX_SIZE);
-void __init nmi_alloc_boot_cpu(struct lowcore *lc)
+void __init nmi_alloc_mcesa_early(u64 *mcesad)
{
if (!nmi_needs_mcesa())
return;
- lc->mcesad = (unsigned long) &boot_mcesa;
+ *mcesad = __pa(&boot_mcesa);
if (MACHINE_HAS_GS)
- lc->mcesad |= ilog2(MCESA_MAX_SIZE);
+ *mcesad |= ilog2(MCESA_MAX_SIZE);
}
-static int __init nmi_init(void)
+static void __init nmi_alloc_cache(void)
{
- unsigned long origin, cr0, size;
+ unsigned long size;
if (!nmi_needs_mcesa())
- return 0;
+ return;
size = nmi_get_mcesa_size();
if (size > MCESA_MIN_SIZE)
mcesa_origin_lc = ilog2(size);
@@ -86,40 +88,31 @@ static int __init nmi_init(void)
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)
+int __ref nmi_alloc_mcesa(u64 *mcesad)
{
unsigned long origin;
+ *mcesad = 0;
if (!nmi_needs_mcesa())
return 0;
+ if (!mcesa_cache)
+ nmi_alloc_cache();
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;
+ *mcesad = __pa(origin) | mcesa_origin_lc;
return 0;
}
-void nmi_free_per_cpu(struct lowcore *lc)
+void nmi_free_mcesa(u64 *mcesad)
{
if (!nmi_needs_mcesa())
return;
- kmem_cache_free(mcesa_cache, (void *)(lc->mcesad & MCESA_ORIGIN_MASK));
+ kmem_cache_free(mcesa_cache, __va(*mcesad & MCESA_ORIGIN_MASK));
}
static notrace void s390_handle_damage(void)
@@ -175,14 +168,16 @@ void __s390_handle_mcck(void)
"malfunction (code 0x%016lx).\n", mcck.mcck_code);
printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
current->comm, current->pid);
- do_exit(SIGSEGV);
+ make_task_dead(SIGSEGV);
}
}
-void noinstr s390_handle_mcck(void)
+void noinstr s390_handle_mcck(struct pt_regs *regs)
{
trace_hardirqs_off();
+ pai_kernel_enter(regs);
__s390_handle_mcck();
+ pai_kernel_exit(regs);
trace_hardirqs_on();
}
/*
@@ -246,7 +241,7 @@ static int notrace s390_validate_registers(union mci mci, int umode)
: "Q" (S390_lowcore.fpt_creg_save_area));
}
- mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
+ mcesa = __va(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
if (!MACHINE_HAS_VX) {
/* Validate floating point registers */
asm volatile(
@@ -273,7 +268,14 @@ static int notrace s390_validate_registers(union mci mci, int umode)
/* Validate vector registers */
union ctlreg0 cr0;
- if (!mci.vr) {
+ /*
+ * The vector validity must only be checked if not running a
+ * KVM guest. For KVM guests the machine check is forwarded by
+ * KVM and it is the responsibility of the guest to take
+ * appropriate actions. The host vector or FPU values have been
+ * saved by KVM and will be restored by KVM.
+ */
+ if (!mci.vr && !test_cpu_flag(CIF_MCCK_GUEST)) {
/*
* Vector registers can't be restored. If the kernel
* currently uses vector registers the system is
@@ -316,11 +318,21 @@ static int notrace s390_validate_registers(union mci mci, int umode)
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.
+ * 2 cases:
+ * - machine check in kernel or userspace
+ * - machine check while running SIE (KVM guest)
+ * For kernel or userspace the userspace values of
+ * guarded storage control can not be recreated, the
+ * process must be terminated.
+ * For SIE the guest values of guarded storage can not
+ * be recreated. This is either due to a bug or due to
+ * GS being disabled in the guest. The guest will be
+ * notified by KVM code and the guests machine check
+ * handling must take care of this. The host values
+ * are saved by KVM and are not affected.
*/
- kill_task = 1;
+ if (!test_cpu_flag(CIF_MCCK_GUEST))
+ kill_task = 1;
} else {
load_gs_cb((struct gs_cb *)mcesa->guarded_storage_save_area);
}
@@ -386,11 +398,12 @@ int notrace s390_do_machine_check(struct pt_regs *regs)
static unsigned long long last_ipd;
struct mcck_struct *mcck;
unsigned long long tmp;
+ irqentry_state_t irq_state;
union mci mci;
unsigned long mcck_dam_code;
int mcck_pending = 0;
- nmi_enter();
+ irq_state = irqentry_nmi_enter(regs);
if (user_mode(regs))
update_timer_mcck();
@@ -493,14 +506,14 @@ int notrace s390_do_machine_check(struct pt_regs *regs)
clear_cpu_flag(CIF_MCCK_GUEST);
if (user_mode(regs) && mcck_pending) {
- nmi_exit();
+ irqentry_nmi_exit(regs, irq_state);
return 1;
}
if (mcck_pending)
schedule_mcck_handler();
- nmi_exit();
+ irqentry_nmi_exit(regs, irq_state);
return 0;
}
NOKPROBE_SYMBOL(s390_do_machine_check);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.