diff options
Diffstat (limited to 'arch/s390/kernel/nmi.c')
| -rw-r--r-- | arch/s390/kernel/nmi.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c index eb3e702cee30..7f6779695a43 100644 --- a/arch/s390/kernel/nmi.c +++ b/arch/s390/kernel/nmi.c @@ -12,7 +12,9 @@ #include <linux/init.h> #include <linux/errno.h> #include <linux/hardirq.h> +#include <linux/log2.h> #include <linux/kprobes.h> +#include <linux/slab.h> #include <linux/time.h> #include <linux/module.h> #include <linux/sched/signal.h> @@ -38,6 +40,86 @@ struct mcck_struct { }; 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) { |