From 6c81511ca1f52a0bbe921b2b98e34319a4ca59ed Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Thu, 12 Oct 2017 13:24:47 +0200 Subject: [PATCH] s390/nmi: allocation of the extended save area The machine check extended save area is needed to store the vector registers and the guarded storage control block when a CPU is interrupted by a machine check. Move the slab cache allocation of the full save area to nmi.c, for early boot use a static __initdata block. Reviewed-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/nmi.h | 10 ++++- arch/s390/kernel/nmi.c | 82 +++++++++++++++++++++++++++++++++++++ arch/s390/kernel/setup.c | 11 +---- arch/s390/kernel/smp.c | 43 ++++--------------- 4 files changed, 99 insertions(+), 47 deletions(-) diff --git a/arch/s390/include/asm/nmi.h b/arch/s390/include/asm/nmi.h index 77a7d9445e33..ed41c424448d 100644 --- a/arch/s390/include/asm/nmi.h +++ b/arch/s390/include/asm/nmi.h @@ -80,6 +80,8 @@ union mci { #define MCESA_ORIGIN_MASK (~0x3ffUL) #define MCESA_LC_MASK (0xfUL) +#define MCESA_MIN_SIZE (1024) +#define MCESA_MAX_SIZE (2048) struct mcesa { u8 vector_save_area[1024]; @@ -88,8 +90,12 @@ struct mcesa { struct pt_regs; -extern void s390_handle_mcck(void); -extern void s390_do_machine_check(struct pt_regs *regs); +void nmi_alloc_boot_cpu(struct lowcore *lc); +int nmi_alloc_per_cpu(struct lowcore *lc); +void nmi_free_per_cpu(struct lowcore *lc); + +void s390_handle_mcck(void); +void s390_do_machine_check(struct pt_regs *regs); #endif /* __ASSEMBLY__ */ #endif /* _ASM_S390_NMI_H */ 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 #include #include +#include #include +#include #include #include #include @@ -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) { diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index bf139f9e120e..b0943ef8cc31 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -55,6 +55,7 @@ #include #include #include +#include #include #include #include @@ -340,15 +341,7 @@ static void __init setup_lowcore(void) lc->stfl_fac_list = S390_lowcore.stfl_fac_list; memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list, MAX_FACILITY_BIT/8); - if (MACHINE_HAS_VX || MACHINE_HAS_GS) { - unsigned long bits, size; - - bits = MACHINE_HAS_GS ? 11 : 10; - size = 1UL << bits; - lc->mcesad = (__u64) memblock_virt_alloc(size, size); - if (MACHINE_HAS_GS) - lc->mcesad |= bits; - } + nmi_alloc_boot_cpu(lc); vdso_alloc_boot_cpu(lc); lc->sync_enter_timer = S390_lowcore.sync_enter_timer; lc->async_enter_timer = S390_lowcore.async_enter_timer; diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 2dba3e88a972..6d17ff46b749 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -81,8 +81,6 @@ struct pcpu { static u8 boot_core_type; static struct pcpu pcpu_devices[NR_CPUS]; -static struct kmem_cache *pcpu_mcesa_cache; - unsigned int smp_cpu_mt_shift; EXPORT_SYMBOL(smp_cpu_mt_shift); @@ -193,10 +191,8 @@ static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit) static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu) { unsigned long async_stack, panic_stack; - unsigned long mcesa_origin, mcesa_bits; struct lowcore *lc; - mcesa_origin = mcesa_bits = 0; if (pcpu != &pcpu_devices[0]) { pcpu->lowcore = (struct lowcore *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER); @@ -204,40 +200,30 @@ static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu) panic_stack = __get_free_page(GFP_KERNEL); if (!pcpu->lowcore || !panic_stack || !async_stack) goto out; - if (MACHINE_HAS_VX || MACHINE_HAS_GS) { - mcesa_origin = (unsigned long) - kmem_cache_alloc(pcpu_mcesa_cache, GFP_KERNEL); - if (!mcesa_origin) - goto out; - /* The pointer is stored with mcesa_bits ORed in */ - kmemleak_not_leak((void *) mcesa_origin); - mcesa_bits = MACHINE_HAS_GS ? 11 : 0; - } } else { async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET; panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET; - mcesa_origin = pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK; - mcesa_bits = pcpu->lowcore->mcesad & MCESA_LC_MASK; } lc = pcpu->lowcore; memcpy(lc, &S390_lowcore, 512); memset((char *) lc + 512, 0, sizeof(*lc) - 512); lc->async_stack = async_stack + ASYNC_FRAME_OFFSET; lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET; - lc->mcesad = mcesa_origin | mcesa_bits; lc->cpu_nr = cpu; lc->spinlock_lockval = arch_spin_lockval(cpu); lc->spinlock_index = 0; - if (vdso_alloc_per_cpu(lc)) + if (nmi_alloc_per_cpu(lc)) goto out; + if (vdso_alloc_per_cpu(lc)) + goto out_mcesa; lowcore_ptr[cpu] = lc; pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc); return 0; + +out_mcesa: + nmi_free_per_cpu(lc); out: if (pcpu != &pcpu_devices[0]) { - if (mcesa_origin) - kmem_cache_free(pcpu_mcesa_cache, - (void *) mcesa_origin); free_page(panic_stack); free_pages(async_stack, ASYNC_ORDER); free_pages((unsigned long) pcpu->lowcore, LC_ORDER); @@ -249,17 +235,12 @@ out: static void pcpu_free_lowcore(struct pcpu *pcpu) { - unsigned long mcesa_origin; - pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0); lowcore_ptr[pcpu - pcpu_devices] = NULL; vdso_free_per_cpu(pcpu->lowcore); + nmi_free_per_cpu(pcpu->lowcore); if (pcpu == &pcpu_devices[0]) return; - if (MACHINE_HAS_VX || MACHINE_HAS_GS) { - mcesa_origin = pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK; - kmem_cache_free(pcpu_mcesa_cache, (void *) mcesa_origin); - } free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET); free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER); free_pages((unsigned long) pcpu->lowcore, LC_ORDER); @@ -936,22 +917,12 @@ void __init smp_fill_possible_mask(void) void __init smp_prepare_cpus(unsigned int max_cpus) { - unsigned long size; - /* request the 0x1201 emergency signal external interrupt */ if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt)) panic("Couldn't request external interrupt 0x1201"); /* request the 0x1202 external call external interrupt */ if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt)) panic("Couldn't request external interrupt 0x1202"); - /* create slab cache for the machine-check-extended-save-areas */ - if (MACHINE_HAS_VX || MACHINE_HAS_GS) { - size = 1UL << (MACHINE_HAS_GS ? 11 : 10); - pcpu_mcesa_cache = kmem_cache_create("nmi_save_areas", - size, size, 0, NULL); - if (!pcpu_mcesa_cache) - panic("Couldn't create nmi save area cache"); - } } void __init smp_prepare_boot_cpu(void)