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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 <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2017-10-12 13:24:47 +02:00
parent cc65450c83
commit 6c81511ca1
4 changed files with 99 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/s390/include/asm/nmi.h
View File

@ -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 */

82
arch/s390/kernel/nmi.c
View File

@ -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)
{

11
arch/s390/kernel/setup.c
View File

@ -55,6 +55,7 @@
#include <asm/mmu_context.h>
#include <asm/cpcmd.h>
#include <asm/lowcore.h>
#include <asm/nmi.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/ptrace.h>
@ -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;

43
arch/s390/kernel/smp.c
View File

@ -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)