kernel_optimize_test/arch/s390/include/asm/mmu.h
Martin Schwidefsky 1b948d6cae s390/mm,tlb: optimize TLB flushing for zEC12
The zEC12 machines introduced the local-clearing control for the IDTE
and IPTE instruction. If the control is set only the TLB of the local
CPU is cleared of entries, either all entries of a single address space
for IDTE, or the entry for a single page-table entry for IPTE.
Without the local-clearing control the TLB flush is broadcasted to all
CPUs in the configuration, which is expensive.

The reset of the bit mask of the CPUs that need flushing after a
non-local IDTE is tricky. As TLB entries for an address space remain
in the TLB even if the address space is detached a new bit field is
required to keep track of attached CPUs vs. CPUs in the need of a
flush. After a non-local flush with IDTE the bit-field of attached CPUs
is copied to the bit-field of CPUs in need of a flush. The ordering
of operations on cpu_attach_mask, attach_count and mm_cpumask(mm) is
such that an underindication in mm_cpumask(mm) is prevented but an
overindication in mm_cpumask(mm) is possible.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-04-03 14:31:00 +02:00

41 lines
907 B
C

#ifndef __MMU_H
#define __MMU_H
#include <linux/cpumask.h>
#include <linux/errno.h>
typedef struct {
cpumask_t cpu_attach_mask;
atomic_t attach_count;
unsigned int flush_mm;
spinlock_t list_lock;
struct list_head pgtable_list;
struct list_head gmap_list;
unsigned long asce_bits;
unsigned long asce_limit;
unsigned long vdso_base;
/* The mmu context has extended page tables. */
unsigned int has_pgste:1;
} mm_context_t;
#define INIT_MM_CONTEXT(name) \
.context.list_lock = __SPIN_LOCK_UNLOCKED(name.context.list_lock), \
.context.pgtable_list = LIST_HEAD_INIT(name.context.pgtable_list), \
.context.gmap_list = LIST_HEAD_INIT(name.context.gmap_list),
static inline int tprot(unsigned long addr)
{
int rc = -EFAULT;
asm volatile(
" tprot 0(%1),0\n"
"0: ipm %0\n"
" srl %0,28\n"
"1:\n"
EX_TABLE(0b,1b)
: "+d" (rc) : "a" (addr) : "cc");
return rc;
}
#endif