linux_dsm_epyc7002/arch/s390/include/asm/tlbflush.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

212 lines
5.1 KiB
C

#ifndef _S390_TLBFLUSH_H
#define _S390_TLBFLUSH_H
#include <linux/mm.h>
#include <linux/sched.h>
#include <asm/processor.h>
#include <asm/pgalloc.h>
/*
* Flush all TLB entries on the local CPU.
*/
static inline void __tlb_flush_local(void)
{
asm volatile("ptlb" : : : "memory");
}
/*
* Flush TLB entries for a specific ASCE on all CPUs
*/
static inline void __tlb_flush_idte(unsigned long asce)
{
/* Global TLB flush for the mm */
asm volatile(
" .insn rrf,0xb98e0000,0,%0,%1,0"
: : "a" (2048), "a" (asce) : "cc");
}
/*
* Flush TLB entries for a specific ASCE on the local CPU
*/
static inline void __tlb_flush_idte_local(unsigned long asce)
{
/* Local TLB flush for the mm */
asm volatile(
" .insn rrf,0xb98e0000,0,%0,%1,1"
: : "a" (2048), "a" (asce) : "cc");
}
#ifdef CONFIG_SMP
void smp_ptlb_all(void);
/*
* Flush all TLB entries on all CPUs.
*/
static inline void __tlb_flush_global(void)
{
register unsigned long reg2 asm("2");
register unsigned long reg3 asm("3");
register unsigned long reg4 asm("4");
long dummy;
#ifndef CONFIG_64BIT
if (!MACHINE_HAS_CSP) {
smp_ptlb_all();
return;
}
#endif /* CONFIG_64BIT */
dummy = 0;
reg2 = reg3 = 0;
reg4 = ((unsigned long) &dummy) + 1;
asm volatile(
" csp %0,%2"
: : "d" (reg2), "d" (reg3), "d" (reg4), "m" (dummy) : "cc" );
}
/*
* Flush TLB entries for a specific mm on all CPUs (in case gmap is used
* this implicates multiple ASCEs!).
*/
static inline void __tlb_flush_full(struct mm_struct *mm)
{
preempt_disable();
atomic_add(0x10000, &mm->context.attach_count);
if (cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id()))) {
/* Local TLB flush */
__tlb_flush_local();
} else {
/* Global TLB flush */
__tlb_flush_global();
/* Reset TLB flush mask */
if (MACHINE_HAS_TLB_LC)
cpumask_copy(mm_cpumask(mm),
&mm->context.cpu_attach_mask);
}
atomic_sub(0x10000, &mm->context.attach_count);
preempt_enable();
}
/*
* Flush TLB entries for a specific ASCE on all CPUs.
*/
static inline void __tlb_flush_asce(struct mm_struct *mm, unsigned long asce)
{
int active, count;
preempt_disable();
active = (mm == current->active_mm) ? 1 : 0;
count = atomic_add_return(0x10000, &mm->context.attach_count);
if (MACHINE_HAS_TLB_LC && (count & 0xffff) <= active &&
cpumask_equal(mm_cpumask(mm), cpumask_of(smp_processor_id()))) {
__tlb_flush_idte_local(asce);
} else {
if (MACHINE_HAS_IDTE)
__tlb_flush_idte(asce);
else
__tlb_flush_global();
/* Reset TLB flush mask */
if (MACHINE_HAS_TLB_LC)
cpumask_copy(mm_cpumask(mm),
&mm->context.cpu_attach_mask);
}
atomic_sub(0x10000, &mm->context.attach_count);
preempt_enable();
}
static inline void __tlb_flush_kernel(void)
{
if (MACHINE_HAS_IDTE)
__tlb_flush_idte((unsigned long) init_mm.pgd |
init_mm.context.asce_bits);
else
__tlb_flush_global();
}
#else
#define __tlb_flush_global() __tlb_flush_local()
#define __tlb_flush_full(mm) __tlb_flush_local()
/*
* Flush TLB entries for a specific ASCE on all CPUs.
*/
static inline void __tlb_flush_asce(struct mm_struct *mm, unsigned long asce)
{
if (MACHINE_HAS_TLB_LC)
__tlb_flush_idte_local(asce);
else
__tlb_flush_local();
}
static inline void __tlb_flush_kernel(void)
{
if (MACHINE_HAS_TLB_LC)
__tlb_flush_idte_local((unsigned long) init_mm.pgd |
init_mm.context.asce_bits);
else
__tlb_flush_local();
}
#endif
static inline void __tlb_flush_mm(struct mm_struct * mm)
{
/*
* If the machine has IDTE we prefer to do a per mm flush
* on all cpus instead of doing a local flush if the mm
* only ran on the local cpu.
*/
if (MACHINE_HAS_IDTE && list_empty(&mm->context.gmap_list))
__tlb_flush_asce(mm, (unsigned long) mm->pgd |
mm->context.asce_bits);
else
__tlb_flush_full(mm);
}
static inline void __tlb_flush_mm_lazy(struct mm_struct * mm)
{
if (mm->context.flush_mm) {
__tlb_flush_mm(mm);
mm->context.flush_mm = 0;
}
}
/*
* TLB flushing:
* flush_tlb() - flushes the current mm struct TLBs
* flush_tlb_all() - flushes all processes TLBs
* flush_tlb_mm(mm) - flushes the specified mm context TLB's
* flush_tlb_page(vma, vmaddr) - flushes one page
* flush_tlb_range(vma, start, end) - flushes a range of pages
* flush_tlb_kernel_range(start, end) - flushes a range of kernel pages
*/
/*
* flush_tlb_mm goes together with ptep_set_wrprotect for the
* copy_page_range operation and flush_tlb_range is related to
* ptep_get_and_clear for change_protection. ptep_set_wrprotect and
* ptep_get_and_clear do not flush the TLBs directly if the mm has
* only one user. At the end of the update the flush_tlb_mm and
* flush_tlb_range functions need to do the flush.
*/
#define flush_tlb() do { } while (0)
#define flush_tlb_all() do { } while (0)
#define flush_tlb_page(vma, addr) do { } while (0)
static inline void flush_tlb_mm(struct mm_struct *mm)
{
__tlb_flush_mm_lazy(mm);
}
static inline void flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
__tlb_flush_mm_lazy(vma->vm_mm);
}
static inline void flush_tlb_kernel_range(unsigned long start,
unsigned long end)
{
__tlb_flush_kernel();
}
#endif /* _S390_TLBFLUSH_H */