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linux_dsm_epyc7002/arch/mips/include/asm/mmu_context.h
Jayachandran C f4ae17aa0f MIPS: mm: Use scratch for PGD when !CONFIG_MIPS_PGD_C0_CONTEXT 
Allow usage of scratch register for current pgd even when
MIPS_PGD_C0_CONTEXT is not configured. MIPS_PGD_C0_CONTEXT is set
for 64r2 platforms to indicate availability of Xcontext for saving
cpuid, thus freeing Context to be used for saving PGD. This option
was also tied to using a scratch register for storing PGD.

This commit will allow usage of scratch register to store the current
pgd if one can be allocated for the platform, even when
MIPS_PGD_C0_CONTEXT is not set. The cpuid will be kept in the CP0
Context register in this case.

The code to store the current pgd for the TLB miss handler is now
generated in all cases. When scratch register is available, the PGD
is also stored in the scratch register.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Patchwork: https://patchwork.linux-mips.org/patch/5906/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-10-29 21:24:51 +01:00

308 lines
8.3 KiB
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/*
* Switch a MMU context.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1996, 1997, 1998, 1999 by Ralf Baechle
* Copyright (C) 1999 Silicon Graphics, Inc.
*/
#ifndef _ASM_MMU_CONTEXT_H
#define _ASM_MMU_CONTEXT_H
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <asm/cacheflush.h>
#include <asm/hazards.h>
#include <asm/tlbflush.h>
#ifdef CONFIG_MIPS_MT_SMTC
#include <asm/mipsmtregs.h>
#include <asm/smtc.h>
#endif /* SMTC */
#include <asm-generic/mm_hooks.h>
#define TLBMISS_HANDLER_SETUP_PGD(pgd) \
do { \
extern void tlbmiss_handler_setup_pgd(unsigned long); \
tlbmiss_handler_setup_pgd((unsigned long)(pgd)); \
} while (0)
#ifdef CONFIG_MIPS_PGD_C0_CONTEXT
#define TLBMISS_HANDLER_SETUP() \
do { \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir); \
write_c0_xcontext((unsigned long) smp_processor_id() << \
SMP_CPUID_REGSHIFT); \
} while (0)
#else /* !CONFIG_MIPS_PGD_C0_CONTEXT: using pgd_current*/
/*
* For the fast tlb miss handlers, we keep a per cpu array of pointers
* to the current pgd for each processor. Also, the proc. id is stuffed
* into the context register.
*/
extern unsigned long pgd_current[];
#define TLBMISS_HANDLER_SETUP() \
write_c0_context((unsigned long) smp_processor_id() << \
SMP_CPUID_REGSHIFT); \
back_to_back_c0_hazard(); \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
#endif /* CONFIG_MIPS_PGD_C0_CONTEXT*/
#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
#define ASID_INC 0x40
#define ASID_MASK 0xfc0
#elif defined(CONFIG_CPU_R8000)
#define ASID_INC 0x10
#define ASID_MASK 0xff0
#elif defined(CONFIG_MIPS_MT_SMTC)
#define ASID_INC 0x1
extern unsigned long smtc_asid_mask;
#define ASID_MASK (smtc_asid_mask)
#define HW_ASID_MASK 0xff
/* End SMTC/34K debug hack */
#else /* FIXME: not correct for R6000 */
#define ASID_INC 0x1
#define ASID_MASK 0xff
#endif
#define cpu_context(cpu, mm) ((mm)->context.asid[cpu])
#define cpu_asid(cpu, mm) (cpu_context((cpu), (mm)) & ASID_MASK)
#define asid_cache(cpu) (cpu_data[cpu].asid_cache)
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
}
/*
* All unused by hardware upper bits will be considered
* as a software asid extension.
*/
#define ASID_VERSION_MASK ((unsigned long)~(ASID_MASK|(ASID_MASK-1)))
#define ASID_FIRST_VERSION ((unsigned long)(~ASID_VERSION_MASK) + 1)
#ifndef CONFIG_MIPS_MT_SMTC
/* Normal, classic MIPS get_new_mmu_context */
static inline void
get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
{
extern void kvm_local_flush_tlb_all(void);
unsigned long asid = asid_cache(cpu);
if (! ((asid += ASID_INC) & ASID_MASK) ) {
if (cpu_has_vtag_icache)
flush_icache_all();
#ifdef CONFIG_KVM
kvm_local_flush_tlb_all(); /* start new asid cycle */
#else
local_flush_tlb_all(); /* start new asid cycle */
#endif
if (!asid) /* fix version if needed */
asid = ASID_FIRST_VERSION;
}
cpu_context(cpu, mm) = asid_cache(cpu) = asid;
}
#else /* CONFIG_MIPS_MT_SMTC */
#define get_new_mmu_context(mm, cpu) smtc_get_new_mmu_context((mm), (cpu))
#endif /* CONFIG_MIPS_MT_SMTC */
/*
* Initialize the context related info for a new mm_struct
* instance.
*/
static inline int
init_new_context(struct task_struct *tsk, struct mm_struct *mm)
{
int i;
for_each_possible_cpu(i)
cpu_context(i, mm) = 0;
return 0;
}
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
unsigned int cpu = smp_processor_id();
unsigned long flags;
#ifdef CONFIG_MIPS_MT_SMTC
unsigned long oldasid;
unsigned long mtflags;
int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
local_irq_save(flags);
mtflags = dvpe();
#else /* Not SMTC */
local_irq_save(flags);
#endif /* CONFIG_MIPS_MT_SMTC */
/* Check if our ASID is of an older version and thus invalid */
if ((cpu_context(cpu, next) ^ asid_cache(cpu)) & ASID_VERSION_MASK)
get_new_mmu_context(next, cpu);
#ifdef CONFIG_MIPS_MT_SMTC
/*
* If the EntryHi ASID being replaced happens to be
* the value flagged at ASID recycling time as having
* an extended life, clear the bit showing it being
* in use by this "CPU", and if that's the last bit,
* free up the ASID value for use and flush any old
* instances of it from the TLB.
*/
oldasid = (read_c0_entryhi() & ASID_MASK);
if(smtc_live_asid[mytlb][oldasid]) {
smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
if(smtc_live_asid[mytlb][oldasid] == 0)
smtc_flush_tlb_asid(oldasid);
}
/*
* Tread softly on EntryHi, and so long as we support
* having ASID_MASK smaller than the hardware maximum,
* make sure no "soft" bits become "hard"...
*/
write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) |
cpu_asid(cpu, next));
ehb(); /* Make sure it propagates to TCStatus */
evpe(mtflags);
#else
write_c0_entryhi(cpu_asid(cpu, next));
#endif /* CONFIG_MIPS_MT_SMTC */
TLBMISS_HANDLER_SETUP_PGD(next->pgd);
/*
* Mark current->active_mm as not "active" anymore.
* We don't want to mislead possible IPI tlb flush routines.
*/
cpumask_clear_cpu(cpu, mm_cpumask(prev));
cpumask_set_cpu(cpu, mm_cpumask(next));
local_irq_restore(flags);
}
/*
* Destroy context related info for an mm_struct that is about
* to be put to rest.
*/
static inline void destroy_context(struct mm_struct *mm)
{
}
#define deactivate_mm(tsk, mm) do { } while (0)
/*
* After we have set current->mm to a new value, this activates
* the context for the new mm so we see the new mappings.
*/
static inline void
activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
unsigned long flags;
unsigned int cpu = smp_processor_id();
#ifdef CONFIG_MIPS_MT_SMTC
unsigned long oldasid;
unsigned long mtflags;
int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
#endif /* CONFIG_MIPS_MT_SMTC */
local_irq_save(flags);
/* Unconditionally get a new ASID. */
get_new_mmu_context(next, cpu);
#ifdef CONFIG_MIPS_MT_SMTC
/* See comments for similar code above */
mtflags = dvpe();
oldasid = read_c0_entryhi() & ASID_MASK;
if(smtc_live_asid[mytlb][oldasid]) {
smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
if(smtc_live_asid[mytlb][oldasid] == 0)
smtc_flush_tlb_asid(oldasid);
}
/* See comments for similar code above */
write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) |
cpu_asid(cpu, next));
ehb(); /* Make sure it propagates to TCStatus */
evpe(mtflags);
#else
write_c0_entryhi(cpu_asid(cpu, next));
#endif /* CONFIG_MIPS_MT_SMTC */
TLBMISS_HANDLER_SETUP_PGD(next->pgd);
/* mark mmu ownership change */
cpumask_clear_cpu(cpu, mm_cpumask(prev));
cpumask_set_cpu(cpu, mm_cpumask(next));
local_irq_restore(flags);
}
/*
* If mm is currently active_mm, we can't really drop it. Instead,
* we will get a new one for it.
*/
static inline void
drop_mmu_context(struct mm_struct *mm, unsigned cpu)
{
unsigned long flags;
#ifdef CONFIG_MIPS_MT_SMTC
unsigned long oldasid;
/* Can't use spinlock because called from TLB flush within DVPE */
unsigned int prevvpe;
int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
#endif /* CONFIG_MIPS_MT_SMTC */
local_irq_save(flags);
if (cpumask_test_cpu(cpu, mm_cpumask(mm))) {
get_new_mmu_context(mm, cpu);
#ifdef CONFIG_MIPS_MT_SMTC
/* See comments for similar code above */
prevvpe = dvpe();
oldasid = (read_c0_entryhi() & ASID_MASK);
if (smtc_live_asid[mytlb][oldasid]) {
smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
if(smtc_live_asid[mytlb][oldasid] == 0)
smtc_flush_tlb_asid(oldasid);
}
/* See comments for similar code above */
write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
| cpu_asid(cpu, mm));
ehb(); /* Make sure it propagates to TCStatus */
evpe(prevvpe);
#else /* not CONFIG_MIPS_MT_SMTC */
write_c0_entryhi(cpu_asid(cpu, mm));
#endif /* CONFIG_MIPS_MT_SMTC */
} else {
/* will get a new context next time */
#ifndef CONFIG_MIPS_MT_SMTC
cpu_context(cpu, mm) = 0;
#else /* SMTC */
int i;
/* SMTC shares the TLB (and ASIDs) across VPEs */
for_each_online_cpu(i) {
if((smtc_status & SMTC_TLB_SHARED)
|| (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id))
cpu_context(i, mm) = 0;
}
#endif /* CONFIG_MIPS_MT_SMTC */
}
local_irq_restore(flags);
}
#endif /* _ASM_MMU_CONTEXT_H */
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