/*
* Copyright (C) 1999 Niibe Yutaka
* Copyright (C) 2003 Paul Mundt
*
* ASID handling idea taken from MIPS implementation.
*/
#ifndef __ASM_SH_MMU_CONTEXT_H
#define __ASM_SH_MMU_CONTEXT_H
#ifdef __KERNEL__
#include <asm/cpu/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
#include <asm/io.h>
/*
* The MMU "context" consists of two things:
* (a) TLB cache version (or round, cycle whatever expression you like)
* (b) ASID (Address Space IDentifier)
*/
/*
* Cache of MMU context last used.
*/
extern unsigned long mmu_context_cache;
#define MMU_CONTEXT_ASID_MASK 0x000000ff
#define MMU_CONTEXT_VERSION_MASK 0xffffff00
#define MMU_CONTEXT_FIRST_VERSION 0x00000100
#define NO_CONTEXT 0
/* ASID is 8-bit value, so it can't be 0x100 */
#define MMU_NO_ASID 0x100
/*
* Virtual Page Number mask
*/
#define MMU_VPN_MASK 0xfffff000
#ifdef CONFIG_MMU
/*
* Get MMU context if needed.
*/
static __inline__ void
get_mmu_context(struct mm_struct *mm)
{
extern void flush_tlb_all(void);
unsigned long mc = mmu_context_cache;
/* Check if we have old version of context. */
if (((mm->context ^ mc) & MMU_CONTEXT_VERSION_MASK) == 0)
/* It's up to date, do nothing */
return;
/* It's old, we need to get new context with new version. */
mc = ++mmu_context_cache;
if (!(mc & MMU_CONTEXT_ASID_MASK)) {
/*
* We exhaust ASID of this version.
* Flush all TLB and start new cycle.
*/
flush_tlb_all();
/*
* Fix version; Note that we avoid version #0
* to distingush NO_CONTEXT.
*/
if (!mc)
mmu_context_cache = mc = MMU_CONTEXT_FIRST_VERSION;
}
mm->context = mc;
}
/*
* 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)
{
mm->context = NO_CONTEXT;
return 0;
}
/*
* 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)
{
/* Do nothing */
}
static __inline__ void set_asid(unsigned long asid)
{
unsigned long __dummy;
__asm__ __volatile__ ("mov.l %2, %0\n\t"
"and %3, %0\n\t"
"or %1, %0\n\t"
"mov.l %0, %2"
: "=&r" (__dummy)
: "r" (asid), "m" (__m(MMU_PTEH)),
"r" (0xffffff00));
}
static __inline__ unsigned long get_asid(void)
{
unsigned long asid;
__asm__ __volatile__ ("mov.l %1, %0"
: "=r" (asid)
: "m" (__m(MMU_PTEH)));
asid &= MMU_CONTEXT_ASID_MASK;
return asid;
}
/*
* 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_context(struct mm_struct *mm)
{
get_mmu_context(mm);
set_asid(mm->context & MMU_CONTEXT_ASID_MASK);
}
/* MMU_TTB can be used for optimizing the fault handling.
(Currently not used) */
static __inline__ void switch_mm(struct mm_struct *prev,
struct mm_struct *next,
struct task_struct *tsk)
{
if (likely(prev != next)) {
unsigned long __pgdir = (unsigned long)next->pgd;
__asm__ __volatile__("mov.l %0, %1"
: /* no output */
: "r" (__pgdir), "m" (__m(MMU_TTB)));
activate_context(next);
}
}
#define deactivate_mm(tsk,mm) do { } while (0)
#define activate_mm(prev, next) \
switch_mm((prev),(next),NULL)
static __inline__ void
enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
}
#else /* !CONFIG_MMU */
#define get_mmu_context(mm) do { } while (0)
#define init_new_context(tsk,mm) (0)
#define destroy_context(mm) do { } while (0)
#define set_asid(asid) do { } while (0)
#define get_asid() (0)
#define activate_context(mm) do { } while (0)
#define switch_mm(prev,next,tsk) do { } while (0)
#define deactivate_mm(tsk,mm) do { } while (0)
#define activate_mm(prev,next) do { } while (0)
#define enter_lazy_tlb(mm,tsk) do { } while (0)
#endif /* CONFIG_MMU */
#if defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH4)
/*
* If this processor has an MMU, we need methods to turn it off/on ..
* paging_init() will also have to be updated for the processor in
* question.
*/
static inline void enable_mmu(void)
{
/* Enable MMU */
ctrl_outl(MMU_CONTROL_INIT, MMUCR);
/* The manual suggests doing some nops after turning on the MMU */
__asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop\n\t");
if (mmu_context_cache == NO_CONTEXT)
mmu_context_cache = MMU_CONTEXT_FIRST_VERSION;
set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK);
}
static inline void disable_mmu(void)
{
unsigned long cr;
cr = ctrl_inl(MMUCR);
cr &= ~MMU_CONTROL_INIT;
ctrl_outl(cr, MMUCR);
__asm__ __volatile__ ("nop;nop;nop;nop;nop;nop;nop;nop\n\t");
}
#else
/*
* MMU control handlers for processors lacking memory
* management hardware.
*/
#define enable_mmu() do { BUG(); } while (0)
#define disable_mmu() do { BUG(); } while (0)
#endif
#endif /* __KERNEL__ */
#endif /* __ASM_SH_MMU_CONTEXT_H */
