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kernel-ark/include/asm-powerpc/mmu.h
Paul Mackerras bf72aeba2f powerpc: Use 64k pages without needing cache-inhibited large pages 
Some POWER5+ machines can do 64k hardware pages for normal memory but
not for cache-inhibited pages.  This patch lets us use 64k hardware
pages for most user processes on such machines (assuming the kernel
has been configured with CONFIG_PPC_64K_PAGES=y).  User processes
start out using 64k pages and get switched to 4k pages if they use any
non-cacheable mappings.

With this, we use 64k pages for the vmalloc region and 4k pages for
the imalloc region.  If anything creates a non-cacheable mapping in
the vmalloc region, the vmalloc region will get switched to 4k pages.
I don't know of any driver other than the DRM that would do this,
though, and these machines don't have AGP.

When a region gets switched from 64k pages to 4k pages, we do not have
to clear out all the 64k HPTEs from the hash table immediately.  We
use the _PAGE_COMBO bit in the Linux PTE to indicate whether the page
was hashed in as a 64k page or a set of 4k pages.  If hash_page is
trying to insert a 4k page for a Linux PTE and it sees that it has
already been inserted as a 64k page, it first invalidates the 64k HPTE
before inserting the 4k HPTE.  The hash invalidation routines also use
the _PAGE_COMBO bit, to determine whether to look for a 64k HPTE or a
set of 4k HPTEs to remove.  With those two changes, we can tolerate a
mix of 4k and 64k HPTEs in the hash table, and they will all get
removed when the address space is torn down.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-06-15 10:45:18 +10:00

424 lines
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#ifndef _ASM_POWERPC_MMU_H_
#define _ASM_POWERPC_MMU_H_
#ifdef __KERNEL__
#ifndef CONFIG_PPC64
#include <asm-ppc/mmu.h>
#else
/*
* PowerPC memory management structures
*
* Dave Engebretsen & Mike Corrigan <{engebret|mikejc}@us.ibm.com>
* PPC64 rework.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/asm-compat.h>
#include <asm/page.h>
/*
* Segment table
*/
#define STE_ESID_V 0x80
#define STE_ESID_KS 0x20
#define STE_ESID_KP 0x10
#define STE_ESID_N 0x08
#define STE_VSID_SHIFT 12
/* Location of cpu0's segment table */
#define STAB0_PAGE 0x6
#define STAB0_OFFSET (STAB0_PAGE << 12)
#define STAB0_PHYS_ADDR (STAB0_OFFSET + PHYSICAL_START)
#ifndef __ASSEMBLY__
extern char initial_stab[];
#endif /* ! __ASSEMBLY */
/*
* SLB
*/
#define SLB_NUM_BOLTED 3
#define SLB_CACHE_ENTRIES 8
/* Bits in the SLB ESID word */
#define SLB_ESID_V ASM_CONST(0x0000000008000000) /* valid */
/* Bits in the SLB VSID word */
#define SLB_VSID_SHIFT 12
#define SLB_VSID_B ASM_CONST(0xc000000000000000)
#define SLB_VSID_B_256M ASM_CONST(0x0000000000000000)
#define SLB_VSID_B_1T ASM_CONST(0x4000000000000000)
#define SLB_VSID_KS ASM_CONST(0x0000000000000800)
#define SLB_VSID_KP ASM_CONST(0x0000000000000400)
#define SLB_VSID_N ASM_CONST(0x0000000000000200) /* no-execute */
#define SLB_VSID_L ASM_CONST(0x0000000000000100)
#define SLB_VSID_C ASM_CONST(0x0000000000000080) /* class */
#define SLB_VSID_LP ASM_CONST(0x0000000000000030)
#define SLB_VSID_LP_00 ASM_CONST(0x0000000000000000)
#define SLB_VSID_LP_01 ASM_CONST(0x0000000000000010)
#define SLB_VSID_LP_10 ASM_CONST(0x0000000000000020)
#define SLB_VSID_LP_11 ASM_CONST(0x0000000000000030)
#define SLB_VSID_LLP (SLB_VSID_L|SLB_VSID_LP)
#define SLB_VSID_KERNEL (SLB_VSID_KP)
#define SLB_VSID_USER (SLB_VSID_KP|SLB_VSID_KS|SLB_VSID_C)
#define SLBIE_C (0x08000000)
/*
* Hash table
*/
#define HPTES_PER_GROUP 8
#define HPTE_V_AVPN_SHIFT 7
#define HPTE_V_AVPN ASM_CONST(0xffffffffffffff80)
#define HPTE_V_AVPN_VAL(x) (((x) & HPTE_V_AVPN) >> HPTE_V_AVPN_SHIFT)
#define HPTE_V_COMPARE(x,y) (!(((x) ^ (y)) & HPTE_V_AVPN))
#define HPTE_V_BOLTED ASM_CONST(0x0000000000000010)
#define HPTE_V_LOCK ASM_CONST(0x0000000000000008)
#define HPTE_V_LARGE ASM_CONST(0x0000000000000004)
#define HPTE_V_SECONDARY ASM_CONST(0x0000000000000002)
#define HPTE_V_VALID ASM_CONST(0x0000000000000001)
#define HPTE_R_PP0 ASM_CONST(0x8000000000000000)
#define HPTE_R_TS ASM_CONST(0x4000000000000000)
#define HPTE_R_RPN_SHIFT 12
#define HPTE_R_RPN ASM_CONST(0x3ffffffffffff000)
#define HPTE_R_FLAGS ASM_CONST(0x00000000000003ff)
#define HPTE_R_PP ASM_CONST(0x0000000000000003)
#define HPTE_R_N ASM_CONST(0x0000000000000004)
#define HPTE_R_C ASM_CONST(0x0000000000000080)
#define HPTE_R_R ASM_CONST(0x0000000000000100)
/* Values for PP (assumes Ks=0, Kp=1) */
/* pp0 will always be 0 for linux */
#define PP_RWXX 0 /* Supervisor read/write, User none */
#define PP_RWRX 1 /* Supervisor read/write, User read */
#define PP_RWRW 2 /* Supervisor read/write, User read/write */
#define PP_RXRX 3 /* Supervisor read, User read */
#ifndef __ASSEMBLY__
typedef struct {
unsigned long v;
unsigned long r;
} hpte_t;
extern hpte_t *htab_address;
extern unsigned long htab_size_bytes;
extern unsigned long htab_hash_mask;
/*
* Page size definition
*
* shift : is the "PAGE_SHIFT" value for that page size
* sllp : is a bit mask with the value of SLB L || LP to be or'ed
* directly to a slbmte "vsid" value
* penc : is the HPTE encoding mask for the "LP" field:
*
*/
struct mmu_psize_def
{
unsigned int shift; /* number of bits */
unsigned int penc; /* HPTE encoding */
unsigned int tlbiel; /* tlbiel supported for that page size */
unsigned long avpnm; /* bits to mask out in AVPN in the HPTE */
unsigned long sllp; /* SLB L||LP (exact mask to use in slbmte) */
};
#endif /* __ASSEMBLY__ */
/*
* The kernel use the constants below to index in the page sizes array.
* The use of fixed constants for this purpose is better for performances
* of the low level hash refill handlers.
*
* A non supported page size has a "shift" field set to 0
*
* Any new page size being implemented can get a new entry in here. Whether
* the kernel will use it or not is a different matter though. The actual page
* size used by hugetlbfs is not defined here and may be made variable
*/
#define MMU_PAGE_4K 0 /* 4K */
#define MMU_PAGE_64K 1 /* 64K */
#define MMU_PAGE_64K_AP 2 /* 64K Admixed (in a 4K segment) */
#define MMU_PAGE_1M 3 /* 1M */
#define MMU_PAGE_16M 4 /* 16M */
#define MMU_PAGE_16G 5 /* 16G */
#define MMU_PAGE_COUNT 6
#ifndef __ASSEMBLY__
/*
* The current system page sizes
*/
extern struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
extern int mmu_linear_psize;
extern int mmu_virtual_psize;
extern int mmu_vmalloc_psize;
extern int mmu_io_psize;
/*
* If the processor supports 64k normal pages but not 64k cache
* inhibited pages, we have to be prepared to switch processes
* to use 4k pages when they create cache-inhibited mappings.
* If this is the case, mmu_ci_restrictions will be set to 1.
*/
extern int mmu_ci_restrictions;
#ifdef CONFIG_HUGETLB_PAGE
/*
* The page size index of the huge pages for use by hugetlbfs
*/
extern int mmu_huge_psize;
#endif /* CONFIG_HUGETLB_PAGE */
/*
* This function sets the AVPN and L fields of the HPTE appropriately
* for the page size
*/
static inline unsigned long hpte_encode_v(unsigned long va, int psize)
{
unsigned long v =
v = (va >> 23) & ~(mmu_psize_defs[psize].avpnm);
v <<= HPTE_V_AVPN_SHIFT;
if (psize != MMU_PAGE_4K)
v |= HPTE_V_LARGE;
return v;
}
/*
* This function sets the ARPN, and LP fields of the HPTE appropriately
* for the page size. We assume the pa is already "clean" that is properly
* aligned for the requested page size
*/
static inline unsigned long hpte_encode_r(unsigned long pa, int psize)
{
unsigned long r;
/* A 4K page needs no special encoding */
if (psize == MMU_PAGE_4K)
return pa & HPTE_R_RPN;
else {
unsigned int penc = mmu_psize_defs[psize].penc;
unsigned int shift = mmu_psize_defs[psize].shift;
return (pa & ~((1ul << shift) - 1)) | (penc << 12);
}
return r;
}
/*
* This hashes a virtual address for a 256Mb segment only for now
*/
static inline unsigned long hpt_hash(unsigned long va, unsigned int shift)
{
return ((va >> 28) & 0x7fffffffffUL) ^ ((va & 0x0fffffffUL) >> shift);
}
extern int __hash_page_4K(unsigned long ea, unsigned long access,
unsigned long vsid, pte_t *ptep, unsigned long trap,
unsigned int local);
extern int __hash_page_64K(unsigned long ea, unsigned long access,
unsigned long vsid, pte_t *ptep, unsigned long trap,
unsigned int local);
struct mm_struct;
extern int hash_huge_page(struct mm_struct *mm, unsigned long access,
unsigned long ea, unsigned long vsid, int local,
unsigned long trap);
extern void htab_finish_init(void);
extern int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
unsigned long pstart, unsigned long mode,
int psize);
extern void htab_initialize(void);
extern void htab_initialize_secondary(void);
extern void hpte_init_native(void);
extern void hpte_init_lpar(void);
extern void hpte_init_iSeries(void);
extern long pSeries_lpar_hpte_insert(unsigned long hpte_group,
unsigned long va, unsigned long prpn,
unsigned long rflags,
unsigned long vflags, int psize);
extern long native_hpte_insert(unsigned long hpte_group,
unsigned long va, unsigned long prpn,
unsigned long rflags,
unsigned long vflags, int psize);
extern long iSeries_hpte_insert(unsigned long hpte_group,
unsigned long va, unsigned long prpn,
unsigned long rflags,
unsigned long vflags, int psize);
extern void stabs_alloc(void);
extern void slb_initialize(void);
extern void slb_flush_and_rebolt(void);
extern void stab_initialize(unsigned long stab);
#endif /* __ASSEMBLY__ */
/*
* VSID allocation
*
* We first generate a 36-bit "proto-VSID". For kernel addresses this
* is equal to the ESID, for user addresses it is:
* (context << 15) | (esid & 0x7fff)
*
* The two forms are distinguishable because the top bit is 0 for user
* addresses, whereas the top two bits are 1 for kernel addresses.
* Proto-VSIDs with the top two bits equal to 0b10 are reserved for
* now.
*
* The proto-VSIDs are then scrambled into real VSIDs with the
* multiplicative hash:
*
* VSID = (proto-VSID * VSID_MULTIPLIER) % VSID_MODULUS
* where VSID_MULTIPLIER = 268435399 = 0xFFFFFC7
* VSID_MODULUS = 2^36-1 = 0xFFFFFFFFF
*
* This scramble is only well defined for proto-VSIDs below
* 0xFFFFFFFFF, so both proto-VSID and actual VSID 0xFFFFFFFFF are
* reserved. VSID_MULTIPLIER is prime, so in particular it is
* co-prime to VSID_MODULUS, making this a 1:1 scrambling function.
* Because the modulus is 2^n-1 we can compute it efficiently without
* a divide or extra multiply (see below).
*
* This scheme has several advantages over older methods:
*
* - We have VSIDs allocated for every kernel address
* (i.e. everything above 0xC000000000000000), except the very top
* segment, which simplifies several things.
*
* - We allow for 15 significant bits of ESID and 20 bits of
* context for user addresses. i.e. 8T (43 bits) of address space for
* up to 1M contexts (although the page table structure and context
* allocation will need changes to take advantage of this).
*
* - The scramble function gives robust scattering in the hash
* table (at least based on some initial results). The previous
* method was more susceptible to pathological cases giving excessive
* hash collisions.
*/
/*
* WARNING - If you change these you must make sure the asm
* implementations in slb_allocate (slb_low.S), do_stab_bolted
* (head.S) and ASM_VSID_SCRAMBLE (below) are changed accordingly.
*
* You'll also need to change the precomputed VSID values in head.S
* which are used by the iSeries firmware.
*/
#define VSID_MULTIPLIER ASM_CONST(200730139) /* 28-bit prime */
#define VSID_BITS 36
#define VSID_MODULUS ((1UL<<VSID_BITS)-1)
#define CONTEXT_BITS 19
#define USER_ESID_BITS 16
#define USER_VSID_RANGE (1UL << (USER_ESID_BITS + SID_SHIFT))
/*
* This macro generates asm code to compute the VSID scramble
* function. Used in slb_allocate() and do_stab_bolted. The function
* computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS
*
* rt = register continaing the proto-VSID and into which the
* VSID will be stored
* rx = scratch register (clobbered)
*
* - rt and rx must be different registers
* - The answer will end up in the low 36 bits of rt. The higher
* bits may contain other garbage, so you may need to mask the
* result.
*/
#define ASM_VSID_SCRAMBLE(rt, rx) \
lis rx,VSID_MULTIPLIER@h; \
ori rx,rx,VSID_MULTIPLIER@l; \
mulld rt,rt,rx; /* rt = rt * MULTIPLIER */ \
\
srdi rx,rt,VSID_BITS; \
clrldi rt,rt,(64-VSID_BITS); \
add rt,rt,rx; /* add high and low bits */ \
/* Now, r3 == VSID (mod 2^36-1), and lies between 0 and \
* 2^36-1+2^28-1. That in particular means that if r3 >= \
* 2^36-1, then r3+1 has the 2^36 bit set. So, if r3+1 has \
* the bit clear, r3 already has the answer we want, if it \
* doesn't, the answer is the low 36 bits of r3+1. So in all \
* cases the answer is the low 36 bits of (r3 + ((r3+1) >> 36))*/\
addi rx,rt,1; \
srdi rx,rx,VSID_BITS; /* extract 2^36 bit */ \
add rt,rt,rx
#ifndef __ASSEMBLY__
typedef unsigned long mm_context_id_t;
typedef struct {
mm_context_id_t id;
u16 user_psize; /* page size index */
u16 sllp; /* SLB entry page size encoding */
#ifdef CONFIG_HUGETLB_PAGE
u16 low_htlb_areas, high_htlb_areas;
#endif
unsigned long vdso_base;
} mm_context_t;
static inline unsigned long vsid_scramble(unsigned long protovsid)
{
#if 0
/* The code below is equivalent to this function for arguments
* < 2^VSID_BITS, which is all this should ever be called
* with. However gcc is not clever enough to compute the
* modulus (2^n-1) without a second multiply. */
return ((protovsid * VSID_MULTIPLIER) % VSID_MODULUS);
#else /* 1 */
unsigned long x;
x = protovsid * VSID_MULTIPLIER;
x = (x >> VSID_BITS) + (x & VSID_MODULUS);
return (x + ((x+1) >> VSID_BITS)) & VSID_MODULUS;
#endif /* 1 */
}
/* This is only valid for addresses >= KERNELBASE */
static inline unsigned long get_kernel_vsid(unsigned long ea)
{
return vsid_scramble(ea >> SID_SHIFT);
}
/* This is only valid for user addresses (which are below 2^41) */
static inline unsigned long get_vsid(unsigned long context, unsigned long ea)
{
return vsid_scramble((context << USER_ESID_BITS)
| (ea >> SID_SHIFT));
}
#define VSID_SCRAMBLE(pvsid) (((pvsid) * VSID_MULTIPLIER) % VSID_MODULUS)
#define KERNEL_VSID(ea) VSID_SCRAMBLE(GET_ESID(ea))
/* Physical address used by some IO functions */
typedef unsigned long phys_addr_t;
#endif /* __ASSEMBLY */
#endif /* CONFIG_PPC64 */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_MMU_H_ */
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