/*
* 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.
*/
#ifndef _PPC64_MMU_H_
#define _PPC64_MMU_H_
#include <linux/config.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 0x9
#define STAB0_PHYS_ADDR (STAB0_PAGE<<PAGE_SHIFT)
#define STAB0_VIRT_ADDR (KERNELBASE+STAB0_PHYS_ADDR)
/*
* 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_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) /* largepage 16M */
#define SLB_VSID_C ASM_CONST(0x0000000000000080) /* class */
#define SLB_VSID_KERNEL (SLB_VSID_KP|SLB_VSID_C)
#define SLB_VSID_USER (SLB_VSID_KP|SLB_VSID_KS)
/*
* Hash table
*/
#define HPTES_PER_GROUP 8
/* 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__
/* Hardware Page Table Entry */
typedef struct {
unsigned long avpn:57; /* vsid | api == avpn */
unsigned long : 2; /* Software use */
unsigned long bolted: 1; /* HPTE is "bolted" */
unsigned long lock: 1; /* lock on pSeries SMP */
unsigned long l: 1; /* Virtual page is large (L=1) or 4 KB (L=0) */
unsigned long h: 1; /* Hash function identifier */
unsigned long v: 1; /* Valid (v=1) or invalid (v=0) */
} Hpte_dword0;
typedef struct {
unsigned long pp0: 1; /* Page protection bit 0 */
unsigned long ts: 1; /* Tag set bit */
unsigned long rpn: 50; /* Real page number */
unsigned long : 2; /* Reserved */
unsigned long ac: 1; /* Address compare */
unsigned long r: 1; /* Referenced */
unsigned long c: 1; /* Changed */
unsigned long w: 1; /* Write-thru cache mode */
unsigned long i: 1; /* Cache inhibited */
unsigned long m: 1; /* Memory coherence required */
unsigned long g: 1; /* Guarded */
unsigned long n: 1; /* No-execute */
unsigned long pp: 2; /* Page protection bits 1:2 */
} Hpte_dword1;
typedef struct {
char padding[6]; /* padding */
unsigned long : 6; /* padding */
unsigned long flags: 10; /* HPTE flags */
} Hpte_dword1_flags;
typedef struct {
union {
unsigned long dword0;
Hpte_dword0 dw0;
} dw0;
union {
unsigned long dword1;
Hpte_dword1 dw1;
Hpte_dword1_flags flags;
} dw1;
} HPTE;
extern HPTE * htab_address;
extern unsigned long htab_hash_mask;
static inline unsigned long hpt_hash(unsigned long vpn, int large)
{
unsigned long vsid;
unsigned long page;
if (large) {
vsid = vpn >> 4;
page = vpn & 0xf;
} else {
vsid = vpn >> 16;
page = vpn & 0xffff;
}
return (vsid & 0x7fffffffffUL) ^ page;
}
static inline void __tlbie(unsigned long va, int large)
{
/* clear top 16 bits, non SLS segment */
va &= ~(0xffffULL << 48);
if (large) {
va &= HPAGE_MASK;
asm volatile("tlbie %0,1" : : "r"(va) : "memory");
} else {
va &= PAGE_MASK;
asm volatile("tlbie %0,0" : : "r"(va) : "memory");
}
}
static inline void tlbie(unsigned long va, int large)
{
asm volatile("ptesync": : :"memory");
__tlbie(va, large);
asm volatile("eieio; tlbsync; ptesync": : :"memory");
}
static inline void __tlbiel(unsigned long va)
{
/* clear top 16 bits, non SLS segment */
va &= ~(0xffffULL << 48);
va &= PAGE_MASK;
/*
* Thanks to Alan Modra we are now able to use machine specific
* assembly instructions (like tlbiel) by using the gas -many flag.
* However we have to support older toolchains so for the moment
* we hardwire it.
*/
#if 0
asm volatile("tlbiel %0" : : "r"(va) : "memory");
#else
asm volatile(".long 0x7c000224 | (%0 << 11)" : : "r"(va) : "memory");
#endif
}
static inline void tlbiel(unsigned long va)
{
asm volatile("ptesync": : :"memory");
__tlbiel(va);
asm volatile("ptesync": : :"memory");
}
/*
* Handle a fault by adding an HPTE. If the address can't be determined
* to be valid via Linux page tables, return 1. If handled return 0
*/
extern int __hash_page(unsigned long ea, unsigned long access,
unsigned long vsid, pte_t *ptep, unsigned long trap,
int local);
extern void htab_finish_init(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,
int secondary, unsigned long hpteflags,
int bolted, int large);
extern long native_hpte_insert(unsigned long hpte_group, unsigned long va,
unsigned long prpn, int secondary,
unsigned long hpteflags, int bolted, int large);
#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 20
#define USER_ESID_BITS 15
/*
* 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;
#ifdef CONFIG_HUGETLB_PAGE
pgd_t *huge_pgdir;
u16 htlb_segs; /* bitmask */
#endif
} 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));
}
#endif /* __ASSEMBLY */
#endif /* _PPC64_MMU_H_ */
