diff options
Diffstat (limited to 'arch/powerpc/include/asm/mmu-hash64.h')
| -rw-r--r-- | arch/powerpc/include/asm/mmu-hash64.h | 169 |
1 files changed, 120 insertions, 49 deletions
diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h index 1c65a59..9673f73 100644 --- a/arch/powerpc/include/asm/mmu-hash64.h +++ b/arch/powerpc/include/asm/mmu-hash64.h @@ -16,6 +16,13 @@ #include <asm/page.h> /* + * This is necessary to get the definition of PGTABLE_RANGE which we + * need for various slices related matters. Note that this isn't the + * complete pgtable.h but only a portion of it. + */ +#include <asm/pgtable-ppc64.h> + +/* * Segment table */ @@ -154,9 +161,25 @@ struct mmu_psize_def #define MMU_SEGSIZE_256M 0 #define MMU_SEGSIZE_1T 1 +/* + * encode page number shift. + * in order to fit the 78 bit va in a 64 bit variable we shift the va by + * 12 bits. This enable us to address upto 76 bit va. + * For hpt hash from a va we can ignore the page size bits of va and for + * hpte encoding we ignore up to 23 bits of va. So ignoring lower 12 bits ensure + * we work in all cases including 4k page size. + */ +#define VPN_SHIFT 12 #ifndef __ASSEMBLY__ +static inline int segment_shift(int ssize) +{ + if (ssize == MMU_SEGSIZE_256M) + return SID_SHIFT; + return SID_SHIFT_1T; +} + /* * The current system page and segment sizes */ @@ -180,18 +203,39 @@ extern unsigned long tce_alloc_start, tce_alloc_end; extern int mmu_ci_restrictions; /* + * This computes the AVPN and B fields of the first dword of a HPTE, + * for use when we want to match an existing PTE. The bottom 7 bits + * of the returned value are zero. + */ +static inline unsigned long hpte_encode_avpn(unsigned long vpn, int psize, + int ssize) +{ + unsigned long v; + /* + * The AVA field omits the low-order 23 bits of the 78 bits VA. + * These bits are not needed in the PTE, because the + * low-order b of these bits are part of the byte offset + * into the virtual page and, if b < 23, the high-order + * 23-b of these bits are always used in selecting the + * PTEGs to be searched + */ + v = (vpn >> (23 - VPN_SHIFT)) & ~(mmu_psize_defs[psize].avpnm); + v <<= HPTE_V_AVPN_SHIFT; + v |= ((unsigned long) ssize) << HPTE_V_SSIZE_SHIFT; + return v; +} + +/* * 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, - int ssize) +static inline unsigned long hpte_encode_v(unsigned long vpn, + int psize, int ssize) { unsigned long v; - v = (va >> 23) & ~(mmu_psize_defs[psize].avpnm); - v <<= HPTE_V_AVPN_SHIFT; + v = hpte_encode_avpn(vpn, psize, ssize); if (psize != MMU_PAGE_4K) v |= HPTE_V_LARGE; - v |= ((unsigned long) ssize) << HPTE_V_SSIZE_SHIFT; return v; } @@ -216,30 +260,37 @@ static inline unsigned long hpte_encode_r(unsigned long pa, int psize) } /* - * Build a VA given VSID, EA and segment size + * Build a VPN_SHIFT bit shifted va given VSID, EA and segment size. */ -static inline unsigned long hpt_va(unsigned long ea, unsigned long vsid, - int ssize) +static inline unsigned long hpt_vpn(unsigned long ea, + unsigned long vsid, int ssize) { - if (ssize == MMU_SEGSIZE_256M) - return (vsid << 28) | (ea & 0xfffffffUL); - return (vsid << 40) | (ea & 0xffffffffffUL); + unsigned long mask; + int s_shift = segment_shift(ssize); + + mask = (1ul << (s_shift - VPN_SHIFT)) - 1; + return (vsid << (s_shift - VPN_SHIFT)) | ((ea >> VPN_SHIFT) & mask); } /* * This hashes a virtual address */ - -static inline unsigned long hpt_hash(unsigned long va, unsigned int shift, - int ssize) +static inline unsigned long hpt_hash(unsigned long vpn, + unsigned int shift, int ssize) { + int mask; unsigned long hash, vsid; + /* VPN_SHIFT can be atmost 12 */ if (ssize == MMU_SEGSIZE_256M) { - hash = (va >> 28) ^ ((va & 0x0fffffffUL) >> shift); + mask = (1ul << (SID_SHIFT - VPN_SHIFT)) - 1; + hash = (vpn >> (SID_SHIFT - VPN_SHIFT)) ^ + ((vpn & mask) >> (shift - VPN_SHIFT)); } else { - vsid = va >> 40; - hash = vsid ^ (vsid << 25) ^ ((va & 0xffffffffffUL) >> shift); + mask = (1ul << (SID_SHIFT_1T - VPN_SHIFT)) - 1; + vsid = vpn >> (SID_SHIFT_1T - VPN_SHIFT); + hash = vsid ^ (vsid << 25) ^ + ((vpn & mask) >> (shift - VPN_SHIFT)) ; } return hash & 0x7fffffffffUL; } @@ -280,63 +331,61 @@ extern void slb_set_size(u16 size); #endif /* __ASSEMBLY__ */ /* - * VSID allocation + * VSID allocation (256MB segment) + * + * We first generate a 38-bit "proto-VSID". For kernel addresses this + * is equal to the ESID | 1 << 37, for user addresses it is: + * (context << USER_ESID_BITS) | (esid & ((1U << USER_ESID_BITS) - 1) * - * 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) + * This splits the proto-VSID into the below range + * 0 - (2^(CONTEXT_BITS + USER_ESID_BITS) - 1) : User proto-VSID range + * 2^(CONTEXT_BITS + USER_ESID_BITS) - 2^(VSID_BITS) : Kernel proto-VSID range * - * 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. + * We also have CONTEXT_BITS + USER_ESID_BITS = VSID_BITS - 1 + * That is, we assign half of the space to user processes and half + * to the kernel. * * 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 + * 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 + * - 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 16 significant bits of ESID and 19 bits of - * context for user addresses. i.e. 16T (44 bits) of address space for - * up to half a million contexts. + * - We allow for USER_ESID_BITS significant bits of ESID and + * CONTEXT_BITS bits of context for user addresses. + * i.e. 64T (46 bits) of address space for up to half a million contexts. * - * - The scramble function gives robust scattering in the hash + * - 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. + * This should be computed such that protovosid * vsid_mulitplier + * doesn't overflow 64 bits. It should also be co-prime to vsid_modulus */ - -#define VSID_MULTIPLIER_256M ASM_CONST(200730139) /* 28-bit prime */ -#define VSID_BITS_256M 36 +#define VSID_MULTIPLIER_256M ASM_CONST(12538073) /* 24-bit prime */ +#define VSID_BITS_256M 38 #define VSID_MODULUS_256M ((1UL<<VSID_BITS_256M)-1) #define VSID_MULTIPLIER_1T ASM_CONST(12538073) /* 24-bit prime */ -#define VSID_BITS_1T 24 +#define VSID_BITS_1T 26 #define VSID_MODULUS_1T ((1UL<<VSID_BITS_1T)-1) #define CONTEXT_BITS 19 -#define USER_ESID_BITS 16 -#define USER_ESID_BITS_1T 4 +#define USER_ESID_BITS 18 +#define USER_ESID_BITS_1T 6 #define USER_VSID_RANGE (1UL << (USER_ESID_BITS + SID_SHIFT)) @@ -372,6 +421,8 @@ extern void slb_set_size(u16 size); srdi rx,rx,VSID_BITS_##size; /* extract 2^VSID_BITS bit */ \ add rt,rt,rx +/* 4 bits per slice and we have one slice per 1TB */ +#define SLICE_ARRAY_SIZE (PGTABLE_RANGE >> 41) #ifndef __ASSEMBLY__ @@ -416,7 +467,7 @@ typedef struct { #ifdef CONFIG_PPC_MM_SLICES u64 low_slices_psize; /* SLB page size encodings */ - u64 high_slices_psize; /* 4 bits per slice for now */ + unsigned char high_slices_psize[SLICE_ARRAY_SIZE]; #else u16 sllp; /* SLB page size encoding */ #endif @@ -452,12 +503,32 @@ typedef struct { }) #endif /* 1 */ -/* This is only valid for addresses >= PAGE_OFFSET */ +/* + * This is only valid for addresses >= PAGE_OFFSET + * The proto-VSID space is divided into two class + * User: 0 to 2^(CONTEXT_BITS + USER_ESID_BITS) -1 + * kernel: 2^(CONTEXT_BITS + USER_ESID_BITS) to 2^(VSID_BITS) - 1 + * + * With KERNEL_START at 0xc000000000000000, the proto vsid for + * the kernel ends up with 0xc00000000 (36 bits). With 64TB + * support we need to have kernel proto-VSID in the + * [2^37 to 2^38 - 1] range due to the increased USER_ESID_BITS. + */ static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize) { - if (ssize == MMU_SEGSIZE_256M) - return vsid_scramble(ea >> SID_SHIFT, 256M); - return vsid_scramble(ea >> SID_SHIFT_1T, 1T); + unsigned long proto_vsid; + /* + * We need to make sure proto_vsid for the kernel is + * >= 2^(CONTEXT_BITS + USER_ESID_BITS[_1T]) + */ + if (ssize == MMU_SEGSIZE_256M) { + proto_vsid = ea >> SID_SHIFT; + proto_vsid |= (1UL << (CONTEXT_BITS + USER_ESID_BITS)); + return vsid_scramble(proto_vsid, 256M); + } + proto_vsid = ea >> SID_SHIFT_1T; + proto_vsid |= (1UL << (CONTEXT_BITS + USER_ESID_BITS_1T)); + return vsid_scramble(proto_vsid, 1T); } /* Returns the segment size indicator for a user address */ |
