[POWERPC] Prepare for splitting up mmu.h by MMU type

Currently asm-powerpc/mmu.h has definitions for the 64-bit hash based
MMU.  If CONFIG_PPC64 is not set, it instead includes asm-ppc/mmu.h
which contains a particularly horrible mess of #ifdefs giving the
definitions for all the various 32-bit MMUs.

It would be nice to have the low level definitions for each MMU type
neatly in their own separate files.  It would also be good to wean
arch/powerpc off dependence on the old asm-ppc/mmu.h.

This patch makes a start on such a cleanup by moving the definitions
for the 64-bit hash MMU to their own file, asm-powerpc/mmu_hash64.h.
Definitions for the other MMUs still all come from asm-ppc/mmu.h,
however each MMU type can now be one-by-one moved over to their own
file, in the process cleaning them up stripping them of cruft no
longer necessary in arch/powerpc.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 400 insertions, 0 deletions

diff --git a/include/asm-powerpc/mmu-hash64.h b/include/asm-powerpc/mmu-hash64.h
new file mode 100644
index 00000000000..6739457d8bc
--- /dev/null
+++ b/include/asm-powerpc/mmu-hash64.h
@@ -0,0 +1,400 @@
+#ifndef _ASM_POWERPC_MMU_HASH64_H_
+#define _ASM_POWERPC_MMU_HASH64_H_
+/*
+ * PowerPC64 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_page(unsigned long ea, unsigned long access, unsigned long trap);
+extern int hash_huge_page(struct mm_struct *mm, unsigned long access,
+			  unsigned long ea, unsigned long vsid, int local,
+			  unsigned long trap);
+
+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 void hpte_init_beat(void);
+
+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 /* _ASM_POWERPC_MMU_HASH64_H_ */