POWERPC: Allow 32-bit hashed pgtable code to support 36-bit physical

This rearranges a bit of code, and adds support for
36-bit physical addressing for configs that use a
hashed page table.  The 36b physical support is not
enabled by default on any config - it must be
explicitly enabled via the config system.

This patch *only* expands the page table code to accomodate
large physical addresses on 32-bit systems and enables the
PHYS_64BIT config option for 86xx.  It does *not*
allow you to boot a board with more than about 3.5GB of
RAM - for that, SWIOTLB support is also required (and
coming soon).

Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

10 files changed, 109 insertions, 33 deletions

diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index 77c7fa025e65..08266d2728b3 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -711,7 +711,7 @@ static inline void * phys_to_virt(unsigned long address)
 /*
  * Change "struct page" to physical address.
  */
-#define page_to_phys(page)      (page_to_pfn(page) << PAGE_SHIFT)
+#define page_to_phys(page)      ((phys_addr_t)page_to_pfn(page) << PAGE_SHIFT)
 
 /* We do NOT want virtual merging, it would put too much pressure on
  * our iommu allocator. Instead, we want drivers to be smart enough
diff --git a/arch/powerpc/include/asm/page_32.h b/arch/powerpc/include/asm/page_32.h
index ebfae530a379..d77072a32cc6 100644
--- a/arch/powerpc/include/asm/page_32.h
+++ b/arch/powerpc/include/asm/page_32.h
@@ -13,10 +13,16 @@
 #define ARCH_KMALLOC_MINALIGN   L1_CACHE_BYTES
 #endif
 
+#ifdef CONFIG_PTE_64BIT
+#define PTE_FLAGS_OFFSET        4       /* offset of PTE flags, in bytes */
+#else
+#define PTE_FLAGS_OFFSET        0
+#endif
+
 #ifndef __ASSEMBLY__
 /*
  * The basic type of a PTE - 64 bits for those CPUs with > 32 bit
- * physical addressing.  For now this just the IBM PPC440.
+ * physical addressing.
  */
 #ifdef CONFIG_PTE_64BIT
 typedef unsigned long long pte_basic_t;
diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h
index c2e58b41bc78..29c83d85b04f 100644
--- a/arch/powerpc/include/asm/pgtable-ppc32.h
+++ b/arch/powerpc/include/asm/pgtable-ppc32.h
@@ -369,7 +369,12 @@ extern int icache_44x_need_flush;
 #define _PAGE_RW        0x400   /* software: user write access allowed */
 #define _PAGE_SPECIAL   0x800   /* software: Special page */
 
+#ifdef CONFIG_PTE_64BIT
+/* We never clear the high word of the pte */
+#define _PTE_NONE_MASK  (0xffffffff00000000ULL | _PAGE_HASHPTE)
+#else
 #define _PTE_NONE_MASK  _PAGE_HASHPTE
+#endif
 
 #define _PMD_PRESENT    0
 #define _PMD_PRESENT_MASK (PAGE_MASK)
@@ -587,6 +592,10 @@ extern int flush_hash_pages(unsigned context, unsigned long va,
 extern void add_hash_page(unsigned context, unsigned long va,
                           unsigned long pmdval);
 
+/* Flush an entry from the TLB/hash table */
+extern void flush_hash_entry(struct mm_struct *mm, pte_t *ptep,
+                             unsigned long address);
+
 /*
  * Atomic PTE updates.
  *
@@ -665,9 +674,13 @@ static inline unsigned long long pte_update(pte_t *p,
 static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
                               pte_t *ptep, pte_t pte)
 {
-#if _PAGE_HASHPTE != 0
+#if (_PAGE_HASHPTE != 0) && defined(CONFIG_SMP) && !defined(CONFIG_PTE_64BIT)
         pte_update(ptep, ~_PAGE_HASHPTE, pte_val(pte) & ~_PAGE_HASHPTE);
 #elif defined(CONFIG_PTE_64BIT) && defined(CONFIG_SMP)
+#if _PAGE_HASHPTE != 0
+        if (pte_val(*ptep) & _PAGE_HASHPTE)
+                flush_hash_entry(mm, ptep, addr);
+#endif
         __asm__ __volatile__("\
                 stw%U0%X0 %2,%0\n\
                 eieio\n\
@@ -675,7 +688,7 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
         : "=m" (*ptep), "=m" (*((unsigned char *)ptep+4))
         : "r" (pte) : "memory");
 #else
-        *ptep = pte;
+        *ptep = (*ptep & _PAGE_HASHPTE) | (pte & ~_PAGE_HASHPTE);
 #endif
 }
 
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index e9c4044012bd..09febc582584 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -352,6 +352,7 @@ int main(void)
 #endif
 
         DEFINE(PGD_TABLE_SIZE, PGD_TABLE_SIZE);
+        DEFINE(PTE_SIZE, sizeof(pte_t));
 
 #ifdef CONFIG_KVM
         DEFINE(TLBE_BYTES, sizeof(struct tlbe));
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 8bb657519299..a6de6dbc5ed8 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -369,13 +369,13 @@ i##n:								\
 DataAccess:
         EXCEPTION_PROLOG
         mfspr   r10,SPRN_DSISR
+        stw     r10,_DSISR(r11)
         andis.  r0,r10,0xa470           /* weird error? */
         bne     1f                      /* if not, try to put a PTE */
         mfspr   r4,SPRN_DAR             /* into the hash table */
         rlwinm  r3,r10,32-15,21,21      /* DSISR_STORE -> _PAGE_RW */
         bl      hash_page
-1:      stw     r10,_DSISR(r11)
-        mr      r5,r10
+1:      lwz     r5,_DSISR(r11)          /* get DSISR value */
         mfspr   r4,SPRN_DAR
         EXC_XFER_EE_LITE(0x300, handle_page_fault)
 
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index 377e0c155c95..18c0093f9323 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -422,7 +422,6 @@ skpinv:	addi	r6,r6,1				/* Increment */
  *   r12 is pointer to the pte
  */
 #ifdef CONFIG_PTE_64BIT
-#define PTE_FLAGS_OFFSET        4
 #define FIND_PTE        \
         rlwinm  r12, r10, 13, 19, 29;   /* Compute pgdir/pmd offset */  \
         lwzx    r11, r12, r11;          /* Get pgd/pmd entry */         \
@@ -431,7 +430,6 @@ skpinv:	addi	r6,r6,1				/* Increment */
         rlwimi  r12, r10, 23, 20, 28;   /* Compute pte address */       \
         lwz     r11, 4(r12);            /* Get pte entry */
 #else
-#define PTE_FLAGS_OFFSET        0
 #define FIND_PTE        \
         rlwimi  r11, r10, 12, 20, 29;   /* Create L1 (pgdir/pmd) address */     \
         lwz     r11, 0(r11);            /* Get L1 entry */                      \
diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S
index c41d658176ac..7bffb70b9fe2 100644
--- a/arch/powerpc/mm/hash_low_32.S
+++ b/arch/powerpc/mm/hash_low_32.S
@@ -75,7 +75,7 @@ _GLOBAL(hash_page_sync)
  * Returns to the caller if the access is illegal or there is no
  * mapping for the address.  Otherwise it places an appropriate PTE
  * in the hash table and returns from the exception.
- * Uses r0, r3 - r8, ctr, lr.
+ * Uses r0, r3 - r8, r10, ctr, lr.
  */
         .text
 _GLOBAL(hash_page)
@@ -106,9 +106,15 @@ _GLOBAL(hash_page)
         addi    r5,r5,swapper_pg_dir@l  /* kernel page table */
         rlwimi  r3,r9,32-12,29,29       /* MSR_PR -> _PAGE_USER */
 112:    add     r5,r5,r7                /* convert to phys addr */
+#ifndef CONFIG_PTE_64BIT
         rlwimi  r5,r4,12,20,29          /* insert top 10 bits of address */
         lwz     r8,0(r5)                /* get pmd entry */
         rlwinm. r8,r8,0,0,19            /* extract address of pte page */
+#else
+        rlwinm  r8,r4,13,19,29          /* Compute pgdir/pmd offset */
+        lwzx    r8,r8,r5                /* Get L1 entry */
+        rlwinm. r8,r8,0,0,20            /* extract pt base address */
+#endif
 #ifdef CONFIG_SMP
         beq-    hash_page_out           /* return if no mapping */
 #else
@@ -118,7 +124,11 @@ _GLOBAL(hash_page)
            to the address following the rfi. */
         beqlr-
 #endif
+#ifndef CONFIG_PTE_64BIT
         rlwimi  r8,r4,22,20,29          /* insert next 10 bits of address */
+#else
+        rlwimi  r8,r4,23,20,28          /* compute pte address */
+#endif
         rlwinm  r0,r3,32-3,24,24        /* _PAGE_RW access -> _PAGE_DIRTY */
         ori     r0,r0,_PAGE_ACCESSED|_PAGE_HASHPTE
 
@@ -127,9 +137,15 @@ _GLOBAL(hash_page)
          * because almost always, there won't be a permission violation
          * and there won't already be an HPTE, and thus we will have
          * to update the PTE to set _PAGE_HASHPTE.  -- paulus.
+         *
+         * If PTE_64BIT is set, the low word is the flags word; use that
+         * word for locking since it contains all the interesting bits.
          */
+#if (PTE_FLAGS_OFFSET != 0)
+        addi    r8,r8,PTE_FLAGS_OFFSET
+#endif
 retry:
-        lwarx   r6,0,r8                 /* get linux-style pte */
+        lwarx   r6,0,r8                 /* get linux-style pte, flag word */
         andc.   r5,r3,r6                /* check access & ~permission */
 #ifdef CONFIG_SMP
         bne-    hash_page_out           /* return if access not permitted */
@@ -137,6 +153,15 @@ retry:
         bnelr-
 #endif
         or      r5,r0,r6                /* set accessed/dirty bits */
+#ifdef CONFIG_PTE_64BIT
+#ifdef CONFIG_SMP
+        subf    r10,r6,r8               /* create false data dependency */
+        subi    r10,r10,PTE_FLAGS_OFFSET
+        lwzx    r10,r6,r10              /* Get upper PTE word */
+#else
+        lwz     r10,-PTE_FLAGS_OFFSET(r8)
+#endif /* CONFIG_SMP */
+#endif /* CONFIG_PTE_64BIT */
         stwcx.  r5,0,r8                 /* attempt to update PTE */
         bne-    retry                   /* retry if someone got there first */
 
@@ -203,9 +228,9 @@ _GLOBAL(add_hash_page)
          * we can't take a hash table miss (assuming the code is
          * covered by a BAT).  -- paulus
          */
-        mfmsr   r10
+        mfmsr   r9
         SYNC
-        rlwinm  r0,r10,0,17,15          /* clear bit 16 (MSR_EE) */
+        rlwinm  r0,r9,0,17,15           /* clear bit 16 (MSR_EE) */
         rlwinm  r0,r0,0,28,26           /* clear MSR_DR */
         mtmsr   r0
         SYNC_601
@@ -214,14 +239,14 @@ _GLOBAL(add_hash_page)
         tophys(r7,0)
 
 #ifdef CONFIG_SMP
-        addis   r9,r7,mmu_hash_lock@ha
-        addi    r9,r9,mmu_hash_lock@l
-10:     lwarx   r0,0,r9                 /* take the mmu_hash_lock */
+        addis   r6,r7,mmu_hash_lock@ha
+        addi    r6,r6,mmu_hash_lock@l
+10:     lwarx   r0,0,r6                 /* take the mmu_hash_lock */
         cmpi    0,r0,0
         bne-    11f
-        stwcx.  r8,0,r9
+        stwcx.  r8,0,r6
         beq+    12f
-11:     lwz     r0,0(r9)
+11:     lwz     r0,0(r6)
         cmpi    0,r0,0
         beq     10b
         b       11b
@@ -234,10 +259,24 @@ _GLOBAL(add_hash_page)
          * HPTE, so we just unlock and return.
          */
         mr      r8,r5
+#ifndef CONFIG_PTE_64BIT
         rlwimi  r8,r4,22,20,29
+#else
+        rlwimi  r8,r4,23,20,28
+        addi    r8,r8,PTE_FLAGS_OFFSET
+#endif
 1:      lwarx   r6,0,r8
         andi.   r0,r6,_PAGE_HASHPTE
         bne     9f                      /* if HASHPTE already set, done */
+#ifdef CONFIG_PTE_64BIT
+#ifdef CONFIG_SMP
+        subf    r10,r6,r8               /* create false data dependency */
+        subi    r10,r10,PTE_FLAGS_OFFSET
+        lwzx    r10,r6,r10              /* Get upper PTE word */
+#else
+        lwz     r10,-PTE_FLAGS_OFFSET(r8)
+#endif /* CONFIG_SMP */
+#endif /* CONFIG_PTE_64BIT */
         ori     r5,r6,_PAGE_HASHPTE
         stwcx.  r5,0,r8
         bne-    1b
@@ -246,13 +285,15 @@ _GLOBAL(add_hash_page)
 
 9:
 #ifdef CONFIG_SMP
+        addis   r6,r7,mmu_hash_lock@ha
+        addi    r6,r6,mmu_hash_lock@l
         eieio
         li      r0,0
-        stw     r0,0(r9)                /* clear mmu_hash_lock */
+        stw     r0,0(r6)                /* clear mmu_hash_lock */
 #endif
 
         /* reenable interrupts and DR */
-        mtmsr   r10
+        mtmsr   r9
         SYNC_601
         isync
 
@@ -267,7 +308,8 @@ _GLOBAL(add_hash_page)
  * r5 contains the linux PTE, r6 contains the old value of the
  * linux PTE (before setting _PAGE_HASHPTE) and r7 contains the
  * offset to be added to addresses (0 if the MMU is on,
- * -KERNELBASE if it is off).
+ * -KERNELBASE if it is off).  r10 contains the upper half of
+ * the PTE if CONFIG_PTE_64BIT.
  * On SMP, the caller should have the mmu_hash_lock held.
  * We assume that the caller has (or will) set the _PAGE_HASHPTE
  * bit in the linux PTE in memory.  The value passed in r6 should
@@ -313,6 +355,11 @@ _GLOBAL(create_hpte)
 BEGIN_FTR_SECTION
         ori     r8,r8,_PAGE_COHERENT    /* set M (coherence required) */
 END_FTR_SECTION_IFSET(CPU_FTR_NEED_COHERENT)
+#ifdef CONFIG_PTE_64BIT
+        /* Put the XPN bits into the PTE */
+        rlwimi  r8,r10,8,20,22
+        rlwimi  r8,r10,2,29,29
+#endif
 
         /* Construct the high word of the PPC-style PTE (r5) */
         rlwinm  r5,r3,7,1,24            /* put VSID in 0x7fffff80 bits */
@@ -499,14 +546,18 @@ _GLOBAL(flush_hash_pages)
         isync
 
         /* First find a PTE in the range that has _PAGE_HASHPTE set */
+#ifndef CONFIG_PTE_64BIT
         rlwimi  r5,r4,22,20,29
-1:      lwz     r0,0(r5)
+#else
+        rlwimi  r5,r4,23,20,28
+#endif
+1:      lwz     r0,PTE_FLAGS_OFFSET(r5)
         cmpwi   cr1,r6,1
         andi.   r0,r0,_PAGE_HASHPTE
         bne     2f
         ble     cr1,19f
         addi    r4,r4,0x1000
-        addi    r5,r5,4
+        addi    r5,r5,PTE_SIZE
         addi    r6,r6,-1
         b       1b
 
@@ -545,7 +596,10 @@ _GLOBAL(flush_hash_pages)
          * already clear, we're done (for this pte).  If not,
          * clear it (atomically) and proceed.  -- paulus.
          */
-33:     lwarx   r8,0,r5                 /* fetch the pte */
+#if (PTE_FLAGS_OFFSET != 0)
+        addi    r5,r5,PTE_FLAGS_OFFSET
+#endif
+33:     lwarx   r8,0,r5                 /* fetch the pte flags word */
         andi.   r0,r8,_PAGE_HASHPTE
         beq     8f                      /* done if HASHPTE is already clear */
         rlwinm  r8,r8,0,31,29           /* clear HASHPTE bit */
@@ -590,7 +644,7 @@ _GLOBAL(flush_hash_patch_B)
 
 8:      ble     cr1,9f                  /* if all ptes checked */
 81:     addi    r6,r6,-1
-        addi    r5,r5,4                 /* advance to next pte */
+        addi    r5,r5,PTE_SIZE
         addi    r4,r4,0x1000
         lwz     r0,0(r5)                /* check next pte */
         cmpwi   cr1,r6,1
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 2001abdb1912..c31d6d26f0b5 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -73,7 +73,7 @@ extern unsigned long p_mapped_by_tlbcam(unsigned long pa);
 #endif /* HAVE_TLBCAM */
 
 #ifdef CONFIG_PTE_64BIT
-/* 44x uses an 8kB pgdir because it has 8-byte Linux PTEs. */
+/* Some processors use an 8kB pgdir because they have 8-byte Linux PTEs. */
 #define PGDIR_ORDER     1
 #else
 #define PGDIR_ORDER     0
@@ -288,7 +288,7 @@ int map_page(unsigned long va, phys_addr_t pa, int flags)
 }
 
 /*
- * Map in all of physical memory starting at KERNELBASE.
+ * Map in a big chunk of physical memory starting at KERNELBASE.
  */
 void __init mapin_ram(void)
 {
diff --git a/arch/powerpc/mm/tlb_32.c b/arch/powerpc/mm/tlb_32.c
index eb4b512d65fa..f9a47fee3927 100644
--- a/arch/powerpc/mm/tlb_32.c
+++ b/arch/powerpc/mm/tlb_32.c
@@ -45,6 +45,7 @@ void flush_hash_entry(struct mm_struct *mm, pte_t *ptep, unsigned long addr)
                 flush_hash_pages(mm->context.id, addr, ptephys, 1);
         }
 }
+EXPORT_SYMBOL(flush_hash_entry);
 
 /*
  * Called by ptep_set_access_flags, must flush on CPUs for which the
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 7f6512733862..439c5ba34ecf 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -50,6 +50,7 @@ config 44x
         select PPC_UDBG_16550
         select 4xx_SOC
         select PPC_PCI_CHOICE
+        select PHYS_64BIT
 
 config E200
         bool "Freescale e200"
@@ -128,18 +129,20 @@ config FSL_EMB_PERFMON
 
 config PTE_64BIT
         bool
-        depends on 44x || E500
-        default y if 44x
-        default y if E500 && PHYS_64BIT
+        depends on 44x || E500 || PPC_86xx
+        default y if PHYS_64BIT
 
 config PHYS_64BIT
-        bool 'Large physical address support' if E500
-        depends on 44x || E500
+        bool 'Large physical address support' if E500 || PPC_86xx
+        depends on (44x || E500 || PPC_86xx) && !PPC_83xx && !PPC_82xx
         select RESOURCES_64BIT
-        default y if 44x
         ---help---
           This option enables kernel support for larger than 32-bit physical
-          addresses.  This features is not be available on all e500 cores.
+          addresses.  This feature may not be available on all cores.
+
+          If you have more than 3.5GB of RAM or so, you also need to enable
+          SWIOTLB under Kernel Options for this to work.  The actual number
+          is platform-dependent.
 
           If in doubt, say N here.