--- /dev/null
+/*
+ * ppc64 MMU hashtable management routines
+ *
+ * (c) Copyright IBM Corp. 2003
+ *
+ * Maintained by: Benjamin Herrenschmidt
+ * <benh@kernel.crashing.org>
+ *
+ * This file is covered by the GNU Public Licence v2 as
+ * described in the kernel's COPYING file.
+ */
+
+#include <linux/config.h>
+#include <asm/processor.h>
+#include <asm/pgtable.h>
+#include <asm/mmu.h>
+#include <asm/page.h>
+#include <asm/types.h>
+#include <asm/ppc_asm.h>
+#include <asm/offsets.h>
+#include <asm/cputable.h>
+
+ .text
+
+/*
+ * Stackframe:
+ *
+ * +-> Back chain (SP + 256)
+ * | General register save area (SP + 112)
+ * | Parameter save area (SP + 48)
+ * | TOC save area (SP + 40)
+ * | link editor doubleword (SP + 32)
+ * | compiler doubleword (SP + 24)
+ * | LR save area (SP + 16)
+ * | CR save area (SP + 8)
+ * SP ---> +-- Back chain (SP + 0)
+ */
+#define STACKFRAMESIZE 256
+
+/* Save parameters offsets */
+#define STK_PARM(i) (STACKFRAMESIZE + 48 + ((i)-3)*8)
+
+/* Save non-volatile offsets */
+#define STK_REG(i) (112 + ((i)-14)*8)
+
+/*
+ * _hash_page(unsigned long ea, unsigned long access, unsigned long vsid,
+ * pte_t *ptep, unsigned long trap, int local)
+ *
+ * Adds a page to the hash table. This is the non-LPAR version for now
+ */
+
+_GLOBAL(__hash_page)
+ mflr r0
+ std r0,16(r1)
+ stdu r1,-STACKFRAMESIZE(r1)
+ /* Save all params that we need after a function call */
+ std r6,STK_PARM(r6)(r1)
+ std r8,STK_PARM(r8)(r1)
+
+ /* Add _PAGE_PRESENT to access */
+ ori r4,r4,_PAGE_PRESENT
+
+ /* Save non-volatile registers.
+ * r31 will hold "old PTE"
+ * r30 is "new PTE"
+ * r29 is "va"
+ * r28 is a hash value
+ * r27 is hashtab mask (maybe dynamic patched instead ?)
+ */
+ std r27,STK_REG(r27)(r1)
+ std r28,STK_REG(r28)(r1)
+ std r29,STK_REG(r29)(r1)
+ std r30,STK_REG(r30)(r1)
+ std r31,STK_REG(r31)(r1)
+
+ /* Step 1:
+ *
+ * Check permissions, atomically mark the linux PTE busy
+ * and hashed.
+ */
+1:
+ ldarx r31,0,r6
+ /* Check access rights (access & ~(pte_val(*ptep))) */
+ andc. r0,r4,r31
+ bne- htab_wrong_access
+ /* Check if PTE is busy */
+ andi. r0,r31,_PAGE_BUSY
+ bne- 1b
+ /* Prepare new PTE value (turn access RW into DIRTY, then
+ * add BUSY,HASHPTE and ACCESSED)
+ */
+ rlwinm r30,r4,5,24,24 /* _PAGE_RW -> _PAGE_DIRTY */
+ or r30,r30,r31
+ ori r30,r30,_PAGE_BUSY | _PAGE_ACCESSED | _PAGE_HASHPTE
+ /* Write the linux PTE atomically (setting busy) */
+ stdcx. r30,0,r6
+ bne- 1b
+
+
+ /* Step 2:
+ *
+ * Insert/Update the HPTE in the hash table. At this point,
+ * r4 (access) is re-useable, we use it for the new HPTE flags
+ */
+
+ /* Calc va and put it in r29 */
+ rldicr r29,r5,28,63-28
+ rldicl r3,r3,0,36
+ or r29,r3,r29
+
+ /* Calculate hash value for primary slot and store it in r28 */
+ rldicl r5,r5,0,25 /* vsid & 0x0000007fffffffff */
+ rldicl r0,r3,64-12,48 /* (ea >> 12) & 0xffff */
+ xor r28,r5,r0
+
+ /* Convert linux PTE bits into HW equivalents
+ */
+ andi. r3,r30,0x1fa /* Get basic set of flags */
+ rlwinm r0,r30,32-2+1,30,30 /* _PAGE_RW -> _PAGE_USER (r0) */
+ rlwinm r4,r30,32-7+1,30,30 /* _PAGE_DIRTY -> _PAGE_USER (r4) */
+ and r0,r0,r4 /* _PAGE_RW & _PAGE_DIRTY -> r0 bit 30 */
+ andc r0,r30,r0 /* r0 = pte & ~r0 */
+ rlwimi r3,r0,32-1,31,31 /* Insert result into PP lsb */
+
+ /* We eventually do the icache sync here (maybe inline that
+ * code rather than call a C function...)
+ */
+BEGIN_FTR_SECTION
+ mr r4,r30
+ mr r5,r7
+ bl .hash_page_do_lazy_icache
+END_FTR_SECTION_IFSET(CPU_FTR_NOEXECUTE)
+
+ /* At this point, r3 contains new PP bits, save them in
+ * place of "access" in the param area (sic)
+ */
+ std r3,STK_PARM(r4)(r1)
+
+ /* Get htab_hash_mask */
+ ld r4,htab_data@got(2)
+ ld r27,16(r4) /* htab_data.htab_hash_mask -> r27 */
+
+ /* Check if we may already be in the hashtable, in this case, we
+ * go to out-of-line code to try to modify the HPTE
+ */
+ andi. r0,r31,_PAGE_HASHPTE
+ bne htab_modify_pte
+
+htab_insert_pte:
+ /* Clear hpte bits in new pte (we also clear BUSY btw) and
+ * add _PAGE_HASHPTE
+ */
+ lis r0,_PAGE_HPTEFLAGS@h
+ ori r0,r0,_PAGE_HPTEFLAGS@l
+ andc r30,r30,r0
+ ori r30,r30,_PAGE_HASHPTE
+
+ /* page number in r5 */
+ rldicl r5,r31,64-PTE_SHIFT,PTE_SHIFT
+
+ /* Calculate primary group hash */
+ and r0,r28,r27
+ rldicr r3,r0,3,63-3 /* r0 = (hash & mask) << 3 */
+
+ /* Call ppc_md.hpte_insert */
+ ld r7,STK_PARM(r4)(r1) /* Retreive new pp bits */
+ mr r4,r29 /* Retreive va */
+ li r6,0 /* primary slot */
+ li r8,0 /* not bolted and not large */
+ li r9,0
+_GLOBAL(htab_call_hpte_insert1)
+ bl . /* Will be patched by htab_finish_init() */
+ cmpi 0,r3,0
+ bge htab_pte_insert_ok /* Insertion successful */
+ cmpi 0,r3,-2 /* Critical failure */
+ beq- htab_pte_insert_failure
+
+ /* Now try secondary slot */
+ ori r30,r30,_PAGE_SECONDARY
+
+ /* page number in r5 */
+ rldicl r5,r31,64-PTE_SHIFT,PTE_SHIFT
+
+ /* Calculate secondary group hash */
+ andc r0,r27,r28
+ rldicr r3,r0,3,63-3 /* r0 = (~hash & mask) << 3 */
+
+ /* Call ppc_md.hpte_insert */
+ ld r7,STK_PARM(r4)(r1) /* Retreive new pp bits */
+ mr r4,r29 /* Retreive va */
+ li r6,1 /* secondary slot */
+ li r8,0 /* not bolted and not large */
+ li r9,0
+_GLOBAL(htab_call_hpte_insert2)
+ bl . /* Will be patched by htab_finish_init() */
+ cmpi 0,r3,0
+ bge+ htab_pte_insert_ok /* Insertion successful */
+ cmpi 0,r3,-2 /* Critical failure */
+ beq- htab_pte_insert_failure
+
+ /* Both are full, we need to evict something */
+ mftb r0
+ /* Pick a random group based on TB */
+ andi. r0,r0,1
+ mr r5,r28
+ bne 2f
+ not r5,r5
+2: and r0,r5,r27
+ rldicr r3,r0,3,63-3 /* r0 = (hash & mask) << 3 */
+ /* Call ppc_md.hpte_remove */
+_GLOBAL(htab_call_hpte_remove)
+ bl . /* Will be patched by htab_finish_init() */
+
+ /* Try all again */
+ b htab_insert_pte
+
+htab_pte_insert_ok:
+ /* Insert slot number in PTE */
+ rldimi r30,r3,12,63-14
+
+ /* Write out the PTE with a normal write
+ * (maybe add eieio may be good still ?)
+ */
+htab_write_out_pte:
+ ld r6,STK_PARM(r6)(r1)
+ std r30,0(r6)
+ li r3, 0
+bail:
+ ld r27,STK_REG(r27)(r1)
+ ld r28,STK_REG(r28)(r1)
+ ld r29,STK_REG(r29)(r1)
+ ld r30,STK_REG(r30)(r1)
+ ld r31,STK_REG(r31)(r1)
+ addi r1,r1,STACKFRAMESIZE
+ ld r0,16(r1)
+ mtlr r0
+ blr
+
+htab_modify_pte:
+ /* Keep PP bits in r4 and slot idx from the PTE around in r3 */
+ mr r4,r3
+ rlwinm r3,r31,32-12,29,31
+
+ /* Secondary group ? if yes, get a inverted hash value */
+ mr r5,r28
+ andi. r0,r31,_PAGE_SECONDARY
+ beq 1f
+ not r5,r5
+1:
+ /* Calculate proper slot value for ppc_md.hpte_updatepp */
+ and r0,r5,r27
+ rldicr r0,r0,3,63-3 /* r0 = (hash & mask) << 3 */
+ add r3,r0,r3 /* add slot idx */
+
+ /* Call ppc_md.hpte_updatepp */
+ mr r5,r29 /* va */
+ li r6,0 /* large is 0 */
+ ld r7,STK_PARM(r8)(r1) /* get "local" param */
+_GLOBAL(htab_call_hpte_updatepp)
+ bl . /* Will be patched by htab_finish_init() */
+
+ /* if we failed because typically the HPTE wasn't really here
+ * we try an insertion.
+ */
+ cmpi 0,r3,-1
+ beq- htab_insert_pte
+
+ /* Clear the BUSY bit and Write out the PTE */
+ li r0,_PAGE_BUSY
+ andc r30,r30,r0
+ b htab_write_out_pte
+
+htab_wrong_access:
+ /* Bail out clearing reservation */
+ stdcx. r31,0,r6
+ li r3,1
+ b bail
+
+htab_pte_insert_failure:
+ b .htab_insert_failure
+
+
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