[PATCH] Restore missing ppc64 hash_low.S file

This went missing somewhere.  Here's a patch which puts it back.

arch/ppc64/mm/hash_low.S

+/*
+ * 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
+
+