Subject: [PATCH V2 24/31] powerpc/mm: Convert __hash_page_64K to C

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Wed, 30 Sep 2015 07:57:17 +0530

Convert from asm to C

Signed-off-by: Aneesh Kumar K.V <[email-masked]>
---
 arch/powerpc/include/asm/book3s/64/hash-64k.h |   3 +-
 arch/powerpc/include/asm/book3s/64/hash.h     |   1 +
 arch/powerpc/mm/hash64_64k.c                  | 134 +++++++++++-
 arch/powerpc/mm/hash_low_64.S                 | 290 +-------------------------
 arch/powerpc/mm/hash_utils_64.c               |  19 +-
 5 files changed, 137 insertions(+), 310 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index b363d73ca225..f46fbd6cd837 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -35,7 +35,8 @@
 #define _PAGE_4K_PFN	0x00040000 /* PFN is for a single 4k page */
 
 /* PTE flags to conserve for HPTE identification */
-#define _PAGE_HPTEFLAGS (_PAGE_BUSY | _PAGE_HASHPTE | _PAGE_COMBO)
+#define _PAGE_HPTEFLAGS (_PAGE_BUSY | _PAGE_F_SECOND | \
+			 _PAGE_F_GIX | _PAGE_HASHPTE | _PAGE_COMBO)
 
 /* Shift to put page number into pte.
  *
diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index f5b57d1c00dc..e84987ade89c 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -86,6 +86,7 @@
 #define _PAGE_HASHPTE		0x00400 /* software: pte has an associated HPTE */
 #define _PAGE_BUSY		0x00800 /* software: PTE & hash are busy */
 #define _PAGE_F_GIX		0x07000 /* full page: hidx bits */
+#define _PAGE_F_GIX_SHIFT	12
 #define _PAGE_F_SECOND		0x08000 /* Whether to use secondary hash or not */
 #define _PAGE_SPECIAL		0x10000 /* software: special page */
 
diff --git a/arch/powerpc/mm/hash64_64k.c b/arch/powerpc/mm/hash64_64k.c
index 2beead9c760e..5736940f0b86 100644
--- a/arch/powerpc/mm/hash64_64k.c
+++ b/arch/powerpc/mm/hash64_64k.c
@@ -44,10 +44,10 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
 	real_pte_t rpte;
 	unsigned long hpte_group;
 	unsigned int subpg_index;
-	unsigned long shift = 12; /* 4K */
 	unsigned long rflags, pa, hidx;
 	unsigned long old_pte, new_pte, subpg_pte;
 	unsigned long vpn, hash, slot;
+	unsigned long shift = mmu_psize_defs[MMU_PAGE_4K].shift;
 
 	/*
 	 * atomically mark the linux large page PTE busy and dirty
@@ -212,7 +212,7 @@ repeat:
 	 * nobody is undating hidx.
 	 */
 	rpte.hidx[subpg_index] = (unsigned char)(slot << 4 | 0x1 << 3);
-	new_pte |= _PAGE_HASHPTE;
+	new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE | _PAGE_COMBO;
 	/*
 	 * check __real_pte for details on matching smp_rmb()
 	 */
@@ -220,3 +220,133 @@ repeat:
 	*ptep = __pte(new_pte & ~_PAGE_BUSY);
 	return 0;
 }
+
+int __hash_page_64K(unsigned long ea, unsigned long access,
+		    unsigned long vsid, pte_t *ptep, unsigned long trap,
+		    unsigned long flags, int ssize)
+{
+
+	unsigned long hpte_group;
+	unsigned long rflags, pa;
+	unsigned long old_pte, new_pte;
+	unsigned long vpn, hash, slot;
+	unsigned long shift = mmu_psize_defs[MMU_PAGE_64K].shift;
+
+	/*
+	 * atomically mark the linux large page PTE busy and dirty
+	 */
+	do {
+		pte_t pte = READ_ONCE(*ptep);
+
+		old_pte = pte_val(pte);
+		/* If PTE busy, retry the access */
+		if (unlikely(old_pte & _PAGE_BUSY))
+			return 0;
+		/* If PTE permissions don't match, take page fault */
+		if (unlikely(access & ~old_pte))
+			return 1;
+		/*
+		 * Check if PTE has the cache-inhibit bit set
+		 * If so, bail out and refault as a 4k page
+		 */
+		if (!mmu_has_feature(MMU_FTR_CI_LARGE_PAGE) &&
+		    unlikely(old_pte & _PAGE_NO_CACHE))
+			return 0;
+		/*
+		 * Try to lock the PTE, add ACCESSED and DIRTY if it was
+		 * a write access. Since this is 4K insert of 64K page size
+		 * also add _PAGE_COMBO
+		 */
+		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
+		if (access & _PAGE_RW)
+			new_pte |= _PAGE_DIRTY;
+	} while (old_pte != __cmpxchg_u64((unsigned long *)ptep,
+					  old_pte, new_pte));
+	/*
+	 * PP bits. _PAGE_USER is already PP bit 0x2, so we only
+	 * need to add in 0x1 if it's a read-only user page
+	 */
+	rflags = new_pte & _PAGE_USER;
+	if ((new_pte & _PAGE_USER) && !((new_pte & _PAGE_RW) &&
+					(new_pte & _PAGE_DIRTY)))
+		rflags |= 0x1;
+	/*
+	 * _PAGE_EXEC -> HW_NO_EXEC since it's inverted
+	 */
+	rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
+	/*
+	 * Always add C and Memory coherence bit
+	 */
+	rflags |= HPTE_R_C | HPTE_R_M;
+	/*
+	 * Add in WIMG bits
+	 */
+	rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
+				_PAGE_COHERENT | _PAGE_GUARDED));
+
+	if (!cpu_has_feature(CPU_FTR_NOEXECUTE) &&
+	    !cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+		rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
+
+	vpn  = hpt_vpn(ea, vsid, ssize);
+	if (unlikely(old_pte & _PAGE_HASHPTE)) {
+		/*
+		 * There MIGHT be an HPTE for this pte
+		 */
+		hash = hpt_hash(vpn, shift, ssize);
+		if (old_pte & _PAGE_F_SECOND)
+			hash = ~hash;
+		slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+		slot += (old_pte & _PAGE_F_GIX) >> _PAGE_F_GIX_SHIFT;
+
+		if (ppc_md.hpte_updatepp(slot, rflags, vpn, MMU_PAGE_64K,
+					 MMU_PAGE_64K, ssize, flags) == -1)
+			old_pte &= ~_PAGE_HPTEFLAGS;
+	}
+
+	if (likely(!(old_pte & _PAGE_HASHPTE))) {
+
+		pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
+		hash = hpt_hash(vpn, shift, ssize);
+
+repeat:
+		hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
+
+		/* Insert into the hash table, primary slot */
+		slot = ppc_md.hpte_insert(hpte_group, vpn, pa, rflags, 0,
+				  MMU_PAGE_64K, MMU_PAGE_64K, ssize);
+		/*
+		 * Primary is full, try the secondary
+		 */
+		if (unlikely(slot == -1)) {
+			hpte_group = ((~hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
+			slot = ppc_md.hpte_insert(hpte_group, vpn, pa,
+						  rflags, HPTE_V_SECONDARY,
+						  MMU_PAGE_64K, MMU_PAGE_64K, ssize);
+			if (slot == -1) {
+				if (mftb() & 0x1)
+					hpte_group = ((hash & htab_hash_mask) *
+						      HPTES_PER_GROUP) & ~0x7UL;
+				ppc_md.hpte_remove(hpte_group);
+				/*
+				 * FIXME!! Should be try the group from which we removed ?
+				 */
+				goto repeat;
+			}
+		}
+		/*
+		 * Hypervisor failure. Restore old pmd and return -1
+		 * similar to __hash_page_*
+		 */
+		if (unlikely(slot == -2)) {
+			*ptep = __pte(old_pte);
+			hash_failure_debug(ea, access, vsid, trap, ssize,
+					   MMU_PAGE_64K, MMU_PAGE_64K, old_pte);
+			return -1;
+		}
+		new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
+		new_pte |= (slot << _PAGE_F_GIX_SHIFT) & (_PAGE_F_SECOND | _PAGE_F_GIX);
+	}
+	*ptep = __pte(new_pte & ~_PAGE_BUSY);
+	return 0;
+}
diff --git a/arch/powerpc/mm/hash_low_64.S b/arch/powerpc/mm/hash_low_64.S
index 359839a57f26..f7d49cf0ccb7 100644
--- a/arch/powerpc/mm/hash_low_64.S
+++ b/arch/powerpc/mm/hash_low_64.S
@@ -328,292 +328,4 @@ htab_pte_insert_failure:
 	li	r3,-1
 	b	htab_bail
 
-#else /* CONFIG_PPC_64K_PAGES */
-
-/*****************************************************************************
- *                                                                           *
- *           64K SW & 64K HW in a 64K segment pages implementation           *
- *                                                                           *
- *****************************************************************************/
-
-_GLOBAL(__hash_page_64K)
-	mflr	r0
-	std	r0,16(r1)
-	stdu	r1,-STACKFRAMESIZE(r1)
-	/* Save all params that we need after a function call */
-	std	r6,STK_PARAM(R6)(r1)
-	std	r8,STK_PARAM(R8)(r1)
-	std	r9,STK_PARAM(R9)(r1)
-
-	/* Save non-volatile registers.
-	 * r31 will hold "old PTE"
-	 * r30 is "new PTE"
-	 * r29 is vpn
-	 * 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-	ht64_wrong_access
-	/* Check if PTE is busy */
-	andi.	r0,r31,_PAGE_BUSY
-	/* If so, just bail out and refault if needed. Someone else
-	 * is changing this PTE anyway and might hash it.
-	 */
-	bne-	ht64_bail_ok
-BEGIN_FTR_SECTION
-	/* Check if PTE has the cache-inhibit bit set */
-	andi.	r0,r31,_PAGE_NO_CACHE
-	/* If so, bail out and refault as a 4k page */
-	bne-	ht64_bail_ok
-END_MMU_FTR_SECTION_IFCLR(MMU_FTR_CI_LARGE_PAGE)
-	/* Prepare new PTE value (turn access RW into DIRTY, then
-	 * add BUSY and ACCESSED)
-	 */
-	rlwinm	r30,r4,32-9+7,31-7,31-7	/* _PAGE_RW -> _PAGE_DIRTY */
-	or	r30,r30,r31
-	ori	r30,r30,_PAGE_BUSY | _PAGE_ACCESSED
-	/* Write the linux PTE atomically (setting busy) */
-	stdcx.	r30,0,r6
-	bne-	1b
-	isync
-
-	/* 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
-	 */
-
-BEGIN_FTR_SECTION
-	cmpdi	r9,0			/* check segment size */
-	bne	3f
-END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
-	/* Calc vpn and put it in r29 */
-	sldi	r29,r5,SID_SHIFT - VPN_SHIFT
-	rldicl  r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT - VPN_SHIFT)
-	or	r29,r28,r29
-
-	/* Calculate hash value for primary slot and store it in r28
-	 * r3 = va, r5 = vsid
-	 * r0 = (va >> 16) & ((1ul << (28 - 16)) -1)
-	 */
-	rldicl	r0,r3,64-16,52
-	xor	r28,r5,r0		/* hash */
-	b	4f
-
-3:	/* Calc vpn and put it in r29 */
-	sldi	r29,r5,SID_SHIFT_1T - VPN_SHIFT
-	rldicl  r28,r3,64 - VPN_SHIFT,64 - (SID_SHIFT_1T - VPN_SHIFT)
-	or	r29,r28,r29
-	/*
-	 * calculate hash value for primary slot and
-	 * store it in r28 for 1T segment
-	 * r3 = va, r5 = vsid
-	 */
-	sldi	r28,r5,25		/* vsid << 25 */
-	/* r0 = (va >> 16) & ((1ul << (40 - 16)) -1) */
-	rldicl	r0,r3,64-16,40
-	xor	r28,r28,r5		/* vsid ^ ( vsid << 25) */
-	xor	r28,r28,r0		/* hash */
-
-	/* Convert linux PTE bits into HW equivalents */
-4:	andi.	r3,r30,0x1fe		/* Get basic set of flags */
-	xori	r3,r3,HPTE_R_N		/* _PAGE_EXEC -> NOEXEC */
-	rlwinm	r0,r30,32-9+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 */
-	/*
-	 * Always add "C" bit for perf. Memory coherence is always enabled
-	 */
-	ori	r3,r3,HPTE_R_C | HPTE_R_M
-
-	/* 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(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, 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_PARAM(R4)(r1)
-
-	/* Get htab_hash_mask */
-	ld	r4,htab_hash_mask@got(2)
-	ld	r27,0(r4)	/* 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
-	 */
-	rldicl.	r0,r31,64-12,48
-	bne	ht64_modify_pte
-
-ht64_insert_pte:
-	/* Clear hpte bits in new pte (we also clear BUSY btw) and
-	 * add _PAGE_HPTE_SUB0
-	 */
-	lis	r0,_PAGE_HPTEFLAGS@h
-	ori	r0,r0,_PAGE_HPTEFLAGS@l
-	andc	r30,r30,r0
-	ori	r30,r30,_PAGE_HASHPTE
-	/* Phyical address in r5 */
-	rldicl	r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
-	sldi	r5,r5,PAGE_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	r6,STK_PARAM(R4)(r1)	/* Retrieve new pp bits */
-	mr	r4,r29			/* Retrieve vpn */
-	li	r7,0			/* !bolted, !secondary */
-	li	r8,MMU_PAGE_64K
-	li	r9,MMU_PAGE_64K		/* actual page size */
-	ld	r10,STK_PARAM(R9)(r1)	/* segment size */
-.globl ht64_call_hpte_insert1
-ht64_call_hpte_insert1:
-	bl	.			/* patched by htab_finish_init() */
-	cmpdi	0,r3,0
-	bge	ht64_pte_insert_ok	/* Insertion successful */
-	cmpdi	0,r3,-2			/* Critical failure */
-	beq-	ht64_pte_insert_failure
-
-	/* Now try secondary slot */
-
-	/* Phyical address in r5 */
-	rldicl	r5,r31,64-PTE_RPN_SHIFT,PTE_RPN_SHIFT
-	sldi	r5,r5,PAGE_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	r6,STK_PARAM(R4)(r1)	/* Retrieve new pp bits */
-	mr	r4,r29			/* Retrieve vpn */
-	li	r7,HPTE_V_SECONDARY	/* !bolted, secondary */
-	li	r8,MMU_PAGE_64K
-	li	r9,MMU_PAGE_64K		/* actual page size */
-	ld	r10,STK_PARAM(R9)(r1)	/* segment size */
-.globl ht64_call_hpte_insert2
-ht64_call_hpte_insert2:
-	bl	.			/* patched by htab_finish_init() */
-	cmpdi	0,r3,0
-	bge+	ht64_pte_insert_ok	/* Insertion successful */
-	cmpdi	0,r3,-2			/* Critical failure */
-	beq-	ht64_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 */
-.globl ht64_call_hpte_remove
-ht64_call_hpte_remove:
-	bl	.			/* patched by htab_finish_init() */
-
-	/* Try all again */
-	b	ht64_insert_pte
-
-ht64_bail_ok:
-	li	r3,0
-	b	ht64_bail
-
-ht64_pte_insert_ok:
-	/* Insert slot number & secondary bit in PTE */
-	rldimi	r30,r3,12,63-15
-
-	/* Write out the PTE with a normal write
-	 * (maybe add eieio may be good still ?)
-	 */
-ht64_write_out_pte:
-	ld	r6,STK_PARAM(R6)(r1)
-	std	r30,0(r6)
-	li	r3, 0
-ht64_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
-
-ht64_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_F_SECOND
-	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			/* vpn */
-	li	r6,MMU_PAGE_64K		/* base page size */
-	li	r7,MMU_PAGE_64K		/* actual page size */
-	ld	r8,STK_PARAM(R9)(r1)	/* segment size */
-	ld	r9,STK_PARAM(R8)(r1)	/* get "flags" param */
-.globl ht64_call_hpte_updatepp
-ht64_call_hpte_updatepp:
-	bl	.			/* patched by htab_finish_init() */
-
-	/* if we failed because typically the HPTE wasn't really here
-	 * we try an insertion.
-	 */
-	cmpdi	0,r3,-1
-	beq-	ht64_insert_pte
-
-	/* Clear the BUSY bit and Write out the PTE */
-	li	r0,_PAGE_BUSY
-	andc	r30,r30,r0
-	b	ht64_write_out_pte
-
-ht64_wrong_access:
-	/* Bail out clearing reservation */
-	stdcx.	r31,0,r6
-	li	r3,1
-	b	ht64_bail
-
-ht64_pte_insert_failure:
-	/* Bail out restoring old PTE */
-	ld	r6,STK_PARAM(R6)(r1)
-	std	r31,0(r6)
-	li	r3,-1
-	b	ht64_bail
-
-
-#endif /* CONFIG_PPC_64K_PAGES */
+#endif
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 67e1fe696ae5..2419866671c4 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -633,28 +633,11 @@ extern u32 htab_call_hpte_insert1[];
 extern u32 htab_call_hpte_insert2[];
 extern u32 htab_call_hpte_remove[];
 extern u32 htab_call_hpte_updatepp[];
-extern u32 ht64_call_hpte_insert1[];
-extern u32 ht64_call_hpte_insert2[];
-extern u32 ht64_call_hpte_remove[];
-extern u32 ht64_call_hpte_updatepp[];
 
 static void __init htab_finish_init(void)
 {
-#ifdef CONFIG_PPC_64K_PAGES
-	patch_branch(ht64_call_hpte_insert1,
-		ppc_function_entry(ppc_md.hpte_insert),
-		BRANCH_SET_LINK);
-	patch_branch(ht64_call_hpte_insert2,
-		ppc_function_entry(ppc_md.hpte_insert),
-		BRANCH_SET_LINK);
-	patch_branch(ht64_call_hpte_remove,
-		ppc_function_entry(ppc_md.hpte_remove),
-		BRANCH_SET_LINK);
-	patch_branch(ht64_call_hpte_updatepp,
-		ppc_function_entry(ppc_md.hpte_updatepp),
-		BRANCH_SET_LINK);
-#else /* !CONFIG_PPC_64K_PAGES */
 
+#ifdef CONFIG_PPC_4K_PAGES
 	patch_branch(htab_call_hpte_insert1,
 		ppc_function_entry(ppc_md.hpte_insert),
 		BRANCH_SET_LINK);
-- 
2.5.0