From 8b234274418d6d79527c4ac3a72da446ca4cb35f Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@sunset.davemloft.net>
Date: Fri, 17 Feb 2006 18:01:02 -0800
Subject: [PATCH] [SPARC64]: More TLB/TSB handling fixes.

The SUN4V convention with non-shared TSBs is that the context
bit of the TAG is clear.  So we have to choose an "invalid"
bit and initialize new TSBs appropriately.  Otherwise a zero
TAG looks "valid".

Make sure, for the window fixup cases, that we use the right
global registers and that we don't potentially trample on
the live global registers in etrap/rtrap handling (%g2 and
%g6) and that we put the missing virtual address properly
in %g5.

Signed-off-by: David S. Miller <davem@davemloft.net>
---
 arch/sparc64/kernel/dtlb_miss.S      |  4 +--
 arch/sparc64/kernel/itlb_miss.S      | 12 ++++-----
 arch/sparc64/kernel/ktlb.S           | 14 ++++++----
 arch/sparc64/kernel/sun4v_tlb_miss.S | 39 +++++++++++++++-------------
 arch/sparc64/kernel/tsb.S            | 17 +++++++-----
 arch/sparc64/mm/init.c               |  4 ++-
 arch/sparc64/mm/tsb.c                | 25 +++++++++---------
 include/asm-sparc64/tsb.h            |  8 ++++++
 include/asm-sparc64/ttable.h         | 12 ++++-----
 9 files changed, 78 insertions(+), 57 deletions(-)

diff --git a/arch/sparc64/kernel/dtlb_miss.S b/arch/sparc64/kernel/dtlb_miss.S
index 2ef6f6e6e72b..09a6a15a7105 100644
--- a/arch/sparc64/kernel/dtlb_miss.S
+++ b/arch/sparc64/kernel/dtlb_miss.S
@@ -2,10 +2,10 @@
 	ldxa	[%g0] ASI_DMMU_TSB_8KB_PTR, %g1	! Get TSB 8K pointer
 	ldxa	[%g0] ASI_DMMU, %g6		! Get TAG TARGET
 	srlx	%g6, 48, %g5			! Get context
+	sllx	%g6, 22, %g6			! Zero out context
 	brz,pn	%g5, kvmap_dtlb			! Context 0 processing
-	 nop					! Delay slot (fill me)
+	 srlx	%g6, 22, %g6			! Delay slot
 	TSB_LOAD_QUAD(%g1, %g4)			! Load TSB entry
-	nop					! Push branch to next I$ line
 	cmp	%g4, %g6			! Compare TAG
 
 /* DTLB ** ICACHE line 2: TSB compare and TLB load	*/
diff --git a/arch/sparc64/kernel/itlb_miss.S b/arch/sparc64/kernel/itlb_miss.S
index 730caa4a1506..6dfe3968c379 100644
--- a/arch/sparc64/kernel/itlb_miss.S
+++ b/arch/sparc64/kernel/itlb_miss.S
@@ -2,25 +2,25 @@
 	ldxa	[%g0] ASI_IMMU_TSB_8KB_PTR, %g1	! Get TSB 8K pointer
 	ldxa	[%g0] ASI_IMMU, %g6		! Get TAG TARGET
 	srlx	%g6, 48, %g5			! Get context
+	sllx	%g6, 22, %g6			! Zero out context
 	brz,pn	%g5, kvmap_itlb			! Context 0 processing
-	 nop					! Delay slot (fill me)
+	 srlx	%g6, 22, %g6			! Delay slot
 	TSB_LOAD_QUAD(%g1, %g4)			! Load TSB entry
 	cmp	%g4, %g6			! Compare TAG
-	sethi	%hi(PAGE_EXEC), %g4		! Setup exec check
 
 /* ITLB ** ICACHE line 2: TSB compare and TLB load	*/
+	sethi	%hi(PAGE_EXEC), %g4		! Setup exec check
 	ldx	[%g4 + %lo(PAGE_EXEC)], %g4
 	bne,pn	%xcc, tsb_miss_itlb		! Miss
 	 mov	FAULT_CODE_ITLB, %g3
 	andcc	%g5, %g4, %g0			! Executable?
 	be,pn	%xcc, tsb_do_fault
 	 nop					! Delay slot, fill me
-	stxa	%g5, [%g0] ASI_ITLB_DATA_IN	! Load TLB
-	retry					! Trap done
+	nop
 
 /* ITLB ** ICACHE line 3: 				*/
-	nop
-	nop
+	stxa	%g5, [%g0] ASI_ITLB_DATA_IN	! Load TLB
+	retry					! Trap done
 	nop
 	nop
 	nop
diff --git a/arch/sparc64/kernel/ktlb.S b/arch/sparc64/kernel/ktlb.S
index 47dfd45971e8..ac29da915d09 100644
--- a/arch/sparc64/kernel/ktlb.S
+++ b/arch/sparc64/kernel/ktlb.S
@@ -52,8 +52,10 @@ kvmap_itlb_vmalloc_addr:
 
 	/* Load and check PTE.  */
 	ldxa		[%g5] ASI_PHYS_USE_EC, %g5
+	mov		1, %g7
+	sllx		%g7, TSB_TAG_INVALID_BIT, %g7
 	brgez,a,pn	%g5, kvmap_itlb_longpath
-	 KTSB_STORE(%g1, %g0)
+	 KTSB_STORE(%g1, %g7)
 
 	KTSB_WRITE(%g1, %g5, %g6)
 
@@ -146,8 +148,10 @@ kvmap_dtlb_vmalloc_addr:
 
 	/* Load and check PTE.  */
 	ldxa		[%g5] ASI_PHYS_USE_EC, %g5
+	mov		1, %g7
+	sllx		%g7, TSB_TAG_INVALID_BIT, %g7
 	brgez,a,pn	%g5, kvmap_dtlb_longpath
-	 KTSB_STORE(%g1, %g0)
+	 KTSB_STORE(%g1, %g7)
 
 	KTSB_WRITE(%g1, %g5, %g6)
 
@@ -215,8 +219,8 @@ kvmap_dtlb_longpath:
 	wrpr	%g5, PSTATE_AG | PSTATE_MG, %pstate
 	.section .sun4v_2insn_patch, "ax"
 	.word	661b
-	nop
-	nop
+	SET_GL(1)
+	ldxa		[%g0] ASI_SCRATCHPAD, %g5
 	.previous
 
 	rdpr	%tl, %g3
@@ -226,7 +230,7 @@ kvmap_dtlb_longpath:
 	ldxa	[%g4] ASI_DMMU, %g5
 	.section .sun4v_2insn_patch, "ax"
 	.word	661b
-	mov	%g4, %g5
+	ldx	[%g5 + HV_FAULT_D_ADDR_OFFSET], %g5
 	nop
 	.previous
 
diff --git a/arch/sparc64/kernel/sun4v_tlb_miss.S b/arch/sparc64/kernel/sun4v_tlb_miss.S
index 244d50de8499..57ccdaec7ccb 100644
--- a/arch/sparc64/kernel/sun4v_tlb_miss.S
+++ b/arch/sparc64/kernel/sun4v_tlb_miss.S
@@ -16,15 +16,14 @@
 	ldx	[BASE + HV_FAULT_D_ADDR_OFFSET], VADDR; \
 	ldx	[BASE + HV_FAULT_D_CTX_OFFSET], CTX;
 
-	/* DEST = (CTX << 48) | (VADDR >> 22)
+	/* DEST = (VADDR >> 22)
 	 *
 	 * Branch to ZERO_CTX_LABEL is context is zero.
 	 */
-#define	COMPUTE_TAG_TARGET(DEST, VADDR, CTX, TMP, ZERO_CTX_LABEL) \
-	srlx	VADDR, 22, TMP; \
-	sllx	CTX, 48, DEST; \
+#define	COMPUTE_TAG_TARGET(DEST, VADDR, CTX, ZERO_CTX_LABEL) \
+	srlx	VADDR, 22, DEST; \
 	brz,pn	CTX, ZERO_CTX_LABEL; \
-	 or	DEST, TMP, DEST;
+	 nop;
 
 	/* Create TSB pointer.  This is something like:
 	 *
@@ -53,7 +52,7 @@ sun4v_itlb_miss:
 	ldxa	[%g1] ASI_SCRATCHPAD, %g1
 
 	LOAD_ITLB_INFO(%g2, %g4, %g5)
-	COMPUTE_TAG_TARGET(%g6, %g4, %g5, %g3, kvmap_itlb_4v)
+	COMPUTE_TAG_TARGET(%g6, %g4, %g5, kvmap_itlb_4v)
 	COMPUTE_TSB_PTR(%g1, %g4, %g3, %g7)
 
 	/* Load TSB tag/pte into %g2/%g3 and compare the tag.  */
@@ -72,15 +71,15 @@ sun4v_itlb_miss:
 	 *
 	 * %g3:	PTE
 	 * %g4:	vaddr
-	 * %g6:	TAG TARGET (only "CTX << 48" part matters)
 	 */
 sun4v_itlb_load:
+	ldxa	[%g0] ASI_SCRATCHPAD, %g6
 	mov	%o0, %g1		! save %o0
 	mov	%o1, %g2		! save %o1
 	mov	%o2, %g5		! save %o2
 	mov	%o3, %g7		! save %o3
 	mov	%g4, %o0		! vaddr
-	srlx	%g6, 48, %o1		! ctx
+	ldx	[%g6 + HV_FAULT_I_CTX_OFFSET], %o1	! ctx
 	mov	%g3, %o2		! PTE
 	mov	HV_MMU_IMMU, %o3	! flags
 	ta	HV_MMU_MAP_ADDR_TRAP
@@ -101,7 +100,7 @@ sun4v_dtlb_miss:
 	ldxa	[%g1] ASI_SCRATCHPAD, %g1
 
 	LOAD_DTLB_INFO(%g2, %g4, %g5)
-	COMPUTE_TAG_TARGET(%g6, %g4, %g5, %g3, kvmap_dtlb_4v)
+	COMPUTE_TAG_TARGET(%g6, %g4, %g5, kvmap_dtlb_4v)
 	COMPUTE_TSB_PTR(%g1, %g4, %g3, %g7)
 
 	/* Load TSB tag/pte into %g2/%g3 and compare the tag.  */
@@ -115,15 +114,15 @@ sun4v_dtlb_miss:
 	 *
 	 * %g3:	PTE
 	 * %g4:	vaddr
-	 * %g6:	TAG TARGET (only "CTX << 48" part matters)
 	 */
 sun4v_dtlb_load:
+	ldxa	[%g0] ASI_SCRATCHPAD, %g6
 	mov	%o0, %g1		! save %o0
 	mov	%o1, %g2		! save %o1
 	mov	%o2, %g5		! save %o2
 	mov	%o3, %g7		! save %o3
 	mov	%g4, %o0		! vaddr
-	srlx	%g6, 48, %o1		! ctx
+	ldx	[%g6 + HV_FAULT_D_CTX_OFFSET], %o1	! ctx
 	mov	%g3, %o2		! PTE
 	mov	HV_MMU_DMMU, %o3	! flags
 	ta	HV_MMU_MAP_ADDR_TRAP
@@ -136,16 +135,18 @@ sun4v_dtlb_load:
 	retry
 
 sun4v_dtlb_prot:
+	SET_GL(1)
+
 	/* Load MMU Miss base into %g2.  */
-	ldxa	[%g0] ASI_SCRATCHPAD, %g2
+	ldxa	[%g0] ASI_SCRATCHPAD, %g5
 	
-	ldx	[%g2 + HV_FAULT_D_ADDR_OFFSET], %g5
+	ldx	[%g5 + HV_FAULT_D_ADDR_OFFSET], %g5
 	rdpr	%tl, %g1
 	cmp	%g1, 1
-	bgu,pn		%xcc, winfix_trampoline
+	bgu,pn	%xcc, winfix_trampoline
 	 nop
-	ba,pt		%xcc, sparc64_realfault_common
-	 mov		FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4
+	ba,pt	%xcc, sparc64_realfault_common
+	 mov	FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4
 
 	/* Called from trap table with TAG TARGET placed into
 	 * %g6, SCRATCHPAD_UTSBREG1 contents in %g1, and
@@ -189,7 +190,8 @@ sun4v_itlb_error:
 	sethi	%hi(sun4v_err_itlb_vaddr), %g1
 	stx	%g4, [%g1 + %lo(sun4v_err_itlb_vaddr)]
 	sethi	%hi(sun4v_err_itlb_ctx), %g1
-	srlx	%g6, 48, %o1		! ctx
+	ldxa	[%g0] ASI_SCRATCHPAD, %g6
+	ldx	[%g6 + HV_FAULT_I_CTX_OFFSET], %o1
 	stx	%o1, [%g1 + %lo(sun4v_err_itlb_ctx)]
 	sethi	%hi(sun4v_err_itlb_pte), %g1
 	stx	%g3, [%g1 + %lo(sun4v_err_itlb_pte)]
@@ -214,7 +216,8 @@ sun4v_dtlb_error:
 	sethi	%hi(sun4v_err_dtlb_vaddr), %g1
 	stx	%g4, [%g1 + %lo(sun4v_err_dtlb_vaddr)]
 	sethi	%hi(sun4v_err_dtlb_ctx), %g1
-	srlx	%g6, 48, %o1		! ctx
+	ldxa	[%g0] ASI_SCRATCHPAD, %g6
+	ldx	[%g6 + HV_FAULT_D_CTX_OFFSET], %o1
 	stx	%o1, [%g1 + %lo(sun4v_err_dtlb_ctx)]
 	sethi	%hi(sun4v_err_dtlb_pte), %g1
 	stx	%g3, [%g1 + %lo(sun4v_err_dtlb_pte)]
diff --git a/arch/sparc64/kernel/tsb.S b/arch/sparc64/kernel/tsb.S
index a17259cf34b8..cc225c0563c3 100644
--- a/arch/sparc64/kernel/tsb.S
+++ b/arch/sparc64/kernel/tsb.S
@@ -36,7 +36,7 @@ tsb_miss_itlb:
 	/* At this point we have:
 	 * %g4 --	missing virtual address
 	 * %g1 --	TSB entry address
-	 * %g6 --	TAG TARGET ((vaddr >> 22) | (ctx << 48))
+	 * %g6 --	TAG TARGET (vaddr >> 22)
 	 */
 tsb_miss_page_table_walk:
 	TRAP_LOAD_PGD_PHYS(%g7, %g5)
@@ -50,8 +50,10 @@ tsb_reload:
 
 	/* Load and check PTE.  */
 	ldxa		[%g5] ASI_PHYS_USE_EC, %g5
+	mov		1, %g7
+	sllx		%g7, TSB_TAG_INVALID_BIT, %g7
 	brgez,a,pn	%g5, tsb_do_fault
-	 TSB_STORE(%g1, %g0)
+	 TSB_STORE(%g1, %g7)
 
 	/* If it is larger than the base page size, don't
 	 * bother putting it into the TSB.
@@ -62,8 +64,10 @@ tsb_reload:
 	sethi		%hi(_PAGE_SZBITS), %g7
 	ldx		[%g7 + %lo(_PAGE_SZBITS)], %g7
 	cmp		%g2, %g7
+	mov		1, %g7
+	sllx		%g7, TSB_TAG_INVALID_BIT, %g7
 	bne,a,pn	%xcc, tsb_tlb_reload
-	 TSB_STORE(%g1, %g0)
+	 TSB_STORE(%g1, %g7)
 
 	TSB_WRITE(%g1, %g5, %g6)
 
@@ -136,7 +140,7 @@ tsb_do_fault:
 	.section	.sun4v_2insn_patch, "ax"
 	.word		661b
 	SET_GL(1)
-	ldxa		[%g0] ASI_SCRATCHPAD, %g2
+	ldxa		[%g0] ASI_SCRATCHPAD, %g4
 	.previous
 
 	bne,pn		%xcc, tsb_do_itlb_fault
@@ -150,7 +154,7 @@ tsb_do_dtlb_fault:
 	ldxa	[%g4] ASI_DMMU, %g5
 	.section .sun4v_2insn_patch, "ax"
 	.word	661b
-	ldx	[%g2 + HV_FAULT_D_ADDR_OFFSET], %g5
+	ldx	[%g4 + HV_FAULT_D_ADDR_OFFSET], %g5
 	nop
 	.previous
 
@@ -217,8 +221,9 @@ tsb_flush:
 	bne,pn	%icc, 1b
 	 membar	#LoadLoad
 	cmp	%g1, %o1
+	mov	1, %o3
 	bne,pt	%xcc, 2f
-	 clr	%o3
+	 sllx	%o3, TSB_TAG_INVALID_BIT, %o3
 	TSB_CAS_TAG(%o0, %g1, %o3)
 	cmp	%g1, %o3
 	bne,pn	%xcc, 1b
diff --git a/arch/sparc64/mm/init.c b/arch/sparc64/mm/init.c
index bd9e3205674b..aa2aec6373c3 100644
--- a/arch/sparc64/mm/init.c
+++ b/arch/sparc64/mm/init.c
@@ -296,7 +296,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t p
 
 		tsb = &mm->context.tsb[(address >> PAGE_SHIFT) &
 				       (mm->context.tsb_nentries - 1UL)];
-		tag = (address >> 22UL) | CTX_HWBITS(mm->context) << 48UL;
+		tag = (address >> 22UL);
 		tsb_insert(tsb, tag, pte_val(pte));
 	}
 }
@@ -1110,6 +1110,8 @@ void __init paging_init(void)
 	kern_base = (prom_boot_mapping_phys_low >> 22UL) << 22UL;
 	kern_size = (unsigned long)&_end - (unsigned long)KERNBASE;
 
+	memset(swapper_tsb, 0x40, sizeof(swapper_tsb));
+
 	if (tlb_type == hypervisor)
 		sun4v_pgprot_init();
 	else
diff --git a/arch/sparc64/mm/tsb.c b/arch/sparc64/mm/tsb.c
index 3c1ff05038b1..353cb060561b 100644
--- a/arch/sparc64/mm/tsb.c
+++ b/arch/sparc64/mm/tsb.c
@@ -20,9 +20,9 @@ static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long nentries
 	return vaddr & (nentries - 1);
 }
 
-static inline int tag_compare(unsigned long tag, unsigned long vaddr, unsigned long context)
+static inline int tag_compare(unsigned long tag, unsigned long vaddr)
 {
-	return (tag == ((vaddr >> 22) | (context << 48)));
+	return (tag == (vaddr >> 22));
 }
 
 /* TSB flushes need only occur on the processor initiating the address
@@ -38,8 +38,8 @@ void flush_tsb_kernel_range(unsigned long start, unsigned long end)
 		unsigned long hash = tsb_hash(v, KERNEL_TSB_NENTRIES);
 		struct tsb *ent = &swapper_tsb[hash];
 
-		if (tag_compare(ent->tag, v, 0)) {
-			ent->tag = 0UL;
+		if (tag_compare(ent->tag, v)) {
+			ent->tag = (1UL << TSB_TAG_INVALID_BIT);
 			membar_storeload_storestore();
 		}
 	}
@@ -50,14 +50,9 @@ void flush_tsb_user(struct mmu_gather *mp)
 	struct mm_struct *mm = mp->mm;
 	struct tsb *tsb = mm->context.tsb;
 	unsigned long nentries = mm->context.tsb_nentries;
-	unsigned long ctx, base;
+	unsigned long base;
 	int i;
 
-	if (unlikely(!CTX_VALID(mm->context)))
-		return;
-
-	ctx = CTX_HWBITS(mm->context);
-
 	if (tlb_type == cheetah_plus || tlb_type == hypervisor)
 		base = __pa(tsb);
 	else
@@ -71,7 +66,7 @@ void flush_tsb_user(struct mmu_gather *mp)
 
 		hash = tsb_hash(v, nentries);
 		ent = base + (hash * sizeof(struct tsb));
-		tag = (v >> 22UL) | (ctx << 48UL);
+		tag = (v >> 22UL);
 
 		tsb_flush(ent, tag);
 	}
@@ -243,7 +238,8 @@ static void copy_tsb(struct tsb *old_tsb, unsigned long old_size,
 				  "i" (ASI_NUCLEUS_QUAD_LDD));
 		}
 
-		if (!tag || (tag & (1UL << TSB_TAG_LOCK_BIT)))
+		if (tag & ((1UL << TSB_TAG_LOCK_BIT) |
+			   (1UL << TSB_TAG_INVALID_BIT)))
 			continue;
 
 		/* We only put base page size PTEs into the TSB,
@@ -315,10 +311,13 @@ void tsb_grow(struct mm_struct *mm, unsigned long rss, gfp_t gfp_flags)
 			break;
 	}
 
-	page = alloc_pages(gfp_flags | __GFP_ZERO, get_order(size));
+	page = alloc_pages(gfp_flags, get_order(size));
 	if (unlikely(!page))
 		return;
 
+	/* Mark all tags as invalid.  */
+	memset(page_address(page), 0x40, size);
+
 	if (size == max_tsb_size)
 		mm->context.tsb_rss_limit = ~0UL;
 	else
diff --git a/include/asm-sparc64/tsb.h b/include/asm-sparc64/tsb.h
index 7f3abc32c4dd..6e6768067e38 100644
--- a/include/asm-sparc64/tsb.h
+++ b/include/asm-sparc64/tsb.h
@@ -12,6 +12,8 @@
  *
  * 	ldxa		[%g0] ASI_{D,I}MMU_TSB_8KB_PTR, %g1
  * 	ldxa		[%g0] ASI_{D,I}MMU, %g6
+ *	sllx		%g6, 22, %g6
+ *	srlx		%g6, 22, %g6
  * 	ldda		[%g1] ASI_NUCLEUS_QUAD_LDD, %g4
  * 	cmp		%g4, %g6
  * 	bne,pn	%xcc, tsb_miss_{d,i}tlb
@@ -29,6 +31,9 @@
  * -------------------------------------------------
  *  63 61 60      48 47 42 41                     0
  *
+ * But actually, since we use per-mm TSB's, we zero out the CONTEXT
+ * field.
+ *
  * Like the powerpc hashtables we need to use locking in order to
  * synchronize while we update the entries.  PTE updates need locking
  * as well.
@@ -42,6 +47,9 @@
 #define TSB_TAG_LOCK_BIT	47
 #define TSB_TAG_LOCK_HIGH	(1 << (TSB_TAG_LOCK_BIT - 32))
 
+#define TSB_TAG_INVALID_BIT	46
+#define TSB_TAG_INVALID_HIGH	(1 << (TSB_TAG_INVALID_BIT - 32))
+
 #define TSB_MEMBAR	membar	#StoreStore
 
 /* Some cpus support physical address quad loads.  We want to use
diff --git a/include/asm-sparc64/ttable.h b/include/asm-sparc64/ttable.h
index 9e28b240f3aa..2d5e3c464df5 100644
--- a/include/asm-sparc64/ttable.h
+++ b/include/asm-sparc64/ttable.h
@@ -184,20 +184,20 @@
 	ldxa	[%g0] ASI_SCRATCHPAD, %g2;		\
 	ldx	[%g2 + HV_FAULT_I_ADDR_OFFSET], %g4;	\
 	ldx	[%g2 + HV_FAULT_I_CTX_OFFSET], %g5;	\
-	srlx	%g4, 22, %g7;				\
-	sllx	%g5, 48, %g6;				\
+	srlx	%g4, 22, %g6;				\
 	ba,pt	%xcc, sun4v_itsb_miss;			\
-	 or	%g6, %g7, %g6;				\
+	 nop;						\
+	nop;						\
 	nop;
 
 #define SUN4V_DTSB_MISS					\
 	ldxa	[%g0] ASI_SCRATCHPAD, %g2;		\
 	ldx	[%g2 + HV_FAULT_D_ADDR_OFFSET], %g4;	\
 	ldx	[%g2 + HV_FAULT_D_CTX_OFFSET], %g5;	\
-	srlx	%g4, 22, %g7;				\
-	sllx	%g5, 48, %g6;				\
+	srlx	%g4, 22, %g6;				\
 	ba,pt	%xcc, sun4v_dtsb_miss;			\
-	 or	%g6, %g7, %g6;				\
+	 nop;						\
+	nop;						\
 	nop;
 
 /* Before touching these macros, you owe it to yourself to go and
-- 
2.39.5