[PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S

[PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S

[John David Anglin]

TLB operations only need to be serialized on machines with the Merced (Stretch) bus.
The only machines in this category are L and N class, and they require a 64-bit PA 2.0
kernel.  On these machines, we use local TLB purges in the tmpalias routines.  We don't
need to serialize TLB purges on all other machines.  Thus, the lock/unlock code can be
removed when CONFIG_PA20 is not defined.  Further, when CONFIG_PA20 is not defined,
alternative patching converts the TLB purges to local purges when PA 2.0 hardware has
been detected.

Signed-off-by: John David Anglin <dave.anglin@bell.net>

diff --git a/arch/parisc/kernel/pacache.S b/arch/parisc/kernel/pacache.S
index 187f032c9dd8..4e4e8eb25874 100644
--- a/arch/parisc/kernel/pacache.S
+++ b/arch/parisc/kernel/pacache.S
@@ -311,39 +311,6 @@ fdsync:
 	nop
 ENDPROC_CFI(flush_data_cache_local)

-/* Macros to serialize TLB purge operations on SMP.  */
-
-	.macro	tlb_lock	la,flags,tmp
-#ifdef CONFIG_SMP
-98:
-#if __PA_LDCW_ALIGNMENT > 4
-	load32		pa_tlb_lock + __PA_LDCW_ALIGNMENT-1, \la
-	depi		0,31,__PA_LDCW_ALIGN_ORDER, \la
-#else
-	load32		pa_tlb_lock, \la
-#endif
-	rsm		PSW_SM_I,\flags
-1:	LDCW		0(\la),\tmp
-	cmpib,<>,n	0,\tmp,3f
-2:	ldw		0(\la),\tmp
-	cmpb,<>		%r0,\tmp,1b
-	nop
-	b,n		2b
-3:
-99:	ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
-#endif
-	.endm
-
-	.macro	tlb_unlock	la,flags,tmp
-#ifdef CONFIG_SMP
-98:	ldi		1,\tmp
-	sync
-	stw		\tmp,0(\la)
-	mtsm		\flags
-99:	ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
-#endif
-	.endm
-
 /* Clear page using kernel mapping.  */

 ENTRY_CFI(clear_page_asm)
@@ -601,10 +568,8 @@ ENTRY_CFI(copy_user_page_asm)
 	pdtlb,l		%r0(%r28)
 	pdtlb,l		%r0(%r29)
 #else
-	tlb_lock	%r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
 1:	pdtlb		%r0(%r29)
-	tlb_unlock	%r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 	ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif
@@ -743,9 +708,7 @@ ENTRY_CFI(clear_user_page_asm)
 #ifdef CONFIG_PA20
 	pdtlb,l		%r0(%r28)
 #else
-	tlb_lock	%r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
-	tlb_unlock	%r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif

@@ -821,9 +784,7 @@ ENTRY_CFI(flush_dcache_page_asm)
 #ifdef CONFIG_PA20
 	pdtlb,l		%r0(%r28)
 #else
-	tlb_lock	%r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
-	tlb_unlock	%r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif

@@ -882,9 +843,7 @@ ENTRY_CFI(purge_dcache_page_asm)
 #ifdef CONFIG_PA20
 	pdtlb,l		%r0(%r28)
 #else
-	tlb_lock	%r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
-	tlb_unlock	%r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif

@@ -948,10 +907,8 @@ ENTRY_CFI(flush_icache_page_asm)
 1:	pitlb,l         %r0(%sr4,%r28)
 	ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SPLIT_TLB, INSN_NOP)
 #else
-	tlb_lock        %r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
 1:	pitlb           %r0(%sr4,%r28)
-	tlb_unlock      %r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 	ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 	ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SPLIT_TLB, INSN_NOP)

Re: [PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S

[Sven Schnelle]

On Fri, Apr 12, 2019 at 07:12:04PM -0400, John David Anglin wrote:
> TLB operations only need to be serialized on machines with the Merced (Stretch) bus.
> The only machines in this category are L and N class, and they require a 64-bit PA 2.0
> kernel.  On these machines, we use local TLB purges in the tmpalias routines.  We don't
> need to serialize TLB purges on all other machines.  Thus, the lock/unlock code can be
> removed when CONFIG_PA20 is not defined.  Further, when CONFIG_PA20 is not defined,
> alternative patching converts the TLB purges to local purges when PA 2.0 hardware has
> been detected.
> 
> Signed-off-by: John David Anglin <dave.anglin@bell.net>

I had this patch running on my C8000 and J5000 for a few days, and haven't
encountered any issues.

Tested-By: Sven Schnelle <svens@stackframe.org>

Regards
Sven

Re: [PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S

[Helge Deller]

On 17.04.19 22:55, Sven Schnelle wrote:
> On Fri, Apr 12, 2019 at 07:12:04PM -0400, John David Anglin wrote:
>> TLB operations only need to be serialized on machines with the Merced (Stretch) bus.
>> The only machines in this category are L and N class, and they require a 64-bit PA 2.0
>> kernel.  On these machines, we use local TLB purges in the tmpalias routines.  We don't
>> need to serialize TLB purges on all other machines.  Thus, the lock/unlock code can be
>> removed when CONFIG_PA20 is not defined.  Further, when CONFIG_PA20 is not defined,
>> alternative patching converts the TLB purges to local purges when PA 2.0 hardware has
>> been detected.
>>
>> Signed-off-by: John David Anglin <dave.anglin@bell.net>
>
> I had this patch running on my C8000 and J5000 for a few days, and haven't
> encountered any issues.

Nah...
I do have one of the critical machines (rp5470), and I tried
to add the necessary code to detect and handle the TLB serialization.
Until now the patch sadly doesn't work yet (hangs at boot), it still needs more work.
You can find it in my git tree:
https://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux.git/commit/?h=tlb-flush-merced-bus&id=fc6044f83cb9828ec6ebecb23a46549d9ebc518f

Helge

Re: [PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S

[Helge Deller]

On 17.04.19 22:58, Helge Deller wrote:
> On 17.04.19 22:55, Sven Schnelle wrote:
>> On Fri, Apr 12, 2019 at 07:12:04PM -0400, John David Anglin wrote:
>>> TLB operations only need to be serialized on machines with the Merced (Stretch) bus.
>>> The only machines in this category are L and N class, and they require a 64-bit PA 2.0
>>> kernel.  On these machines, we use local TLB purges in the tmpalias routines.  We don't
>>> need to serialize TLB purges on all other machines.  Thus, the lock/unlock code can be
>>> removed when CONFIG_PA20 is not defined.  Further, when CONFIG_PA20 is not defined,
>>> alternative patching converts the TLB purges to local purges when PA 2.0 hardware has
>>> been detected.
>>>
>>> Signed-off-by: John David Anglin <dave.anglin@bell.net>
>>
>> I had this patch running on my C8000 and J5000 for a few days, and haven't
>> encountered any issues.
>
> Nah...
> I do have one of the critical machines (rp5470), and I tried
> to add the necessary code to detect and handle the TLB serialization.
> Until now the patch sadly doesn't work yet (hangs at boot), it still needs more work.
> You can find it in my git tree:
> https://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux.git/commit/?h=tlb-flush-merced-bus&id=fc6044f83cb9828ec6ebecb23a46549d9ebc518f

Please ignore my comments.
Dave's patch is OK.

I mixed it up with the Mikulas Patocka's patch: "use per-pagetable spinlock"
https://patchwork.kernel.org/patch/10888249/

Helge

Re: [PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S

[John David Anglin]

On 2019-04-17 5:01 p.m., Helge Deller wrote:
> On 17.04.19 22:58, Helge Deller wrote:
>> On 17.04.19 22:55, Sven Schnelle wrote:
>>> On Fri, Apr 12, 2019 at 07:12:04PM -0400, John David Anglin wrote:
>>>> TLB operations only need to be serialized on machines with the Merced (Stretch) bus.
>>>> The only machines in this category are L and N class, and they require a 64-bit PA 2.0
>>>> kernel.  On these machines, we use local TLB purges in the tmpalias routines.  We don't
>>>> need to serialize TLB purges on all other machines.  Thus, the lock/unlock code can be
>>>> removed when CONFIG_PA20 is not defined.  Further, when CONFIG_PA20 is not defined,
>>>> alternative patching converts the TLB purges to local purges when PA 2.0 hardware has
>>>> been detected.
>>>>
>>>> Signed-off-by: John David Anglin <dave.anglin@bell.net>
>>> I had this patch running on my C8000 and J5000 for a few days, and haven't
>>> encountered any issues.
>> Nah...
>> I do have one of the critical machines (rp5470), and I tried
>> to add the necessary code to detect and handle the TLB serialization.
>> Until now the patch sadly doesn't work yet (hangs at boot), it still needs more work.
>> You can find it in my git tree:
>> https://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux.git/commit/?h=tlb-flush-merced-bus&id=fc6044f83cb9828ec6ebecb23a46549d9ebc518f
> Please ignore my comments.
> Dave's patch is OK.
>
> I mixed it up with the Mikulas Patocka's patch: "use per-pagetable spinlock"
> https://patchwork.kernel.org/patch/10888249/

I think this hunk needs fixing to handle merced case:

diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 5796524a3137..3e11fdd9d3af 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -48,14 +48,9 @@
     .level 2.0
 #endif
 
-    .import        pa_tlb_lock,data
-    .macro  load_pa_tlb_lock reg
-#if __PA_LDCW_ALIGNMENT > 4
-    load32    PA(pa_tlb_lock) + __PA_LDCW_ALIGNMENT-1, \reg
-    depi    0,31,__PA_LDCW_ALIGN_ORDER, \reg
-#else
-    load32    PA(pa_tlb_lock), \reg
-#endif
+    .macro  load_process_pte_lock reg
+    mfctl        %cr25,\reg
+    addil        L%((PAGE_SIZE << PGD_ALLOC_ORDER) - PAGE_SIZE),\reg
     .endm
 
     /* space_to_prot macro creates a prot id from a space id */


-- 
John David Anglin  dave.anglin@bell.net

Re: [PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S

[John David Anglin]

On 2019-04-17 5:09 p.m., John David Anglin wrote:
> On 2019-04-17 5:01 p.m., Helge Deller wrote:
>> On 17.04.19 22:58, Helge Deller wrote:
>>> On 17.04.19 22:55, Sven Schnelle wrote:
>>>> On Fri, Apr 12, 2019 at 07:12:04PM -0400, John David Anglin wrote:
>>>>> TLB operations only need to be serialized on machines with the Merced (Stretch) bus.
>>>>> The only machines in this category are L and N class, and they require a 64-bit PA 2.0
>>>>> kernel.  On these machines, we use local TLB purges in the tmpalias routines.  We don't
>>>>> need to serialize TLB purges on all other machines.  Thus, the lock/unlock code can be
>>>>> removed when CONFIG_PA20 is not defined.  Further, when CONFIG_PA20 is not defined,
>>>>> alternative patching converts the TLB purges to local purges when PA 2.0 hardware has
>>>>> been detected.
>>>>>
>>>>> Signed-off-by: John David Anglin <dave.anglin@bell.net>
>>>> I had this patch running on my C8000 and J5000 for a few days, and haven't
>>>> encountered any issues.
>>> Nah...
>>> I do have one of the critical machines (rp5470), and I tried
>>> to add the necessary code to detect and handle the TLB serialization.
>>> Until now the patch sadly doesn't work yet (hangs at boot), it still needs more work.
>>> You can find it in my git tree:
>>> https://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux.git/commit/?h=tlb-flush-merced-bus&id=fc6044f83cb9828ec6ebecb23a46549d9ebc518f
>> Please ignore my comments.
>> Dave's patch is OK.
>>
>> I mixed it up with the Mikulas Patocka's patch: "use per-pagetable spinlock"
>> https://patchwork.kernel.org/patch/10888249/
> I think this hunk needs fixing to handle merced case:
>
> diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
> index 5796524a3137..3e11fdd9d3af 100644
> --- a/arch/parisc/kernel/entry.S
> +++ b/arch/parisc/kernel/entry.S
> @@ -48,14 +48,9 @@
>      .level 2.0
>  #endif
>  
> -    .import        pa_tlb_lock,data
> -    .macro  load_pa_tlb_lock reg
> -#if __PA_LDCW_ALIGNMENT > 4
> -    load32    PA(pa_tlb_lock) + __PA_LDCW_ALIGNMENT-1, \reg
> -    depi    0,31,__PA_LDCW_ALIGN_ORDER, \reg
> -#else
> -    load32    PA(pa_tlb_lock), \reg
> -#endif
> +    .macro  load_process_pte_lock reg
> +    mfctl        %cr25,\reg
> +    addil        L%((PAGE_SIZE << PGD_ALLOC_ORDER) - PAGE_SIZE),\reg
>      .endm
>  
>      /* space_to_prot macro creates a prot id from a space id */

Another option might be to remove pa_serialize_tlb_flushes here:
+    if (unlikely(pgd == swapper_pg_dir) || pa_serialize_tlb_flushes)
+        return &pa_tlb_flush_lock;
This might be the better solution.  You have serialized the TLB purges using the pa_tlb_flush_lock.

Dave

-- 
John David Anglin  dave.anglin@bell.net

Re: [PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S

[John David Anglin]

On 2019-04-17 4:58 p.m., Helge Deller wrote:
> On 17.04.19 22:55, Sven Schnelle wrote:
>> On Fri, Apr 12, 2019 at 07:12:04PM -0400, John David Anglin wrote:
>>> TLB operations only need to be serialized on machines with the Merced (Stretch) bus.
>>> The only machines in this category are L and N class, and they require a 64-bit PA 2.0
>>> kernel.  On these machines, we use local TLB purges in the tmpalias routines.  We don't
>>> need to serialize TLB purges on all other machines.  Thus, the lock/unlock code can be
>>> removed when CONFIG_PA20 is not defined.  Further, when CONFIG_PA20 is not defined,
>>> alternative patching converts the TLB purges to local purges when PA 2.0 hardware has
>>> been detected.
>>>
>>> Signed-off-by: John David Anglin <dave.anglin@bell.net>
>> I had this patch running on my C8000 and J5000 for a few days, and haven't
>> encountered any issues.
> Nah...
> I do have one of the critical machines (rp5470), and I tried
> to add the necessary code to detect and handle the TLB serialization.
> Until now the patch sadly doesn't work yet (hangs at boot), it still needs more work.
> You can find it in my git tree:
> https://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux.git/commit/?h=tlb-flush-merced-bus&id=fc6044f83cb9828ec6ebecb23a46549d9ebc518f
I don't see it...

Dave

-- 
John David Anglin  dave.anglin@bell.net

Re: [PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S

[John David Anglin]

On 2019-04-17 4:58 p.m., Helge Deller wrote:
> On 17.04.19 22:55, Sven Schnelle wrote:
>> On Fri, Apr 12, 2019 at 07:12:04PM -0400, John David Anglin wrote:
>>> TLB operations only need to be serialized on machines with the Merced (Stretch) bus.
>>> The only machines in this category are L and N class, and they require a 64-bit PA 2.0
>>> kernel.  On these machines, we use local TLB purges in the tmpalias routines.  We don't
>>> need to serialize TLB purges on all other machines.  Thus, the lock/unlock code can be
>>> removed when CONFIG_PA20 is not defined.  Further, when CONFIG_PA20 is not defined,
>>> alternative patching converts the TLB purges to local purges when PA 2.0 hardware has
>>> been detected.
>>>
>>> Signed-off-by: John David Anglin <dave.anglin@bell.net>
>>
>> I had this patch running on my C8000 and J5000 for a few days, and haven't
>> encountered any issues.
> 
> Nah...
> I do have one of the critical machines (rp5470), and I tried
> to add the necessary code to detect and handle the TLB serialization.
> Until now the patch sadly doesn't work yet (hangs at boot), it still needs more work.
> You can find it in my git tree:
> https://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux.git/commit/?h=tlb-flush-merced-bus&id=fc6044f83cb9828ec6ebecb23a46549d9ebc518f

I worked on the above patch to try fix the TLB serialization.  I think this version
will probably boot on rp5470.

There's now separate locks to serialize TLB and page table updates.  I also added
a lock for swapper page updates.  I'm not sure how important this is but I wanted
a separate lock for TLB serialization.

To add the TLB lock, I had to move some defines from tlbflush.h to pgtable.h.  The
issue is pgtable.h needs to be included before tlbflush.h, so we can't have dependencies
on tlbflush.h in pgtable.h.  It might be possible to move this stuff into cache.h.

I've tested the change on c8000. Compared to the patch posted by Mikulas, the additional
lock code results in a few percent reduction in performance on c8000.  With Mikulas'
patch, my kernel build takes about 37 minutes.  Build time increases by 1 to 3 minutes
with the included patch.  So, the impact is significant even machines that don't need
TLB serialization.  Maybe we need a kernel config option.

I also think the code in./mm/hugetlbpage.c needs review.

Dave

diff --git a/arch/parisc/include/asm/hardware.h b/arch/parisc/include/asm/hardware.h
index d6e1ed145031..9d3d7737c58b 100644
--- a/arch/parisc/include/asm/hardware.h
+++ b/arch/parisc/include/asm/hardware.h
@@ -120,7 +120,7 @@ extern void get_pci_node_path(struct pci_dev *dev, struct hardware_path *path);
 extern void init_parisc_bus(void);
 extern struct device *hwpath_to_device(struct hardware_path *modpath);
 extern void device_to_hwpath(struct device *dev, struct hardware_path *path);
-
+extern int machine_has_merced_bus(void);

 /* inventory.c: */
 extern void do_memory_inventory(void);
diff --git a/arch/parisc/include/asm/pgalloc.h b/arch/parisc/include/asm/pgalloc.h
index d05c678c77c4..ea75cc966dae 100644
--- a/arch/parisc/include/asm/pgalloc.h
+++ b/arch/parisc/include/asm/pgalloc.h
@@ -41,6 +41,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 		__pgd_val_set(*pgd, PxD_FLAG_ATTACHED);
 #endif
 	}
+	spin_lock_init(pgd_spinlock(actual_pgd));
 	return actual_pgd;
 }

diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index c7bb74e22436..be13b1bf0345 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -17,7 +17,7 @@
 #include <asm/processor.h>
 #include <asm/cache.h>

-extern spinlock_t pa_tlb_lock;
+static inline spinlock_t *pgd_spinlock(pgd_t *);

 /*
  * kern_addr_valid(ADDR) tests if ADDR is pointing to valid kernel
@@ -34,16 +34,43 @@ extern spinlock_t pa_tlb_lock;
  */
 #define kern_addr_valid(addr)	(1)

-/* Purge data and instruction TLB entries.  Must be called holding
- * the pa_tlb_lock.  The TLB purge instructions are slow on SMP
- * machines since the purge must be broadcast to all CPUs.
+/* This is for the serialization of PxTLB broadcasts.  At least on the
+ * N class systems, only one PxTLB inter processor broadcast can be
+ * active at any one time on the Merced bus.
+
+ * PTE updates are protected by locks in the PMD.
+ */
+extern spinlock_t pa_tlb_flush_lock;
+#ifdef CONFIG_64BIT
+extern int pa_serialize_tlb_flushes;
+#else
+#define pa_serialize_tlb_flushes        (0)
+#endif
+
+#define purge_tlb_start(flags)  \
+        if (pa_serialize_tlb_flushes)   \
+                spin_lock_irqsave(&pa_tlb_flush_lock, flags); \
+        else \
+                local_irq_save(flags)
+#define purge_tlb_end(flags)    \
+        if (pa_serialize_tlb_flushes)   \
+                spin_unlock_irqrestore(&pa_tlb_flush_lock, flags); \
+        else \
+                local_irq_restore(flags)
+
+/* Purge data and instruction TLB entries. The TLB purge instructions
+ * are slow on SMP machines since the purge must be broadcast to all CPUs.
  */

 static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
 {
+	unsigned long flags;
+
+	purge_tlb_start(flags);
 	mtsp(mm->context, 1);
 	pdtlb(addr);
 	pitlb(addr);
+	purge_tlb_end(flags);
 }

 /* Certain architectures need to do special things when PTEs
@@ -59,11 +86,11 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
 	do {							\
 		pte_t old_pte;					\
 		unsigned long flags;				\
-		spin_lock_irqsave(&pa_tlb_lock, flags);		\
+		spin_lock_irqsave(pgd_spinlock((mm)->pgd), flags);\
 		old_pte = *ptep;				\
 		set_pte(ptep, pteval);				\
 		purge_tlb_entries(mm, addr);			\
-		spin_unlock_irqrestore(&pa_tlb_lock, flags);	\
+		spin_unlock_irqrestore(pgd_spinlock((mm)->pgd), flags);\
 	} while (0)

 #endif /* !__ASSEMBLY__ */
@@ -88,10 +115,10 @@ static inline void purge_tlb_entries(struct mm_struct *mm, unsigned long addr)
 #if CONFIG_PGTABLE_LEVELS == 3
 #define PGD_ORDER	1 /* Number of pages per pgd */
 #define PMD_ORDER	1 /* Number of pages per pmd */
-#define PGD_ALLOC_ORDER	2 /* first pgd contains pmd */
+#define PGD_ALLOC_ORDER	(2 + 1) /* first pgd contains pmd */
 #else
 #define PGD_ORDER	1 /* Number of pages per pgd */
-#define PGD_ALLOC_ORDER	PGD_ORDER
+#define PGD_ALLOC_ORDER	(PGD_ORDER + 1)
 #endif

 /* Definitions for 3rd level (we use PLD here for Page Lower directory
@@ -459,6 +486,17 @@ extern void update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t *);
 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })

+
+static inline spinlock_t *pgd_spinlock(pgd_t *pgd)
+{
+	extern spinlock_t pa_swapper_pg_lock;
+
+	if (unlikely(pgd == swapper_pg_dir))
+		return &pa_swapper_pg_lock;
+	return (spinlock_t *)((char *)pgd + (PAGE_SIZE << (PGD_ALLOC_ORDER - 1)));
+}
+
+
 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
 {
 	pte_t pte;
@@ -467,15 +505,15 @@ static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned
 	if (!pte_young(*ptep))
 		return 0;

-	spin_lock_irqsave(&pa_tlb_lock, flags);
+	spin_lock_irqsave(pgd_spinlock(vma->vm_mm->pgd), flags);
 	pte = *ptep;
 	if (!pte_young(pte)) {
-		spin_unlock_irqrestore(&pa_tlb_lock, flags);
+		spin_unlock_irqrestore(pgd_spinlock(vma->vm_mm->pgd), flags);
 		return 0;
 	}
 	set_pte(ptep, pte_mkold(pte));
 	purge_tlb_entries(vma->vm_mm, addr);
-	spin_unlock_irqrestore(&pa_tlb_lock, flags);
+	spin_unlock_irqrestore(pgd_spinlock(vma->vm_mm->pgd), flags);
 	return 1;
 }

@@ -485,11 +523,11 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 	pte_t old_pte;
 	unsigned long flags;

-	spin_lock_irqsave(&pa_tlb_lock, flags);
+	spin_lock_irqsave(pgd_spinlock(mm->pgd), flags);
 	old_pte = *ptep;
 	set_pte(ptep, __pte(0));
 	purge_tlb_entries(mm, addr);
-	spin_unlock_irqrestore(&pa_tlb_lock, flags);
+	spin_unlock_irqrestore(pgd_spinlock(mm->pgd), flags);

 	return old_pte;
 }
@@ -497,10 +535,10 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
 	unsigned long flags;
-	spin_lock_irqsave(&pa_tlb_lock, flags);
+	spin_lock_irqsave(pgd_spinlock(mm->pgd), flags);
 	set_pte(ptep, pte_wrprotect(*ptep));
 	purge_tlb_entries(mm, addr);
-	spin_unlock_irqrestore(&pa_tlb_lock, flags);
+	spin_unlock_irqrestore(pgd_spinlock(mm->pgd), flags);
 }

 #define pte_same(A,B)	(pte_val(A) == pte_val(B))
diff --git a/arch/parisc/include/asm/tlbflush.h b/arch/parisc/include/asm/tlbflush.h
index 6804374efa66..c5ded01d45be 100644
--- a/arch/parisc/include/asm/tlbflush.h
+++ b/arch/parisc/include/asm/tlbflush.h
@@ -8,21 +8,6 @@
 #include <linux/sched.h>
 #include <asm/mmu_context.h>

-
-/* This is for the serialisation of PxTLB broadcasts.  At least on the
- * N class systems, only one PxTLB inter processor broadcast can be
- * active at any one time on the Merced bus.  This tlb purge
- * synchronisation is fairly lightweight and harmless so we activate
- * it on all systems not just the N class.
-
- * It is also used to ensure PTE updates are atomic and consistent
- * with the TLB.
- */
-extern spinlock_t pa_tlb_lock;
-
-#define purge_tlb_start(flags)	spin_lock_irqsave(&pa_tlb_lock, flags)
-#define purge_tlb_end(flags)	spin_unlock_irqrestore(&pa_tlb_lock, flags)
-
 extern void flush_tlb_all(void);
 extern void flush_tlb_all_local(void *);

@@ -79,13 +64,6 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
 static inline void flush_tlb_page(struct vm_area_struct *vma,
 	unsigned long addr)
 {
-	unsigned long flags, sid;
-
-	sid = vma->vm_mm->context;
-	purge_tlb_start(flags);
-	mtsp(sid, 1);
-	pdtlb(addr);
-	pitlb(addr);
-	purge_tlb_end(flags);
+	purge_tlb_entries(vma->vm_mm, addr);
 }
 #endif
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 804880efa11e..848020f0a85e 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -40,13 +40,20 @@ void purge_dcache_page_asm(unsigned long phys_addr, unsigned long vaddr);
 void flush_icache_page_asm(unsigned long phys_addr, unsigned long vaddr);


-/* On some machines (e.g. ones with the Merced bus), there can be
+/* On some machines (i.e., ones with the Merced bus), there can be
  * only a single PxTLB broadcast at a time; this must be guaranteed
- * by software.  We put a spinlock around all TLB flushes  to
- * ensure this.
+ * by software. We need a spinlock around all TLB flushes to ensure
+ * this.
  */
-DEFINE_SPINLOCK(pa_tlb_lock);
+DEFINE_SPINLOCK(pa_tlb_flush_lock);

+/* Swapper page setup lock. */
+DEFINE_SPINLOCK(pa_swapper_pg_lock);
+
+#ifdef CONFIG_64BIT
+int pa_serialize_tlb_flushes __read_mostly;
+#endif
+
 struct pdc_cache_info cache_info __read_mostly;
 #ifndef CONFIG_PA20
 static struct pdc_btlb_info btlb_info __read_mostly;
diff --git a/arch/parisc/kernel/drivers.c b/arch/parisc/kernel/drivers.c
index 5eb979d04b90..b26b1d2a2ea9 100644
--- a/arch/parisc/kernel/drivers.c
+++ b/arch/parisc/kernel/drivers.c
@@ -38,6 +38,7 @@
 #include <asm/io.h>
 #include <asm/pdc.h>
 #include <asm/parisc-device.h>
+#include <asm/ropes.h>

 /* See comments in include/asm-parisc/pci.h */
 const struct dma_map_ops *hppa_dma_ops __read_mostly;
@@ -257,6 +258,30 @@ static struct parisc_device *find_device_by_addr(unsigned long hpa)
 	return ret ? d.dev : NULL;
 }

+static int is_IKE_device(struct device *dev, void *data)
+{
+	struct parisc_device * pdev = to_parisc_device(dev);
+
+	if (!check_dev(dev))
+		return 0;
+	if (pdev->id.hw_type != HPHW_BCPORT)
+		return 0;
+	if (IS_IKE(pdev) ||
+		(pdev->id.hversion == REO_MERCED_PORT) ||
+		(pdev->id.hversion == REOG_MERCED_PORT)) {
+			return 1;
+	}
+	return 0;
+}
+
+int __init machine_has_merced_bus(void)
+{
+	int ret;
+
+	ret = for_each_padev(is_IKE_device, NULL);
+	return ret ? 1 : 0;
+}
+
 /**
  * find_pa_parent_type - Find a parent of a specific type
  * @dev: The device to start searching from
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index d5eb19efa65b..a1fc04570ade 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -50,12 +50,8 @@

 	.import		pa_tlb_lock,data
 	.macro  load_pa_tlb_lock reg
-#if __PA_LDCW_ALIGNMENT > 4
-	load32	PA(pa_tlb_lock) + __PA_LDCW_ALIGNMENT-1, \reg
-	depi	0,31,__PA_LDCW_ALIGN_ORDER, \reg
-#else
-	load32	PA(pa_tlb_lock), \reg
-#endif
+	mfctl		%cr25,\reg
+	addil		L%(PAGE_SIZE << (PGD_ALLOC_ORDER - 1)),\reg
 	.endm

 	/* space_to_prot macro creates a prot id from a space id */
diff --git a/arch/parisc/kernel/inventory.c b/arch/parisc/kernel/inventory.c
index 35d05fdd7483..1a86220539d9 100644
--- a/arch/parisc/kernel/inventory.c
+++ b/arch/parisc/kernel/inventory.c
@@ -31,6 +31,7 @@
 #include <asm/processor.h>
 #include <asm/page.h>
 #include <asm/parisc-device.h>
+#include <asm/tlbflush.h>

 /*
 ** Debug options
@@ -638,4 +639,12 @@ void __init do_device_inventory(void)
 	}
 	printk(KERN_INFO "Found devices:\n");
 	print_parisc_devices();
+
+#ifdef CONFIG_64BIT
+	pa_serialize_tlb_flushes = machine_has_merced_bus();
+	if (pa_serialize_tlb_flushes)
+		printk(KERN_INFO "Enabled slow TLB syncronization for Merced bus.\n");
+	else
+		printk(KERN_INFO "No Merced bus found: Enabled fast TLB flushes.\n");
+#endif
 }





-- 
John David Anglin  dave.anglin@bell.net