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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH -V3 09/11] arch/powerpc: Use 50 bits of VSID in slbmte
Date: Mon, 23 Jul 2012 13:51:49 +0530	[thread overview]
Message-ID: <87394ij3aa.fsf@skywalker.in.ibm.com> (raw)
In-Reply-To: <20120723000658.GH17790@bloggs.ozlabs.ibm.com>

Paul Mackerras <paulus@samba.org> writes:

> On Mon, Jul 09, 2012 at 06:43:39PM +0530, Aneesh Kumar K.V wrote:
>> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>> 
>> Increase the number of valid VSID bits in slbmte instruction.
>> We will use the new bits when we increase valid VSID bits.
>> 
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
>> ---
>>  arch/powerpc/mm/slb_low.S |    4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>> 
>> diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
>> index c355af6..c1fc81c 100644
>> --- a/arch/powerpc/mm/slb_low.S
>> +++ b/arch/powerpc/mm/slb_low.S
>> @@ -226,7 +226,7 @@ _GLOBAL(slb_allocate_user)
>>   */
>>  slb_finish_load:
>>  	ASM_VSID_SCRAMBLE(r10,r9,256M)
>> -	rldimi	r11,r10,SLB_VSID_SHIFT,16	/* combine VSID and flags */
>> +	rldimi	r11,r10,SLB_VSID_SHIFT,2	/* combine VSID and flags */
>
> You can't do that without either changing ASM_VSID_SCRAMBLE or masking
> the VSID it generates to 36 bits, since the logic in ASM_VSID_SCRAMBLE
> can leave non-zero bits in the high 28 bits of the result.  Similarly
> for the 1T case.
>

How about change ASM_VSID_SCRAMBLE to clear the high bits ? That would
also make it close to vsid_scramble()

diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index d24d484..173bb34 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -420,7 +420,8 @@ extern void slb_set_size(u16 size);
 	 * cases the answer is the low 36 bits of (r3 + ((r3+1) >> 36))*/\
 	addi	rx,rt,1;						\
 	srdi	rx,rx,VSID_BITS_##size;	/* extract 2^VSID_BITS bit */	\
-	add	rt,rt,rx
+	add	rt,rt,rx;						\
+	clrldi   rt,rt,(64 - VSID_BITS_##size);
 
 /* 4 bits per slice and we have one slice per 1TB */
 #if 0 /* We can't directly include pgtable.h hence this hack */

  reply	other threads:[~2012-07-23  8:21 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-09 13:13 [PATCH -V3 0/11] arch/powerpc: Add 64TB support to ppc64 Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 01/11] arch/powerpc: Use hpt_va to compute virtual address Aneesh Kumar K.V
2012-07-22 23:17   ` Paul Mackerras
2012-07-09 13:13 ` [PATCH -V3 02/11] arch/powerpc: Simplify hpte_decode Aneesh Kumar K.V
2012-07-22 23:26   ` Paul Mackerras
2012-07-23  5:41     ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 03/11] arch/powerpc: Convert virtual address to vpn Aneesh Kumar K.V
2012-07-09 22:41   ` Stephen Rothwell
2012-07-10  6:12     ` Aneesh Kumar K.V
2012-07-09 23:06   ` Stephen Rothwell
2012-07-10  6:15     ` Aneesh Kumar K.V
2012-07-22 23:42   ` Paul Mackerras
2012-07-23  5:54     ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 04/11] arch/powerpc: Rename va " Aneesh Kumar K.V
2012-07-22 23:46   ` Paul Mackerras
2012-07-23  6:14     ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 05/11] arch/powerpc: remove masking top 16 bit of va in tlb invalidate Aneesh Kumar K.V
2012-07-22 23:56   ` Paul Mackerras
2012-07-23  1:22     ` Benjamin Herrenschmidt
2012-07-23  3:49       ` Paul Mackerras
2012-07-23  6:44         ` Aneesh Kumar K.V
2012-07-23  6:48           ` Benjamin Herrenschmidt
2012-07-09 13:13 ` [PATCH -V3 06/11] arch/powerpc: Make KERN_VIRT_SIZE not dependend on PGTABLE_RANGE Aneesh Kumar K.V
2012-07-22 23:57   ` Paul Mackerras
2012-07-09 13:13 ` [PATCH -V3 07/11] arch/powerpc: Increase the slice range to 64TB Aneesh Kumar K.V
2012-07-23  0:00   ` Paul Mackerras
2012-07-23  7:13     ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 08/11] arch/powerpc: Make some of the PGTABLE_RANGE dependency explicit Aneesh Kumar K.V
2012-07-23  0:20   ` Paul Mackerras
2012-07-23  7:29     ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 09/11] arch/powerpc: Use 50 bits of VSID in slbmte Aneesh Kumar K.V
2012-07-23  0:06   ` Paul Mackerras
2012-07-23  8:21     ` Aneesh Kumar K.V [this message]
2012-07-23  9:36       ` Paul Mackerras
2012-07-23 10:22         ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 10/11] arch/powerpc: Use 32bit array for slb cache Aneesh Kumar K.V
2012-07-23  0:27   ` Paul Mackerras
2012-07-23  8:25     ` Aneesh Kumar K.V
2012-07-09 13:13 ` [PATCH -V3 11/11] arch/powerpc: Add 64TB support Aneesh Kumar K.V
2012-07-23  0:15   ` Paul Mackerras
2012-07-23  8:49     ` Aneesh Kumar K.V
2012-07-23  9:39   ` Paul Mackerras
2012-07-23 10:22     ` Aneesh Kumar K.V
2012-07-23 11:06       ` Paul Mackerras
2012-07-24  8:37         ` Aneesh Kumar K.V
2012-07-24  9:14           ` Aneesh Kumar K.V
2012-07-24 19:50             ` Aneesh Kumar K.V

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