Subject: Re: Re[3]: PS3 platform is broken on Linux 3.7.0

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Mon, 11 Feb 2013 15:56:18 +0530

"Aneesh Kumar K.V" <[email-masked]> writes:

> Phileas Fogg <[email-masked]> writes:
>
>>  And another note.
>> I took a look at the MMU chapter in the Cell Architecture handbook and indeed the first 15 bits in VA are treated as 0 by the hardware.
>>
>> Quote:
>>
>> 1. High-order bits above 65 bits in the 80-bit virtual address (VA[0:14]) are not implemented. The hardware always
>>    treats these bits as `0'. Software must not set these bits to any other value than `0' or the results are undefined in
>>    the PPE.
>>
>>
>
> True, we missed the below part of ISA doc:
>
> ISA doc says
>
> "On implementations that support a virtual address size
> of only n bits, n < 78, bits 0:77-n of the AVA field must be
> zeros. "
>
> The Cell document I found at 
>
> https://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/7A77CCDF14FE70D5852575CA0074E8ED/$file/CellBE_Handbook_v1.12_3Apr09_pub.pdf
>
> gives 
>
> Virtual Address (VA) Size -> 65 bits
>
> So as per ISA, bits 0:12 should be zero, which should make 0:14 of PTE
> fields zero for Cell.
>
> I will try to do a patch. 
>

Can you try this patch ?

diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index 2fdb47a..f01fd9a 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -381,21 +381,37 @@ extern void slb_set_size(u16 size);
  * hash collisions.
  */
 
+/* This should go in Kconfig */
+/*
+ * Be careful with this value. This determines the VSID_MODULUS_*  and that
+ * need to be co-prime with VSID_MULTIPLIER*
+ */
+#if 1
+#define MAX_VIRTUAL_ADDR_BITS	65
+#else
+#define MAX_VIRTUAL_ADDR_BITS	66
+#endif
+/*
+ * One bit is taken by the kernel, only the rest of space is available for the
+ * user space.
+ */
+#define CONTEXT_BITS		(MAX_VIRTUAL_ADDR_BITS - \
+				 (USER_ESID_BITS + SID_SHIFT + 1))
+#define USER_ESID_BITS		18
+#define USER_ESID_BITS_1T	6
+
 /*
  * This should be computed such that protovosid * vsid_mulitplier
  * doesn't overflow 64 bits. It should also be co-prime to vsid_modulus
  */
 #define VSID_MULTIPLIER_256M	ASM_CONST(12538073)	/* 24-bit prime */
-#define VSID_BITS_256M		38
+#define VSID_BITS_256M		(CONTEXT_BITS + USER_ESID_BITS + 1)
 #define VSID_MODULUS_256M	((1UL<<VSID_BITS_256M)-1)
 
 #define VSID_MULTIPLIER_1T	ASM_CONST(12538073)	/* 24-bit prime */
-#define VSID_BITS_1T		26
+#define VSID_BITS_1T		(CONTEXT_BITS + USER_ESID_BITS_1T + 1)
 #define VSID_MODULUS_1T		((1UL<<VSID_BITS_1T)-1)
 
-#define CONTEXT_BITS		19
-#define USER_ESID_BITS		18
-#define USER_ESID_BITS_1T	6
 
 #define USER_VSID_RANGE	(1UL << (USER_ESID_BITS + SID_SHIFT))