[POWERPC] Use 1TB segments

This makes the kernel use 1TB segments for all kernel mappings and for
user addresses of 1TB and above, on machines which support them
(currently POWER5+, POWER6 and PA6T).

We detect that the machine supports 1TB segments by looking at the
ibm,processor-segment-sizes property in the device tree.

We don't currently use 1TB segments for user addresses < 1T, since
that would effectively prevent 32-bit processes from using huge pages
unless we also had a way to revert to using 256MB segments.  That
would be possible but would involve extra complications (such as
keeping track of which segment size was used when HPTEs were inserted)
and is not addressed here.

Parts of this patch were originally written by Ben Herrenschmidt.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 65 insertions, 8 deletions

diff --git a/arch/powerpc/mm/hash_low_64.S b/arch/powerpc/mm/hash_low_64.S
index 35eabfb50723..ad253b959030 100644
--- a/arch/powerpc/mm/hash_low_64.S
+++ b/arch/powerpc/mm/hash_low_64.S
@@ -54,7 +54,7 @@
 
 /*
  * _hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
- *		 pte_t *ptep, unsigned long trap, int local)
+ *		 pte_t *ptep, unsigned long trap, int local, int ssize)
  *
  * Adds a 4K page to the hash table in a segment of 4K pages only
  */
@@ -66,6 +66,7 @@ _GLOBAL(__hash_page_4K)
 	/* Save all params that we need after a function call */
 	std	r6,STK_PARM(r6)(r1)
 	std	r8,STK_PARM(r8)(r1)
+	std	r9,STK_PARM(r9)(r1)
 	
 	/* Add _PAGE_PRESENT to access */
 	ori	r4,r4,_PAGE_PRESENT
@@ -117,6 +118,10 @@ _GLOBAL(__hash_page_4K)
 	 * 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_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT)
 	/* Calc va and put it in r29 */
 	rldicr	r29,r5,28,63-28
 	rldicl	r3,r3,0,36
@@ -126,9 +131,20 @@ _GLOBAL(__hash_page_4K)
 	rldicl	r5,r5,0,25		/* vsid & 0x0000007fffffffff */
 	rldicl	r0,r3,64-12,48		/* (ea >> 12) & 0xffff */
 	xor	r28,r5,r0
+	b	4f
+
+3:	/* Calc VA and hash in r29 and r28 for 1T segment */
+	sldi	r29,r5,40		/* vsid << 40 */
+	clrldi	r3,r3,24		/* ea & 0xffffffffff */
+	rldic	r28,r5,25,25		/* (vsid << 25) & 0x7fffffffff */
+	clrldi	r5,r5,40		/* vsid & 0xffffff */
+	rldicl	r0,r3,64-12,36		/* (ea >> 12) & 0xfffffff */
+	xor	r28,r28,r5
+	or	r29,r3,r29		/* VA */
+	xor	r28,r28,r0		/* hash */
 
 	/* Convert linux PTE bits into HW equivalents */
-	andi.	r3,r30,0x1fe		/* Get basic set of flags */
+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) */
@@ -183,6 +199,7 @@ htab_insert_pte:
 	mr	r4,r29			/* Retreive va */
 	li	r7,0			/* !bolted, !secondary */
 	li	r8,MMU_PAGE_4K		/* page size */
+	ld	r9,STK_PARM(r9)(r1)	/* segment size */
 _GLOBAL(htab_call_hpte_insert1)
 	bl	.			/* Patched by htab_finish_init() */
 	cmpdi	0,r3,0
@@ -205,6 +222,7 @@ _GLOBAL(htab_call_hpte_insert1)
 	mr	r4,r29			/* Retreive va */
 	li	r7,HPTE_V_SECONDARY	/* !bolted, secondary */
 	li	r8,MMU_PAGE_4K		/* page size */
+	ld	r9,STK_PARM(r9)(r1)	/* segment size */
 _GLOBAL(htab_call_hpte_insert2)
 	bl	.			/* Patched by htab_finish_init() */
 	cmpdi	0,r3,0
@@ -273,7 +291,8 @@ htab_modify_pte:
 	/* Call ppc_md.hpte_updatepp */
 	mr	r5,r29			/* va */
 	li	r6,MMU_PAGE_4K		/* page size */
-	ld	r7,STK_PARM(r8)(r1)	/* get "local" param */
+	ld	r7,STK_PARM(r9)(r1)	/* segment size */
+	ld	r8,STK_PARM(r8)(r1)	/* get "local" param */
 _GLOBAL(htab_call_hpte_updatepp)
 	bl	.			/* Patched by htab_finish_init() */
 
@@ -325,6 +344,7 @@ _GLOBAL(__hash_page_4K)
 	/* Save all params that we need after a function call */
 	std	r6,STK_PARM(r6)(r1)
 	std	r8,STK_PARM(r8)(r1)
+	std	r9,STK_PARM(r9)(r1)
 
 	/* Add _PAGE_PRESENT to access */
 	ori	r4,r4,_PAGE_PRESENT
@@ -383,18 +403,33 @@ _GLOBAL(__hash_page_4K)
 	/* Load the hidx index */
 	rldicl	r25,r3,64-12,60
 
+BEGIN_FTR_SECTION
+	cmpdi	r9,0			/* check segment size */
+	bne	3f
+END_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT)
 	/* Calc va and put it in r29 */
 	rldicr	r29,r5,28,63-28		/* r29 = (vsid << 28) */
 	rldicl	r3,r3,0,36		/* r3 = (ea & 0x0fffffff) */
-	or	r29,r3,r29		/* r29 = va
+	or	r29,r3,r29		/* r29 = va */
 
 	/* Calculate hash value for primary slot and store it in r28 */
 	rldicl	r5,r5,0,25		/* vsid & 0x0000007fffffffff */
 	rldicl	r0,r3,64-12,48		/* (ea >> 12) & 0xffff */
 	xor	r28,r5,r0
+	b	4f
+
+3:	/* Calc VA and hash in r29 and r28 for 1T segment */
+	sldi	r29,r5,40		/* vsid << 40 */
+	clrldi	r3,r3,24		/* ea & 0xffffffffff */
+	rldic	r28,r5,25,25		/* (vsid << 25) & 0x7fffffffff */
+	clrldi	r5,r5,40		/* vsid & 0xffffff */
+	rldicl	r0,r3,64-12,36		/* (ea >> 12) & 0xfffffff */
+	xor	r28,r28,r5
+	or	r29,r3,r29		/* VA */
+	xor	r28,r28,r0		/* hash */
 
 	/* Convert linux PTE bits into HW equivalents */
-	andi.	r3,r30,0x1fe		/* Get basic set of flags */
+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) */
@@ -462,6 +497,7 @@ htab_special_pfn:
 	mr	r4,r29			/* Retreive va */
 	li	r7,0			/* !bolted, !secondary */
 	li	r8,MMU_PAGE_4K		/* page size */
+	ld	r9,STK_PARM(r9)(r1)	/* segment size */
 _GLOBAL(htab_call_hpte_insert1)
 	bl	.			/* patched by htab_finish_init() */
 	cmpdi	0,r3,0
@@ -488,6 +524,7 @@ _GLOBAL(htab_call_hpte_insert1)
 	mr	r4,r29			/* Retreive va */
 	li	r7,HPTE_V_SECONDARY	/* !bolted, secondary */
 	li	r8,MMU_PAGE_4K		/* page size */
+	ld	r9,STK_PARM(r9)(r1)	/* segment size */
 _GLOBAL(htab_call_hpte_insert2)
 	bl	.			/* patched by htab_finish_init() */
 	cmpdi	0,r3,0
@@ -586,7 +623,8 @@ htab_modify_pte:
 	/* Call ppc_md.hpte_updatepp */
 	mr	r5,r29			/* va */
 	li	r6,MMU_PAGE_4K		/* page size */
-	ld	r7,STK_PARM(r8)(r1)	/* get "local" param */
+	ld	r7,STK_PARM(r9)(r1)	/* segment size */
+	ld	r8,STK_PARM(r8)(r1)	/* get "local" param */
 _GLOBAL(htab_call_hpte_updatepp)
 	bl	.			/* patched by htab_finish_init() */
 
@@ -634,6 +672,7 @@ _GLOBAL(__hash_page_64K)
 	/* Save all params that we need after a function call */
 	std	r6,STK_PARM(r6)(r1)
 	std	r8,STK_PARM(r8)(r1)
+	std	r9,STK_PARM(r9)(r1)
 
 	/* Add _PAGE_PRESENT to access */
 	ori	r4,r4,_PAGE_PRESENT
@@ -690,6 +729,10 @@ END_FTR_SECTION_IFCLR(CPU_FTR_CI_LARGE_PAGE)
 	 * 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_FTR_SECTION_IFSET(CPU_FTR_1T_SEGMENT)
 	/* Calc va and put it in r29 */
 	rldicr	r29,r5,28,63-28
 	rldicl	r3,r3,0,36
@@ -699,9 +742,20 @@ END_FTR_SECTION_IFCLR(CPU_FTR_CI_LARGE_PAGE)
 	rldicl	r5,r5,0,25		/* vsid & 0x0000007fffffffff */
 	rldicl	r0,r3,64-16,52		/* (ea >> 16) & 0xfff */
 	xor	r28,r5,r0
+	b	4f
+
+3:	/* Calc VA and hash in r29 and r28 for 1T segment */
+	sldi	r29,r5,40		/* vsid << 40 */
+	clrldi	r3,r3,24		/* ea & 0xffffffffff */
+	rldic	r28,r5,25,25		/* (vsid << 25) & 0x7fffffffff */
+	clrldi	r5,r5,40		/* vsid & 0xffffff */
+	rldicl	r0,r3,64-16,40		/* (ea >> 16) & 0xffffff */
+	xor	r28,r28,r5
+	or	r29,r3,r29		/* VA */
+	xor	r28,r28,r0		/* hash */
 
 	/* Convert linux PTE bits into HW equivalents */
-	andi.	r3,r30,0x1fe		/* Get basic set of flags */
+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) */
@@ -756,6 +810,7 @@ ht64_insert_pte:
 	mr	r4,r29			/* Retreive va */
 	li	r7,0			/* !bolted, !secondary */
 	li	r8,MMU_PAGE_64K
+	ld	r9,STK_PARM(r9)(r1)	/* segment size */
 _GLOBAL(ht64_call_hpte_insert1)
 	bl	.			/* patched by htab_finish_init() */
 	cmpdi	0,r3,0
@@ -778,6 +833,7 @@ _GLOBAL(ht64_call_hpte_insert1)
 	mr	r4,r29			/* Retreive va */
 	li	r7,HPTE_V_SECONDARY	/* !bolted, secondary */
 	li	r8,MMU_PAGE_64K
+	ld	r9,STK_PARM(r9)(r1)	/* segment size */
 _GLOBAL(ht64_call_hpte_insert2)
 	bl	.			/* patched by htab_finish_init() */
 	cmpdi	0,r3,0
@@ -846,7 +902,8 @@ ht64_modify_pte:
 	/* Call ppc_md.hpte_updatepp */
 	mr	r5,r29			/* va */
 	li	r6,MMU_PAGE_64K
-	ld	r7,STK_PARM(r8)(r1)	/* get "local" param */
+	ld	r7,STK_PARM(r9)(r1)	/* segment size */
+	ld	r8,STK_PARM(r8)(r1)	/* get "local" param */
 _GLOBAL(ht64_call_hpte_updatepp)
 	bl	.			/* patched by htab_finish_init() */