[PATCH] ppc64: support 64k pages

Adds a new CONFIG_PPC_64K_PAGES which, when enabled, changes the kernel
base page size to 64K.  The resulting kernel still boots on any
hardware.  On current machines with 4K pages support only, the kernel
will maintain 16 "subpages" for each 64K page transparently.

Note that while real 64K capable HW has been tested, the current patch
will not enable it yet as such hardware is not released yet, and I'm
still verifying with the firmware architects the proper to get the
information from the newer hypervisors.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 223 insertions, 77 deletions

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 45d8197..16ab40d 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -195,11 +195,11 @@ exception_marker:
 #define EX_R12		24
 #define EX_R13		32
 #define EX_SRR0		40
-#define EX_R3		40	/* SLB miss saves R3, but not SRR0 */
 #define EX_DAR		48
-#define EX_LR		48	/* SLB miss saves LR, but not DAR */
 #define EX_DSISR	56
 #define EX_CCR		60
+#define EX_R3		64
+#define EX_LR		72
 
 #define EXCEPTION_PROLOG_PSERIES(area, label)				\
 	mfspr	r13,SPRN_SPRG3;		/* get paca address into r13 */	\
@@ -419,17 +419,22 @@ data_access_slb_pSeries:
 	mtspr	SPRN_SPRG1,r13
 	RUNLATCH_ON(r13)
 	mfspr	r13,SPRN_SPRG3		/* get paca address into r13 */
+	std	r3,PACA_EXSLB+EX_R3(r13)
+	mfspr	r3,SPRN_DAR
 	std	r9,PACA_EXSLB+EX_R9(r13)	/* save r9 - r12 */
+	mfcr	r9
+#ifdef __DISABLED__
+	/* Keep that around for when we re-implement dynamic VSIDs */
+	cmpdi	r3,0
+	bge	slb_miss_user_pseries
+#endif /* __DISABLED__ */
 	std	r10,PACA_EXSLB+EX_R10(r13)
 	std	r11,PACA_EXSLB+EX_R11(r13)
 	std	r12,PACA_EXSLB+EX_R12(r13)
-	std	r3,PACA_EXSLB+EX_R3(r13)
-	mfspr	r9,SPRN_SPRG1
-	std	r9,PACA_EXSLB+EX_R13(r13)
-	mfcr	r9
+	mfspr	r10,SPRN_SPRG1
+	std	r10,PACA_EXSLB+EX_R13(r13)
 	mfspr	r12,SPRN_SRR1		/* and SRR1 */
-	mfspr	r3,SPRN_DAR
-	b	.do_slb_miss		/* Rel. branch works in real mode */
+	b	.slb_miss_realmode	/* Rel. branch works in real mode */
 
 	STD_EXCEPTION_PSERIES(0x400, instruction_access)
 
@@ -440,17 +445,22 @@ instruction_access_slb_pSeries:
 	mtspr	SPRN_SPRG1,r13
 	RUNLATCH_ON(r13)
 	mfspr	r13,SPRN_SPRG3		/* get paca address into r13 */
+	std	r3,PACA_EXSLB+EX_R3(r13)
+	mfspr	r3,SPRN_SRR0		/* SRR0 is faulting address */
 	std	r9,PACA_EXSLB+EX_R9(r13)	/* save r9 - r12 */
+	mfcr	r9
+#ifdef __DISABLED__
+	/* Keep that around for when we re-implement dynamic VSIDs */
+	cmpdi	r3,0
+	bge	slb_miss_user_pseries
+#endif /* __DISABLED__ */
 	std	r10,PACA_EXSLB+EX_R10(r13)
 	std	r11,PACA_EXSLB+EX_R11(r13)
 	std	r12,PACA_EXSLB+EX_R12(r13)
-	std	r3,PACA_EXSLB+EX_R3(r13)
-	mfspr	r9,SPRN_SPRG1
-	std	r9,PACA_EXSLB+EX_R13(r13)
-	mfcr	r9
+	mfspr	r10,SPRN_SPRG1
+	std	r10,PACA_EXSLB+EX_R13(r13)
 	mfspr	r12,SPRN_SRR1		/* and SRR1 */
-	mfspr	r3,SPRN_SRR0			/* SRR0 is faulting address */
-	b	.do_slb_miss		/* Rel. branch works in real mode */
+	b	.slb_miss_realmode	/* Rel. branch works in real mode */
 
 	STD_EXCEPTION_PSERIES(0x500, hardware_interrupt)
 	STD_EXCEPTION_PSERIES(0x600, alignment)
@@ -509,6 +519,38 @@ _GLOBAL(do_stab_bolted_pSeries)
 	EXCEPTION_PROLOG_PSERIES(PACA_EXSLB, .do_stab_bolted)
 
 /*
+ * We have some room here  we use that to put
+ * the peries slb miss user trampoline code so it's reasonably
+ * away from slb_miss_user_common to avoid problems with rfid
+ *
+ * This is used for when the SLB miss handler has to go virtual,
+ * which doesn't happen for now anymore but will once we re-implement
+ * dynamic VSIDs for shared page tables
+ */
+#ifdef __DISABLED__
+slb_miss_user_pseries:
+	std	r10,PACA_EXGEN+EX_R10(r13)
+	std	r11,PACA_EXGEN+EX_R11(r13)
+	std	r12,PACA_EXGEN+EX_R12(r13)
+	mfspr	r10,SPRG1
+	ld	r11,PACA_EXSLB+EX_R9(r13)
+	ld	r12,PACA_EXSLB+EX_R3(r13)
+	std	r10,PACA_EXGEN+EX_R13(r13)
+	std	r11,PACA_EXGEN+EX_R9(r13)
+	std	r12,PACA_EXGEN+EX_R3(r13)
+	clrrdi	r12,r13,32
+	mfmsr	r10
+	mfspr	r11,SRR0			/* save SRR0 */
+	ori	r12,r12,slb_miss_user_common@l	/* virt addr of handler */
+	ori	r10,r10,MSR_IR|MSR_DR|MSR_RI
+	mtspr	SRR0,r12
+	mfspr	r12,SRR1			/* and SRR1 */
+	mtspr	SRR1,r10
+	rfid
+	b	.				/* prevent spec. execution */
+#endif /* __DISABLED__ */
+
+/*
  * Vectors for the FWNMI option.  Share common code.
  */
 	.globl system_reset_fwnmi
@@ -559,22 +601,59 @@ END_FTR_SECTION_IFCLR(CPU_FTR_SLB)
 	.globl	data_access_slb_iSeries
 data_access_slb_iSeries:
 	mtspr	SPRN_SPRG1,r13		/* save r13 */
-	EXCEPTION_PROLOG_ISERIES_1(PACA_EXSLB)
+	mfspr	r13,SPRN_SPRG3		/* get paca address into r13 */
 	std	r3,PACA_EXSLB+EX_R3(r13)
-	ld	r12,PACALPPACA+LPPACASRR1(r13)
 	mfspr	r3,SPRN_DAR
-	b	.do_slb_miss
+	std	r9,PACA_EXSLB+EX_R9(r13)
+	mfcr	r9
+#ifdef __DISABLED__
+	cmpdi	r3,0
+	bge	slb_miss_user_iseries
+#endif
+	std	r10,PACA_EXSLB+EX_R10(r13)
+	std	r11,PACA_EXSLB+EX_R11(r13)
+	std	r12,PACA_EXSLB+EX_R12(r13)
+	mfspr	r10,SPRN_SPRG1
+	std	r10,PACA_EXSLB+EX_R13(r13)
+	ld	r12,PACALPPACA+LPPACASRR1(r13);
+	b	.slb_miss_realmode
 
 	STD_EXCEPTION_ISERIES(0x400, instruction_access, PACA_EXGEN)
 
 	.globl	instruction_access_slb_iSeries
 instruction_access_slb_iSeries:
 	mtspr	SPRN_SPRG1,r13		/* save r13 */
-	EXCEPTION_PROLOG_ISERIES_1(PACA_EXSLB)
+	mfspr	r13,SPRN_SPRG3		/* get paca address into r13 */
 	std	r3,PACA_EXSLB+EX_R3(r13)
-	ld	r12,PACALPPACA+LPPACASRR1(r13)
-	ld	r3,PACALPPACA+LPPACASRR0(r13)
-	b	.do_slb_miss
+	ld	r3,PACALPPACA+LPPACASRR0(r13)	/* get SRR0 value */
+	std	r9,PACA_EXSLB+EX_R9(r13)
+	mfcr	r9
+#ifdef __DISABLED__
+	cmpdi	r3,0
+	bge	.slb_miss_user_iseries
+#endif
+	std	r10,PACA_EXSLB+EX_R10(r13)
+	std	r11,PACA_EXSLB+EX_R11(r13)
+	std	r12,PACA_EXSLB+EX_R12(r13)
+	mfspr	r10,SPRN_SPRG1
+	std	r10,PACA_EXSLB+EX_R13(r13)
+	ld	r12,PACALPPACA+LPPACASRR1(r13);
+	b	.slb_miss_realmode
+
+#ifdef __DISABLED__
+slb_miss_user_iseries:
+	std	r10,PACA_EXGEN+EX_R10(r13)
+	std	r11,PACA_EXGEN+EX_R11(r13)
+	std	r12,PACA_EXGEN+EX_R12(r13)
+	mfspr	r10,SPRG1
+	ld	r11,PACA_EXSLB+EX_R9(r13)
+	ld	r12,PACA_EXSLB+EX_R3(r13)
+	std	r10,PACA_EXGEN+EX_R13(r13)
+	std	r11,PACA_EXGEN+EX_R9(r13)
+	std	r12,PACA_EXGEN+EX_R3(r13)
+	EXCEPTION_PROLOG_ISERIES_2
+	b	slb_miss_user_common
+#endif
 
 	MASKABLE_EXCEPTION_ISERIES(0x500, hardware_interrupt)
 	STD_EXCEPTION_ISERIES(0x600, alignment, PACA_EXGEN)
@@ -809,6 +888,126 @@ instruction_access_common:
 	li	r5,0x400
 	b	.do_hash_page		/* Try to handle as hpte fault */
 
+/*
+ * Here is the common SLB miss user that is used when going to virtual
+ * mode for SLB misses, that is currently not used
+ */
+#ifdef __DISABLED__
+	.align	7
+	.globl	slb_miss_user_common
+slb_miss_user_common:
+	mflr	r10
+	std	r3,PACA_EXGEN+EX_DAR(r13)
+	stw	r9,PACA_EXGEN+EX_CCR(r13)
+	std	r10,PACA_EXGEN+EX_LR(r13)
+	std	r11,PACA_EXGEN+EX_SRR0(r13)
+	bl	.slb_allocate_user
+
+	ld	r10,PACA_EXGEN+EX_LR(r13)
+	ld	r3,PACA_EXGEN+EX_R3(r13)
+	lwz	r9,PACA_EXGEN+EX_CCR(r13)
+	ld	r11,PACA_EXGEN+EX_SRR0(r13)
+	mtlr	r10
+	beq-	slb_miss_fault
+
+	andi.	r10,r12,MSR_RI		/* check for unrecoverable exception */
+	beq-	unrecov_user_slb
+	mfmsr	r10
+
+.machine push
+.machine "power4"
+	mtcrf	0x80,r9
+.machine pop
+
+	clrrdi	r10,r10,2		/* clear RI before setting SRR0/1 */
+	mtmsrd	r10,1
+
+	mtspr	SRR0,r11
+	mtspr	SRR1,r12
+
+	ld	r9,PACA_EXGEN+EX_R9(r13)
+	ld	r10,PACA_EXGEN+EX_R10(r13)
+	ld	r11,PACA_EXGEN+EX_R11(r13)
+	ld	r12,PACA_EXGEN+EX_R12(r13)
+	ld	r13,PACA_EXGEN+EX_R13(r13)
+	rfid
+	b	.
+
+slb_miss_fault:
+	EXCEPTION_PROLOG_COMMON(0x380, PACA_EXGEN)
+	ld	r4,PACA_EXGEN+EX_DAR(r13)
+	li	r5,0
+	std	r4,_DAR(r1)
+	std	r5,_DSISR(r1)
+	b	.handle_page_fault
+
+unrecov_user_slb:
+	EXCEPTION_PROLOG_COMMON(0x4200, PACA_EXGEN)
+	DISABLE_INTS
+	bl	.save_nvgprs
+1:	addi	r3,r1,STACK_FRAME_OVERHEAD
+	bl	.unrecoverable_exception
+	b	1b
+
+#endif /* __DISABLED__ */
+
+
+/*
+ * r13 points to the PACA, r9 contains the saved CR,
+ * r12 contain the saved SRR1, SRR0 is still ready for return
+ * r3 has the faulting address
+ * r9 - r13 are saved in paca->exslb.
+ * r3 is saved in paca->slb_r3
+ * We assume we aren't going to take any exceptions during this procedure.
+ */
+_GLOBAL(slb_miss_realmode)
+	mflr	r10
+
+	stw	r9,PACA_EXSLB+EX_CCR(r13)	/* save CR in exc. frame */
+	std	r10,PACA_EXSLB+EX_LR(r13)	/* save LR */
+
+	bl	.slb_allocate_realmode
+
+	/* All done -- return from exception. */
+
+	ld	r10,PACA_EXSLB+EX_LR(r13)
+	ld	r3,PACA_EXSLB+EX_R3(r13)
+	lwz	r9,PACA_EXSLB+EX_CCR(r13)	/* get saved CR */
+#ifdef CONFIG_PPC_ISERIES
+	ld	r11,PACALPPACA+LPPACASRR0(r13)	/* get SRR0 value */
+#endif /* CONFIG_PPC_ISERIES */
+
+	mtlr	r10
+
+	andi.	r10,r12,MSR_RI	/* check for unrecoverable exception */
+	beq-	unrecov_slb
+
+.machine	push
+.machine	"power4"
+	mtcrf	0x80,r9
+	mtcrf	0x01,r9		/* slb_allocate uses cr0 and cr7 */
+.machine	pop
+
+#ifdef CONFIG_PPC_ISERIES
+	mtspr	SPRN_SRR0,r11
+	mtspr	SPRN_SRR1,r12
+#endif /* CONFIG_PPC_ISERIES */
+	ld	r9,PACA_EXSLB+EX_R9(r13)
+	ld	r10,PACA_EXSLB+EX_R10(r13)
+	ld	r11,PACA_EXSLB+EX_R11(r13)
+	ld	r12,PACA_EXSLB+EX_R12(r13)
+	ld	r13,PACA_EXSLB+EX_R13(r13)
+	rfid
+	b	.	/* prevent speculative execution */
+
+unrecov_slb:
+	EXCEPTION_PROLOG_COMMON(0x4100, PACA_EXSLB)
+	DISABLE_INTS
+	bl	.save_nvgprs
+1:	addi	r3,r1,STACK_FRAME_OVERHEAD
+	bl	.unrecoverable_exception
+	b	1b
+
 	.align	7
 	.globl hardware_interrupt_common
 	.globl hardware_interrupt_entry
@@ -1139,62 +1338,6 @@ _GLOBAL(do_stab_bolted)
 	b	.	/* prevent speculative execution */
 
 /*
- * r13 points to the PACA, r9 contains the saved CR,
- * r11 and r12 contain the saved SRR0 and SRR1.
- * r3 has the faulting address
- * r9 - r13 are saved in paca->exslb.
- * r3 is saved in paca->slb_r3
- * We assume we aren't going to take any exceptions during this procedure.
- */
-_GLOBAL(do_slb_miss)
-	mflr	r10
-
-	stw	r9,PACA_EXSLB+EX_CCR(r13)	/* save CR in exc. frame */
-	std	r10,PACA_EXSLB+EX_LR(r13)	/* save LR */
-
-	bl	.slb_allocate			/* handle it */
-
-	/* All done -- return from exception. */
-
-	ld	r10,PACA_EXSLB+EX_LR(r13)
-	ld	r3,PACA_EXSLB+EX_R3(r13)
-	lwz	r9,PACA_EXSLB+EX_CCR(r13)	/* get saved CR */
-#ifdef CONFIG_PPC_ISERIES
-	ld	r11,PACALPPACA+LPPACASRR0(r13)	/* get SRR0 value */
-#endif /* CONFIG_PPC_ISERIES */
-
-	mtlr	r10
-
-	andi.	r10,r12,MSR_RI	/* check for unrecoverable exception */
-	beq-	unrecov_slb
-
-.machine	push
-.machine	"power4"
-	mtcrf	0x80,r9
-	mtcrf	0x01,r9		/* slb_allocate uses cr0 and cr7 */
-.machine	pop
-
-#ifdef CONFIG_PPC_ISERIES
-	mtspr	SPRN_SRR0,r11
-	mtspr	SPRN_SRR1,r12
-#endif /* CONFIG_PPC_ISERIES */
-	ld	r9,PACA_EXSLB+EX_R9(r13)
-	ld	r10,PACA_EXSLB+EX_R10(r13)
-	ld	r11,PACA_EXSLB+EX_R11(r13)
-	ld	r12,PACA_EXSLB+EX_R12(r13)
-	ld	r13,PACA_EXSLB+EX_R13(r13)
-	rfid
-	b	.	/* prevent speculative execution */
-
-unrecov_slb:
-	EXCEPTION_PROLOG_COMMON(0x4100, PACA_EXSLB)
-	DISABLE_INTS
-	bl	.save_nvgprs
-1:	addi	r3,r1,STACK_FRAME_OVERHEAD
-	bl	.unrecoverable_exception
-	b	1b
-
-/*
  * Space for CPU0's segment table.
  *
  * On iSeries, the hypervisor must fill in at least one entry before
@@ -1569,7 +1712,10 @@ _GLOBAL(__secondary_start)
 #endif
 	/* Initialize the first segment table (or SLB) entry		 */
 	ld	r3,PACASTABVIRT(r13)	/* get addr of segment table	 */
+BEGIN_FTR_SECTION
 	bl	.stab_initialize
+END_FTR_SECTION_IFCLR(CPU_FTR_SLB)
+	bl	.slb_initialize
 
 	/* Initialize the kernel stack.  Just a repeat for iSeries.	 */
 	LOADADDR(r3,current_set)