[SPARC64]: Move kernel TLB miss handling into a seperate file.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 174 insertions, 0 deletions

diff --git a/arch/sparc64/kernel/ktlb.S b/arch/sparc64/kernel/ktlb.S
new file mode 100644
index 000000000000..b7176792c9a2
--- /dev/null
+++ b/arch/sparc64/kernel/ktlb.S
@@ -0,0 +1,174 @@
+/* arch/sparc64/kernel/ktlb.S: Kernel mapping TLB miss handling.
+ *
+ * Copyright (C) 1995, 1997, 2005 David S. Miller <davem@davemloft.net>
+ * Copyright (C) 1996 Eddie C. Dost        (ecd@brainaid.de)
+ * Copyright (C) 1996 Miguel de Icaza      (miguel@nuclecu.unam.mx)
+ * Copyright (C) 1996,98,99 Jakub Jelinek  (jj@sunsite.mff.cuni.cz)
+*/
+
+#include <linux/config.h>
+#include <asm/head.h>
+#include <asm/asi.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+	.text
+	.align		32
+
+	.globl		sparc64_vpte_patchme1
+	.globl		sparc64_vpte_patchme2
+/*
+ * On a second level vpte miss, check whether the original fault is to the OBP 
+ * range (note that this is only possible for instruction miss, data misses to
+ * obp range do not use vpte). If so, go back directly to the faulting address.
+ * This is because we want to read the tpc, otherwise we have no way of knowing
+ * the 8k aligned faulting address if we are using >8k kernel pagesize. This
+ * also ensures no vpte range addresses are dropped into tlb while obp is
+ * executing (see inherit_locked_prom_mappings() rant).
+ */
+sparc64_vpte_nucleus:
+	/* Note that kvmap below has verified that the address is
+	 * in the range MODULES_VADDR --> VMALLOC_END already.  So
+	 * here we need only check if it is an OBP address or not.
+	 */
+	sethi		%hi(LOW_OBP_ADDRESS), %g5
+	cmp		%g4, %g5
+	blu,pn		%xcc, sparc64_vpte_patchme1
+	 mov		0x1, %g5
+	sllx		%g5, 32, %g5
+	cmp		%g4, %g5
+	blu,pn		%xcc, obp_iaddr_patch
+	 nop
+
+	/* These two instructions are patched by paginig_init().  */
+sparc64_vpte_patchme1:
+	sethi		%hi(0), %g5
+sparc64_vpte_patchme2:
+	or		%g5, %lo(0), %g5
+
+	/* With kernel PGD in %g5, branch back into dtlb_backend.  */
+	ba,pt		%xcc, sparc64_kpte_continue
+	 andn		%g1, 0x3, %g1	/* Finish PMD offset adjustment.  */
+
+vpte_noent:
+	/* Restore previous TAG_ACCESS, %g5 is zero, and we will
+	 * skip over the trap instruction so that the top level
+	 * TLB miss handler will thing this %g5 value is just an
+	 * invalid PTE, thus branching to full fault processing.
+	 */
+	mov		TLB_SFSR, %g1
+	stxa		%g4, [%g1 + %g1] ASI_DMMU
+	done
+
+	.globl		obp_iaddr_patch
+obp_iaddr_patch:
+	/* These two instructions patched by inherit_prom_mappings().  */
+	sethi		%hi(0), %g5
+	or		%g5, %lo(0), %g5
+
+	/* Behave as if we are at TL0.  */
+	wrpr		%g0, 1, %tl
+	rdpr		%tpc, %g4	/* Find original faulting iaddr */
+	srlx		%g4, 13, %g4	/* Throw out context bits */
+	sllx		%g4, 13, %g4	/* g4 has vpn + ctx0 now */
+
+	/* Restore previous TAG_ACCESS.  */
+	mov		TLB_SFSR, %g1
+	stxa		%g4, [%g1 + %g1] ASI_IMMU
+
+	/* Get PMD offset.  */
+	srlx		%g4, 23, %g6
+	and		%g6, 0x7ff, %g6
+	sllx		%g6, 2, %g6
+
+	/* Load PMD, is it valid?  */
+	lduwa		[%g5 + %g6] ASI_PHYS_USE_EC, %g5
+	brz,pn		%g5, longpath
+	 sllx		%g5, 11, %g5
+
+	/* Get PTE offset.  */
+	srlx		%g4, 13, %g6
+	and		%g6, 0x3ff, %g6
+	sllx		%g6, 3, %g6
+
+	/* Load PTE.  */
+	ldxa		[%g5 + %g6] ASI_PHYS_USE_EC, %g5
+	brgez,pn	%g5, longpath
+	 nop
+
+	/* TLB load and return from trap.  */
+	stxa		%g5, [%g0] ASI_ITLB_DATA_IN
+	retry
+
+	.globl		obp_daddr_patch
+obp_daddr_patch:
+	/* These two instructions patched by inherit_prom_mappings().  */
+	sethi		%hi(0), %g5
+	or		%g5, %lo(0), %g5
+
+	/* Get PMD offset.  */
+	srlx		%g4, 23, %g6
+	and		%g6, 0x7ff, %g6
+	sllx		%g6, 2, %g6
+
+	/* Load PMD, is it valid?  */
+	lduwa		[%g5 + %g6] ASI_PHYS_USE_EC, %g5
+	brz,pn		%g5, longpath
+	 sllx		%g5, 11, %g5
+
+	/* Get PTE offset.  */
+	srlx		%g4, 13, %g6
+	and		%g6, 0x3ff, %g6
+	sllx		%g6, 3, %g6
+
+	/* Load PTE.  */
+	ldxa		[%g5 + %g6] ASI_PHYS_USE_EC, %g5
+	brgez,pn	%g5, longpath
+	 nop
+
+	/* TLB load and return from trap.  */
+	stxa		%g5, [%g0] ASI_DTLB_DATA_IN
+	retry
+
+/*
+ * On a first level data miss, check whether this is to the OBP range (note
+ * that such accesses can be made by prom, as well as by kernel using
+ * prom_getproperty on "address"), and if so, do not use vpte access ...
+ * rather, use information saved during inherit_prom_mappings() using 8k
+ * pagesize.
+ */
+	.align		32
+kvmap:
+	brlz,pt		%g4, kvmap_load
+	 xor		%g2, %g4, %g5
+
+kvmap_nonlinear:
+	sethi		%hi(MODULES_VADDR), %g5
+	cmp		%g4, %g5
+	blu,pn		%xcc, longpath
+	 mov		(VMALLOC_END >> 24), %g5
+	sllx		%g5, 24, %g5
+	cmp		%g4, %g5
+	bgeu,pn		%xcc, longpath
+	 nop
+
+kvmap_check_obp:
+	sethi		%hi(LOW_OBP_ADDRESS), %g5
+	cmp		%g4, %g5
+	blu,pn		%xcc, kvmap_vmalloc_addr
+	 mov		0x1, %g5
+	sllx		%g5, 32, %g5
+	cmp		%g4, %g5
+	blu,pn		%xcc, obp_daddr_patch
+	 nop
+
+kvmap_vmalloc_addr:
+	/* If we get here, a vmalloc addr was accessed, load kernel VPTE.  */
+	ldxa		[%g3 + %g6] ASI_N, %g5
+	brgez,pn	%g5, longpath
+	 nop
+
+kvmap_load:
+	/* PTE is valid, load into TLB and return from trap.  */
+	stxa		%g5, [%g0] ASI_DTLB_DATA_IN	! Reload TLB
+	retry