arch/sparc/include/asm/tsb.h

#ifndef _SPARC64_TSB_H
#define _SPARC64_TSB_H

/* The sparc64 TSB is similar to the powerpc hashtables.  It's a
 * power-of-2 sized table of TAG/PTE pairs.  The cpu precomputes
 * pointers into this table for 8K and 64K page sizes, and also a
 * comparison TAG based upon the virtual address and context which
 * faults.
 *
 * TLB miss trap handler software does the actual lookup via something
 * of the form:
 *
 * 	ldxa		[%g0] ASI_{D,I}MMU_TSB_8KB_PTR, %g1
 * 	ldxa		[%g0] ASI_{D,I}MMU, %g6
 *	sllx		%g6, 22, %g6
 *	srlx		%g6, 22, %g6
 * 	ldda		[%g1] ASI_NUCLEUS_QUAD_LDD, %g4
 * 	cmp		%g4, %g6
 * 	bne,pn	%xcc, tsb_miss_{d,i}tlb
 * 	 mov		FAULT_CODE_{D,I}TLB, %g3
 * 	stxa		%g5, [%g0] ASI_{D,I}TLB_DATA_IN
 * 	retry
 *
 *
 * Each 16-byte slot of the TSB is the 8-byte tag and then the 8-byte
 * PTE.  The TAG is of the same layout as the TLB TAG TARGET mmu
 * register which is:
 *
 * -------------------------------------------------
 * |  -  |  CONTEXT |  -  |    VADDR bits 63:22    |
 * -------------------------------------------------
 *  63 61 60      48 47 42 41                     0
 *
 * But actually, since we use per-mm TSB's, we zero out the CONTEXT
 * field.
 *
 * Like the powerpc hashtables we need to use locking in order to
 * synchronize while we update the entries.  PTE updates need locking
 * as well.
 *
 * We need to carefully choose a lock bits for the TSB entry.  We
 * choose to use bit 47 in the tag.  Also, since we never map anything
 * at page zero in context zero, we use zero as an invalid tag entry.
 * When the lock bit is set, this forces a tag comparison failure.
 */

#define TSB_TAG_LOCK_BIT	47
#define TSB_TAG_LOCK_HIGH	(1 << (TSB_TAG_LOCK_BIT - 32))

#define TSB_TAG_INVALID_BIT	46
#define TSB_TAG_INVALID_HIGH	(1 << (TSB_TAG_INVALID_BIT - 32))

/* Some cpus support physical address quad loads.  We want to use
 * those if possible so we don't need to hard-lock the TSB mapping
 * into the TLB.  We encode some instruction patching in order to
 * support this.
 *
 * The kernel TSB is locked into the TLB by virtue of being in the
 * kernel image, so we don't play these games for swapper_tsb access.
 */
#ifndef __ASSEMBLY__
struct tsb_ldquad_phys_patch_entry {
	unsigned int	addr;
	unsigned int	sun4u_insn;
	unsigned int	sun4v_insn;
};
extern struct tsb_ldquad_phys_patch_entry __tsb_ldquad_phys_patch,
	__tsb_ldquad_phys_patch_end;

struct tsb_phys_patch_entry {
	unsigned int	addr;
	unsigned int	insn;
};
extern struct tsb_phys_patch_entry __tsb_phys_patch, __tsb_phys_patch_end;
#endif
#define TSB_LOAD_QUAD(TSB, REG)	\
661:	ldda		[TSB] ASI_NUCLEUS_QUAD_LDD, REG; \
	.section	.tsb_ldquad_phys_patch, "ax"; \
	.word		661b; \
	ldda		[TSB] ASI_QUAD_LDD_PHYS, REG; \
	ldda		[TSB] ASI_QUAD_LDD_PHYS_4V, REG; \
	.previous

#define TSB_LOAD_TAG_HIGH(TSB, REG) \
661:	lduwa		[TSB] ASI_N, REG; \
	.section	.tsb_phys_patch, "ax"; \
	.word		661b; \
	lduwa		[TSB] ASI_PHYS_USE_EC, REG; \
	.previous

#define TSB_LOAD_TAG(TSB, REG) \
661:	ldxa		[TSB] ASI_N, REG; \
	.section	.tsb_phys_patch, "ax"; \
	.word		661b; \
	ldxa		[TSB] ASI_PHYS_USE_EC, REG; \
	.previous

#define TSB_CAS_TAG_HIGH(TSB, REG1, REG2) \
661:	casa		[TSB] ASI_N, REG1, REG2; \
	.section	.tsb_phys_patch, "ax"; \
	.word		661b; \
	casa		[TSB] ASI_PHYS_USE_EC, REG1, REG2; \
	.previous

#define TSB_CAS_TAG(TSB, REG1, REG2) \
661:	casxa		[TSB] ASI_N, REG1, REG2; \
	.section	.tsb_phys_patch, "ax"; \
	.word		661b; \
	casxa		[TSB] ASI_PHYS_USE_EC, REG1, REG2; \
	.previous

#define TSB_STORE(ADDR, VAL) \
661:	stxa		VAL, [ADDR] ASI_N; \
	.section	.tsb_phys_patch, "ax"; \
	.word		661b; \
	stxa		VAL, [ADDR] ASI_PHYS_USE_EC; \
	.previous

#define TSB_LOCK_TAG(TSB, REG1, REG2)	\
99:	TSB_LOAD_TAG_HIGH(TSB, REG1);	\
	sethi	%hi(TSB_TAG_LOCK_HIGH), REG2;\
	andcc	REG1, REG2, %g0;	\
	bne,pn	%icc, 99b;		\
	 nop;				\
	TSB_CAS_TAG_HIGH(TSB, REG1, REG2);	\
	cmp	REG1, REG2;		\
	bne,pn	%icc, 99b;		\
	 nop;				\

#define TSB_WRITE(TSB, TTE, TAG) \
	add	TSB, 0x8, TSB;   \
	TSB_STORE(TSB, TTE);     \
	sub	TSB, 0x8, TSB;   \
	TSB_STORE(TSB, TAG);

	/* Do a kernel page table walk.  Leaves physical PTE pointer in
	 * REG1.  Jumps to FAIL_LABEL on early page table walk termination.
	 * VADDR will not be clobbered, but REG2 will.
	 */
#define KERN_PGTABLE_WALK(VADDR, REG1, REG2, FAIL_LABEL)	\
	sethi		%hi(swapper_pg_dir), REG1; \
	or		REG1, %lo(swapper_pg_dir), REG1; \
	sllx		VADDR, 64 - (PGDIR_SHIFT + PGDIR_BITS), REG2; \
	srlx		REG2, 64 - PAGE_SHIFT, REG2; \
	andn		REG2, 0x3, REG2; \
	lduw		[REG1 + REG2], REG1; \
	brz,pn		REG1, FAIL_LABEL; \
	 sllx		VADDR, 64 - (PMD_SHIFT + PMD_BITS), REG2; \
	srlx		REG2, 64 - PAGE_SHIFT, REG2; \
	sllx		REG1, PGD_PADDR_SHIFT, REG1; \
	andn		REG2, 0x3, REG2; \
	lduwa		[REG1 + REG2] ASI_PHYS_USE_EC, REG1; \
	brz,pn		REG1, FAIL_LABEL; \
	 sllx		VADDR, 64 - PMD_SHIFT, REG2; \
	srlx		REG2, 64 - (PAGE_SHIFT - 1), REG2; \
	sllx		REG1, PMD_PADDR_SHIFT, REG1; \
	andn		REG2, 0x7, REG2; \
	add		REG1, REG2, REG1;

	/* This macro exists only to make the PMD translator below easier
	 * to read.  It hides the ELF section switch for the sun4v code
	 * patching.
	 */
#define OR_PTE_BIT(REG, NAME)				\
661:	or		REG, _PAGE_##NAME##_4U, REG;	\
	.section	.sun4v_1insn_patch, "ax";	\
	.word		661b;				\
	or		REG, _PAGE_##NAME##_4V, REG;	\
	.previous;

	/* Load into REG the PTE value for VALID, CACHE, and SZHUGE.  */
#define BUILD_PTE_VALID_SZHUGE_CACHE(REG)				   \
661:	sethi		%uhi(_PAGE_VALID|_PAGE_SZHUGE_4U), REG;		   \
	.section	.sun4v_1insn_patch, "ax";			   \
	.word		661b;						   \
	sethi		%uhi(_PAGE_VALID), REG;				   \
	.previous;							   \
	sllx		REG, 32, REG;					   \
661:	or		REG, _PAGE_CP_4U|_PAGE_CV_4U, REG;		   \
	.section	.sun4v_1insn_patch, "ax";			   \
	.word		661b;						   \
	or		REG, _PAGE_CP_4V|_PAGE_CV_4V|_PAGE_SZHUGE_4V, REG; \
	.previous;

	/* PMD has been loaded into REG1, interpret the value, seeing
	 * if it is a HUGE PMD or a normal one.  If it is not valid
	 * then jump to FAIL_LABEL.  If it is a HUGE PMD, and it
	 * translates to a valid PTE, branch to PTE_LABEL.
	 *
	 * We translate the PMD by hand, one bit at a time,
	 * constructing the huge PTE.
	 *
	 * So we construct the PTE in REG2 as follows:
	 *
	 * 1) Extract the PMD PFN from REG1 and place it into REG2.
	 *
	 * 2) Translate PMD protection bits in REG1 into REG2, one bit
	 *    at a time using andcc tests on REG1 and OR's into REG2.
	 *
	 *    Only two bits to be concerned with here, EXEC and WRITE.
	 *    Now REG1 is freed up and we can use it as a temporary.
	 *
	 * 3) Construct the VALID, CACHE, and page size PTE bits in
	 *    REG1, OR with REG2 to form final PTE.
	 */
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define USER_PGTABLE_CHECK_PMD_HUGE(VADDR, REG1, REG2, FAIL_LABEL, PTE_LABEL) \
	brz,pn		REG1, FAIL_LABEL;				      \
	 andcc		REG1, PMD_ISHUGE, %g0;				      \
	be,pt		%xcc, 700f;					      \
	 and		REG1, PMD_HUGE_PRESENT|PMD_HUGE_ACCESSED, REG2;	      \
	cmp		REG2, PMD_HUGE_PRESENT|PMD_HUGE_ACCESSED;	      \
	bne,pn		%xcc, FAIL_LABEL;				      \
	 andn		REG1, PMD_HUGE_PROTBITS, REG2;			      \
	sllx		REG2, PMD_PADDR_SHIFT, REG2;			      \
	/* REG2 now holds PFN << PAGE_SHIFT */				      \
	andcc		REG1, PMD_HUGE_EXEC, %g0;			      \
	bne,a,pt	%xcc, 1f;					      \
	 OR_PTE_BIT(REG2, EXEC);					      \
1:	andcc		REG1, PMD_HUGE_WRITE, %g0;			      \
	bne,a,pt	%xcc, 1f;					      \
	 OR_PTE_BIT(REG2, W);						      \
	/* REG1 can now be clobbered, build final PTE */		      \
1:	BUILD_PTE_VALID_SZHUGE_CACHE(REG1);				      \
	ba,pt		%xcc, PTE_LABEL;				      \
	 or		REG1, REG2, REG1;				      \
700:
#else
#define USER_PGTABLE_CHECK_PMD_HUGE(VADDR, REG1, REG2, FAIL_LABEL, PTE_LABEL) \
	brz,pn		REG1, FAIL_LABEL; \
	 nop;
#endif

	/* Do a user page table walk in MMU globals.  Leaves final,
	 * valid, PTE value in REG1.  Jumps to FAIL_LABEL on early
	 * page table walk termination or if the PTE is not valid.
	 *
	 * Physical base of page tables is in PHYS_PGD which will not
	 * be modified.
	 *
	 * VADDR will not be clobbered, but REG1 and REG2 will.
	 */
#define USER_PGTABLE_WALK_TL1(VADDR, PHYS_PGD, REG1, REG2, FAIL_LABEL)	\
	sllx		VADDR, 64 - (PGDIR_SHIFT + PGDIR_BITS), REG2; \
	srlx		REG2, 64 - PAGE_SHIFT, REG2; \
	andn		REG2, 0x3, REG2; \
	lduwa		[PHYS_PGD + REG2] ASI_PHYS_USE_EC, REG1; \
	brz,pn		REG1, FAIL_LABEL; \
	 sllx		VADDR, 64 - (PMD_SHIFT + PMD_BITS), REG2; \
	srlx		REG2, 64 - PAGE_SHIFT, REG2; \
	sllx		REG1, PGD_PADDR_SHIFT, REG1; \
	andn		REG2, 0x3, REG2; \
	lduwa		[REG1 + REG2] ASI_PHYS_USE_EC, REG1; \
	USER_PGTABLE_CHECK_PMD_HUGE(VADDR, REG1, REG2, FAIL_LABEL, 800f) \
	sllx		VADDR, 64 - PMD_SHIFT, REG2; \
	srlx		REG2, 64 - (PAGE_SHIFT - 1), REG2; \
	sllx		REG1, PMD_PADDR_SHIFT, REG1; \
	andn		REG2, 0x7, REG2; \
	add		REG1, REG2, REG1; \
	ldxa		[REG1] ASI_PHYS_USE_EC, REG1; \
	brgez,pn	REG1, FAIL_LABEL; \
	 nop; \
800:

/* Lookup a OBP mapping on VADDR in the prom_trans[] table at TL>0.
 * If no entry is found, FAIL_LABEL will be branched to.  On success
 * the resulting PTE value will be left in REG1.  VADDR is preserved
 * by this routine.
 */
#define OBP_TRANS_LOOKUP(VADDR, REG1, REG2, REG3, FAIL_LABEL) \
	sethi		%hi(prom_trans), REG1; \
	or		REG1, %lo(prom_trans), REG1; \
97:	ldx		[REG1 + 0x00], REG2; \
	brz,pn		REG2, FAIL_LABEL; \
	 nop; \
	ldx		[REG1 + 0x08], REG3; \
	add		REG2, REG3, REG3; \
	cmp		REG2, VADDR; \
	bgu,pt		%xcc, 98f; \
	 cmp		VADDR, REG3; \
	bgeu,pt		%xcc, 98f; \
	 ldx		[REG1 + 0x10], REG3; \
	sub		VADDR, REG2, REG2; \
	ba,pt		%xcc, 99f; \
	 add		REG3, REG2, REG1; \
98:	ba,pt		%xcc, 97b; \
	 add		REG1, (3 * 8), REG1; \
99:

	/* We use a 32K TSB for the whole kernel, this allows to
	 * handle about 16MB of modules and vmalloc mappings without
	 * incurring many hash conflicts.
	 */
#define KERNEL_TSB_SIZE_BYTES	(32 * 1024)
#define KERNEL_TSB_NENTRIES	\
	(KERNEL_TSB_SIZE_BYTES / 16)
#define KERNEL_TSB4M_NENTRIES	4096

#define KTSB_PHYS_SHIFT		15

	/* Do a kernel TSB lookup at tl>0 on VADDR+TAG, branch to OK_LABEL
	 * on TSB hit.  REG1, REG2, REG3, and REG4 are used as temporaries
	 * and the found TTE will be left in REG1.  REG3 and REG4 must
	 * be an even/odd pair of registers.
	 *
	 * VADDR and TAG will be preserved and not clobbered by this macro.
	 */
#define KERN_TSB_LOOKUP_TL1(VADDR, TAG, REG1, REG2, REG3, REG4, OK_LABEL) \
661:	sethi		%hi(swapper_tsb), REG1;			\
	or		REG1, %lo(swapper_tsb), REG1; \
	.section	.swapper_tsb_phys_patch, "ax"; \
	.word		661b; \
	.previous; \
661:	nop; \
	.section	.tsb_ldquad_phys_patch, "ax"; \
	.word		661b; \
	sllx		REG1, KTSB_PHYS_SHIFT, REG1; \
	sllx		REG1, KTSB_PHYS_SHIFT, REG1; \
	.previous; \
	srlx		VADDR, PAGE_SHIFT, REG2; \
	and		REG2, (KERNEL_TSB_NENTRIES - 1), REG2; \
	sllx		REG2, 4, REG2; \
	add		REG1, REG2, REG2; \
	TSB_LOAD_QUAD(REG2, REG3); \
	cmp		REG3, TAG; \
	be,a,pt		%xcc, OK_LABEL; \
	 mov		REG4, REG1;

#ifndef CONFIG_DEBUG_PAGEALLOC
	/* This version uses a trick, the TAG is already (VADDR >> 22) so
	 * we can make use of that for the index computation.
	 */
#define KERN_TSB4M_LOOKUP_TL1(TAG, REG1, REG2, REG3, REG4, OK_LABEL) \
661:	sethi		%hi(swapper_4m_tsb), REG1;	     \
	or		REG1, %lo(swapper_4m_tsb), REG1; \
	.section	.swapper_4m_tsb_phys_patch, "ax"; \
	.word		661b; \
	.previous; \
661:	nop; \
	.section	.tsb_ldquad_phys_patch, "ax"; \
	.word		661b; \
	sllx		REG1, KTSB_PHYS_SHIFT, REG1; \
	sllx		REG1, KTSB_PHYS_SHIFT, REG1; \
	.previous; \
	and		TAG, (KERNEL_TSB4M_NENTRIES - 1), REG2; \
	sllx		REG2, 4, REG2; \
	add		REG1, REG2, REG2; \
	TSB_LOAD_QUAD(REG2, REG3); \
	cmp		REG3, TAG; \
	be,a,pt		%xcc, OK_LABEL; \
	 mov		REG4, REG1;
#endif

#endif /* !(_SPARC64_TSB_H) */