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/* $Id: itlb_base.S,v 1.12 2002/02/09 19:49:30 davem Exp $
* itlb_base.S: Front end to ITLB miss replacement strategy.
* This is included directly into the trap table.
*
* Copyright (C) 1996,1998 David S. Miller (davem@redhat.com)
* Copyright (C) 1997,1998 Jakub Jelinek (jj@ultra.linux.cz)
*/
#if PAGE_SHIFT == 13
/*
* To compute vpte offset, we need to do ((addr >> 13) << 3),
* which can be optimized to (addr >> 10) if bits 10/11/12 can
* be guaranteed to be 0 ... mmu_context.h does guarantee this
* by only using 10 bits in the hwcontext value.
*/
#define CREATE_VPTE_OFFSET1(r1, r2) \
srax r1, 10, r2
#define CREATE_VPTE_OFFSET2(r1, r2)
#define CREATE_VPTE_NOP nop
#else /* PAGE_SHIFT */
#define CREATE_VPTE_OFFSET1(r1, r2) \
srax r1, PAGE_SHIFT, r2
#define CREATE_VPTE_OFFSET2(r1, r2) \
sllx r2, 3, r2
#define CREATE_VPTE_NOP
#endif /* PAGE_SHIFT */
/* Ways we can get here:
*
* 1) Nucleus instruction misses from module code.
* 2) All user instruction misses.
*
* All real page faults merge their code paths to the
* sparc64_realfault_common label below.
*/
/* ITLB ** ICACHE line 1: Quick user TLB misses */
ldxa [%g1 + %g1] ASI_IMMU, %g4 ! Get TAG_ACCESS
CREATE_VPTE_OFFSET1(%g4, %g6) ! Create VPTE offset
CREATE_VPTE_OFFSET2(%g4, %g6) ! Create VPTE offset
ldxa [%g3 + %g6] ASI_P, %g5 ! Load VPTE
1: brgez,pn %g5, 3f ! Not valid, branch out
sethi %hi(_PAGE_EXEC), %g4 ! Delay-slot
andcc %g5, %g4, %g0 ! Executable?
be,pn %xcc, 3f ! Nope, branch.
nop ! Delay-slot
2: stxa %g5, [%g0] ASI_ITLB_DATA_IN ! Load PTE into TLB
retry ! Trap return
3: rdpr %pstate, %g4 ! Move into alternate globals
/* ITLB ** ICACHE line 2: Real faults */
wrpr %g4, PSTATE_AG|PSTATE_MG, %pstate
rdpr %tpc, %g5 ! And load faulting VA
mov FAULT_CODE_ITLB, %g4 ! It was read from ITLB
sparc64_realfault_common: ! Called by TL0 dtlb_miss too
stb %g4, [%g6 + TI_FAULT_CODE]
stx %g5, [%g6 + TI_FAULT_ADDR]
ba,pt %xcc, etrap ! Save state
1: rd %pc, %g7 ! ...
nop
/* ITLB ** ICACHE line 3: Finish faults + window fixups */
call do_sparc64_fault ! Call fault handler
add %sp, PTREGS_OFF, %o0! Compute pt_regs arg
ba,pt %xcc, rtrap_clr_l6 ! Restore cpu state
nop
winfix_trampoline:
rdpr %tpc, %g3 ! Prepare winfixup TNPC
or %g3, 0x7c, %g3 ! Compute offset to branch
wrpr %g3, %tnpc ! Write it into TNPC
done ! Do it to it
/* ITLB ** ICACHE line 4: Unused... */
nop
nop
nop
nop
CREATE_VPTE_NOP
#undef CREATE_VPTE_OFFSET1
#undef CREATE_VPTE_OFFSET2
#undef CREATE_VPTE_NOP
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