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/* clear_page.S: UltraSparc optimized clear page.
*
* Copyright (C) 1996, 1998, 1999, 2000, 2004 David S. Miller (davem@redhat.com)
* Copyright (C) 1997 Jakub Jelinek (jakub@redhat.com)
*/
#include <asm/visasm.h>
#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/spitfire.h>
/* What we used to do was lock a TLB entry into a specific
* TLB slot, clear the page with interrupts disabled, then
* restore the original TLB entry. This was great for
* disturbing the TLB as little as possible, but it meant
* we had to keep interrupts disabled for a long time.
*
* Now, we simply use the normal TLB loading mechanism,
* and this makes the cpu choose a slot all by itself.
* Then we do a normal TLB flush on exit. We need only
* disable preemption during the clear.
*/
#define TTE_BITS_TOP (_PAGE_VALID | _PAGE_SZBITS)
#define TTE_BITS_BOTTOM (_PAGE_CP | _PAGE_CV | _PAGE_P | _PAGE_L | _PAGE_W)
.text
.globl _clear_page
_clear_page: /* %o0=dest */
ba,pt %xcc, clear_page_common
clr %o4
/* This thing is pretty important, it shows up
* on the profiles via do_anonymous_page().
*/
.align 32
.globl clear_user_page
clear_user_page: /* %o0=dest, %o1=vaddr */
lduw [%g6 + TI_PRE_COUNT], %o2
sethi %uhi(PAGE_OFFSET), %g2
sethi %hi(PAGE_SIZE), %o4
sllx %g2, 32, %g2
sethi %uhi(TTE_BITS_TOP), %g3
sllx %g3, 32, %g3
sub %o0, %g2, %g1 ! paddr
or %g3, TTE_BITS_BOTTOM, %g3
and %o1, %o4, %o0 ! vaddr D-cache alias bit
or %g1, %g3, %g1 ! TTE data
sethi %hi(TLBTEMP_BASE), %o3
add %o2, 1, %o4
add %o0, %o3, %o0 ! TTE vaddr
/* Disable preemption. */
mov TLB_TAG_ACCESS, %g3
stw %o4, [%g6 + TI_PRE_COUNT]
/* Load TLB entry. */
rdpr %pstate, %o4
wrpr %o4, PSTATE_IE, %pstate
stxa %o0, [%g3] ASI_DMMU
stxa %g1, [%g0] ASI_DTLB_DATA_IN
flush %g6
wrpr %o4, 0x0, %pstate
mov 1, %o4
clear_page_common:
VISEntryHalf
membar #StoreLoad | #StoreStore | #LoadStore
fzero %f0
sethi %hi(PAGE_SIZE/64), %o1
mov %o0, %g1 ! remember vaddr for tlbflush
fzero %f2
or %o1, %lo(PAGE_SIZE/64), %o1
faddd %f0, %f2, %f4
fmuld %f0, %f2, %f6
faddd %f0, %f2, %f8
fmuld %f0, %f2, %f10
faddd %f0, %f2, %f12
fmuld %f0, %f2, %f14
1: stda %f0, [%o0 + %g0] ASI_BLK_P
subcc %o1, 1, %o1
bne,pt %icc, 1b
add %o0, 0x40, %o0
membar #Sync
VISExitHalf
brz,pn %o4, out
nop
stxa %g0, [%g1] ASI_DMMU_DEMAP
membar #Sync
stw %o2, [%g6 + TI_PRE_COUNT]
out: retl
nop
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