linux/arch/sparc64/lib/clear_page.S
David S. Miller c4bce90ea2 [SPARC64]: Deal with PTE layout differences in SUN4V.
Yes, you heard it right, they changed the PTE layout for
SUN4V.  Ho hum...

This is the simple and inefficient way to support this.
It'll get optimized, don't worry.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 01:12:25 -08:00

104 lines
2.4 KiB
ArmAsm

/* 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>
#include <asm/head.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.
*/
.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 %hi(PAGE_KERNEL_LOCKED), %g3
ldx [%g3 + %lo(PAGE_KERNEL_LOCKED)], %g3
sub %o0, %g2, %g1 ! paddr
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
sethi %hi(KERNBASE), %g1
flush %g1
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