1/* clear_page.S: UltraSparc optimized clear page. 2 * 3 * Copyright (C) 1996, 1998, 1999, 2000, 2004 David S. Miller (davem@redhat.com) 4 * Copyright (C) 1997 Jakub Jelinek (jakub@redhat.com) 5 */ 6 7#include <asm/visasm.h> 8#include <asm/thread_info.h> 9#include <asm/page.h> 10#include <asm/pgtable.h> 11#include <asm/spitfire.h> 12#include <asm/head.h> 13 14 /* What we used to do was lock a TLB entry into a specific 15 * TLB slot, clear the page with interrupts disabled, then 16 * restore the original TLB entry. This was great for 17 * disturbing the TLB as little as possible, but it meant 18 * we had to keep interrupts disabled for a long time. 19 * 20 * Now, we simply use the normal TLB loading mechanism, 21 * and this makes the cpu choose a slot all by itself. 22 * Then we do a normal TLB flush on exit. We need only 23 * disable preemption during the clear. 24 */ 25 26 .text 27 28 .globl _clear_page 29_clear_page: /* %o0=dest */ 30 ba,pt %xcc, clear_page_common 31 clr %o4 32 33 /* This thing is pretty important, it shows up 34 * on the profiles via do_anonymous_page(). 35 */ 36 .align 32 37 .globl clear_user_page 38clear_user_page: /* %o0=dest, %o1=vaddr */ 39 lduw [%g6 + TI_PRE_COUNT], %o2 40 sethi %hi(PAGE_OFFSET), %g2 41 sethi %hi(PAGE_SIZE), %o4 42 43 ldx [%g2 + %lo(PAGE_OFFSET)], %g2 44 sethi %hi(PAGE_KERNEL_LOCKED), %g3 45 46 ldx [%g3 + %lo(PAGE_KERNEL_LOCKED)], %g3 47 sub %o0, %g2, %g1 ! paddr 48 49 and %o1, %o4, %o0 ! vaddr D-cache alias bit 50 51 or %g1, %g3, %g1 ! TTE data 52 sethi %hi(TLBTEMP_BASE), %o3 53 54 add %o2, 1, %o4 55 add %o0, %o3, %o0 ! TTE vaddr 56 57 /* Disable preemption. */ 58 mov TLB_TAG_ACCESS, %g3 59 stw %o4, [%g6 + TI_PRE_COUNT] 60 61 /* Load TLB entry. */ 62 rdpr %pstate, %o4 63 wrpr %o4, PSTATE_IE, %pstate 64 stxa %o0, [%g3] ASI_DMMU 65 stxa %g1, [%g0] ASI_DTLB_DATA_IN 66 sethi %hi(KERNBASE), %g1 67 flush %g1 68 wrpr %o4, 0x0, %pstate 69 70 mov 1, %o4 71 72clear_page_common: 73 VISEntryHalf 74 membar #StoreLoad | #StoreStore | #LoadStore 75 fzero %f0 76 sethi %hi(PAGE_SIZE/64), %o1 77 mov %o0, %g1 ! remember vaddr for tlbflush 78 fzero %f2 79 or %o1, %lo(PAGE_SIZE/64), %o1 80 faddd %f0, %f2, %f4 81 fmuld %f0, %f2, %f6 82 faddd %f0, %f2, %f8 83 fmuld %f0, %f2, %f10 84 85 faddd %f0, %f2, %f12 86 fmuld %f0, %f2, %f14 871: stda %f0, [%o0 + %g0] ASI_BLK_P 88 subcc %o1, 1, %o1 89 bne,pt %icc, 1b 90 add %o0, 0x40, %o0 91 membar #Sync 92 VISExitHalf 93 94 brz,pn %o4, out 95 nop 96 97 stxa %g0, [%g1] ASI_DMMU_DEMAP 98 membar #Sync 99 stw %o2, [%g6 + TI_PRE_COUNT] 100 101out: retl 102 nop 103 104