diff options
Diffstat (limited to 'arch/sparc/lib/clear_page.S')
| -rw-r--r-- | arch/sparc/lib/clear_page.S | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/arch/sparc/lib/clear_page.S b/arch/sparc/lib/clear_page.S new file mode 100644 index 000000000..302d3454a --- /dev/null +++ b/arch/sparc/lib/clear_page.S @@ -0,0 +1,107 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* 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 <linux/pgtable.h> +#include <asm/visasm.h> +#include <asm/thread_info.h> +#include <asm/page.h> +#include <asm/spitfire.h> +#include <asm/head.h> +#include <asm/export.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 + EXPORT_SYMBOL(_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 + EXPORT_SYMBOL(clear_user_page) +clear_user_page: /* %o0=dest, %o1=vaddr */ + lduw [%g6 + TI_PRE_COUNT], %o2 + sethi %hi(PAGE_OFFSET), %g2 + sethi %hi(PAGE_SIZE), %o4 + + ldx [%g2 + %lo(PAGE_OFFSET)], %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 + |