Subversion Repositories or1k

/* $Id: winfixup.S,v 1.1.1.1 2004-04-15 01:34:04 phoenix Exp $
 *
 * winfixup.S: Handle cases where user stack pointer is found to be bogus.
 *
 * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
 */

#include <asm/asi.h>
#include <asm/head.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/spitfire.h>
#include <asm/asm_offsets.h>

        .text
        .align  32

        /* Here are the rules, pay attention.
         *
         * The kernel is disallowed from touching user space while
         * the trap level is greater than zero, except for from within
         * the window spill/fill handlers.  This must be followed
         * so that we can easily detect the case where we tried to
         * spill/fill with a bogus (or unmapped) user stack pointer.
         *
         * These are layed out in a special way for cache reasons,
         * don't touch...
         */
        .globl  fill_fixup, spill_fixup
fill_fixup:
        rdpr            %tstate, %g1
        andcc           %g1, TSTATE_PRIV, %g0
        or              %g4, FAULT_CODE_WINFIXUP, %g4
        be,pt           %xcc, window_scheisse_from_user_common
         and            %g1, TSTATE_CWP, %g1

        /* This is the extremely complex case, but it does happen from
         * time to time if things are just right.  Essentially the restore
         * done in rtrap right before going back to user mode, with tl=1
         * and that levels trap stack registers all setup, took a fill trap,
         * the user stack was not mapped in the tlb, and tlb miss occurred,
         * the pte found was not valid, and a simple ref bit watch update
         * could not satisfy the miss, so we got here.
         *
         * We must carefully unwind the state so we get back to tl=0, preserve
         * all the register values we were going to give to the user.  Luckily
         * most things are where they need to be, we also have the address
         * which triggered the fault handy as well.
         *
         * Also note that we must preserve %l5 and %l6.  If the user was
         * returning from a system call, we must make it look this way
         * after we process the fill fault on the users stack.
         *
         * First, get into the window where the original restore was executed.
         */

        rdpr            %wstate, %g2                    ! Grab user mode wstate.
        wrpr            %g1, %cwp                       ! Get into the right window.
        sll             %g2, 3, %g2                     ! NORMAL-->OTHER

        wrpr            %g0, 0x0, %canrestore           ! Standard etrap stuff.
        wrpr            %g2, 0x0, %wstate               ! This must be consistant.
        wrpr            %g0, 0x0, %otherwin             ! We know this.
        mov             PRIMARY_CONTEXT, %g1            ! Change contexts...
        stxa            %g0, [%g1] ASI_DMMU             ! Back into the nucleus.
        flush           %g6                             ! Flush instruction buffers
        rdpr            %pstate, %l1                    ! Prepare to change globals.
        mov             %g6, %o7                        ! Get current.

        andn            %l1, PSTATE_MM, %l1             ! We want to be in RMO
        stb             %g4, [%g6 + AOFF_task_thread + AOFF_thread_fault_code]
        stx             %g5, [%g6 + AOFF_task_thread + AOFF_thread_fault_address]
        wrpr            %g0, 0x0, %tl                   ! Out of trap levels.
        wrpr            %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
        sethi           %uhi(PAGE_OFFSET), %g4          ! Prepare page_offset global reg
        mov             %o7, %g6
        sllx            %g4, 32, %g4                    ! and finish it...

        /* This is the same as below, except we handle this a bit special
         * since we must preserve %l5 and %l6, see comment above.
         */
        call            do_sparc64_fault
         add            %sp, PTREGS_OFF, %o0
        ba,pt           %xcc, rtrap
         nop                                            ! yes, nop is correct

        /* Be very careful about usage of the alternate globals here.
         * You cannot touch %g4/%g5 as that has the fault information
         * should this be from usermode.  Also be careful for the case
         * where we get here from the save instruction in etrap.S when
         * coming from either user or kernel (does not matter which, it
         * is the same problem in both cases).  Essentially this means
         * do not touch %g7 or %g2 so we handle the two cases fine.
         */
spill_fixup:
        ldub            [%g6 + AOFF_task_thread + AOFF_thread_flags], %g1
        andcc           %g1, SPARC_FLAG_32BIT, %g0
        ldub            [%g6 + AOFF_task_thread + AOFF_thread_w_saved], %g1

        sll             %g1, 3, %g3
        add             %g6, %g3, %g3
        stx             %sp, [%g3 + AOFF_task_thread + AOFF_thread_rwbuf_stkptrs]
        sll             %g1, 7, %g3
        bne,pt          %xcc, 1f
         add            %g6, %g3, %g3
        stx             %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
        stx             %l1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]

        stx             %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
        stx             %l3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
        stx             %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]
        stx             %l5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
        stx             %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
        stx             %l7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
        stx             %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x40]
        stx             %i1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x48]

        stx             %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x50]
        stx             %i3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x58]
        stx             %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x60]
        stx             %i5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x68]
        stx             %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x70]
        b,pt            %xcc, 2f
         stx            %i7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x78]
1:      stw             %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]

        stw             %l1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x04]
        stw             %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
        stw             %l3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x0c]
        stw             %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
        stw             %l5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x14]
        stw             %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
        stw             %l7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x1c]
        stw             %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]

        stw             %i1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x24]
        stw             %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
        stw             %i3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x2c]
        stw             %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
        stw             %i5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x34]
        stw             %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
        stw             %i7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x3c]
2:      add             %g1, 1, %g1

        stb             %g1, [%g6 + AOFF_task_thread + AOFF_thread_w_saved]
        rdpr            %tstate, %g1
        andcc           %g1, TSTATE_PRIV, %g0
        saved
        and             %g1, TSTATE_CWP, %g1
        be,pn           %xcc, window_scheisse_from_user_common
         mov            FAULT_CODE_WRITE | FAULT_CODE_DTLB | FAULT_CODE_WINFIXUP, %g4
        retry

window_scheisse_from_user_common:
        stb             %g4, [%g6 + AOFF_task_thread + AOFF_thread_fault_code]
        stx             %g5, [%g6 + AOFF_task_thread + AOFF_thread_fault_address]
        wrpr            %g1, %cwp
        ba,pt           %xcc, etrap
         rd             %pc, %g7
        call            do_sparc64_fault
         add            %sp, PTREGS_OFF, %o0
        ba,a,pt         %xcc, rtrap_clr_l6

        .globl          winfix_mna, fill_fixup_mna, spill_fixup_mna
winfix_mna:
        andn            %g3, 0x7f, %g3
        add             %g3, 0x78, %g3
        wrpr            %g3, %tnpc
        done
fill_fixup_mna:
        rdpr            %tstate, %g1
        andcc           %g1, TSTATE_PRIV, %g0
        be,pt           %xcc, window_mna_from_user_common
         and            %g1, TSTATE_CWP, %g1

        /* Please, see fill_fixup commentary about why we must preserve
         * %l5 and %l6 to preserve absolute correct semantics.
         */
        rdpr            %wstate, %g2                    ! Grab user mode wstate.
        wrpr            %g1, %cwp                       ! Get into the right window.
        sll             %g2, 3, %g2                     ! NORMAL-->OTHER
        wrpr            %g0, 0x0, %canrestore           ! Standard etrap stuff.

        wrpr            %g2, 0x0, %wstate               ! This must be consistant.
        wrpr            %g0, 0x0, %otherwin             ! We know this.
        mov             PRIMARY_CONTEXT, %g1            ! Change contexts...
        stxa            %g0, [%g1] ASI_DMMU             ! Back into the nucleus.
        flush           %g6                             ! Flush instruction buffers
        rdpr            %pstate, %l1                    ! Prepare to change globals.
        mov             %g4, %o2                        ! Setup args for
        mov             %g5, %o1                        ! final call to mem_address_unaligned.
        andn            %l1, PSTATE_MM, %l1             ! We want to be in RMO

        mov             %g6, %o7                        ! Stash away current.
        wrpr            %g0, 0x0, %tl                   ! Out of trap levels.
        wrpr            %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
        sethi           %uhi(PAGE_OFFSET), %g4          ! Set page_offset global reg.
        mov             %o7, %g6                        ! Get current back.
        sllx            %g4, 32, %g4                    ! Finish it.
        call            mem_address_unaligned
         add            %sp, PTREGS_OFF, %o0

        b,pt            %xcc, rtrap
         nop                                            ! yes, the nop is correct
spill_fixup_mna:
        ldub            [%g6 + AOFF_task_thread + AOFF_thread_flags], %g1
        andcc           %g1, SPARC_FLAG_32BIT, %g0
        ldub            [%g6 + AOFF_task_thread + AOFF_thread_w_saved], %g1
        sll             %g1, 3, %g3
        add             %g6, %g3, %g3
        stx             %sp, [%g3 + AOFF_task_thread + AOFF_thread_rwbuf_stkptrs]

        sll             %g1, 7, %g3
        bne,pt          %xcc, 1f
         add            %g6, %g3, %g3
        stx             %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
        stx             %l1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
        stx             %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
        stx             %l3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
        stx             %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]

        stx             %l5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
        stx             %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
        stx             %l7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
        stx             %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x40]
        stx             %i1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x48]
        stx             %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x50]
        stx             %i3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x58]
        stx             %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x60]

        stx             %i5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x68]
        stx             %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x70]
        stx             %i7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x78]
        b,pt            %xcc, 2f
         add            %g1, 1, %g1
1:      std             %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
        std             %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
        std             %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]

        std             %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
        std             %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]
        std             %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
        std             %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
        std             %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
        add             %g1, 1, %g1
2:      stb             %g1, [%g6 + AOFF_task_thread + AOFF_thread_w_saved]
        rdpr            %tstate, %g1

        andcc           %g1, TSTATE_PRIV, %g0
        saved
        be,pn           %xcc, window_mna_from_user_common
         and            %g1, TSTATE_CWP, %g1
        retry
window_mna_from_user_common:
        wrpr            %g1, %cwp
        sethi           %hi(109f), %g7
        ba,pt           %xcc, etrap
109:     or             %g7, %lo(109b), %g7
        mov             %l4, %o2
        mov             %l5, %o1
        call            mem_address_unaligned
         add            %sp, PTREGS_OFF, %o0
        ba,pt           %xcc, rtrap
         clr            %l6
        
        /* These are only needed for 64-bit mode processes which
         * put their stack pointer into the VPTE area and there
         * happens to be a VPTE tlb entry mapped there during
         * a spill/fill trap to that stack frame.
         */
        .globl          winfix_dax, fill_fixup_dax, spill_fixup_dax
winfix_dax:
        andn            %g3, 0x7f, %g3
        add             %g3, 0x74, %g3
        wrpr            %g3, %tnpc
        done
fill_fixup_dax:
        rdpr            %tstate, %g1
        andcc           %g1, TSTATE_PRIV, %g0
        be,pt           %xcc, window_dax_from_user_common
         and            %g1, TSTATE_CWP, %g1

        /* Please, see fill_fixup commentary about why we must preserve
         * %l5 and %l6 to preserve absolute correct semantics.
         */
        rdpr            %wstate, %g2                    ! Grab user mode wstate.
        wrpr            %g1, %cwp                       ! Get into the right window.
        sll             %g2, 3, %g2                     ! NORMAL-->OTHER
        wrpr            %g0, 0x0, %canrestore           ! Standard etrap stuff.

        wrpr            %g2, 0x0, %wstate               ! This must be consistant.
        wrpr            %g0, 0x0, %otherwin             ! We know this.
        mov             PRIMARY_CONTEXT, %g1            ! Change contexts...
        stxa            %g0, [%g1] ASI_DMMU             ! Back into the nucleus.
        flush           %g6                             ! Flush instruction buffers
        rdpr            %pstate, %l1                    ! Prepare to change globals.
        mov             %g4, %o1                        ! Setup args for
        mov             %g5, %o2                        ! final call to data_access_exception.
        andn            %l1, PSTATE_MM, %l1             ! We want to be in RMO

        mov             %g6, %o7                        ! Stash away current.
        wrpr            %g0, 0x0, %tl                   ! Out of trap levels.
        wrpr            %l1, (PSTATE_IE | PSTATE_AG | PSTATE_RMO), %pstate
        sethi           %uhi(PAGE_OFFSET), %g4          ! Set page_offset global reg.
        mov             %o7, %g6                        ! Get current back.
        sllx            %g4, 32, %g4                    ! Finish it.
        call            data_access_exception
         add            %sp, PTREGS_OFF, %o0

        b,pt            %xcc, rtrap
         nop                                            ! yes, the nop is correct
spill_fixup_dax:
        ldub            [%g6 + AOFF_task_thread + AOFF_thread_flags], %g1
        andcc           %g1, SPARC_FLAG_32BIT, %g0
        ldub            [%g6 + AOFF_task_thread + AOFF_thread_w_saved], %g1
        sll             %g1, 3, %g3
        add             %g6, %g3, %g3
        stx             %sp, [%g3 + AOFF_task_thread + AOFF_thread_rwbuf_stkptrs]

        sll             %g1, 7, %g3
        bne,pt          %xcc, 1f
         add            %g6, %g3, %g3
        stx             %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
        stx             %l1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
        stx             %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]
        stx             %l3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
        stx             %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]

        stx             %l5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
        stx             %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
        stx             %l7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
        stx             %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x40]
        stx             %i1, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x48]
        stx             %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x50]
        stx             %i3, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x58]
        stx             %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x60]

        stx             %i5, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x68]
        stx             %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x70]
        stx             %i7, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x78]
        b,pt            %xcc, 2f
         add            %g1, 1, %g1
1:      std             %l0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x00]
        std             %l2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x08]
        std             %l4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x10]

        std             %l6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x18]
        std             %i0, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x20]
        std             %i2, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x28]
        std             %i4, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x30]
        std             %i6, [%g3 + AOFF_task_thread + AOFF_thread_reg_window + 0x38]
        add             %g1, 1, %g1
2:      stb             %g1, [%g6 + AOFF_task_thread + AOFF_thread_w_saved]
        rdpr            %tstate, %g1

        andcc           %g1, TSTATE_PRIV, %g0
        saved
        be,pn           %xcc, window_dax_from_user_common
         and            %g1, TSTATE_CWP, %g1
        retry
window_dax_from_user_common:
        wrpr            %g1, %cwp
        sethi           %hi(109f), %g7
        ba,pt           %xcc, etrap
109:     or             %g7, %lo(109b), %g7
        mov             %l4, %o1
        mov             %l5, %o2
        call            data_access_exception
         add            %sp, PTREGS_OFF, %o0
        ba,pt           %xcc, rtrap
         clr            %l6