1 files changed, 319 insertions, 0 deletions

diff --git a/arch/sparc/kernel/rtrap.S b/arch/sparc/kernel/rtrap.S
new file mode 100644
index 000000000000..f7460d897e79
--- /dev/null
+++ b/arch/sparc/kernel/rtrap.S
@@ -0,0 +1,319 @@
+/* $Id: rtrap.S,v 1.58 2002/01/31 03:30:05 davem Exp $
+ * rtrap.S: Return from Sparc trap low-level code.
+ *
+ * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#include <asm/page.h>
+#include <asm/ptrace.h>
+#include <asm/psr.h>
+#include <asm/asi.h>
+#include <asm/smp.h>
+#include <asm/contregs.h>
+#include <asm/winmacro.h>
+#include <asm/asmmacro.h>
+#include <asm/thread_info.h>
+
+#define t_psr     l0
+#define t_pc      l1
+#define t_npc     l2
+#define t_wim     l3
+#define twin_tmp1 l4
+#define glob_tmp  g4
+#define curptr    g6
+
+        /* 7 WINDOW SPARC PATCH INSTRUCTIONS */
+        .globl  rtrap_7win_patch1, rtrap_7win_patch2, rtrap_7win_patch3
+        .globl  rtrap_7win_patch4, rtrap_7win_patch5
+rtrap_7win_patch1:      srl     %t_wim, 0x6, %glob_tmp
+rtrap_7win_patch2:      and     %glob_tmp, 0x7f, %glob_tmp
+rtrap_7win_patch3:      srl     %g1, 7, %g2
+rtrap_7win_patch4:      srl     %g2, 6, %g2
+rtrap_7win_patch5:      and     %g1, 0x7f, %g1
+        /* END OF PATCH INSTRUCTIONS */
+
+        /* We need to check for a few things which are:
+         * 1) The need to call schedule() because this
+         *    processes quantum is up.
+         * 2) Pending signals for this process, if any
+         *    exist we need to call do_signal() to do
+         *    the needy.
+         *
+         * Else we just check if the rett would land us
+         * in an invalid window, if so we need to grab
+         * it off the user/kernel stack first.
+         */
+
+        .globl  ret_trap_entry, rtrap_patch1, rtrap_patch2
+        .globl  rtrap_patch3, rtrap_patch4, rtrap_patch5
+        .globl  ret_trap_lockless_ipi
+ret_trap_entry:
+ret_trap_lockless_ipi:
+        andcc   %t_psr, PSR_PS, %g0
+        be      1f
+         nop
+
+        wr      %t_psr, 0x0, %psr
+        b       ret_trap_kernel
+         nop
+
+1:
+        ld      [%curptr + TI_FLAGS], %g2
+        andcc   %g2, (_TIF_NEED_RESCHED), %g0
+        be      signal_p
+         nop
+
+        call    schedule
+         nop
+
+        ld      [%curptr + TI_FLAGS], %g2
+signal_p:
+        andcc   %g2, (_TIF_NOTIFY_RESUME|_TIF_SIGPENDING), %g0
+        bz,a    ret_trap_continue
+         ld     [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
+
+        clr     %o0
+        mov     %l5, %o2
+        mov     %l6, %o3
+        call    do_signal
+         add    %sp, STACKFRAME_SZ, %o1 ! pt_regs ptr
+
+        /* Fall through. */
+        ld      [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
+        clr     %l6
+ret_trap_continue:
+        wr      %t_psr, 0x0, %psr
+        WRITE_PAUSE
+
+        ld      [%curptr + TI_W_SAVED], %twin_tmp1
+        orcc    %g0, %twin_tmp1, %g0
+        be      ret_trap_nobufwins
+         nop
+
+        wr      %t_psr, PSR_ET, %psr
+        WRITE_PAUSE
+
+        mov     1, %o1
+        call    try_to_clear_window_buffer
+         add    %sp, STACKFRAME_SZ, %o0
+
+        b       signal_p
+         ld     [%curptr + TI_FLAGS], %g2
+
+ret_trap_nobufwins:
+        /* Load up the user's out registers so we can pull
+         * a window from the stack, if necessary.
+         */
+        LOAD_PT_INS(sp)
+
+        /* If there are already live user windows in the
+         * set we can return from trap safely.
+         */
+        ld      [%curptr + TI_UWINMASK], %twin_tmp1
+        orcc    %g0, %twin_tmp1, %g0
+        bne     ret_trap_userwins_ok
+         nop
+
+                /* Calculate new %wim, we have to pull a register
+                 * window from the users stack.
+                 */
+ret_trap_pull_one_window:
+                rd      %wim, %t_wim
+                sll     %t_wim, 0x1, %twin_tmp1
+rtrap_patch1:   srl     %t_wim, 0x7, %glob_tmp
+                or      %glob_tmp, %twin_tmp1, %glob_tmp
+rtrap_patch2:   and     %glob_tmp, 0xff, %glob_tmp
+
+                wr      %glob_tmp, 0x0, %wim
+
+                                /* Here comes the architecture specific 
+                                 * branch to the user stack checking routine
+                                 * for return from traps.
+                                 */
+                                .globl  rtrap_mmu_patchme
+rtrap_mmu_patchme:      b       sun4c_rett_stackchk
+                                 andcc  %fp, 0x7, %g0   
+
+ret_trap_userwins_ok:
+        LOAD_PT_PRIV(sp, t_psr, t_pc, t_npc)
+        or      %t_pc, %t_npc, %g2
+        andcc   %g2, 0x3, %g0
+        be      1f
+         nop
+
+        b       ret_trap_unaligned_pc
+         add    %sp, STACKFRAME_SZ, %o0
+
+1:
+        LOAD_PT_YREG(sp, g1)
+        LOAD_PT_GLOBALS(sp)
+
+        wr      %t_psr, 0x0, %psr
+        WRITE_PAUSE
+
+        jmp     %t_pc
+        rett    %t_npc
+        
+ret_trap_unaligned_pc:
+        ld      [%sp + STACKFRAME_SZ + PT_PC], %o1
+        ld      [%sp + STACKFRAME_SZ + PT_NPC], %o2
+        ld      [%sp + STACKFRAME_SZ + PT_PSR], %o3
+
+        wr      %t_wim, 0x0, %wim               ! or else...
+
+        wr      %t_psr, PSR_ET, %psr
+        WRITE_PAUSE
+
+        call    do_memaccess_unaligned
+         nop
+
+        b       signal_p
+         ld     [%curptr + TI_FLAGS], %g2
+
+ret_trap_kernel:
+                /* Will the rett land us in the invalid window? */
+                mov     2, %g1
+                sll     %g1, %t_psr, %g1
+rtrap_patch3:   srl     %g1, 8, %g2
+                or      %g1, %g2, %g1
+                rd      %wim, %g2
+                andcc   %g2, %g1, %g0
+                be      1f              ! Nope, just return from the trap
+                 sll    %g2, 0x1, %g1
+
+                /* We have to grab a window before returning. */
+rtrap_patch4:   srl     %g2, 7,  %g2
+                or      %g1, %g2, %g1
+rtrap_patch5:   and     %g1, 0xff, %g1
+
+        wr      %g1, 0x0, %wim
+
+        /* Grrr, make sure we load from the right %sp... */
+        LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
+
+        restore %g0, %g0, %g0
+        LOAD_WINDOW(sp)
+        b       2f
+         save   %g0, %g0, %g0
+
+        /* Reload the entire frame in case this is from a
+         * kernel system call or whatever...
+         */
+1:
+        LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
+2:
+        wr      %t_psr, 0x0, %psr
+        WRITE_PAUSE
+
+        jmp     %t_pc
+        rett    %t_npc
+
+ret_trap_user_stack_is_bolixed:
+        wr      %t_wim, 0x0, %wim
+
+        wr      %t_psr, PSR_ET, %psr
+        WRITE_PAUSE
+
+        call    window_ret_fault
+         add    %sp, STACKFRAME_SZ, %o0
+
+        b       signal_p
+         ld     [%curptr + TI_FLAGS], %g2
+
+
+        .globl  sun4c_rett_stackchk
+sun4c_rett_stackchk:
+        be      1f
+         and    %fp, 0xfff, %g1         ! delay slot
+
+        b       ret_trap_user_stack_is_bolixed + 0x4
+         wr     %t_wim, 0x0, %wim
+
+        /* See if we have to check the sanity of one page or two */
+1:
+        add     %g1, 0x38, %g1
+        sra     %fp, 29, %g2
+        add     %g2, 0x1, %g2
+        andncc  %g2, 0x1, %g0
+        be      1f
+         andncc %g1, 0xff8, %g0
+
+        /* %sp is in vma hole, yuck */
+        b       ret_trap_user_stack_is_bolixed + 0x4
+         wr     %t_wim, 0x0, %wim
+
+1:
+        be      sun4c_rett_onepage      /* Only one page to check */
+         lda    [%fp] ASI_PTE, %g2
+
+sun4c_rett_twopages:
+        add     %fp, 0x38, %g1
+        sra     %g1, 29, %g2
+        add     %g2, 0x1, %g2
+        andncc  %g2, 0x1, %g0
+        be      1f
+         lda    [%g1] ASI_PTE, %g2
+
+        /* Second page is in vma hole */
+        b       ret_trap_user_stack_is_bolixed + 0x4
+         wr     %t_wim, 0x0, %wim
+
+1:
+        srl     %g2, 29, %g2
+        andcc   %g2, 0x4, %g0
+        bne     sun4c_rett_onepage
+         lda    [%fp] ASI_PTE, %g2
+
+        /* Second page has bad perms */
+        b       ret_trap_user_stack_is_bolixed + 0x4
+         wr     %t_wim, 0x0, %wim
+
+sun4c_rett_onepage:
+        srl     %g2, 29, %g2
+        andcc   %g2, 0x4, %g0
+        bne,a   1f
+         restore %g0, %g0, %g0
+
+        /* A page had bad page permissions, losing... */
+        b       ret_trap_user_stack_is_bolixed + 0x4
+         wr     %t_wim, 0x0, %wim
+
+        /* Whee, things are ok, load the window and continue. */
+1:
+        LOAD_WINDOW(sp)
+
+        b       ret_trap_userwins_ok
+         save   %g0, %g0, %g0
+
+        .globl  srmmu_rett_stackchk
+srmmu_rett_stackchk:
+        bne     ret_trap_user_stack_is_bolixed
+         sethi   %hi(PAGE_OFFSET), %g1
+        cmp     %g1, %fp
+        bleu    ret_trap_user_stack_is_bolixed
+         mov    AC_M_SFSR, %g1
+        lda     [%g1] ASI_M_MMUREGS, %g0
+
+        lda     [%g0] ASI_M_MMUREGS, %g1
+        or      %g1, 0x2, %g1
+        sta     %g1, [%g0] ASI_M_MMUREGS
+
+        restore %g0, %g0, %g0
+
+        LOAD_WINDOW(sp)
+
+        save    %g0, %g0, %g0
+
+        andn    %g1, 0x2, %g1
+        sta     %g1, [%g0] ASI_M_MMUREGS
+
+        mov     AC_M_SFAR, %g2
+        lda     [%g2] ASI_M_MMUREGS, %g2
+
+        mov     AC_M_SFSR, %g1
+        lda     [%g1] ASI_M_MMUREGS, %g1
+        andcc   %g1, 0x2, %g0
+        be      ret_trap_userwins_ok
+         nop
+
+        b,a     ret_trap_user_stack_is_bolixed