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/*
* 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
sethi %hi(PSR_SYSCALL), %g1
be 1f
andn %t_psr, %g1, %t_psr
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_SIGPENDING|_TIF_RESTORE_SIGMASK), %g0
bz,a ret_trap_continue
ld [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
mov %l5, %o1
call do_signal
add %sp, STACKFRAME_SZ, %o0 ! pt_regs ptr
/* Fall through. */
ld [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
clr %l6
ret_trap_continue:
sethi %hi(PSR_SYSCALL), %g1
andn %t_psr, %g1, %t_psr
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
sethi %hi(PSR_SYSCALL), %g2
be 1f
andn %t_psr, %g2, %t_psr
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:
sethi %hi(PSR_SYSCALL), %twin_tmp1
andn %t_psr, %twin_tmp1, %t_psr
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
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
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