You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
320 lines
9.0 KiB
320 lines
9.0 KiB
/*
|
|
* etrap.S: Sparc trap window preparation for entry into the
|
|
* Linux kernel.
|
|
*
|
|
* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
|
|
*/
|
|
|
|
#include <asm/head.h>
|
|
#include <asm/asi.h>
|
|
#include <asm/contregs.h>
|
|
#include <asm/page.h>
|
|
#include <asm/psr.h>
|
|
#include <asm/ptrace.h>
|
|
#include <asm/winmacro.h>
|
|
#include <asm/asmmacro.h>
|
|
#include <asm/thread_info.h>
|
|
|
|
/* Registers to not touch at all. */
|
|
#define t_psr l0 /* Set by caller */
|
|
#define t_pc l1 /* Set by caller */
|
|
#define t_npc l2 /* Set by caller */
|
|
#define t_wim l3 /* Set by caller */
|
|
#define t_twinmask l4 /* Set at beginning of this entry routine. */
|
|
#define t_kstack l5 /* Set right before pt_regs frame is built */
|
|
#define t_retpc l6 /* If you change this, change winmacro.h header file */
|
|
#define t_systable l7 /* Never touch this, could be the syscall table ptr. */
|
|
#define curptr g6 /* Set after pt_regs frame is built */
|
|
|
|
.text
|
|
.align 4
|
|
|
|
/* SEVEN WINDOW PATCH INSTRUCTIONS */
|
|
.globl tsetup_7win_patch1, tsetup_7win_patch2
|
|
.globl tsetup_7win_patch3, tsetup_7win_patch4
|
|
.globl tsetup_7win_patch5, tsetup_7win_patch6
|
|
tsetup_7win_patch1: sll %t_wim, 0x6, %t_wim
|
|
tsetup_7win_patch2: and %g2, 0x7f, %g2
|
|
tsetup_7win_patch3: and %g2, 0x7f, %g2
|
|
tsetup_7win_patch4: and %g1, 0x7f, %g1
|
|
tsetup_7win_patch5: sll %t_wim, 0x6, %t_wim
|
|
tsetup_7win_patch6: and %g2, 0x7f, %g2
|
|
/* END OF PATCH INSTRUCTIONS */
|
|
|
|
/* At trap time, interrupts and all generic traps do the
|
|
* following:
|
|
*
|
|
* rd %psr, %l0
|
|
* b some_handler
|
|
* rd %wim, %l3
|
|
* nop
|
|
*
|
|
* Then 'some_handler' if it needs a trap frame (ie. it has
|
|
* to call c-code and the trap cannot be handled in-window)
|
|
* then it does the SAVE_ALL macro in entry.S which does
|
|
*
|
|
* sethi %hi(trap_setup), %l4
|
|
* jmpl %l4 + %lo(trap_setup), %l6
|
|
* nop
|
|
*/
|
|
|
|
/* 2 3 4 window number
|
|
* -----
|
|
* O T S mnemonic
|
|
*
|
|
* O == Current window before trap
|
|
* T == Window entered when trap occurred
|
|
* S == Window we will need to save if (1<<T) == %wim
|
|
*
|
|
* Before execution gets here, it must be guaranteed that
|
|
* %l0 contains trap time %psr, %l1 and %l2 contain the
|
|
* trap pc and npc, and %l3 contains the trap time %wim.
|
|
*/
|
|
|
|
.globl trap_setup, tsetup_patch1, tsetup_patch2
|
|
.globl tsetup_patch3, tsetup_patch4
|
|
.globl tsetup_patch5, tsetup_patch6
|
|
trap_setup:
|
|
/* Calculate mask of trap window. See if from user
|
|
* or kernel and branch conditionally.
|
|
*/
|
|
mov 1, %t_twinmask
|
|
andcc %t_psr, PSR_PS, %g0 ! fromsupv_p = (psr & PSR_PS)
|
|
be trap_setup_from_user ! nope, from user mode
|
|
sll %t_twinmask, %t_psr, %t_twinmask ! t_twinmask = (1 << psr)
|
|
|
|
/* From kernel, allocate more kernel stack and
|
|
* build a pt_regs trap frame.
|
|
*/
|
|
sub %fp, (STACKFRAME_SZ + TRACEREG_SZ), %t_kstack
|
|
STORE_PT_ALL(t_kstack, t_psr, t_pc, t_npc, g2)
|
|
|
|
/* See if we are in the trap window. */
|
|
andcc %t_twinmask, %t_wim, %g0
|
|
bne trap_setup_kernel_spill ! in trap window, clean up
|
|
nop
|
|
|
|
/* Trap from kernel with a window available.
|
|
* Just do it...
|
|
*/
|
|
jmpl %t_retpc + 0x8, %g0 ! return to caller
|
|
mov %t_kstack, %sp ! jump onto new stack
|
|
|
|
trap_setup_kernel_spill:
|
|
ld [%curptr + TI_UWINMASK], %g1
|
|
orcc %g0, %g1, %g0
|
|
bne trap_setup_user_spill ! there are some user windows, yuck
|
|
/* Spill from kernel, but only kernel windows, adjust
|
|
* %wim and go.
|
|
*/
|
|
srl %t_wim, 0x1, %g2 ! begin computation of new %wim
|
|
tsetup_patch1:
|
|
sll %t_wim, 0x7, %t_wim ! patched on 7 window Sparcs
|
|
or %t_wim, %g2, %g2
|
|
tsetup_patch2:
|
|
and %g2, 0xff, %g2 ! patched on 7 window Sparcs
|
|
|
|
save %g0, %g0, %g0
|
|
|
|
/* Set new %wim value */
|
|
wr %g2, 0x0, %wim
|
|
|
|
/* Save the kernel window onto the corresponding stack. */
|
|
STORE_WINDOW(sp)
|
|
|
|
restore %g0, %g0, %g0
|
|
|
|
jmpl %t_retpc + 0x8, %g0 ! return to caller
|
|
mov %t_kstack, %sp ! and onto new kernel stack
|
|
|
|
#define STACK_OFFSET (THREAD_SIZE - TRACEREG_SZ - STACKFRAME_SZ)
|
|
|
|
trap_setup_from_user:
|
|
/* We can't use %curptr yet. */
|
|
LOAD_CURRENT(t_kstack, t_twinmask)
|
|
|
|
sethi %hi(STACK_OFFSET), %t_twinmask
|
|
or %t_twinmask, %lo(STACK_OFFSET), %t_twinmask
|
|
add %t_kstack, %t_twinmask, %t_kstack
|
|
|
|
mov 1, %t_twinmask
|
|
sll %t_twinmask, %t_psr, %t_twinmask ! t_twinmask = (1 << psr)
|
|
|
|
/* Build pt_regs frame. */
|
|
STORE_PT_ALL(t_kstack, t_psr, t_pc, t_npc, g2)
|
|
|
|
#if 0
|
|
/* If we're sure every task_struct is THREAD_SIZE aligned,
|
|
we can speed this up. */
|
|
sethi %hi(STACK_OFFSET), %curptr
|
|
or %curptr, %lo(STACK_OFFSET), %curptr
|
|
sub %t_kstack, %curptr, %curptr
|
|
#else
|
|
sethi %hi(~(THREAD_SIZE - 1)), %curptr
|
|
and %t_kstack, %curptr, %curptr
|
|
#endif
|
|
|
|
/* Clear current_thread_info->w_saved */
|
|
st %g0, [%curptr + TI_W_SAVED]
|
|
|
|
/* See if we are in the trap window. */
|
|
andcc %t_twinmask, %t_wim, %g0
|
|
bne trap_setup_user_spill ! yep we are
|
|
orn %g0, %t_twinmask, %g1 ! negate trap win mask into %g1
|
|
|
|
/* Trap from user, but not into the invalid window.
|
|
* Calculate new umask. The way this works is,
|
|
* any window from the %wim at trap time until
|
|
* the window right before the one we are in now,
|
|
* is a user window. A diagram:
|
|
*
|
|
* 7 6 5 4 3 2 1 0 window number
|
|
* ---------------
|
|
* I L T mnemonic
|
|
*
|
|
* Window 'I' is the invalid window in our example,
|
|
* window 'L' is the window the user was in when
|
|
* the trap occurred, window T is the trap window
|
|
* we are in now. So therefore, windows 5, 4 and
|
|
* 3 are user windows. The following sequence
|
|
* computes the user winmask to represent this.
|
|
*/
|
|
subcc %t_wim, %t_twinmask, %g2
|
|
bneg,a 1f
|
|
sub %g2, 0x1, %g2
|
|
1:
|
|
andn %g2, %t_twinmask, %g2
|
|
tsetup_patch3:
|
|
and %g2, 0xff, %g2 ! patched on 7win Sparcs
|
|
st %g2, [%curptr + TI_UWINMASK] ! store new umask
|
|
|
|
jmpl %t_retpc + 0x8, %g0 ! return to caller
|
|
mov %t_kstack, %sp ! and onto kernel stack
|
|
|
|
trap_setup_user_spill:
|
|
/* A spill occurred from either kernel or user mode
|
|
* and there exist some user windows to deal with.
|
|
* A mask of the currently valid user windows
|
|
* is in %g1 upon entry to here.
|
|
*/
|
|
|
|
tsetup_patch4:
|
|
and %g1, 0xff, %g1 ! patched on 7win Sparcs, mask
|
|
srl %t_wim, 0x1, %g2 ! compute new %wim
|
|
tsetup_patch5:
|
|
sll %t_wim, 0x7, %t_wim ! patched on 7win Sparcs
|
|
or %t_wim, %g2, %g2 ! %g2 is new %wim
|
|
tsetup_patch6:
|
|
and %g2, 0xff, %g2 ! patched on 7win Sparcs
|
|
andn %g1, %g2, %g1 ! clear this bit in %g1
|
|
st %g1, [%curptr + TI_UWINMASK]
|
|
|
|
save %g0, %g0, %g0
|
|
|
|
wr %g2, 0x0, %wim
|
|
|
|
/* Call MMU-architecture dependent stack checking
|
|
* routine.
|
|
*/
|
|
.globl tsetup_mmu_patchme
|
|
tsetup_mmu_patchme:
|
|
b tsetup_sun4c_stackchk
|
|
andcc %sp, 0x7, %g0
|
|
|
|
/* Architecture specific stack checking routines. When either
|
|
* of these routines are called, the globals are free to use
|
|
* as they have been safely stashed on the new kernel stack
|
|
* pointer. Thus the definition below for simplicity.
|
|
*/
|
|
#define glob_tmp g1
|
|
|
|
tsetup_sun4c_stackchk:
|
|
/* Done by caller: andcc %sp, 0x7, %g0 */
|
|
bne trap_setup_user_stack_is_bolixed
|
|
sra %sp, 29, %glob_tmp
|
|
|
|
add %glob_tmp, 0x1, %glob_tmp
|
|
andncc %glob_tmp, 0x1, %g0
|
|
bne trap_setup_user_stack_is_bolixed
|
|
and %sp, 0xfff, %glob_tmp ! delay slot
|
|
|
|
/* See if our dump area will be on more than one
|
|
* page.
|
|
*/
|
|
add %glob_tmp, 0x38, %glob_tmp
|
|
andncc %glob_tmp, 0xff8, %g0
|
|
be tsetup_sun4c_onepage ! only one page to check
|
|
lda [%sp] ASI_PTE, %glob_tmp ! have to check first page anyways
|
|
|
|
tsetup_sun4c_twopages:
|
|
/* Is first page ok permission wise? */
|
|
srl %glob_tmp, 29, %glob_tmp
|
|
cmp %glob_tmp, 0x6
|
|
bne trap_setup_user_stack_is_bolixed
|
|
add %sp, 0x38, %glob_tmp /* Is second page in vma hole? */
|
|
|
|
sra %glob_tmp, 29, %glob_tmp
|
|
add %glob_tmp, 0x1, %glob_tmp
|
|
andncc %glob_tmp, 0x1, %g0
|
|
bne trap_setup_user_stack_is_bolixed
|
|
add %sp, 0x38, %glob_tmp
|
|
|
|
lda [%glob_tmp] ASI_PTE, %glob_tmp
|
|
|
|
tsetup_sun4c_onepage:
|
|
srl %glob_tmp, 29, %glob_tmp
|
|
cmp %glob_tmp, 0x6 ! can user write to it?
|
|
bne trap_setup_user_stack_is_bolixed ! failure
|
|
nop
|
|
|
|
STORE_WINDOW(sp)
|
|
|
|
restore %g0, %g0, %g0
|
|
|
|
jmpl %t_retpc + 0x8, %g0
|
|
mov %t_kstack, %sp
|
|
|
|
.globl tsetup_srmmu_stackchk
|
|
tsetup_srmmu_stackchk:
|
|
/* Check results of callers andcc %sp, 0x7, %g0 */
|
|
bne trap_setup_user_stack_is_bolixed
|
|
sethi %hi(PAGE_OFFSET), %glob_tmp
|
|
|
|
cmp %glob_tmp, %sp
|
|
bleu,a 1f
|
|
lda [%g0] ASI_M_MMUREGS, %glob_tmp ! read MMU control
|
|
|
|
trap_setup_user_stack_is_bolixed:
|
|
/* From user/kernel into invalid window w/bad user
|
|
* stack. Save bad user stack, and return to caller.
|
|
*/
|
|
SAVE_BOLIXED_USER_STACK(curptr, g3)
|
|
restore %g0, %g0, %g0
|
|
|
|
jmpl %t_retpc + 0x8, %g0
|
|
mov %t_kstack, %sp
|
|
|
|
1:
|
|
/* Clear the fault status and turn on the no_fault bit. */
|
|
or %glob_tmp, 0x2, %glob_tmp ! or in no_fault bit
|
|
sta %glob_tmp, [%g0] ASI_M_MMUREGS ! set it
|
|
|
|
/* Dump the registers and cross fingers. */
|
|
STORE_WINDOW(sp)
|
|
|
|
/* Clear the no_fault bit and check the status. */
|
|
andn %glob_tmp, 0x2, %glob_tmp
|
|
sta %glob_tmp, [%g0] ASI_M_MMUREGS
|
|
mov AC_M_SFAR, %glob_tmp
|
|
lda [%glob_tmp] ASI_M_MMUREGS, %g0
|
|
mov AC_M_SFSR, %glob_tmp
|
|
lda [%glob_tmp] ASI_M_MMUREGS, %glob_tmp ! save away status of winstore
|
|
andcc %glob_tmp, 0x2, %g0 ! did we fault?
|
|
bne trap_setup_user_stack_is_bolixed ! failure
|
|
nop
|
|
|
|
restore %g0, %g0, %g0
|
|
|
|
jmpl %t_retpc + 0x8, %g0
|
|
mov %t_kstack, %sp
|
|
|
|
|