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/* $FreeBSD$ */
/* $NetBSD: locore.s,v 1.47 1998/03/22 07:26:32 thorpej Exp $ */
/*
* Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Chris G. Demetriou
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#define _LOCORE
#include <machine/asm.h>
#include <machine/mutex.h>
#include "assym.s"
/**************************************************************************/
/*
* Perform actions necessary to switch to a new context. The
* hwpcb should be in a0.
*/
#define SWITCH_CONTEXT \
/* Make a note of the context we're running on. */ \
stq a0, GD_CURPCB(globalp); \
\
/* Swap in the new context. */ \
call_pal PAL_OSF1_swpctx
/*
* savectx: save process context, i.e. callee-saved registers
*
* Note that savectx() only works for processes other than curproc,
* since cpu_switch will copy over the info saved here. (It _can_
* sanely be used for curproc iff cpu_switch won't be called again, e.g.
* from if called from boot().)
*
* Arguments:
* a0 'struct user *' of the process that needs its context saved
*
* Return:
* v0 0. (note that for child processes, it seems
* like savectx() returns 1, because the return address
* in the PCB is set to the return address from savectx().)
*/
LEAF(savectx, 1)
br pv, Lsavectx1
Lsavectx1: LDGP(pv)
stq sp, U_PCB_HWPCB_KSP(a0) /* store sp */
stq s0, U_PCB_CONTEXT+(0 * 8)(a0) /* store s0 - s6 */
stq s1, U_PCB_CONTEXT+(1 * 8)(a0)
stq s2, U_PCB_CONTEXT+(2 * 8)(a0)
stq s3, U_PCB_CONTEXT+(3 * 8)(a0)
stq s4, U_PCB_CONTEXT+(4 * 8)(a0)
stq s5, U_PCB_CONTEXT+(5 * 8)(a0)
stq s6, U_PCB_CONTEXT+(6 * 8)(a0)
stq ra, U_PCB_CONTEXT+(7 * 8)(a0) /* store ra */
call_pal PAL_OSF1_rdps /* NOTE: doesn't kill a0 */
stq v0, U_PCB_CONTEXT+(8 * 8)(a0) /* store ps, for ipl */
mov zero, v0
RET
END(savectx)
/**************************************************************************/
IMPORT(want_resched, 4)
IMPORT(Lev1map, 8)
/*
* cpu_switch()
* Find the highest priority process and resume it.
*/
LEAF(cpu_switch, 1)
LDGP(pv)
/* do an inline savectx(), to save old context */
ldq a0, GD_CURPROC(globalp)
ldq a1, P_ADDR(a0)
ldl t0, sched_lock+MTX_RECURSE /* save sched_lock state */
stl t0, U_PCB_SCHEDNEST(a1)
/* NOTE: ksp is stored by the swpctx */
stq s0, U_PCB_CONTEXT+(0 * 8)(a1) /* store s0 - s6 */
stq s1, U_PCB_CONTEXT+(1 * 8)(a1)
stq s2, U_PCB_CONTEXT+(2 * 8)(a1)
stq s3, U_PCB_CONTEXT+(3 * 8)(a1)
stq s4, U_PCB_CONTEXT+(4 * 8)(a1)
stq s5, U_PCB_CONTEXT+(5 * 8)(a1)
stq s6, U_PCB_CONTEXT+(6 * 8)(a1)
stq ra, U_PCB_CONTEXT+(7 * 8)(a1) /* store ra */
call_pal PAL_OSF1_rdps /* NOTE: doesn't kill a0 */
stq v0, U_PCB_CONTEXT+(8 * 8)(a1) /* store ps, for ipl */
mov a0, s0 /* save old curproc */
mov a1, s1 /* save old U-area */
ldiq a0, ALPHA_PSL_IPL_HIGH /* disable all interrupts */
call_pal PAL_OSF1_swpipl
sw1:
br pv, Lcs1
Lcs1: LDGP(pv)
CALL(chooseproc) /* can't return NULL */
mov v0, s2
ldq s3, P_MD_PCBPADDR(s2) /* save new pcbpaddr */
/*
* Check to see if we're switching to ourself. If we are,
* don't bother loading the new context.
*
* Note that even if we re-enter cpu_switch() from idle(),
* s0 will still contain the old curproc value because any
* users of that register between then and now must have
* saved it. Also note that switch_exit() ensures that
* s0 is clear before jumping here to find a new process.
*/
cmpeq s0, s2, t0 /* oldproc == newproc? */
bne t0, Lcs7 /* Yes! Skip! */
/*
* Deactivate the old address space before activating the
* new one. We need to do this before activating the
* new process's address space in the event that new
* process is using the same vmspace as the old. If we
* do this after we activate, then we might end up
* incorrectly marking the pmap inactive!
*
* We don't deactivate if we came here from switch_exit
* (old pmap no longer exists; vmspace has been freed).
* oldproc will be NULL in this case. We have actually
* taken care of calling pmap_deactivate() in cpu_exit(),
* before the vmspace went away.
*/
beq s0, Lcs6
mov s0, a0 /* pmap_deactivate(oldproc) */
CALL(pmap_deactivate)
Lcs6:
/*
* Activate the new process's address space and perform
* the actual context swap.
*/
mov s2, a0 /* pmap_activate(p) */
CALL(pmap_activate)
mov s3, a0 /* swap the context */
SWITCH_CONTEXT
Lcs7:
/*
* Now that the switch is done, update curproc and other
* globals. We must do this even if switching to ourselves
* because we might have re-entered cpu_switch() from idle(),
* in which case curproc would be NULL.
*/
stq s2, GD_CURPROC(globalp) /* curproc = p */
stl zero, want_resched /* we've rescheduled */
/*
* Now running on the new u struct.
* Restore registers and return.
*/
ldq t0, P_ADDR(s2)
/* NOTE: ksp is restored by the swpctx */
ldq s0, U_PCB_CONTEXT+(0 * 8)(t0) /* restore s0 - s6 */
ldq s1, U_PCB_CONTEXT+(1 * 8)(t0)
ldq s2, U_PCB_CONTEXT+(2 * 8)(t0)
ldq s3, U_PCB_CONTEXT+(3 * 8)(t0)
ldq s4, U_PCB_CONTEXT+(4 * 8)(t0)
ldq s5, U_PCB_CONTEXT+(5 * 8)(t0)
ldq s6, U_PCB_CONTEXT+(6 * 8)(t0)
ldq ra, U_PCB_CONTEXT+(7 * 8)(t0) /* restore ra */
ldl t1, U_PCB_SCHEDNEST(t0)
stl t1, sched_lock+MTX_RECURSE /* restore lock */
ldq t1, GD_CURPROC(globalp)
stq t1, sched_lock+MTX_LOCK
ldq a0, U_PCB_CONTEXT+(8 * 8)(t0) /* restore ipl */
and a0, ALPHA_PSL_IPL_MASK, a0
call_pal PAL_OSF1_swpipl
ldiq v0, 1 /* possible ret to savectx() */
RET
END(cpu_switch)
/*
* switch_trampoline()
*
* Arrange for a function to be invoked neatly, after a cpu_switch().
*
* Invokes the function specified by the s0 register with the return
* address specified by the s1 register and with one argument, a
* pointer to the executing process's proc structure.
*/
LEAF(switch_trampoline, 0)
MTX_EXIT(sched_lock)
mov s0, pv
mov s1, ra
mov s2, a0
jmp zero, (pv)
END(switch_trampoline)
/**************************************************************************/
/*
* exception_return: return from trap, exception, or syscall
*/
IMPORT(ipending, 4)
IMPORT(astpending, 4)
LEAF(exception_return, 1) /* XXX should be NESTED */
br pv, Ler1
Ler1: LDGP(pv)
ldq s1, (FRAME_PS * 8)(sp) /* get the saved PS */
and s1, ALPHA_PSL_IPL_MASK, t0 /* look at the saved IPL */
bne t0, Lrestoreregs /* != 0: can't do AST or SIR */
/* see if we can do an SIR */
ldl t1, ipending /* SIR pending? */
beq t1, Lchkast /* no, try an AST*/
/* We've got a SIR. */
CALL(do_sir) /* do the SIR; lowers IPL */
Lchkast:
and s1, ALPHA_PSL_USERMODE, t0 /* are we returning to user? */
beq t0, Lrestoreregs /* no: just return */
ldl t2, GD_ASTPENDING(globalp) /* AST pending? */
beq t2, Lrestoreregs /* no: return */
/* We've got an AST. Handle it. */
ldiq a0, ALPHA_PSL_IPL_0 /* drop IPL to zero */
call_pal PAL_OSF1_swpipl
mov sp, a0 /* only arg is frame */
CALL(ast)
Lrestoreregs:
/* set the hae register if this process has specified a value */
ldq t0, GD_CURPROC(globalp)
beq t0, Lnohae
ldq t1, P_MD_FLAGS(t0)
and t1, MDP_HAEUSED
beq t1, Lnohae
ldq a0, P_MD_HAE(t0)
ldq pv, chipset + CHIPSET_WRITE_HAE
CALL((pv))
Lnohae:
/* restore the registers, and return */
bsr ra, exception_restore_regs /* jmp/CALL trashes pv/t12 */
ldq ra,(FRAME_RA*8)(sp)
.set noat
ldq at_reg,(FRAME_AT*8)(sp)
lda sp,(FRAME_SW_SIZE*8)(sp)
call_pal PAL_OSF1_rti
.set at
END(exception_return)
LEAF(exception_save_regs, 0)
stq v0,(FRAME_V0*8)(sp)
stq a3,(FRAME_A3*8)(sp)
stq a4,(FRAME_A4*8)(sp)
stq a5,(FRAME_A5*8)(sp)
stq s0,(FRAME_S0*8)(sp)
stq s1,(FRAME_S1*8)(sp)
stq s2,(FRAME_S2*8)(sp)
stq s3,(FRAME_S3*8)(sp)
stq s4,(FRAME_S4*8)(sp)
stq s5,(FRAME_S5*8)(sp)
stq s6,(FRAME_S6*8)(sp)
stq t0,(FRAME_T0*8)(sp)
stq t1,(FRAME_T1*8)(sp)
stq t2,(FRAME_T2*8)(sp)
stq t3,(FRAME_T3*8)(sp)
stq t4,(FRAME_T4*8)(sp)
stq t5,(FRAME_T5*8)(sp)
stq t6,(FRAME_T6*8)(sp)
stq t7,(FRAME_T7*8)(sp)
stq t8,(FRAME_T8*8)(sp)
stq t9,(FRAME_T9*8)(sp)
stq t10,(FRAME_T10*8)(sp)
stq t11,(FRAME_T11*8)(sp)
stq t12,(FRAME_T12*8)(sp)
.set noat
lda at_reg,(FRAME_SIZE*8)(sp)
stq at_reg,(FRAME_SP*8)(sp)
.set at
RET
END(exception_save_regs)
LEAF(exception_restore_regs, 0)
ldq v0,(FRAME_V0*8)(sp)
ldq a3,(FRAME_A3*8)(sp)
ldq a4,(FRAME_A4*8)(sp)
ldq a5,(FRAME_A5*8)(sp)
ldq s0,(FRAME_S0*8)(sp)
ldq s1,(FRAME_S1*8)(sp)
ldq s2,(FRAME_S2*8)(sp)
ldq s3,(FRAME_S3*8)(sp)
ldq s4,(FRAME_S4*8)(sp)
ldq s5,(FRAME_S5*8)(sp)
ldq s6,(FRAME_S6*8)(sp)
ldq t0,(FRAME_T0*8)(sp)
ldq t1,(FRAME_T1*8)(sp)
ldq t2,(FRAME_T2*8)(sp)
ldq t3,(FRAME_T3*8)(sp)
ldq t4,(FRAME_T4*8)(sp)
ldq t5,(FRAME_T5*8)(sp)
ldq t6,(FRAME_T6*8)(sp)
ldq t7,(FRAME_T7*8)(sp)
ldq t8,(FRAME_T8*8)(sp)
ldq t9,(FRAME_T9*8)(sp)
ldq t10,(FRAME_T10*8)(sp)
ldq t11,(FRAME_T11*8)(sp)
ldq t12,(FRAME_T12*8)(sp)
RET
END(exception_restore_regs)
|