198 lines
4.8 KiB
ArmAsm
198 lines
4.8 KiB
ArmAsm
/*
|
|
* arch/sh/kernel/cpu/sh5/switchto.S
|
|
*
|
|
* sh64 context switch
|
|
*
|
|
* Copyright (C) 2004 Richard Curnow
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*/
|
|
|
|
.section .text..SHmedia32,"ax"
|
|
.little
|
|
|
|
.balign 32
|
|
|
|
.type sh64_switch_to,@function
|
|
.global sh64_switch_to
|
|
.global __sh64_switch_to_end
|
|
sh64_switch_to:
|
|
|
|
/* Incoming args
|
|
r2 - prev
|
|
r3 - &prev->thread
|
|
r4 - next
|
|
r5 - &next->thread
|
|
|
|
Outgoing results
|
|
r2 - last (=prev) : this just stays in r2 throughout
|
|
|
|
Want to create a full (struct pt_regs) on the stack to allow backtracing
|
|
functions to work. However, we only need to populate the callee-save
|
|
register slots in this structure; since we're a function our ancestors must
|
|
have themselves preserved all caller saved state in the stack. This saves
|
|
some wasted effort since we won't need to look at the values.
|
|
|
|
In particular, all caller-save registers are immediately available for
|
|
scratch use.
|
|
|
|
*/
|
|
|
|
#define FRAME_SIZE (76*8 + 8)
|
|
|
|
movi FRAME_SIZE, r0
|
|
sub.l r15, r0, r15
|
|
! Do normal-style register save to support backtrace
|
|
|
|
st.l r15, 0, r18 ! save link reg
|
|
st.l r15, 4, r14 ! save fp
|
|
add.l r15, r63, r14 ! setup frame pointer
|
|
|
|
! hopefully this looks normal to the backtrace now.
|
|
|
|
addi.l r15, 8, r1 ! base of pt_regs
|
|
addi.l r1, 24, r0 ! base of pt_regs.regs
|
|
addi.l r0, (63*8), r8 ! base of pt_regs.trregs
|
|
|
|
/* Note : to be fixed?
|
|
struct pt_regs is really designed for holding the state on entry
|
|
to an exception, i.e. pc,sr,regs etc. However, for the context
|
|
switch state, some of this is not required. But the unwinder takes
|
|
struct pt_regs * as an arg so we have to build this structure
|
|
to allow unwinding switched tasks in show_state() */
|
|
|
|
st.q r0, ( 9*8), r9
|
|
st.q r0, (10*8), r10
|
|
st.q r0, (11*8), r11
|
|
st.q r0, (12*8), r12
|
|
st.q r0, (13*8), r13
|
|
st.q r0, (14*8), r14 ! for unwind, want to look as though we took a trap at
|
|
! the point where the process is left in suspended animation, i.e. current
|
|
! fp here, not the saved one.
|
|
st.q r0, (16*8), r16
|
|
|
|
st.q r0, (24*8), r24
|
|
st.q r0, (25*8), r25
|
|
st.q r0, (26*8), r26
|
|
st.q r0, (27*8), r27
|
|
st.q r0, (28*8), r28
|
|
st.q r0, (29*8), r29
|
|
st.q r0, (30*8), r30
|
|
st.q r0, (31*8), r31
|
|
st.q r0, (32*8), r32
|
|
st.q r0, (33*8), r33
|
|
st.q r0, (34*8), r34
|
|
st.q r0, (35*8), r35
|
|
|
|
st.q r0, (44*8), r44
|
|
st.q r0, (45*8), r45
|
|
st.q r0, (46*8), r46
|
|
st.q r0, (47*8), r47
|
|
st.q r0, (48*8), r48
|
|
st.q r0, (49*8), r49
|
|
st.q r0, (50*8), r50
|
|
st.q r0, (51*8), r51
|
|
st.q r0, (52*8), r52
|
|
st.q r0, (53*8), r53
|
|
st.q r0, (54*8), r54
|
|
st.q r0, (55*8), r55
|
|
st.q r0, (56*8), r56
|
|
st.q r0, (57*8), r57
|
|
st.q r0, (58*8), r58
|
|
st.q r0, (59*8), r59
|
|
|
|
! do this early as pta->gettr has no pipeline forwarding (=> 5 cycle latency)
|
|
! Use a local label to avoid creating a symbol that will confuse the !
|
|
! backtrace
|
|
pta .Lsave_pc, tr0
|
|
|
|
gettr tr5, r45
|
|
gettr tr6, r46
|
|
gettr tr7, r47
|
|
st.q r8, (5*8), r45
|
|
st.q r8, (6*8), r46
|
|
st.q r8, (7*8), r47
|
|
|
|
! Now switch context
|
|
gettr tr0, r9
|
|
st.l r3, 0, r15 ! prev->thread.sp
|
|
st.l r3, 8, r1 ! prev->thread.kregs
|
|
st.l r3, 4, r9 ! prev->thread.pc
|
|
st.q r1, 0, r9 ! save prev->thread.pc into pt_regs->pc
|
|
|
|
! Load PC for next task (init value or save_pc later)
|
|
ld.l r5, 4, r18 ! next->thread.pc
|
|
! Switch stacks
|
|
ld.l r5, 0, r15 ! next->thread.sp
|
|
ptabs r18, tr0
|
|
|
|
! Update current
|
|
ld.l r4, 4, r9 ! next->thread_info (2nd element of next task_struct)
|
|
putcon r9, kcr0 ! current = next->thread_info
|
|
|
|
! go to save_pc for a reschedule, or the initial thread.pc for a new process
|
|
blink tr0, r63
|
|
|
|
! Restore (when we come back to a previously saved task)
|
|
.Lsave_pc:
|
|
addi.l r15, 32, r0 ! r0 = next's regs
|
|
addi.l r0, (63*8), r8 ! r8 = next's tr_regs
|
|
|
|
ld.q r8, (5*8), r45
|
|
ld.q r8, (6*8), r46
|
|
ld.q r8, (7*8), r47
|
|
ptabs r45, tr5
|
|
ptabs r46, tr6
|
|
ptabs r47, tr7
|
|
|
|
ld.q r0, ( 9*8), r9
|
|
ld.q r0, (10*8), r10
|
|
ld.q r0, (11*8), r11
|
|
ld.q r0, (12*8), r12
|
|
ld.q r0, (13*8), r13
|
|
ld.q r0, (14*8), r14
|
|
ld.q r0, (16*8), r16
|
|
|
|
ld.q r0, (24*8), r24
|
|
ld.q r0, (25*8), r25
|
|
ld.q r0, (26*8), r26
|
|
ld.q r0, (27*8), r27
|
|
ld.q r0, (28*8), r28
|
|
ld.q r0, (29*8), r29
|
|
ld.q r0, (30*8), r30
|
|
ld.q r0, (31*8), r31
|
|
ld.q r0, (32*8), r32
|
|
ld.q r0, (33*8), r33
|
|
ld.q r0, (34*8), r34
|
|
ld.q r0, (35*8), r35
|
|
|
|
ld.q r0, (44*8), r44
|
|
ld.q r0, (45*8), r45
|
|
ld.q r0, (46*8), r46
|
|
ld.q r0, (47*8), r47
|
|
ld.q r0, (48*8), r48
|
|
ld.q r0, (49*8), r49
|
|
ld.q r0, (50*8), r50
|
|
ld.q r0, (51*8), r51
|
|
ld.q r0, (52*8), r52
|
|
ld.q r0, (53*8), r53
|
|
ld.q r0, (54*8), r54
|
|
ld.q r0, (55*8), r55
|
|
ld.q r0, (56*8), r56
|
|
ld.q r0, (57*8), r57
|
|
ld.q r0, (58*8), r58
|
|
ld.q r0, (59*8), r59
|
|
|
|
! epilogue
|
|
ld.l r15, 0, r18
|
|
ld.l r15, 4, r14
|
|
ptabs r18, tr0
|
|
movi FRAME_SIZE, r0
|
|
add r15, r0, r15
|
|
blink tr0, r63
|
|
__sh64_switch_to_end:
|
|
.LFE1:
|
|
.size sh64_switch_to,.LFE1-sh64_switch_to
|
|
|