f-stack/freebsd/arm64/arm64/swtch.S

320 lines
7.8 KiB
ArmAsm

/*-
* Copyright (c) 2014 Andrew Turner
* Copyright (c) 2014 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Andrew Turner under sponsorship from
* the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include "assym.s"
#include "opt_kstack_pages.h"
#include "opt_sched.h"
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
.macro clear_step_flag pcbflags, tmp
tbz \pcbflags, #PCB_SINGLE_STEP_SHIFT, 999f
mrs \tmp, mdscr_el1
bic \tmp, \tmp, #1
msr mdscr_el1, \tmp
isb
999:
.endm
.macro set_step_flag pcbflags, tmp
tbz \pcbflags, #PCB_SINGLE_STEP_SHIFT, 999f
mrs \tmp, mdscr_el1
orr \tmp, \tmp, #1
msr mdscr_el1, \tmp
isb
999:
.endm
/*
* void cpu_throw(struct thread *old, struct thread *new)
*/
ENTRY(cpu_throw)
/* Of old == NULL skip disabling stepping */
cbz x0, 1f
/* If we were single stepping, disable it */
ldr x4, [x0, #TD_PCB]
ldr w5, [x4, #PCB_FLAGS]
clear_step_flag w5, x6
1:
#ifdef VFP
/* Backup the new thread pointer around a call to C code */
mov x19, x1
bl vfp_discard
mov x1, x19
#endif
/* Store the new curthread */
str x1, [x18, #PC_CURTHREAD]
/* And the new pcb */
ldr x4, [x1, #TD_PCB]
str x4, [x18, #PC_CURPCB]
/*
* TODO: We may need to flush the cache here.
*/
/* Switch to the new pmap */
ldr x5, [x4, #PCB_L0ADDR]
msr ttbr0_el1, x5
isb
/* Invalidate the TLB */
dsb sy
tlbi vmalle1is
dsb sy
isb
/* If we are single stepping, enable it */
ldr w5, [x4, #PCB_FLAGS]
set_step_flag w5, x6
/* Restore the registers */
ldp x5, x6, [x4, #PCB_SP]
mov sp, x5
msr tpidr_el0, x6
ldp x8, x9, [x4, #PCB_REGS + 8 * 8]
ldp x10, x11, [x4, #PCB_REGS + 10 * 8]
ldp x12, x13, [x4, #PCB_REGS + 12 * 8]
ldp x14, x15, [x4, #PCB_REGS + 14 * 8]
ldp x16, x17, [x4, #PCB_REGS + 16 * 8]
ldr x19, [x4, #PCB_REGS + 19 * 8]
ldp x20, x21, [x4, #PCB_REGS + 20 * 8]
ldp x22, x23, [x4, #PCB_REGS + 22 * 8]
ldp x24, x25, [x4, #PCB_REGS + 24 * 8]
ldp x26, x27, [x4, #PCB_REGS + 26 * 8]
ldp x28, x29, [x4, #PCB_REGS + 28 * 8]
ldr x30, [x4, #PCB_REGS + 30 * 8]
ret
END(cpu_throw)
/*
* void cpu_switch(struct thread *old, struct thread *new, struct mtx *mtx)
*
* x0 = old
* x1 = new
* x2 = mtx
* x3 to x7, x16 and x17 are caller saved
*/
ENTRY(cpu_switch)
/*
* Save the old context.
*/
ldr x4, [x0, #TD_PCB]
/* Store the callee-saved registers */
stp x8, x9, [x4, #PCB_REGS + 8 * 8]
stp x10, x11, [x4, #PCB_REGS + 10 * 8]
stp x12, x13, [x4, #PCB_REGS + 12 * 8]
stp x14, x15, [x4, #PCB_REGS + 14 * 8]
stp x16, x17, [x4, #PCB_REGS + 16 * 8]
stp x18, x19, [x4, #PCB_REGS + 18 * 8]
stp x20, x21, [x4, #PCB_REGS + 20 * 8]
stp x22, x23, [x4, #PCB_REGS + 22 * 8]
stp x24, x25, [x4, #PCB_REGS + 24 * 8]
stp x26, x27, [x4, #PCB_REGS + 26 * 8]
stp x28, x29, [x4, #PCB_REGS + 28 * 8]
str x30, [x4, #PCB_REGS + 30 * 8]
/* And the old stack pointer */
mov x5, sp
mrs x6, tpidr_el0
stp x5, x6, [x4, #PCB_SP]
/* If we were single stepping, disable it */
ldr w5, [x4, #PCB_FLAGS]
clear_step_flag w5, x6
#ifdef VFP
mov x19, x0
mov x20, x1
mov x21, x2
/* Load the pcb address */
mov x1, x4
bl vfp_save_state
mov x2, x21
mov x1, x20
mov x0, x19
#endif
/* Store the new curthread */
str x1, [x18, #PC_CURTHREAD]
/*
* Restore the saved context and set it as curpcb.
*/
ldr x4, [x1, #TD_PCB]
str x4, [x18, #PC_CURPCB]
/*
* TODO: We may need to flush the cache here if switching
* to a user process.
*/
/* Switch to the new pmap */
ldr x5, [x4, #PCB_L0ADDR]
msr ttbr0_el1, x5
isb
/* Invalidate the TLB */
dsb sy
tlbi vmalle1is
dsb sy
isb
/*
* Release the old thread. This doesn't need to be a store-release
* as the above dsb instruction will provide release semantics.
*/
str x2, [x0, #TD_LOCK]
#if defined(SCHED_ULE) && defined(SMP)
/* Spin if TD_LOCK points to a blocked_lock */
ldr x2, =_C_LABEL(blocked_lock)
1:
ldar x3, [x1, #TD_LOCK]
cmp x3, x2
b.eq 1b
#endif
/* If we are single stepping, enable it */
ldr w5, [x4, #PCB_FLAGS]
set_step_flag w5, x6
/* Restore the registers */
ldp x5, x6, [x4, #PCB_SP]
mov sp, x5
msr tpidr_el0, x6
ldp x8, x9, [x4, #PCB_REGS + 8 * 8]
ldp x10, x11, [x4, #PCB_REGS + 10 * 8]
ldp x12, x13, [x4, #PCB_REGS + 12 * 8]
ldp x14, x15, [x4, #PCB_REGS + 14 * 8]
ldp x16, x17, [x4, #PCB_REGS + 16 * 8]
ldr x19, [x4, #PCB_REGS + 19 * 8]
ldp x20, x21, [x4, #PCB_REGS + 20 * 8]
ldp x22, x23, [x4, #PCB_REGS + 22 * 8]
ldp x24, x25, [x4, #PCB_REGS + 24 * 8]
ldp x26, x27, [x4, #PCB_REGS + 26 * 8]
ldp x28, x29, [x4, #PCB_REGS + 28 * 8]
ldr x30, [x4, #PCB_REGS + 30 * 8]
str xzr, [x4, #PCB_REGS + 18 * 8]
ret
.Lcpu_switch_panic_str:
.asciz "cpu_switch: %p\0"
END(cpu_switch)
ENTRY(fork_trampoline)
mov x0, x8
mov x1, x9
mov x2, sp
mov fp, #0 /* Stack traceback stops here. */
bl _C_LABEL(fork_exit)
/* Restore sp and lr */
ldp x0, x1, [sp]
msr sp_el0, x0
mov lr, x1
/* Restore the registers other than x0 and x1 */
ldp x2, x3, [sp, #TF_X + 2 * 8]
ldp x4, x5, [sp, #TF_X + 4 * 8]
ldp x6, x7, [sp, #TF_X + 6 * 8]
ldp x8, x9, [sp, #TF_X + 8 * 8]
ldp x10, x11, [sp, #TF_X + 10 * 8]
ldp x12, x13, [sp, #TF_X + 12 * 8]
ldp x14, x15, [sp, #TF_X + 14 * 8]
ldp x16, x17, [sp, #TF_X + 16 * 8]
ldr x19, [sp, #TF_X + 19 * 8]
ldp x20, x21, [sp, #TF_X + 20 * 8]
ldp x22, x23, [sp, #TF_X + 22 * 8]
ldp x24, x25, [sp, #TF_X + 24 * 8]
ldp x26, x27, [sp, #TF_X + 26 * 8]
ldp x28, x29, [sp, #TF_X + 28 * 8]
/* Skip x30 as it was restored above as lr */
/*
* Disable interrupts to avoid
* overwriting spsr_el1 by an IRQ exception.
*/
msr daifset, #2
/* Restore elr and spsr */
ldp x0, x1, [sp, #16]
msr elr_el1, x0
msr spsr_el1, x1
/* Finally x0 and x1 */
ldp x0, x1, [sp, #TF_X + 0 * 8]
ldr x18, [sp, #TF_X + 18 * 8]
/*
* No need for interrupts reenabling since PSR
* will be set to the desired value anyway.
*/
eret
END(fork_trampoline)
ENTRY(savectx)
/* Store the callee-saved registers */
stp x8, x9, [x0, #PCB_REGS + 8 * 8]
stp x10, x11, [x0, #PCB_REGS + 10 * 8]
stp x12, x13, [x0, #PCB_REGS + 12 * 8]
stp x14, x15, [x0, #PCB_REGS + 14 * 8]
stp x16, x17, [x0, #PCB_REGS + 16 * 8]
stp x18, x19, [x0, #PCB_REGS + 18 * 8]
stp x20, x21, [x0, #PCB_REGS + 20 * 8]
stp x22, x23, [x0, #PCB_REGS + 22 * 8]
stp x24, x25, [x0, #PCB_REGS + 24 * 8]
stp x26, x27, [x0, #PCB_REGS + 26 * 8]
stp x28, x29, [x0, #PCB_REGS + 28 * 8]
str x30, [x0, #PCB_REGS + 30 * 8]
/* And the old stack pointer */
mov x5, sp
mrs x6, tpidr_el0
stp x5, x6, [x0, #PCB_SP]
/* Store the VFP registers */
#ifdef VFP
mov x28, lr
mov x1, x0 /* move pcb to the correct register */
mov x0, xzr /* td = NULL */
bl vfp_save_state
mov lr, x28
#endif
ret
END(savectx)