Node / public / precursor-lxmfchat.git / files / xous-core / kernel / src / arch / arm / syscall.rs

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// SPDX-FileCopyrightText: 2022 Foundation Devices, Inc <hello@foundationdevices.com>

// SPDX-License-Identifier: Apache-2.0

use crate::services::Thread;

extern "C" {

fn _resume_trampoline(mode: usize, thread: &Thread, enable_irqs: bool) -> !;

}

pub fn invoke(

thread: &mut crate::arch::arm::process::Thread,

_supervisor: bool,

pc: usize,

sp: usize,

ret_addr: usize,

args: &[usize],

) {

assert!(args.len() <= 4, "too many arguments to invoke()");

thread.resume_addr = pc;

thread.sp = sp;

if let Some(arg) = args.get(0) {

thread.r0 = *arg;

}

if let Some(arg) = args.get(1) {

thread.r1 = *arg;

}

if let Some(arg) = args.get(2) {

thread.r2 = *arg;

}

if let Some(arg) = args.get(3) {

thread.r3 = *arg;

}

thread.ret_addr = ret_addr;

}

pub fn resume(supervisor: bool, thread: &Thread) -> ! { resume_inner(supervisor, thread, true) }

pub fn resume_no_irqs(supervisor: bool, thread: &Thread) -> ! { resume_inner(supervisor, thread, false) }

fn resume_inner(supervisor: bool, thread: &Thread, enable_irqs: bool) -> ! {

// Restore thread stack and PC, pass resume arguments via r0-r4

klog!(

"resume: setting sp={:08x}, res_addr={:08x}, lr={:08x} | privileged: {:?} | irqs: {:?} | ret: {:08x}",

thread.sp,

thread.resume_addr,

thread.lr,

supervisor,

enable_irqs,

thread.ret_addr

);

// See ARM ARM

// B1.3.1 ARM processor modes

let mode: usize = if supervisor {

0b11111 // System mode

} else {

0b10000 // User mode

};

unsafe {

_resume_trampoline(mode, thread, enable_irqs);

}

}