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https://github.com/panpaul/tiny_os
synced 2024-09-20 09:45:19 +08:00
feat: uapi/syscall: update message info, add cap n_bits field
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c352a0b8c6
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@ -4,17 +4,10 @@ use uapi::{error::*, syscall::*};
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pub fn handle_syscall(tcb: &mut TcbObject) -> SysResult {
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let info = MessageInfo::try_from(tcb.trapframe.get_reg(0))?;
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let cspace = CNodeCap::try_from(tcb.cspace())?;
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let cap_ptr = tcb.trapframe.get_reg(1);
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let cap = cspace
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.resolve_address_bits(cap_ptr, usize::BITS as usize)
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.map_err(SysError::from)?;
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trace!("handle_syscall: info={:?} cap={:?}", info, cap);
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// Invalid, Debug*, Yield will bypass the capability check
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match info.label() {
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Syscall::Invalid => Ok(()),
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Syscall::Invalid => return Ok(()),
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Syscall::DebugPutChar => {
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if info.length() != 3 {
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return Err(SysError::InvalidArgument);
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@ -22,13 +15,23 @@ pub fn handle_syscall(tcb: &mut TcbObject) -> SysResult {
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let c = tcb.trapframe.get_reg(2) as u8 as char;
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crate::print!("{}", c);
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Ok(())
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return Ok(());
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},
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Syscall::Yield => {
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tcb.clear_timetick();
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Ok(())
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return Ok(());
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},
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_ => (),
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};
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let cspace = CNodeCap::try_from(tcb.cspace())?;
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let cap_ptr = tcb.trapframe.get_reg(1);
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let cap = cspace.resolve_address_bits(cap_ptr, info.bits()).map_err(SysError::from)?;
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trace!("handle_syscall: info={:?} cap={:?}", info, cap);
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match info.label() {
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Syscall::Send => Ok(()),
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_ => unimplemented!("handle_syscall: {:?}, {:?}", info.label(), cap),
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}
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}
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12
root/root.S
12
root/root.S
@ -11,15 +11,15 @@ _start:
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.loop:
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lb a2, 0(t0)
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beqz a2, .yield
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# msg: label = DebugPutChar(1), length = 3
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# ptr: self-referential to cspace, just to create a valid cptr
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syscall (1<<12 | 3), 0x0202020202020202
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# msg: label = DebugPutChar(1), bits = 1, length = 3
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# ptr: (any)
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syscall (1<<13 | 0<<7 | 3), 0
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addi t0, t0, 1
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j .loop
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.yield:
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# msg: label = Yield(2), length = 2
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# ptr: self-referential to cspace, just to create a valid cptr
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syscall (2<<12 | 2), 0x0202020202020202
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# msg: label = Yield(2), bits = 1, length = 2
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# ptr: (any)
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syscall (2<<13 | 0<<7 | 2), 0
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j _start
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.data
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@ -1,9 +1,7 @@
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use core::fmt::Debug;
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use num_traits::{FromPrimitive, ToPrimitive};
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use utils::MASK;
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use crate::error::SysError;
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use core::fmt::Debug;
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use num_traits::{FromPrimitive, ToPrimitive};
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use utils::{then::Then, MASK};
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#[derive(Clone, Copy, Debug, Eq, PartialEq, FromPrimitive, ToPrimitive)]
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pub enum Syscall {
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@ -17,40 +15,62 @@ pub enum Syscall {
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Reply = 7,
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}
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/* in vanilla seL4, MessageInfo layout:
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* > | label | caps | extra_caps | length |
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* > | [63:12] | [11:9] | [8:7] | [6:0] |
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*
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* in out implementation, MessageInfo layout:
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* > label: Syscall
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* > length: args.len()
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*
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* Syscall convention:
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/* Syscall convention:
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* > Call:
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* > > [a0]: MessageInfo
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* > > [a1]: Capability Pointer
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* > > [a2..a7]: extra arguments
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* > > length = (a0..a?).len()
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* >
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* > Reply:
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* > TODO: figure out how vanilla seL4 handle reply
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*/
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/* MessageInfo layout:
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* > | label | bits | length |
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* > | [63:13] | [12:7] | [6:0] |
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* > label: Syscall
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* > bits: cap_ptr n_bits
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* > length: args.len()
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*
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*/
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#[derive(Clone, Copy)]
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pub struct MessageInfo(usize);
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impl MessageInfo {
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const LABEL_MASK: usize = MASK!(63 - 12 + 1);
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const LABEL_MASK: usize = MASK!(63 - 13 + 1);
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const LABEL_OFFSET: usize = 13;
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pub fn new(label: Syscall, length: usize) -> Self {
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Self((label.to_usize().unwrap_or(0)) << 12 | (length & 0x7f))
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const BITS_MASK: usize = MASK!(6);
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const BITS_OFFSET: usize = 7;
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const LENGTH_MASK: usize = MASK!(7);
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const LENGTH_OFFSET: usize = 0;
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pub fn new(label: Syscall, bits: usize, length: usize) -> Self {
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let label = label.to_usize().unwrap_or(0);
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let bits = bits - 1; // stored as n_bits - 1
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assert!(label <= Self::LABEL_MASK);
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assert!(bits <= Self::BITS_MASK);
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assert!(length <= Self::LENGTH_MASK);
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let info = ((label & Self::LABEL_MASK) << Self::LABEL_OFFSET)
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| ((bits & Self::BITS_MASK) << Self::BITS_OFFSET)
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| ((length & Self::LENGTH_MASK) << Self::LENGTH_OFFSET);
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Self(info)
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}
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pub fn label(&self) -> Syscall {
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Syscall::from_usize((self.0 >> 12) & Self::LABEL_MASK).unwrap_or(Syscall::Invalid)
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Syscall::from_usize((self.0 >> Self::LABEL_OFFSET) & Self::LABEL_MASK).unwrap_or(Syscall::Invalid)
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}
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pub fn bits(&self) -> usize {
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((self.0 >> Self::BITS_OFFSET) & Self::BITS_MASK) + 1
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}
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pub fn length(&self) -> usize {
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self.0 & 0x7F
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(self.0 >> Self::LENGTH_OFFSET) & Self::LENGTH_MASK
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}
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pub fn as_usize(&self) -> usize {
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@ -62,6 +82,7 @@ impl Debug for MessageInfo {
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fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
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f.debug_struct("MessageInfo")
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.field("label", &self.label())
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.field("bits", &self.bits())
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.field("length", &self.length())
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.finish()
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}
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@ -71,8 +92,7 @@ impl TryFrom<usize> for MessageInfo {
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type Error = SysError;
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fn try_from(value: usize) -> Result<Self, Self::Error> {
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let syscall = Syscall::from_usize((value >> 12) & MessageInfo::LABEL_MASK).ok_or(SysError::InvalidArgument)?;
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let length = value & 0x7F;
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Ok(Self::new(syscall, length))
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let info = Self(value);
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(info.label() != Syscall::Invalid).then_ok(info, SysError::InvalidArgument)
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}
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}
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