From 43c433a3f055d11d5b12278192d3f6993bbd5dc9 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Sat, 1 Jul 2023 16:17:24 +0200
Subject: [PATCH] Remove FmapCtxt.
---
src/context/context.rs | 4 +-
src/context/memory.rs | 84 +++++++++++++++++++++---------------------
src/scheme/user.rs | 15 +++-----
3 files changed, 50 insertions(+), 53 deletions(-)
diff --git a/src/context/context.rs b/src/context/context.rs
index 854c4bdc..25caf8fd 100644
--- a/src/context/context.rs
+++ b/src/context/context.rs
@@ -30,7 +30,7 @@ use crate::syscall::flag::{SIG_DFL, SigActionFlags};
/// Unique identifier for a context (i.e. `pid`).
use ::core::sync::atomic::AtomicUsize;
-use super::memory::FmapCtxt;
+use super::memory::GrantFileRef;
int_like!(ContextId, AtomicContextId, usize, AtomicUsize);
/// The status of a context - used for scheduling
@@ -64,7 +64,7 @@ impl Status {
#[derive(Clone, Debug)]
pub enum HardBlockedReason {
- AwaitingMmap { ctxt: Arc<FmapCtxt> },
+ AwaitingMmap { file_ref: GrantFileRef },
// TODO: PageFaultOom?
// TODO: NotYetStarted/ManuallyBlocked (when new contexts are created)
// TODO: ptrace_stop?
diff --git a/src/context/memory.rs b/src/context/memory.rs
index 89869638..8fab9636 100644
--- a/src/context/memory.rs
+++ b/src/context/memory.rs
@@ -9,7 +9,7 @@ use syscall::{
flag::MapFlags,
error::*,
};
-use rmm::Arch as _;
+use rmm::{Arch as _, PhysicalAddress};
use crate::arch::paging::PAGE_SIZE;
use crate::memory::{Enomem, Frame, get_page_info, PageInfo};
@@ -90,7 +90,7 @@ impl AddrSpace {
new_mapper,
(),
)?,
- Provider::Allocated { ref fmap } => Grant::cow(
+ Provider::Allocated { ref cow_file_ref } => Grant::cow(
Arc::clone(&self_arc),
grant_base,
grant_base,
@@ -100,12 +100,12 @@ impl AddrSpace {
new_mapper,
&mut this_flusher,
(),
- fmap.as_ref().map(Arc::clone),
+ cow_file_ref.clone(),
)?,
// MAP_SHARED grants are retained by reference, across address space clones (across
// forks on monolithic kernels).
- Provider::External { ref address_space, src_base, ref fmap } => Grant::borrow_grant(
+ Provider::External { ref address_space, src_base } => Grant::borrow_grant(
Arc::clone(&address_space),
grant_base,
grant_base,
@@ -113,7 +113,6 @@ impl AddrSpace {
new_mapper,
(),
false,
- fmap.as_ref().map(Arc::clone),
)?,
// TODO: "clone grant using fmap"
Provider::FmapBorrowed { .. } => continue,
@@ -562,16 +561,11 @@ pub struct GrantInfo {
pub(crate) provider: Provider,
}
-#[derive(Debug)]
-pub struct FmapCtxt {
- pub file_ref: GrantFileRef,
-}
-
#[derive(Debug)]
pub enum Provider {
/// The grant was initialized with (lazy) zeroed memory, and any changes will make it owned by
/// the frame allocator.
- Allocated { fmap: Option<Arc<FmapCtxt>> },
+ Allocated { cow_file_ref: Option<GrantFileRef> },
/// The grant is not owned, but borrowed from physical memory frames that do not belong to the
/// frame allocator.
@@ -579,10 +573,11 @@ pub enum Provider {
/// The memory is borrowed directly from another address space.
///
- /// All grants in the specified range must be of type Allocated.
- External { address_space: Arc<RwLock<AddrSpace>>, src_base: Page, fmap: Option<Arc<FmapCtxt>> },
+ /// Those grants will be pinned, and thus cannot be removed until they are unpinned, when this
+ /// grant is unmapped.
+ External { address_space: Arc<RwLock<AddrSpace>>, src_base: Page },
- FmapBorrowed { fmap: Arc<FmapCtxt> },
+ FmapBorrowed { file_ref: GrantFileRef },
}
#[derive(Debug)]
@@ -638,14 +633,14 @@ impl Grant {
page_count: span.count,
flags,
mapped: true,
- provider: Provider::Allocated { fmap: None },
+ provider: Provider::Allocated { cow_file_ref: None },
},
})
}
// XXX: borrow_grant is needed because of the borrow checker (iterator invalidation), maybe
// borrow_grant/borrow can be abstracted somehow?
- pub fn borrow_grant(src_address_space_lock: Arc<RwLock<AddrSpace>>, src_base: Page, dst_base: Page, src_info: &GrantInfo, mapper: &mut PageMapper, dst_flusher: impl Flusher<RmmA>, eager: bool, fmap: Option<Arc<FmapCtxt>>) -> Result<Grant, Enomem> {
+ pub fn borrow_grant(src_address_space_lock: Arc<RwLock<AddrSpace>>, src_base: Page, dst_base: Page, src_info: &GrantInfo, mapper: &mut PageMapper, dst_flusher: impl Flusher<RmmA>, eager: bool) -> Result<Grant, Enomem> {
Ok(Grant {
base: dst_base,
info: GrantInfo {
@@ -655,13 +650,12 @@ impl Grant {
provider: Provider::External {
src_base,
address_space: src_address_space_lock,
- fmap,
}
},
})
}
- pub fn borrow_fmap(span: PageSpan, flags: PageFlags<RmmA>, fmap: Arc<FmapCtxt>, src: Option<BorrowedFmapSource<'_>>, mapper: &mut PageMapper, mut flusher: impl Flusher<RmmA>) -> Self {
+ pub fn borrow_fmap(span: PageSpan, flags: PageFlags<RmmA>, file_ref: GrantFileRef, src: Option<BorrowedFmapSource<'_>>, mapper: &mut PageMapper, mut flusher: impl Flusher<RmmA>) -> Self {
if let Some(mut src) = src {
for dst_page in span.pages() {
let src_page = src.src_page.next_by(dst_page.offset_from(span.base));
@@ -679,7 +673,7 @@ impl Grant {
page_count: span.count,
mapped: true,
flags,
- provider: Provider::FmapBorrowed { fmap },
+ provider: Provider::FmapBorrowed { file_ref },
}
}
}
@@ -690,6 +684,7 @@ impl Grant {
/// mapping them into `[dst_base, dst_base+page_count)`. The destination pages will lazily read
/// the page tables of the source pages, but once present in the destination address space,
/// pages that are unmaped or moved will not be made visible to the destination address space.
+ // TODO: Return only one grant
pub fn borrow(
src_address_space_lock: Arc<RwLock<AddrSpace>>,
src_address_space: &AddrSpace,
@@ -738,16 +733,15 @@ impl Grant {
flags,
mapped: true,
provider: match src_grant.provider {
- Provider::Allocated { ref fmap } => Provider::External {
+ Provider::Allocated { .. } => Provider::External {
src_base,
address_space: Arc::clone(&src_address_space_lock),
- fmap: fmap.as_ref().map(Arc::clone),
},
Provider::PhysBorrowed { base: src_phys_base } => Provider::PhysBorrowed {
base: src_phys_base.next_by(offset_from_src_base),
},
- Provider::External { ref address_space, src_base, ref fmap } => Provider::External { address_space: Arc::clone(address_space), src_base, fmap: fmap.as_ref().map(Arc::clone) },
- Provider::FmapBorrowed { ref fmap } => Provider::FmapBorrowed { fmap: Arc::clone(fmap) }
+ Provider::External { ref address_space, src_base } => Provider::External { address_space: Arc::clone(address_space), src_base },
+ Provider::FmapBorrowed { ref file_ref } => Provider::FmapBorrowed { file_ref: file_ref.clone() }
}
},
});
@@ -776,7 +770,7 @@ impl Grant {
dst_mapper: &mut PageMapper,
mut src_flusher: impl Flusher<RmmA>,
mut dst_flusher: impl Flusher<RmmA>,
- fmap: Option<Arc<FmapCtxt>>,
+ cow_file_ref: Option<GrantFileRef>,
) -> Result<Grant, Enomem> {
// TODO: Page table iterator
for page_idx in 0..page_count {
@@ -809,7 +803,7 @@ impl Grant {
page_count,
flags,
mapped: true,
- provider: Provider::Allocated { fmap },
+ provider: Provider::Allocated { cow_file_ref },
},
})
}
@@ -868,11 +862,15 @@ impl Grant {
self.info.mapped = false;
+ // Dummy value, won't be read.
+ let dangling_frame = Frame::containing_address(PhysicalAddress::new(PAGE_SIZE));
+ let provider = core::mem::replace(&mut self.info.provider, Provider::PhysBorrowed { base: dangling_frame });
+
UnmapResult {
- file_desc: if let Provider::Allocated { ref mut fmap } | Provider::External { ref mut fmap, .. } = self.info.provider && let Some(fmap) = fmap.take() && let Ok(ctxt) = Arc::try_unwrap(fmap) {
- Some(ctxt.file_ref)
- } else {
- None
+ file_desc: match provider {
+ Provider::Allocated { cow_file_ref } => cow_file_ref,
+ Provider::FmapBorrowed { file_ref } => Some(file_ref),
+ _ => None,
}
}
}
@@ -903,20 +901,20 @@ impl Grant {
mapped: self.info.mapped,
page_count: span.count,
provider: match self.info.provider {
- Provider::External { ref address_space, src_base, ref fmap } => Provider::External {
+ Provider::External { ref address_space, src_base } => Provider::External {
address_space: Arc::clone(address_space),
src_base,
- fmap: fmap.as_ref().map(Arc::clone),
},
- Provider::Allocated { ref fmap } => Provider::Allocated { fmap: fmap.as_ref().map(Arc::clone) },
+ Provider::Allocated { ref cow_file_ref } => Provider::Allocated { cow_file_ref: cow_file_ref.clone() },
Provider::PhysBorrowed { ref base } => Provider::PhysBorrowed { base: base.clone() },
- Provider::FmapBorrowed { ref fmap } => Provider::FmapBorrowed { fmap: Arc::clone(fmap) }
+ Provider::FmapBorrowed { ref file_ref } => Provider::FmapBorrowed { file_ref: file_ref.clone() }
}
},
});
match self.info.provider {
Provider::PhysBorrowed { ref mut base } => *base = base.next_by(before_grant.as_ref().map_or(0, |g| g.info.page_count)),
+ // TODO: Adjust cow_file_ref offset
Provider::Allocated { .. } | Provider::External { .. } | Provider::FmapBorrowed { .. } => (),
}
@@ -928,15 +926,15 @@ impl Grant {
mapped: self.info.mapped,
page_count: span.count,
provider: match self.info.provider {
- Provider::Allocated { ref fmap } => Provider::Allocated { fmap: fmap.as_ref().map(Arc::clone) },
- Provider::External { ref address_space, src_base, ref fmap } => Provider::External {
+ // TODO: Adjust offset
+ Provider::Allocated { ref cow_file_ref } => Provider::Allocated { cow_file_ref: cow_file_ref.clone() },
+ Provider::External { ref address_space, src_base } => Provider::External {
address_space: Arc::clone(address_space),
src_base,
- fmap: fmap.as_ref().map(Arc::clone),
},
Provider::PhysBorrowed { base } => Provider::PhysBorrowed { base: base.next_by(this_span.count) },
- Provider::FmapBorrowed { ref fmap } => Provider::FmapBorrowed { fmap: Arc::clone(fmap) }
+ Provider::FmapBorrowed { ref file_ref } => Provider::FmapBorrowed { file_ref: file_ref.clone() },
}
},
});
@@ -1246,23 +1244,25 @@ pub fn try_correcting_page_tables(faulting_page: Page, access: AccessMode) -> Re
map_zeroed(&mut guard.table.utable, src_page, grant_flags, access == AccessMode::Write)?
}
}
- Provider::FmapBorrowed { ref fmap } => {
- let ctxt = Arc::clone(fmap);
+ // TODO: NonfatalInternalError if !MAP_LAZY and this page fault occurs.
+
+ Provider::FmapBorrowed { ref file_ref } => {
+ let file_ref = file_ref.clone();
let flags = map_flags(grant_info.flags());
drop(addr_space_guard);
- let (scheme_id, scheme_number) = match ctxt.file_ref.description.read() {
+ let (scheme_id, scheme_number) = match file_ref.description.read() {
ref desc => (desc.scheme, desc.number),
};
let user_inner = scheme::schemes()
.get(scheme_id).and_then(|s| s.as_user_inner().transpose().ok().flatten())
.ok_or(PfError::Segv)?;
- let offset = ctxt.file_ref.base_offset as u64 + (pages_from_grant_start * PAGE_SIZE) as u64;
+ let offset = file_ref.base_offset as u64 + (pages_from_grant_start * PAGE_SIZE) as u64;
user_inner.request_fmap(scheme_number, offset, 1, flags).unwrap();
let context_lock = super::current().map_err(|_| PfError::NonfatalInternalError)?;
- context_lock.write().hard_block(HardBlockedReason::AwaitingMmap { ctxt });
+ context_lock.write().hard_block(HardBlockedReason::AwaitingMmap { file_ref });
unsafe { super::switch(); }
diff --git a/src/scheme/user.rs b/src/scheme/user.rs
index 52bc5a6f..09720f36 100644
--- a/src/scheme/user.rs
+++ b/src/scheme/user.rs
@@ -1,7 +1,6 @@
use alloc::sync::{Arc, Weak};
use alloc::boxed::Box;
use alloc::collections::BTreeMap;
-use rmm::PageFlushAll;
use syscall::{SKMSG_FRETURNFD, CallerCtx, SKMSG_PROVIDE_MMAP};
use core::num::NonZeroUsize;
use core::sync::atomic::{AtomicBool, Ordering};
@@ -12,7 +11,7 @@ use spin::{Mutex, RwLock};
use crate::context::context::HardBlockedReason;
use crate::context::{self, Context, BorrowedHtBuf, Status};
use crate::context::file::FileDescription;
-use crate::context::memory::{AddrSpace, DANGLING, Grant, GrantFileRef, PageSpan, MmapMode, page_flags, FmapCtxt, BorrowedFmapSource};
+use crate::context::memory::{AddrSpace, DANGLING, Grant, GrantFileRef, PageSpan, MmapMode, page_flags, BorrowedFmapSource};
use crate::event;
use crate::memory::Frame;
use crate::paging::{PAGE_SIZE, Page, VirtualAddress};
@@ -503,12 +502,10 @@ impl UserInner {
let dst_base = match mode {
MmapMode::Cow => todo!("mmap CoW"),
MmapMode::Shared => {
- let ctxt = Arc::new(FmapCtxt {
- file_ref: GrantFileRef {
- description: desc,
- base_offset: map.offset,
- },
- });
+ let file_ref = GrantFileRef {
+ description: desc,
+ base_offset: map.offset,
+ };
let src_guard = src_address_space.read();
let src = match base_page_opt {
Some(base_addr) => Some(BorrowedFmapSource {
@@ -519,7 +516,7 @@ impl UserInner {
};
let page_count_nz = NonZeroUsize::new(page_count).expect("already validated map.size != 0");
dst_addr_space.write().mmap(dst_base, page_count_nz, map.flags, |dst_base, flags, mapper, flusher| {
- Ok(Grant::borrow_fmap(PageSpan::new(dst_base, page_count), page_flags(map.flags), ctxt, src, mapper, flusher))
+ Ok(Grant::borrow_fmap(PageSpan::new(dst_base, page_count), page_flags(map.flags), file_ref, src, mapper, flusher))
})?
}
};
--
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