Remove the shim kernel crate

kernel/src/syscall/madvise.rs

@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use align_ext::AlignExt;
+
+use super::SyscallReturn;
+use crate::prelude::*;
+
+pub fn sys_madvise(
+    start: Vaddr,
+    len: usize,
+    behavior: i32,
+    ctx: &Context,
+) -> Result<SyscallReturn> {
+    let behavior = MadviseBehavior::try_from(behavior)?;
+    debug!(
+        "start = 0x{:x}, len = 0x{:x}, behavior = {:?}",
+        start, len, behavior
+    );
+
+    if start % PAGE_SIZE != 0 {
+        return_errno_with_message!(Errno::EINVAL, "the start address should be page aligned");
+    }
+    if len == 0 {
+        return Ok(SyscallReturn::Return(0));
+    }
+
+    let len = len.align_up(PAGE_SIZE);
+    match behavior {
+        MadviseBehavior::MADV_NORMAL
+        | MadviseBehavior::MADV_SEQUENTIAL
+        | MadviseBehavior::MADV_WILLNEED => {
+            // perform a read at first
+            let mut buffer = vec![0u8; len];
+            ctx.get_user_space()
+                .read_bytes(start, &mut VmWriter::from(buffer.as_mut_slice()))?;
+        }
+        MadviseBehavior::MADV_DONTNEED => {
+            warn!("MADV_DONTNEED isn't implemented, do nothing for now.");
+        }
+        MadviseBehavior::MADV_FREE => madv_free(start, len, ctx)?,
+        _ => todo!(),
+    }
+    Ok(SyscallReturn::Return(0))
+}
+
+fn madv_free(start: Vaddr, len: usize, ctx: &Context) -> Result<()> {
+    let root_vmar = ctx.process.root_vmar();
+    let advised_range = start..start + len;
+    let _ = root_vmar.destroy(advised_range);
+
+    Ok(())
+}
+
+#[repr(i32)]
+#[derive(Debug, Clone, Copy, TryFromInt)]
+#[allow(non_camel_case_types)]
+/// This definition is the same from linux
+pub enum MadviseBehavior {
+    MADV_NORMAL = 0,     /* no further special treatment */
+    MADV_RANDOM = 1,     /* expect random page references */
+    MADV_SEQUENTIAL = 2, /* expect sequential page references */
+    MADV_WILLNEED = 3,   /* will need these pages */
+    MADV_DONTNEED = 4,   /* don't need these pages */
+
+    /* common parameters: try to keep these consistent across architectures */
+    MADV_FREE = 8,           /* free pages only if memory pressure */
+    MADV_REMOVE = 9,         /* remove these pages & resources */
+    MADV_DONTFORK = 10,      /* don't inherit across fork */
+    MADV_DOFORK = 11,        /* do inherit across fork */
+    MADV_HWPOISON = 100,     /* poison a page for testing */
+    MADV_SOFT_OFFLINE = 101, /* soft offline page for testing */
+
+    MADV_MERGEABLE = 12,   /* KSM may merge identical pages */
+    MADV_UNMERGEABLE = 13, /* KSM may not merge identical pages */
+
+    MADV_HUGEPAGE = 14,   /* Worth backing with hugepages */
+    MADV_NOHUGEPAGE = 15, /* Not worth backing with hugepages */
+
+    MADV_DONTDUMP = 16, /* Explicity exclude from the core dump,
+                        overrides the coredump filter bits */
+    MADV_DODUMP = 17, /* Clear the MADV_DONTDUMP flag */
+
+    MADV_WIPEONFORK = 18, /* Zero memory on fork, child only */
+    MADV_KEEPONFORK = 19, /* Undo MADV_WIPEONFORK */
+
+    MADV_COLD = 20,    /* deactivate these pages */
+    MADV_PAGEOUT = 21, /* reclaim these pages */
+
+    MADV_POPULATE_READ = 22,  /* populate (prefault) page tables readable */
+    MADV_POPULATE_WRITE = 23, /* populate (prefault) page tables writable */
+
+    MADV_DONTNEED_LOCKED = 24, /* like DONTNEED, but drop locked pages too */
+}