Rust-for-Linux · adamrk · May 13, 2021 · May 13, 2021 · Feb 18, 2022 · Feb 19, 2022
diff --git a/.github/workflows/busybox.config b/.github/workflows/busybox.config
@@ -196,7 +196,7 @@ CONFIG_GZIP_FAST=0
 # Coreutils
 #
 # CONFIG_BASENAME is not set
-# CONFIG_CAT is not set
+CONFIG_CAT=y
 # CONFIG_FEATURE_CATN is not set
 # CONFIG_FEATURE_CATV is not set
 # CONFIG_CHGRP is not set
@@ -263,9 +263,9 @@ CONFIG_GZIP_FAST=0
 # CONFIG_SHA512SUM is not set
 # CONFIG_SHA3SUM is not set
 # CONFIG_FEATURE_MD5_SHA1_SUM_CHECK is not set
-# CONFIG_MKDIR is not set
+CONFIG_MKDIR=y
 # CONFIG_MKFIFO is not set
-# CONFIG_MKNOD is not set
+CONFIG_MKNOD=y
 # CONFIG_MKTEMP is not set
 # CONFIG_MV is not set
 # CONFIG_NICE is not set
@@ -280,7 +280,7 @@ CONFIG_GZIP_FAST=0
 # CONFIG_READLINK is not set
 # CONFIG_FEATURE_READLINK_FOLLOW is not set
 # CONFIG_REALPATH is not set
-# CONFIG_RM is not set
+CONFIG_RM=y
 # CONFIG_RMDIR is not set
 # CONFIG_SEQ is not set
 # CONFIG_SHRED is not set
@@ -635,7 +635,7 @@ CONFIG_DEFAULT_DEPMOD_FILE="modules.dep"
 # CONFIG_MKSWAP is not set
 # CONFIG_FEATURE_MKSWAP_UUID is not set
 # CONFIG_MORE is not set
-# CONFIG_MOUNT is not set
+CONFIG_MOUNT=y
 # CONFIG_FEATURE_MOUNT_FAKE is not set
 # CONFIG_FEATURE_MOUNT_VERBOSE is not set
 # CONFIG_FEATURE_MOUNT_HELPERS is not set

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
@@ -11,6 +11,7 @@ jobs:
     timeout-minutes: 20
 
     strategy:
+      fail-fast: false
       matrix:
         arch: [arm, arm64, ppc64le, riscv64, x86_64]
         toolchain: [gcc, clang, llvm]
@@ -360,6 +361,12 @@ jobs:
           grep '] rust_semaphore_c: Rust semaphore sample (in C, for comparison) (init)$' qemu-stdout.log
           grep '] rust_semaphore_c: Rust semaphore sample (in C, for comparison) (exit)$' qemu-stdout.log
 
+      - run: |
+          grep '] rust_seq_file: Rust seq_file sample (init)$'   qemu-stdout.log
+          grep '] rust_seq_file: Rust seq_file sample (exit)$'   qemu-stdout.log
+          grep 'rust_seq_file read log: 1'                       qemu-stdout.log
+          grep 'rust_seq_file read log: 2'                       qemu-stdout.log
+
       # Report
       - run: |
           cat ${{ env.BUILD_DIR }}.config

diff --git a/.github/workflows/kernel-arm-debug.config b/.github/workflows/kernel-arm-debug.config
@@ -1780,6 +1780,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 # CONFIG_STRICT_DEVMEM is not set
 
 #

diff --git a/.github/workflows/kernel-arm-release.config b/.github/workflows/kernel-arm-release.config
@@ -1704,6 +1704,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 # CONFIG_STRICT_DEVMEM is not set
 
 #

diff --git a/.github/workflows/kernel-arm64-debug-thinlto.config b/.github/workflows/kernel-arm64-debug-thinlto.config
@@ -1437,6 +1437,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 
 #
 # arm64 Debugging

diff --git a/.github/workflows/kernel-arm64-debug.config b/.github/workflows/kernel-arm64-debug.config
@@ -1432,6 +1432,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 
 #
 # arm64 Debugging

diff --git a/.github/workflows/kernel-arm64-release-thinlto.config b/.github/workflows/kernel-arm64-release-thinlto.config
@@ -1216,7 +1216,10 @@ CONFIG_FRAME_POINTER=y
 # Generic Kernel Debugging Instruments
 #
 # CONFIG_MAGIC_SYSRQ is not set
-# CONFIG_DEBUG_FS is not set
+CONFIG_DEBUG_FS=y
+CONFIG_DEBUG_FS_ALLOW_ALL=y
+# CONFIG_DEBUG_FS_DISALLOW_MOUNT is not set
+# CONFIG_DEBUG_FS_ALLOW_NONE is not set
 CONFIG_HAVE_ARCH_KGDB=y
 # CONFIG_KGDB is not set
 CONFIG_ARCH_HAS_UBSAN_SANITIZE_ALL=y
@@ -1355,6 +1358,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 
 #
 # arm64 Debugging

diff --git a/.github/workflows/kernel-arm64-release.config b/.github/workflows/kernel-arm64-release.config
@@ -1350,6 +1350,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 
 #
 # arm64 Debugging

diff --git a/.github/workflows/kernel-ppc64le-debug.config b/.github/workflows/kernel-ppc64le-debug.config
@@ -1492,6 +1492,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y
 # CONFIG_STRICT_DEVMEM is not set
 

diff --git a/.github/workflows/kernel-ppc64le-release.config b/.github/workflows/kernel-ppc64le-release.config
@@ -1454,6 +1454,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y
 # CONFIG_STRICT_DEVMEM is not set
 

diff --git a/.github/workflows/kernel-riscv64-debug.config b/.github/workflows/kernel-riscv64-debug.config
@@ -1122,7 +1122,10 @@ CONFIG_FRAME_POINTER=y
 # Generic Kernel Debugging Instruments
 #
 # CONFIG_MAGIC_SYSRQ is not set
-# CONFIG_DEBUG_FS is not set
+CONFIG_DEBUG_FS=y
+CONFIG_DEBUG_FS_ALLOW_ALL=y
+# CONFIG_DEBUG_FS_DISALLOW_MOUNT is not set
+# CONFIG_DEBUG_FS_ALLOW_NONE is not set
 CONFIG_HAVE_ARCH_KGDB=y
 CONFIG_HAVE_ARCH_KGDB_QXFER_PKT=y
 # CONFIG_KGDB is not set
@@ -1286,6 +1289,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 # CONFIG_STRICT_DEVMEM is not set
 
 #

diff --git a/.github/workflows/kernel-riscv64-release.config b/.github/workflows/kernel-riscv64-release.config
@@ -1110,7 +1110,10 @@ CONFIG_FRAME_POINTER=y
 # Generic Kernel Debugging Instruments
 #
 # CONFIG_MAGIC_SYSRQ is not set
-# CONFIG_DEBUG_FS is not set
+CONFIG_DEBUG_FS=y
+CONFIG_DEBUG_FS_ALLOW_ALL=y
+# CONFIG_DEBUG_FS_DISALLOW_MOUNT is not set
+# CONFIG_DEBUG_FS_ALLOW_NONE is not set
 CONFIG_HAVE_ARCH_KGDB=y
 CONFIG_HAVE_ARCH_KGDB_QXFER_PKT=y
 # CONFIG_UBSAN is not set
@@ -1202,6 +1205,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 # CONFIG_STRICT_DEVMEM is not set
 
 #

diff --git a/.github/workflows/kernel-x86_64-debug-thinlto.config b/.github/workflows/kernel-x86_64-debug-thinlto.config
@@ -1222,9 +1222,9 @@ CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE=0x1
 CONFIG_MAGIC_SYSRQ_SERIAL=y
 CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE=""
 CONFIG_DEBUG_FS=y
-# CONFIG_DEBUG_FS_ALLOW_ALL is not set
+CONFIG_DEBUG_FS_ALLOW_ALL=y
 # CONFIG_DEBUG_FS_DISALLOW_MOUNT is not set
-CONFIG_DEBUG_FS_ALLOW_NONE=y
+# CONFIG_DEBUG_FS_ALLOW_NONE is not set
 CONFIG_HAVE_ARCH_KGDB=y
 CONFIG_KGDB=y
 CONFIG_KGDB_HONOUR_BLOCKLIST=y
@@ -1441,6 +1441,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y
 # CONFIG_STRICT_DEVMEM is not set
 

diff --git a/.github/workflows/kernel-x86_64-debug.config b/.github/workflows/kernel-x86_64-debug.config
@@ -1217,9 +1217,9 @@ CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE=0x1
 CONFIG_MAGIC_SYSRQ_SERIAL=y
 CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE=""
 CONFIG_DEBUG_FS=y
-# CONFIG_DEBUG_FS_ALLOW_ALL is not set
+CONFIG_DEBUG_FS_ALLOW_ALL=y
 # CONFIG_DEBUG_FS_DISALLOW_MOUNT is not set
-CONFIG_DEBUG_FS_ALLOW_NONE=y
+# CONFIG_DEBUG_FS_ALLOW_NONE is not set
 CONFIG_HAVE_ARCH_KGDB=y
 CONFIG_KGDB=y
 CONFIG_KGDB_HONOUR_BLOCKLIST=y
@@ -1444,6 +1444,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y
 # CONFIG_STRICT_DEVMEM is not set
 

diff --git a/.github/workflows/kernel-x86_64-release-thinlto.config b/.github/workflows/kernel-x86_64-release-thinlto.config
@@ -1289,7 +1289,10 @@ CONFIG_STACK_VALIDATION=y
 # Generic Kernel Debugging Instruments
 #
 # CONFIG_MAGIC_SYSRQ is not set
-# CONFIG_DEBUG_FS is not set
+CONFIG_DEBUG_FS=y
+CONFIG_DEBUG_FS_ALLOW_ALL=y
+# CONFIG_DEBUG_FS_DISALLOW_MOUNT is not set
+# CONFIG_DEBUG_FS_ALLOW_NONE is not set
 CONFIG_HAVE_ARCH_KGDB=y
 CONFIG_ARCH_HAS_UBSAN_SANITIZE_ALL=y
 # CONFIG_UBSAN is not set
@@ -1397,6 +1400,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y
 # CONFIG_STRICT_DEVMEM is not set
 

diff --git a/.github/workflows/kernel-x86_64-release.config b/.github/workflows/kernel-x86_64-release.config
@@ -1392,6 +1392,7 @@ CONFIG_SAMPLE_RUST_STACK_PROBING=m
 CONFIG_SAMPLE_RUST_SEMAPHORE=m
 CONFIG_SAMPLE_RUST_SEMAPHORE_C=m
 CONFIG_SAMPLE_RUST_RANDOM=m
+CONFIG_SAMPLE_RUST_SEQ_FILE=m
 CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y
 # CONFIG_STRICT_DEVMEM is not set
 

diff --git a/.github/workflows/qemu-init.sh b/.github/workflows/qemu-init.sh
@@ -37,4 +37,17 @@ busybox insmod rust_module_parameters_loadable_custom.ko \
 busybox  rmmod rust_module_parameters_loadable_default.ko
 busybox  rmmod rust_module_parameters_loadable_custom.ko
 
+busybox insmod rust_seq_file.ko
+busybox mkdir proc
+busybox mount -t proc proc /proc
+busybox mkdir debugfs
+busybox mount -t debugfs debugfs /debugfs
+export RUST_SEQ_MINOR=$(busybox cat /proc/misc | busybox grep rust_seq_file | busybox cut -d ' ' -f 1)
+busybox mknod /dev/rust_seq_file0 c 10 $RUST_SEQ_MINOR
+busybox cat /dev/rust_seq_file0
+busybox cat /dev/rust_seq_file0
+busybox cat /debugfs/rust_seq_file
+busybox rm /dev/rust_seq_file0
+busybox rmmod rust_seq_file.ko
+
 busybox reboot -f
diff --git a/.github/workflows/qemu-initramfs.desc b/.github/workflows/qemu-initramfs.desc
@@ -5,7 +5,6 @@ file    /bin/busybox  busybox                         0755 0 0
 slink   /bin/sh       /bin/busybox                    0755 0 0
 file    /init         .github/workflows/qemu-init.sh  0755 0 0
 
-file    /rust_minimal.ko            samples/rust/rust_minimal.ko            0755 0 0
 file    /rust_print.ko              samples/rust/rust_print.ko              0755 0 0
 file    /rust_module_parameters.ko  samples/rust/rust_module_parameters.ko  0755 0 0
 file    /rust_sync.ko               samples/rust/rust_sync.ko               0755 0 0
@@ -17,3 +16,5 @@ file    /rust_semaphore_c.ko        samples/rust/rust_semaphore_c.ko        0755
 
 file    /rust_module_parameters_loadable_default.ko  samples/rust/rust_module_parameters_loadable_default.ko  0755 0 0
 file    /rust_module_parameters_loadable_custom.ko   samples/rust/rust_module_parameters_loadable_custom.ko   0755 0 0
+file    /rust_minimal.ko            samples/rust/rust_minimal.ko            0755 0 0
+file    /rust_seq_file.ko           samples/rust/rust_seq_file.ko           0755 0 0
diff --git a/rust/kernel/bindings_helper.h b/rust/kernel/bindings_helper.h
@@ -2,10 +2,12 @@
 
 #include <linux/cdev.h>
 #include <linux/clk.h>
+#include <linux/debugfs.h>
 #include <linux/errname.h>
 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/random.h>
+#include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/sysctl.h>
 #include <linux/uaccess.h>

diff --git a/rust/kernel/debugfs.rs b/rust/kernel/debugfs.rs
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! TODOABK: finish doc
+
+use core::{
+    marker::{PhantomData, Sync},
+    ptr,
+};
+
+use crate::{bindings, c_types, error, str::CStr, types::PointerWrapper, Result};
+
+/// An `inode` in debugfs with a `T` stored in `i_private`.
+pub(crate) struct DebugFsDirEntry<T: PointerWrapper> {
+    dentry: *mut bindings::dentry,
+    data: *mut c_types::c_void,
+    _wrapper: PhantomData<T>,
+}
+
+// SAFETY: There are methods available on [`DebugFsDirEntry`] so a thread can't
+// actually do anything with a `&DebugFsDirEntry`. This makes it is safe to
+// share across threads.
+unsafe impl<T: PointerWrapper> Sync for DebugFsDirEntry<T> {}
+
+impl<T: PointerWrapper> DebugFsDirEntry<T> {
+    /// Create a file in `debugfs`.
+    ///
+    /// # Safety
+    ///
+    /// `fops` must be valid when opening an `inode` with `data::into_pointer`
+    /// stored in `i_private`.
+    pub(crate) unsafe fn create_file(
+        name: &CStr,
+        data: T,
+        fops: &'static bindings::file_operations,
+    ) -> Result<Self> {
+        let name = name.as_char_ptr();
+        let data = data.into_pointer() as *mut _;
+        // SAFETY: Calling a C function. `name` will be a valid null-terminated
+        // string because it came from a `CStr`. The caller guarantees that
+        // `fops` is valid for an inode with `data` in `i_private`.
+        let dentry_ptr = error::from_kernel_err_ptr(unsafe {
+            bindings::debugfs_create_file(name, 0, ptr::null_mut(), data, fops)
+        });
+        match dentry_ptr {
+            Err(err) => {
+                // SAFETY: `data` was created by `T::into_pointer` just above.
+                drop(unsafe { T::from_pointer(data) });
+                Err(err)
+            }
+            Ok(dentry) => Ok(DebugFsDirEntry {
+                dentry,
+                data,
+                _wrapper: PhantomData,
+            }),
+        }
+    }
+}
+
+impl<T: PointerWrapper> Drop for DebugFsDirEntry<T> {
+    fn drop(&mut self) {
+        // SAFETY: Calling a C function. `dentry` must have been created by a
+        // call to [`DebugFsDirEntry::create_file`] which always returns a valid
+        // `dentry`.
+        unsafe {
+            bindings::debugfs_remove(self.dentry);
+        }
+        // SAFETY: `self.data` was created by a call to `T::into_pointer` in
+        // [`DebugFsDirEntry::create_file`].
+        unsafe { T::from_pointer(self.data) };
+    }
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
@@ -48,6 +48,8 @@ pub mod chrdev;
 #[cfg(CONFIG_COMMON_CLK)]
 pub mod clk;
 pub mod cred;
+#[cfg(CONFIG_DEBUG_FS)]
+pub mod debugfs;
 pub mod device;
 pub mod driver;
 mod error;
@@ -75,6 +77,8 @@ mod build_assert;
 pub mod prelude;
 pub mod print;
 pub mod random;
+#[cfg(CONFIG_DEBUG_FS)]
+pub mod seq_file;
 mod static_assert;
 #[doc(hidden)]
 pub mod std_vendor;