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* rust: add pin-init API coreBenno Lossin2023-04-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This API is used to facilitate safe pinned initialization of structs. It replaces cumbersome `unsafe` manual initialization with elegant safe macro invocations. Due to the size of this change it has been split into six commits: 1. This commit introducing the basic public interface: traits and functions to represent and create initializers. 2. Adds the `#[pin_data]`, `pin_init!`, `try_pin_init!`, `init!` and `try_init!` macros along with their internal types. 3. Adds the `InPlaceInit` trait that allows using an initializer to create an object inside of a `Box<T>` and other smart pointers. 4. Adds the `PinnedDrop` trait and adds macro support for it in the `#[pin_data]` macro. 5. Adds the `stack_pin_init!` macro allowing to pin-initialize a struct on the stack. 6. Adds the `Zeroable` trait and `init::zeroed` function to initialize types that have `0x00` in all bytes as a valid bit pattern. -- In this section the problem that the new pin-init API solves is outlined. This message describes the entirety of the API, not just the parts introduced in this commit. For a more granular explanation and additional information on pinning and this issue, view [1]. Pinning is Rust's way of enforcing the address stability of a value. When a value gets pinned it will be impossible for safe code to move it to another location. This is done by wrapping pointers to said object with `Pin<P>`. This wrapper prevents safe code from creating mutable references to the object, preventing mutable access, which is needed to move the value. `Pin<P>` provides `unsafe` functions to circumvent this and allow modifications regardless. It is then the programmer's responsibility to uphold the pinning guarantee. Many kernel data structures require a stable address, because there are foreign pointers to them which would get invalidated by moving the structure. Since these data structures are usually embedded in structs to use them, this pinning property propagates to the container struct. Resulting in most structs in both Rust and C code needing to be pinned. So if we want to have a `mutex` field in a Rust struct, this struct also needs to be pinned, because a `mutex` contains a `list_head`. Additionally initializing a `list_head` requires already having the final memory location available, because it is initialized by pointing it to itself. But this presents another challenge in Rust: values have to be initialized at all times. There is the `MaybeUninit<T>` wrapper type, which allows handling uninitialized memory, but this requires using the `unsafe` raw pointers and a casting the type to the initialized variant. This problem gets exacerbated when considering encapsulation and the normal safety requirements of Rust code. The fields of the Rust `Mutex<T>` should not be accessible to normal driver code. After all if anyone can modify the fields, there is no way to ensure the invariants of the `Mutex<T>` are upheld. But if the fields are inaccessible, then initialization of a `Mutex<T>` needs to be somehow achieved via a function or a macro. Because the `Mutex<T>` must be pinned in memory, the function cannot return it by value. It also cannot allocate a `Box` to put the `Mutex<T>` into, because that is an unnecessary allocation and indirection which would hurt performance. The solution in the rust tree (e.g. this commit: [2]) that is replaced by this API is to split this function into two parts: 1. A `new` function that returns a partially initialized `Mutex<T>`, 2. An `init` function that requires the `Mutex<T>` to be pinned and that fully initializes the `Mutex<T>`. Both of these functions have to be marked `unsafe`, since a call to `new` needs to be accompanied with a call to `init`, otherwise using the `Mutex<T>` could result in UB. And because calling `init` twice also is not safe. While `Mutex<T>` initialization cannot fail, other structs might also have to allocate memory, which would result in conditional successful initialization requiring even more manual accommodation work. Combine this with the problem of pin-projections -- the way of accessing fields of a pinned struct -- which also have an `unsafe` API, pinned initialization is riddled with `unsafe` resulting in very poor ergonomics. Not only that, but also having to call two functions possibly multiple lines apart makes it very easy to forget it outright or during refactoring. Here is an example of the current way of initializing a struct with two synchronization primitives (see [3] for the full example): struct SharedState { state_changed: CondVar, inner: Mutex<SharedStateInner>, } impl SharedState { fn try_new() -> Result<Arc<Self>> { let mut state = Pin::from(UniqueArc::try_new(Self { // SAFETY: `condvar_init!` is called below. state_changed: unsafe { CondVar::new() }, // SAFETY: `mutex_init!` is called below. inner: unsafe { Mutex::new(SharedStateInner { token_count: 0 }) }, })?); // SAFETY: `state_changed` is pinned when `state` is. let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.state_changed) }; kernel::condvar_init!(pinned, "SharedState::state_changed"); // SAFETY: `inner` is pinned when `state` is. let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.inner) }; kernel::mutex_init!(pinned, "SharedState::inner"); Ok(state.into()) } } The pin-init API of this patch solves this issue by providing a comprehensive solution comprised of macros and traits. Here is the example from above using the pin-init API: #[pin_data] struct SharedState { #[pin] state_changed: CondVar, #[pin] inner: Mutex<SharedStateInner>, } impl SharedState { fn new() -> impl PinInit<Self> { pin_init!(Self { state_changed <- new_condvar!("SharedState::state_changed"), inner <- new_mutex!( SharedStateInner { token_count: 0 }, "SharedState::inner", ), }) } } Notably the way the macro is used here requires no `unsafe` and thus comes with the usual Rust promise of safe code not introducing any memory violations. Additionally it is now up to the caller of `new()` to decide the memory location of the `SharedState`. They can choose at the moment `Arc<T>`, `Box<T>` or the stack. -- The API has the following architecture: 1. Initializer traits `PinInit<T, E>` and `Init<T, E>` that act like closures. 2. Macros to create these initializer traits safely. 3. Functions to allow manually writing initializers. The initializers (an `impl PinInit<T, E>`) receive a raw pointer pointing to uninitialized memory and their job is to fully initialize a `T` at that location. If initialization fails, they return an error (`E`) by value. This way of initializing cannot be safely exposed to the user, since it relies upon these properties outside of the control of the trait: - the memory location (slot) needs to be valid memory, - if initialization fails, the slot should not be read from, - the value in the slot should be pinned, so it cannot move and the memory cannot be deallocated until the value is dropped. This is why using an initializer is facilitated by another trait that ensures these requirements. These initializers can be created manually by just supplying a closure that fulfills the same safety requirements as `PinInit<T, E>`. But this is an `unsafe` operation. To allow safe initializer creation, the `pin_init!` is provided along with three other variants: `try_pin_init!`, `try_init!` and `init!`. These take a modified struct initializer as a parameter and generate a closure that initializes the fields in sequence. The macros take great care in upholding the safety requirements: - A shadowed struct type is used as the return type of the closure instead of `()`. This is to prevent early returns, as these would prevent full initialization. - To ensure every field is only initialized once, a normal struct initializer is placed in unreachable code. The type checker will emit errors if a field is missing or specified multiple times. - When initializing a field fails, the whole initializer will fail and automatically drop fields that have been initialized earlier. - Only the correct initializer type is allowed for unpinned fields. You cannot use a `impl PinInit<T, E>` to initialize a structurally not pinned field. To ensure the last point, an additional macro `#[pin_data]` is needed. This macro annotates the struct itself and the user specifies structurally pinned and not pinned fields. Because dropping a pinned struct is also not allowed to break the pinning invariants, another macro attribute `#[pinned_drop]` is needed. This macro is introduced in a following commit. These two macros also have mechanisms to ensure the overall safety of the API. Additionally, they utilize a combined proc-macro, declarative macro design: first a proc-macro enables the outer attribute syntax `#[...]` and does some important pre-parsing. Notably this prepares the generics such that the declarative macro can handle them using token trees. Then the actual parsing of the structure and the emission of code is handled by a declarative macro. For pin-projections the crates `pin-project` [4] and `pin-project-lite` [5] had been considered, but were ultimately rejected: - `pin-project` depends on `syn` [6] which is a very big dependency, around 50k lines of code. - `pin-project-lite` is a more reasonable 5k lines of code, but contains a very complex declarative macro to parse generics. On top of that it would require modification that would need to be maintained independently. Link: https://rust-for-linux.com/the-safe-pinned-initialization-problem [1] Link: https://github.com/Rust-for-Linux/linux/tree/0a04dc4ddd671efb87eef54dde0fb38e9074f4be [2] Link: https://github.com/Rust-for-Linux/linux/blob/f509ede33fc10a07eba3da14aa00302bd4b5dddd/samples/rust/rust_miscdev.rs [3] Link: https://crates.io/crates/pin-project [4] Link: https://crates.io/crates/pin-project-lite [5] Link: https://crates.io/crates/syn [6] Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Link: https://lore.kernel.org/r/20230408122429.1103522-7-y86-dev@protonmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: enable the `pin_macro` featureBenno Lossin2023-04-121-1/+1
| | | | | | | | | | | | | This feature enables the use of the `pin!` macro for the `stack_pin_init!` macro. This feature is already stabilized in Rust version 1.68. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Acked-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230408122429.1103522-2-y86-dev@protonmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: Enable the new_uninit feature for kernel and driver cratesAsahi Lina2023-04-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | The unstable new_uninit feature enables various library APIs to create uninitialized containers, such as `Box::assume_init()`. This is necessary to build abstractions that directly initialize memory at the target location, instead of doing copies through the stack. Will be used by the DRM scheduler abstraction in the kernel crate, and by field-wise initialization (e.g. using `place!()` or a future replacement macro which may itself live in `kernel`) in driver crates. Link: https://github.com/Rust-for-Linux/linux/issues/879 Link: https://github.com/Rust-for-Linux/linux/issues/2 Link: https://github.com/rust-lang/rust/issues/63291 Signed-off-by: Asahi Lina <lina@asahilina.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Link: https://lore.kernel.org/r/20230224-rust-new_uninit-v1-1-c951443d9e26@asahilina.net [ Reworded to use `Link` tags. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* kbuild: remove sed commands after rustc rulesMasahiro Yamada2023-01-221-14/+4
| | | | | | | | | | | | rustc may put comments in dep-info, so sed is used to drop them before passing it to fixdep. Now that fixdep can remove comments, Makefiles do not need to run sed. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Tested-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
* kbuild: specify output names separately for each emission type from rustcMasahiro Yamada2023-01-221-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In Kbuild, two different rules must not write to the same file, but it happens when compiling rust source files. For example, set CONFIG_SAMPLE_RUST_MINIMAL=m and run the following: $ make -j$(nproc) samples/rust/rust_minimal.o samples/rust/rust_minimal.rsi \ samples/rust/rust_minimal.s samples/rust/rust_minimal.ll [snip] RUSTC [M] samples/rust/rust_minimal.o RUSTC [M] samples/rust/rust_minimal.rsi RUSTC [M] samples/rust/rust_minimal.s RUSTC [M] samples/rust/rust_minimal.ll mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory make[3]: *** [scripts/Makefile.build:334: samples/rust/rust_minimal.ll] Error 1 make[3]: *** Waiting for unfinished jobs.... mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory make[3]: *** [scripts/Makefile.build:309: samples/rust/rust_minimal.o] Error 1 mv: cannot stat 'samples/rust/rust_minimal.d': No such file or directory make[3]: *** [scripts/Makefile.build:326: samples/rust/rust_minimal.s] Error 1 make[2]: *** [scripts/Makefile.build:504: samples/rust] Error 2 make[1]: *** [scripts/Makefile.build:504: samples] Error 2 make: *** [Makefile:2008: .] Error 2 The reason for the error is that 4 threads running in parallel renames the same file, samples/rust/rust_minimal.d. This does not happen when compiling C or assembly files because -Wp,-MMD,$(depfile) explicitly specifies the dependency filepath. $(depfile) is a unique path for each target. Currently, rustc is only given --out-dir and --emit=<list-of-types> So, all the rust build rules output the dep-info into the default <CRATE_NAME>.d, which causes the path conflict. Fortunately, the --emit option is able to specify the output path individually, with the form --emit=<type>=<path>. Add --emit=dep-info=$(depfile) to the common part. Also, remove the redundant --out-dir because the output path is specified for each type. The code gets much cleaner because we do not need to rename *.d files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Tested-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
* Merge tag 'kbuild-v6.2' of ↵Linus Torvalds2022-12-191-6/+8
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Support zstd-compressed debug info - Allow W=1 builds to detect objects shared among multiple modules - Add srcrpm-pkg target to generate a source RPM package - Make the -s option detection work for future GNU Make versions - Add -Werror to KBUILD_CPPFLAGS when CONFIG_WERROR=y - Allow W=1 builds to detect -Wundef warnings in any preprocessed files - Raise the minimum supported version of binutils to 2.25 - Use $(intcmp ...) to compare integers if GNU Make >= 4.4 is used - Use $(file ...) to read a file if GNU Make >= 4.2 is used - Print error if GNU Make older than 3.82 is used - Allow modpost to detect section mismatches with Clang LTO - Include vmlinuz.efi into kernel tarballs for arm64 CONFIG_EFI_ZBOOT=y * tag 'kbuild-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (29 commits) buildtar: fix tarballs with EFI_ZBOOT enabled modpost: Include '.text.*' in TEXT_SECTIONS padata: Mark padata_work_init() as __ref kbuild: ensure Make >= 3.82 is used kbuild: refactor the prerequisites of the modpost rule kbuild: change module.order to list *.o instead of *.ko kbuild: use .NOTINTERMEDIATE for future GNU Make versions kconfig: refactor Makefile to reduce process forks kbuild: add read-file macro kbuild: do not sort after reading modules.order kbuild: add test-{ge,gt,le,lt} macros Documentation: raise minimum supported version of binutils to 2.25 kbuild: add -Wundef to KBUILD_CPPFLAGS for W=1 builds kbuild: move -Werror from KBUILD_CFLAGS to KBUILD_CPPFLAGS kbuild: Port silent mode detection to future gnu make. init/version.c: remove #include <generated/utsrelease.h> firmware_loader: remove #include <generated/utsrelease.h> modpost: Mark uuid_le type to be suitable only for MEI kbuild: add ability to make source rpm buildable using koji kbuild: warn objects shared among multiple modules ...
| * kbuild: change module.order to list *.o instead of *.koMasahiro Yamada2022-12-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | scripts/Makefile.build replaces the suffix .o with .ko, then scripts/Makefile.modpost calls the sed command to change .ko back to the original .o suffix. Instead of converting the suffixes back-and-forth, store the .o paths in modules.order, and replace it with .ko in 'make modules_install'. This avoids the unneeded sed command. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
| * kbuild: warn objects shared among multiple modulesMasahiro Yamada2022-11-221-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If an object is shared among multiple modules, and some of them are configured as 'm', but the others as 'y', the shared object is built as modular, then linked to the modules and vmlinux. This is a potential issue because the expected CFLAGS are different between modules and builtins. Commit 637a642f5ca5 ("zstd: Fixing mixed module-builtin objects") reported that this could be even more fatal in some cases such as Clang LTO. That commit fixed lib/zlib/zstd_{compress,decompress}, but there are still more instances of breakage. This commit adds a W=1 warning for shared objects, so that the kbuild test robot, which provides build tests with W=1, will avoid a new breakage slipping in. Quick compile tests on v6.1-rc4 detected the following: scripts/Makefile.build:252: ./drivers/block/rnbd/Makefile: rnbd-common.o is added to multiple modules: rnbd-client rnbd-server scripts/Makefile.build:252: ./drivers/crypto/marvell/octeontx2/Makefile: cn10k_cpt.o is added to multiple modules: rvu_cptpf rvu_cptvf scripts/Makefile.build:252: ./drivers/crypto/marvell/octeontx2/Makefile: otx2_cptlf.o is added to multiple modules: rvu_cptpf rvu_cptvf scripts/Makefile.build:252: ./drivers/crypto/marvell/octeontx2/Makefile: otx2_cpt_mbox_common.o is added to multiple modules: rvu_cptpf rvu_cptvf scripts/Makefile.build:252: ./drivers/edac/Makefile: skx_common.o is added to multiple modules: i10nm_edac skx_edac scripts/Makefile.build:252: ./drivers/gpu/drm/bridge/imx/Makefile: imx-ldb-helper.o is added to multiple modules: imx8qm-ldb imx8qxp-ldb scripts/Makefile.build:252: ./drivers/mfd/Makefile: rsmu_core.o is added to multiple modules: rsmu-i2c rsmu-spi scripts/Makefile.build:252: ./drivers/mtd/tests/Makefile: mtd_test.o is added to multiple modules: mtd_nandbiterrs mtd_oobtest mtd_pagetest mtd_readtest mtd_speedtest mtd_stresstest mtd_subpagetest mtd_torturetest scripts/Makefile.build:252: ./drivers/net/dsa/ocelot/Makefile: felix.o is added to multiple modules: mscc_felix mscc_seville scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: cn23xx_pf_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: cn23xx_vf_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: cn66xx_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: cn68xx_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: lio_core.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: lio_ethtool.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_device.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_droq.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_mailbox.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_mem_ops.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: octeon_nic.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: request_manager.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/cavium/liquidio/Makefile: response_manager.o is added to multiple modules: liquidio liquidio_vf scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/dpaa2/Makefile: dpaa2-mac.o is added to multiple modules: fsl-dpaa2-eth fsl-dpaa2-switch scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/dpaa2/Makefile: dpmac.o is added to multiple modules: fsl-dpaa2-eth fsl-dpaa2-switch scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/enetc/Makefile: enetc_cbdr.o is added to multiple modules: fsl-enetc fsl-enetc-vf scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/enetc/Makefile: enetc_ethtool.o is added to multiple modules: fsl-enetc fsl-enetc-vf scripts/Makefile.build:252: ./drivers/net/ethernet/freescale/enetc/Makefile: enetc.o is added to multiple modules: fsl-enetc fsl-enetc-vf scripts/Makefile.build:252: ./drivers/net/ethernet/hisilicon/hns3/Makefile: hns3_common/hclge_comm_cmd.o is added to multiple modules: hclge hclgevf scripts/Makefile.build:252: ./drivers/net/ethernet/hisilicon/hns3/Makefile: hns3_common/hclge_comm_rss.o is added to multiple modules: hclge hclgevf scripts/Makefile.build:252: ./drivers/net/ethernet/hisilicon/hns3/Makefile: hns3_common/hclge_comm_tqp_stats.o is added to multiple modules: hclge hclgevf scripts/Makefile.build:252: ./drivers/net/ethernet/marvell/octeontx2/nic/Makefile: otx2_dcbnl.o is added to multiple modules: rvu_nicpf rvu_nicvf scripts/Makefile.build:252: ./drivers/net/ethernet/marvell/octeontx2/nic/Makefile: otx2_devlink.o is added to multiple modules: rvu_nicpf rvu_nicvf scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: cpsw_ale.o is added to multiple modules: keystone_netcp keystone_netcp_ethss ti_cpsw ti_cpsw_new scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: cpsw_ethtool.o is added to multiple modules: ti_cpsw ti_cpsw_new scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: cpsw_priv.o is added to multiple modules: ti_cpsw ti_cpsw_new scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: cpsw_sl.o is added to multiple modules: ti_cpsw ti_cpsw_new scripts/Makefile.build:252: ./drivers/net/ethernet/ti/Makefile: davinci_cpdma.o is added to multiple modules: ti_cpsw ti_cpsw_new ti_davinci_emac scripts/Makefile.build:252: ./drivers/platform/x86/intel/int3472/Makefile: common.o is added to multiple modules: intel_skl_int3472_discrete intel_skl_int3472_tps68470 scripts/Makefile.build:252: ./sound/soc/codecs/Makefile: wcd-clsh-v2.o is added to multiple modules: snd-soc-wcd9335 snd-soc-wcd934x snd-soc-wcd938x Once all the warnings are fixed, it can become an error without the W= option. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Tested-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
| * kbuild: add kbuild-file macroMasahiro Yamada2022-11-221-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | While building, installing, cleaning, Kbuild visits sub-directories and includes 'Kbuild' or 'Makefile' that exists there. Add 'kbuild-file' macro, and reuse it from scripts/Makefie.* Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Tested-by: Alexander Lobakin <alobakin@pm.me>
* | kbuild: Cleanup DT Overlay intermediate files as appropriateAndrew Davis2022-11-181-0/+2
|/ | | | | | | | | | | | | | | | %.dtbo.o and %.dtbo.S files are used to build-in DT Overlay. They should should not be removed by Make or the kernel will be needlessly rebuilt. These should be removed by "clean" and ignored by git like other intermediate files. Reported-by: Andy Shevchenko <andriy.shevchenko@intel.com> Signed-off-by: Andrew Davis <afd@ti.com> Fixes: 941214a512d8 ("kbuild: Allow DTB overlays to built into .dtbo.S files") Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://lore.kernel.org/r/20221114205939.27994-1-afd@ti.com Signed-off-by: Rob Herring <robh@kernel.org>
* kbuild: add -fno-discard-value-names to cmd_cc_ll_cNick Desaulniers2022-10-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When debugging LLVM IR, it can be handy for clang to not discard value names used for local variables and parameters. Compare the generated IR. -fdiscard-value-names: define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) { %6 = alloca i64 %7 = alloca %struct.poll_wqueues %8 = alloca [64 x i32] -fno-discard-value-names: define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp, ptr %end_time) { %expire.i = alloca i64 %table.i = alloca %struct.poll_wqueues %stack_fds = alloca [64 x i32] The rule for generating human readable LLVM IR (.ll) is only useful as a debugging feature: $ make LLVM=1 fs/select.ll As Fangrui notes: A LLVM_ENABLE_ASSERTIONS=off build of Clang defaults to -fdiscard-value-names. A LLVM_ENABLE_ASSERTIONS=on build of Clang defaults to -fno-discard-value-names. Explicitly enable -fno-discard-value-names so that the IR always contains value names regardless of whether assertions were enabled or not. Assertions generally are not enabled in releases of clang packaged by distributions. Link: https://github.com/ClangBuiltLinux/linux/issues/1467 Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Fangrui Song <maskray@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
* Merge tag 'kbuild-v6.1' of ↵Linus Torvalds2022-10-101-39/+17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Remove potentially incomplete targets when Kbuid is interrupted by SIGINT etc in case GNU Make may miss to do that when stderr is piped to another program. - Rewrite the single target build so it works more correctly. - Fix rpm-pkg builds with V=1. - List top-level subdirectories in ./Kbuild. - Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in kallsyms. - Avoid two different modules in lib/zstd/ having shared code, which potentially causes building the common code as build-in and modular back-and-forth. - Unify two modpost invocations to optimize the build process. - Remove head-y syntax in favor of linker scripts for placing particular sections in the head of vmlinux. - Bump the minimal GNU Make version to 3.82. - Clean up misc Makefiles and scripts. * tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits) docs: bump minimal GNU Make version to 3.82 ia64: simplify esi object addition in Makefile Revert "kbuild: Check if linker supports the -X option" kbuild: rebuild .vmlinux.export.o when its prerequisite is updated kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o zstd: Fixing mixed module-builtin objects kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols kallsyms: take the input file instead of reading stdin kallsyms: drop duplicated ignore patterns from kallsyms.c kbuild: reuse mksysmap output for kallsyms mksysmap: update comment about __crc_* kbuild: remove head-y syntax kbuild: use obj-y instead extra-y for objects placed at the head kbuild: hide error checker logs for V=1 builds kbuild: re-run modpost when it is updated kbuild: unify two modpost invocations kbuild: move vmlinux.o rule to the top Makefile kbuild: move .vmlinux.objs rule to Makefile.modpost kbuild: list sub-directories in ./Kbuild Makefile.compiler: replace cc-ifversion with compiler-specific macros ...
| * kbuild: fix and refactor single target buildMasahiro Yamada2022-09-291-38/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The single target build has a subtle bug for the combination for an individual file and a subdirectory. [1] 'make kernel/fork.i' builds only kernel/fork.i $ make kernel/fork.i CALL scripts/checksyscalls.sh DESCEND objtool CPP kernel/fork.i [2] 'make kernel/' builds only under the kernel/ directory. $ make kernel/ CALL scripts/checksyscalls.sh DESCEND objtool CC kernel/fork.o CC kernel/exec_domain.o [snip] CC kernel/rseq.o AR kernel/built-in.a But, if you try to do [1] and [2] in a single command, you will get only [1] with a weird log: $ make kernel/fork.i kernel/ CALL scripts/checksyscalls.sh DESCEND objtool CPP kernel/fork.i make[2]: Nothing to be done for 'kernel/'. With 'make kernel/fork.i kernel/', you should get both [1] and [2]. Rewrite the single target build. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
| * kbuild: do not deduplicate modules.orderMasahiro Yamada2022-09-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The AWK code was added to deduplicate modules.order in case $(obj-m) contains the same module multiple times, but it is actually unneeded since commit b2c885549122 ("kbuild: update modules.order only when contained modules are updated"). The list is already deduplicated before being processed by AWK because $^ is the deduplicated list of prerequisites. (Please note the real-prereqs macro uses $^) Yet, modules.order will contain duplication if two different Makefiles build the same module: foo/Makefile: obj-m += bar/baz.o foo/bar/Makefile: obj-m += baz.o However, the parallel builds cannot properly handle this case in the first place. So, it is better to let it fail (as already done by scripts/modules-check.sh). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
* | Kbuild: add Rust supportMiguel Ojeda2022-09-281-0/+60
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* kbuild: remove sed command from cmd_ar_builtinMasahiro Yamada2022-07-271-3/+2
| | | | | | | Replace a pipeline of echo and sed with printf to decrease process forks. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
* kbuild: avoid regex RS for POSIX awkKevin Locke2022-06-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In 22f26f21774f8 awk was added to deduplicate *.mod files. The awk invocation passes -v RS='( |\n)' to match a space or newline character as the record separator. Unfortunately, POSIX states[1] > If RS contains more than one character, the results are unspecified. Some implementations (such as the One True Awk[2] used by the BSDs) do not treat RS as a regular expression. When awk does not support regex RS, build failures such as the following are produced (first error using allmodconfig): CC [M] arch/x86/events/intel/uncore.o CC [M] arch/x86/events/intel/uncore_nhmex.o CC [M] arch/x86/events/intel/uncore_snb.o CC [M] arch/x86/events/intel/uncore_snbep.o CC [M] arch/x86/events/intel/uncore_discovery.o LD [M] arch/x86/events/intel/intel-uncore.o ld: cannot find uncore_nhmex.o: No such file or directory ld: cannot find uncore_snb.o: No such file or directory ld: cannot find uncore_snbep.o: No such file or directory ld: cannot find uncore_discovery.o: No such file or directory make[3]: *** [scripts/Makefile.build:422: arch/x86/events/intel/intel-uncore.o] Error 1 make[2]: *** [scripts/Makefile.build:487: arch/x86/events/intel] Error 2 make[1]: *** [scripts/Makefile.build:487: arch/x86/events] Error 2 make: *** [Makefile:1839: arch/x86] Error 2 To avoid this, use printf(1) to produce a newline between each object path, instead of the space produced by echo(1), so that the default RS can be used by awk. [1]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/awk.html [2]: https://github.com/onetrueawk/awk Fixes: 22f26f21774f ("kbuild: get rid of duplication in *.mod files") Signed-off-by: Kevin Locke <kevin@kevinlocke.name> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
* kbuild: factor out the common objtool argumentsMasahiro Yamada2022-06-051-26/+0
| | | | | | | | | | | | | | | | scripts/Makefile.build and scripts/link-vmlinux.sh have similar setups for the objtool arguments. It was difficult to factor out them because all the vmlinux build rules were written in a shell script. It is somewhat tedious to touch the two files every time a new objtool option is supported. To reduce the code duplication, move the objtool for vmlinux.o into scripts/Makefile.vmlinux_o. Then, move the common macros to Makefile.lib so they are shared between Makefile.build and Makefile.vmlinux_o. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
* kbuild: rebuild multi-object modules when objtool is updatedMasahiro Yamada2022-06-011-3/+8
| | | | | | | | | | | | | | | When CONFIG_LTO_CLANG or CONFIG_X86_KERNEL_IBT is enabled, objtool for multi-object modules is postponed until the objects are linked together. Make sure to re-run objtool and re-link multi-object modules when objtool is updated. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
* kbuild: make *.mod rule robust against too long argument errorMasahiro Yamada2022-06-011-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | Like built-in.a, the command length of the *.mod rule scales with the depth of the directory times the number of objects in the Makefile. Add $(obj)/ by the shell command (awk) instead of by Make's builtin function. In-tree modules still have some room to the limit (ARG_MAX=2097152), but this is more future-proof for big modules in a deep directory. For example, you can build i915 as a module (CONFIG_DRM_I915=m) and compare drivers/gpu/drm/i915/.i915.mod.cmd with/without this commit. The issue is more critical for external modules because the M= path can be very long as Jeff Johnson reported before [1]. [1] https://lore.kernel.org/linux-kbuild/4c02050c4e95e4cb8cc04282695f8404@codeaurora.org/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
* kbuild: make built-in.a rule robust against too long argument errorMasahiro Yamada2022-06-011-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kbuild runs at the top of objtree instead of changing the working directory to subdirectories. I think this design is nice overall but some commands have a scalability issue. The build command of built-in.a is one of them whose length scales with: O(D * N) Here, D is the length of the directory path (i.e. $(obj)/ prefix), N is the number of objects in the Makefile, O() is the big O notation. The deeper directory the Makefile directory is located, the more easily it will hit the too long argument error. We can make it better. Trim the $(obj)/ by Make's builtin function, and restore it by a shell command (sed). With this, the command length scales with: O(D + N) In-tree modules still have some room to the limit (ARG_MAX=2097152), but this is more future-proof for big modules in a deep directory. For example, you can build i915 as builtin (CONFIG_DRM_I915=y) and compare drivers/gpu/drm/i915/.built-in.a.cmd with/without this commit. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
* kbuild: check static EXPORT_SYMBOL* by script instead of modpostMasahiro Yamada2022-06-011-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 'static' specifier and EXPORT_SYMBOL() are an odd combination. Commit 15bfc2348d54 ("modpost: check for static EXPORT_SYMBOL* functions") tried to detect it, but this check has false negatives. Here is the sample code. Makefile: obj-y += foo1.o foo2.o foo1.c: #include <linux/export.h> static void foo(void) {} EXPORT_SYMBOL(foo); foo2.c: void foo(void) {} foo1.c exports the static symbol 'foo', but modpost cannot catch it because it is fooled by foo2.c, which has a global symbol with the same name. s->is_static is cleared if a global symbol with the same name is found somewhere, but EXPORT_SYMBOL() and the global symbol do not necessarily belong to the same compilation unit. This check should be done per compilation unit, but I do not know how to do it in modpost. modpost runs against vmlinux.o or modules, which merges multiple objects, then forgets their origin. modpost cannot parse individual objects because they may not be ELF but LLVM IR when CONFIG_LTO_CLANG=y. Add a simple bash script to parse the output from ${NM}. This works for CONFIG_LTO_CLANG=y because llvm-nm can dump symbols of LLVM IR files. Revert 15bfc2348d54. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
* kbuild: do not create *.prelink.o for Clang LTO or IBTMasahiro Yamada2022-05-291-43/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When CONFIG_LTO_CLANG=y, additional intermediate *.prelink.o is created for each module. Also, objtool is postponed until LLVM IR is converted to ELF. CONFIG_X86_KERNEL_IBT works in a similar way to postpone objtool until objects are merged together. This commit stops generating *.prelink.o, so the build flow will look similar with/without LTO. The following figures show how the LTO build currently works, and how this commit is changing it. Current build flow ================== [1] single-object module $(LD) $(CC) +objtool $(LD) foo.c --------------------> foo.o -----> foo.prelink.o -----> foo.ko (LLVM IR) (ELF) | (ELF) | foo.mod.o --/ (LLVM IR) [2] multi-object module $(LD) $(CC) $(AR) +objtool $(LD) foo1.c -----> foo1.o -----> foo.o -----> foo.prelink.o -----> foo.ko | (archive) (ELF) | (ELF) foo2.c -----> foo2.o --/ | (LLVM IR) foo.mod.o --/ (LLVM IR) One confusion is that foo.o in multi-object module is an archive despite of its suffix. New build flow ============== [1] single-object module Since there is only one object, there is no need to keep the LLVM IR. Use $(CC)+$(LD) to generate an ELF object in one build rule. When LTO is disabled, $(LD) is unneeded because $(CC) produces an ELF object. $(CC)+$(LD)+objtool $(LD) foo.c ----------------------------> foo.o ---------> foo.ko (ELF) | (ELF) | foo.mod.o --/ (LLVM IR) [2] multi-object module Previously, $(AR) was used to combine LLVM IR files into an archive, but there was no technical reason to do so. Use $(LD) to merge them into a single ELF object. $(LD) $(CC) +objtool $(LD) foo1.c ---------> foo1.o ---------> foo.o ---------> foo.ko | (ELF) | (ELF) foo2.c ---------> foo2.o ----/ | (LLVM IR) foo.mod.o --/ (LLVM IR) Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64) Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
* kbuild: replace $(linked-object) with CONFIG optionsMasahiro Yamada2022-05-291-2/+1
| | | | | | | | | | | | | | | *.prelink.o is created when CONFIG_LTO_CLANG or CONFIG_X86_KERNEL_IBT is enabled. Replace $(linked-object) with $(CONFIG_LTO_CLANG)$(CONFIG_X86_KERNEL_IBT) so you will get a quick idea of when the --link option is passed. No functional change is intended. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14
* Merge tag 'kbuild-v5.19' of ↵Linus Torvalds2022-05-261-94/+39
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Add HOSTPKG_CONFIG env variable to allow users to override pkg-config - Support W=e as a shorthand for KCFLAGS=-Werror - Fix CONFIG_IKHEADERS build to support toybox cpio - Add scripts/dummy-tools/pahole to ease distro packagers' life - Suppress false-positive warnings from checksyscalls.sh for W=2 build - Factor out the common code of arch/*/boot/install.sh into scripts/install.sh - Support 'kernel-install' tool in scripts/prune-kernel - Refactor module-versioning to link the symbol versions at the final link of vmlinux and modules - Remove CONFIG_MODULE_REL_CRCS because module-versioning now works in an arch-agnostic way - Refactor modpost, Makefiles * tag 'kbuild-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (56 commits) genksyms: adjust the output format to modpost kbuild: stop merging *.symversions kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS modpost: extract symbol versions from *.cmd files modpost: add sym_find_with_module() helper modpost: change the license of EXPORT_SYMBOL to bool type modpost: remove left-over cross_compile declaration kbuild: record symbol versions in *.cmd files kbuild: generate a list of objects in vmlinux modpost: move *.mod.c generation to write_mod_c_files() modpost: merge add_{intree_flag,retpoline,staging_flag} to add_header scripts/prune-kernel: Use kernel-install if available kbuild: factor out the common installation code into scripts/install.sh modpost: split new_symbol() to symbol allocation and hash table addition modpost: make sym_add_exported() always allocate a new symbol modpost: make multiple export error modpost: dump Module.symvers in the same order of modules.order modpost: traverse the namespace_list in order modpost: use doubly linked list for dump_lists modpost: traverse unresolved symbols in order ...
| * genksyms: adjust the output format to modpostMasahiro Yamada2022-05-241-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make genksyms output symbol versions in the format modpost expects, so the 'sed' is unneeded. This commit makes *.symversions completely unneeded. I will keep *.symversions in .gitignore and 'make clean' for a while. Otherwise, 'git status' might be surprising. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
| * kbuild: stop merging *.symversionsMasahiro Yamada2022-05-241-19/+2
| | | | | | | | | | | | | | | | | | | | | | Now modpost reads symbol versions from .*.cmd files. The merged *.symversions are no longer needed. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
| * kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCSMasahiro Yamada2022-05-241-23/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | include/{linux,asm-generic}/export.h defines a weak symbol, __crc_* as a placeholder. Genksyms writes the version CRCs into the linker script, which will be used for filling the __crc_* symbols. The linker script format depends on CONFIG_MODULE_REL_CRCS. If it is enabled, __crc_* holds the offset to the reference of CRC. It is time to get rid of this complexity. Now that modpost parses text files (.*.cmd) to collect all the CRCs, it can generate C code that will be linked to the vmlinux or modules. Generate a new C file, .vmlinux.export.c, which contains the CRCs of symbols exported by vmlinux. It is compiled and linked to vmlinux in scripts/link-vmlinux.sh. Put the CRCs of symbols exported by modules into the existing *.mod.c files. No additional build step is needed for modules. As before, *.mod.c are compiled and linked to *.ko in scripts/Makefile.modfinal. No linker magic is used here. The new C implementation works in the same way, whether CONFIG_RELOCATABLE is enabled or not. CONFIG_MODULE_REL_CRCS is no longer needed. Previously, Kbuild invoked additional $(LD) to update the CRCs in objects, but this step is unneeded too. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
| * kbuild: record symbol versions in *.cmd filesMasahiro Yamada2022-05-111-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When CONFIG_MODVERSIONS=y, the output from genksyms is saved in separate *.symversions files, and will be used much later when CONFIG_LTO_CLANG=y because it is impossible to update LLVM bit code here. This approach is not robust because: - *.symversions may or may not exist. If *.symversions does not exist, we never know if it is missing for legitimate reason (i.e. no EXPORT_SYMBOL) or something bad has happened (for example, the user accidentally deleted it). Once it occurs, it is not self-healing because *.symversions is generated as a side effect. - stale (i.e. invalid) *.symversions might be picked up if an object is generated in a non-ordinary way, and corresponding *.symversions (, which was generated by old builds) just happen to exist. A more robust approach is to save symbol versions in *.cmd files because: - *.cmd always exists (if the object is generated by if_changed rule or friends). Even if the user accidentally deletes it, it will be regenerated in the next build. - *.cmd is always re-generated when the object is updated. This avoid stale version information being picked up. I will remove *.symversions later. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
| * kbuild: read *.mod to get objects passed to $(LD) or $(AR)Masahiro Yamada2022-05-081-7/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | ld and ar support @file, which command-line options are read from. Now that *.mod lists the member objects in the correct order, without duplication, it is ready to be passed to ld and ar. By using the @file syntax, people will not be worried about the pitfall described in the NOTE. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
| * kbuild: make *.mod not depend on *.oMasahiro Yamada2022-05-081-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The dependency $(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o ... exists because *.mod files previously contained undefined symbols, which are computed from *.o files when CONFIG_TRIM_UNUSED_KSYMS=y. Now that the undefined symbols are put into separate *.usyms files, there is no reason to make *.mod depend on *.o files. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
| * kbuild: get rid of duplication in *.mod filesMasahiro Yamada2022-05-081-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is allowed to add the same objects multiple times to obj-y / obj-m: obj-y += foo.o foo.o foo.o obj-m += bar.o bar.o bar.o It is also allowed to add the same objects multiple times to a composite module: obj-m += foo.o foo-y := foo1.o foo2.o foo2.o foo1.o This flexibility is useful because the same object might be selected by different CONFIG options, like this: obj-m += foo.o foo-y := foo1.o foo-$(CONFIG_FOO_X) += foo2.o foo-$(CONFIG_FOO_Y) += foo2.o The duplicated objects are omitted at link time. It works naturally in Makefiles because GNU Make removes duplication in $^ without changing the order. It is working well, almost... A small flaw I notice is, *.mod contains duplication in such a case. This is probably not a big deal. As far as I know, the only small problem is scripts/mod/sumversion.c parses the same file multiple times. I am fixing this because I plan to reuse *.mod for other purposes, where the duplication can be problematic. The code change is quite simple. We already use awk to drop duplicated lines in modules.order (see cmd_modules_order in the same file). I copied the code, but changed RS to use spaces as record separators. I also changed the file format to list one object per line. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
| * kbuild: split the second line of *.mod into *.usymsMasahiro Yamada2022-05-081-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The *.mod files have two lines; the first line lists the member objects of the module, and the second line, if CONFIG_TRIM_UNUSED_KSYMS=y, lists the undefined symbols. Currently, we generate *.mod after constructing composite modules, otherwise, we cannot compute the second line. No prerequisite is required to print the first line. They are orthogonal. Splitting them into separate commands will ease further cleanups. This commit splits the list of undefined symbols out to *.usyms files. Previously, the list of undefined symbols ended up with a very long line, but now it has one symbol per line. Use sed like we did before commit 7d32358be8ac ("kbuild: avoid split lines in .mod files"). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
| * kbuild: reuse real-search to simplify cmd_modMasahiro Yamada2022-05-081-1/+1
| | | | | | | | | | | | | | | | The first command in cmd_mod is similar to the real-search macro. Reuse it. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
| * kbuild: refactor cmd_modversions_SMasahiro Yamada2022-05-081-11/+4
| | | | | | | | | | | | | | | | | | Split the code into two macros, cmd_gen_symversions_S for running genksyms, and cmd_modversions for running $(LD) to update the object with CRCs. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
| * kbuild: refactor cmd_modversions_cMasahiro Yamada2022-05-081-14/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cmd_modversions_c implements two parts; run genksyms to calculate CRCs of exported symbols, run $(LD) to update the object with the CRCs. The latter is not executed for CONFIG_LTO_CLANG=y since the object is not ELF but LLVM bit code at this point. The first part can be unified because we can always use $(NM) instead of "$(OBJDUMP) -h" to dump the symbols. Split the code into the two macros, cmd_gen_symversions_c and cmd_modversions. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
| * kbuild: do not remove empty *.symtypes explicitlyMasahiro Yamada2022-04-061-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | Presumably, 'test -s $@ || rm -f $@' intends to remove the output when the genksyms command fails. It is unneeded because .DELETE_ON_ERROR automatically removes the output on failure. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
| * kbuild: factor out genksyms command from cmd_gensymtypes_{c,S}Masahiro Yamada2022-04-061-11/+8
| | | | | | | | | | | | | | | | | | | | | | The genksyms command part in cmd_gensymtypes_{c,S} is duplicated. Factor it out into the 'genksyms' macro. For the readability, I slightly refactor the arguments to genksyms. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
* | Merge tag 'objtool-core-2022-05-23' of ↵Linus Torvalds2022-05-241-9/+14
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: - Comprehensive interface overhaul: ================================= Objtool's interface has some issues: - Several features are done unconditionally, without any way to turn them off. Some of them might be surprising. This makes objtool tricky to use, and prevents porting individual features to other arches. - The config dependencies are too coarse-grained. Objtool enablement is tied to CONFIG_STACK_VALIDATION, but it has several other features independent of that. - The objtool subcmds ("check" and "orc") are clumsy: "check" is really a subset of "orc", so it has all the same options. The subcmd model has never really worked for objtool, as it only has a single purpose: "do some combination of things on an object file". - The '--lto' and '--vmlinux' options are nonsensical and have surprising behavior. Overhaul the interface: - get rid of subcmds - make all features individually selectable - remove and/or clarify confusing/obsolete options - update the documentation - fix some bugs found along the way - Fix x32 regression - Fix Kbuild cleanup bugs - Add scripts/objdump-func helper script to disassemble a single function from an object file. - Rewrite scripts/faddr2line to be section-aware, by basing it on 'readelf', moving it away from 'nm', which doesn't handle multiple sections well, which can result in decoding failure. - Rewrite & fix symbol handling - which had a number of bugs wrt. object files that don't have global symbols - which is rare but possible. Also fix a bunch of symbol handling bugs found along the way. * tag 'objtool-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) objtool: Fix objtool regression on x32 systems objtool: Fix symbol creation scripts/faddr2line: Fix overlapping text section failures scripts: Create objdump-func helper script objtool: Remove libsubcmd.a when make clean objtool: Remove inat-tables.c when make clean objtool: Update documentation objtool: Remove --lto and --vmlinux in favor of --link objtool: Add HAVE_NOINSTR_VALIDATION objtool: Rename "VMLINUX_VALIDATION" -> "NOINSTR_VALIDATION" objtool: Make noinstr hacks optional objtool: Make jump label hack optional objtool: Make static call annotation optional objtool: Make stack validation frame-pointer-specific objtool: Add CONFIG_OBJTOOL objtool: Extricate sls from stack validation objtool: Rework ibt and extricate from stack validation objtool: Make stack validation optional objtool: Add option to print section addresses objtool: Don't print parentheses in function addresses ...
| * | objtool: Remove --lto and --vmlinux in favor of --linkJosh Poimboeuf2022-04-221-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The '--lto' option is a confusing way of telling objtool to do stack validation despite it being a linked object. It's no longer needed now that an explicit '--stackval' option exists. The '--vmlinux' option is also redundant. Remove both options in favor of a straightforward '--link' option which identifies a linked object. Also, implicitly set '--link' with a warning if the user forgets to do so and we can tell that it's a linked object. This makes it easier for manual vmlinux runs. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/dcd3ceffd15a54822c6183e5766d21ad06082b45.1650300597.git.jpoimboe@redhat.com
| * | objtool: Make noinstr hacks optionalJosh Poimboeuf2022-04-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Objtool has some hacks in place to workaround toolchain limitations which otherwise would break no-instrumentation rules. Make the hacks explicit (and optional for other arches) by turning it into a cmdline option and kernel config option. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/b326eeb9c33231b9dfbb925f194ed7ee40edcd7c.1650300597.git.jpoimboe@redhat.com
| * | objtool: Make jump label hack optionalJosh Poimboeuf2022-04-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Objtool secretly does a jump label hack to overcome the limitations of the toolchain. Make the hack explicit (and optional for other arches) by turning it into a cmdline option and kernel config option. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/3bdcbfdd27ecb01ddec13c04bdf756a583b13d24.1650300597.git.jpoimboe@redhat.com
| * | objtool: Make static call annotation optionalJosh Poimboeuf2022-04-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As part of making objtool more modular, put the existing static call code behind a new '--static-call' option. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/d59ac57ef3d6d8380cdce20322314c9e2e556750.1650300597.git.jpoimboe@redhat.com
| * | objtool: Make stack validation frame-pointer-specificJosh Poimboeuf2022-04-221-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that CONFIG_STACK_VALIDATION is frame-pointer specific, do the same for the '--stackval' option. Now the '--no-fp' option is redundant and can be removed. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/f563fa064b3b63d528de250c72012d49e14742a3.1650300597.git.jpoimboe@redhat.com
| * | objtool: Add CONFIG_OBJTOOLJosh Poimboeuf2022-04-221-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that stack validation is an optional feature of objtool, add CONFIG_OBJTOOL and replace most usages of CONFIG_STACK_VALIDATION with it. CONFIG_STACK_VALIDATION can now be considered to be frame-pointer specific. CONFIG_UNWINDER_ORC is already inherently valid for live patching, so no need to "validate" it. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/939bf3d85604b2a126412bf11af6e3bd3b872bcb.1650300597.git.jpoimboe@redhat.com
| * | objtool: Make stack validation optionalJosh Poimboeuf2022-04-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make stack validation an explicit cmdline option so that individual objtool features can be enabled individually by other arches. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/52da143699574d756e65ca4c9d4acaffe9b0fe5f.1650300597.git.jpoimboe@redhat.com
| * | objtool: Ditch subcommandsJosh Poimboeuf2022-04-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Objtool has a fairly singular focus. It runs on object files and does validations and transformations which can be combined in various ways. The subcommand model has never been a good fit, making it awkward to combine and remove options. Remove the "check" and "orc" subcommands in favor of a more traditional cmdline option model. This makes it much more flexible to use, and easier to port individual features to other arches. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/5c61ebf805e90aefc5fa62bc63468ffae53b9df6.1650300597.git.jpoimboe@redhat.com
| * | objtool: Reorganize cmdline optionsJosh Poimboeuf2022-04-221-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Split the existing options into two groups: actions, which actually do something; and options, which modify the actions in some way. Also there's no need to have short flags for all the non-action options. Reserve short flags for the more important actions. While at it: - change a few of the short flags to be more intuitive - make option descriptions more consistently descriptive - sort options in the source like they are when printed - move options to a global struct Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/9dcaa752f83aca24b1b21f0b0eeb28a0c181c0b0.1650300597.git.jpoimboe@redhat.com
* | | Merge tag 'x86_cpu_for_v5.19_rc1' of ↵Linus Torvalds2022-05-231-1/+1
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 CPU feature updates from Borislav Petkov: - Remove a bunch of chicken bit options to turn off CPU features which are not really needed anymore - Misc fixes and cleanups * tag 'x86_cpu_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/speculation: Add missing prototype for unpriv_ebpf_notify() x86/pm: Fix false positive kmemleak report in msr_build_context() x86/speculation/srbds: Do not try to turn mitigation off when not supported x86/cpu: Remove "noclflush" x86/cpu: Remove "noexec" x86/cpu: Remove "nosmep" x86/cpu: Remove CONFIG_X86_SMAP and "nosmap" x86/cpu: Remove "nosep" x86/cpu: Allow feature bit names from /proc/cpuinfo in clearcpuid=
| * | x86/cpu: Remove CONFIG_X86_SMAP and "nosmap"Borislav Petkov2022-04-041-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Those were added as part of the SMAP enablement but SMAP is currently an integral part of kernel proper and there's no need to disable it anymore. Rip out that functionality. Leave --uaccess default on for objtool as this is what objtool should do by default anyway. If still needed - clearcpuid=smap. Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220127115626.14179-4-bp@alien8.de