From patchwork Tue Mar 7 14:25:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Asahi Lina X-Patchwork-Id: 13163702 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F3705C678D5 for ; Tue, 7 Mar 2023 14:27:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2A14710E4AB; Tue, 7 Mar 2023 14:27:28 +0000 (UTC) Received: from mail.marcansoft.com (marcansoft.com [212.63.210.85]) by gabe.freedesktop.org (Postfix) with ESMTPS id D5FF610E4AB for ; Tue, 7 Mar 2023 14:27:26 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: linasend@asahilina.net) by mail.marcansoft.com (Postfix) with ESMTPSA id 40213424E8; Tue, 7 Mar 2023 14:27:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=asahilina.net; s=default; t=1678199245; bh=Myw41AQHjD5rzjM1j2FKHqXtGruOkIC1O9lJa78/vVw=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=m7rJ9bubpU2eWduCvFK5/ydxBV740I3KYlHlxZSn7BX2f/GmL3Hchi/ZRvs3b51Im ahhGj9ECY0CINGig8I7i8iFaPycNS+M4narw/lGH7Dwg4xDH3ndYU+2EIPNz6FJfXM hoCntsHB68dZSgOtMB4G1HYLkypMNEvJCWVMROd7Db9CmH1+kUBNAGwdmQVirB+CTU O3MWJv4BeL/ioBsxWvVAQxp05cAWDGfZJyQ2GyOBv8mn4fXCv0/taSZbd61CWNUwL3 AxRIvjB2j7NjYWFL7GH3XCUsf4l/nsfza/f6oXJR5cTLJhHwQknv52NIS8FJ1BWmNs tlH2eg5ICU+Rg== From: Asahi Lina Date: Tue, 07 Mar 2023 23:25:31 +0900 Subject: [PATCH RFC 06/18] rust: drm: gem: shmem: Add DRM shmem helper abstraction MIME-Version: 1.0 Message-Id: <20230307-rust-drm-v1-6-917ff5bc80a8@asahilina.net> References: <20230307-rust-drm-v1-0-917ff5bc80a8@asahilina.net> In-Reply-To: <20230307-rust-drm-v1-0-917ff5bc80a8@asahilina.net> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , Luben Tuikov , Jarkko Sakkinen , Dave Hansen X-Mailer: b4 0.12.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1678199191; l=17977; i=lina@asahilina.net; s=20230221; h=from:subject:message-id; bh=Myw41AQHjD5rzjM1j2FKHqXtGruOkIC1O9lJa78/vVw=; b=2bzmg2GBDxzMtheU4BnU4u1o1j34J+4xXpa+rnINpwVPG76o6w5BnYjHYSkPaD11xDz8jxumt Pd/z5Mqop8tBilCmR38aV6+KhByVJWsiP0GiYgvMZgiB9wwgcWYKRLZ X-Developer-Key: i=lina@asahilina.net; a=ed25519; pk=Qn8jZuOtR1m5GaiDfTrAoQ4NE1XoYVZ/wmt5YtXWFC4= X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linaro-mm-sig@lists.linaro.org, rust-for-linux@vger.kernel.org, Karol Herbst , asahi@lists.linux.dev, Asahi Lina , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Mary , Alyssa Rosenzweig , linux-sgx@vger.kernel.org, Ella Stanforth , Faith Ekstrand , linux-media@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The DRM shmem helper includes common code useful for drivers which allocate GEM objects as anonymous shmem. Add a Rust abstraction for this. Drivers can choose the raw GEM implementation or the shmem layer, depending on their needs. Signed-off-by: Asahi Lina Signed-off-by: Maíra Canal --- drivers/gpu/drm/Kconfig | 5 + rust/bindings/bindings_helper.h | 2 + rust/helpers.c | 67 +++++++ rust/kernel/drm/gem/mod.rs | 3 + rust/kernel/drm/gem/shmem.rs | 381 ++++++++++++++++++++++++++++++++++++++++ 5 files changed, 458 insertions(+) diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index dab8f0f9aa96..70a983a17ac2 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -34,6 +34,11 @@ config RUST_DRM bool "Rust support for the DRM subsystem" depends on DRM=y +config RUST_DRM_GEM_SHMEM_HELPER + bool + depends on RUST_DRM + select DRM_GEM_SHMEM_HELPER + config DRM_MIPI_DBI tristate depends on DRM diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 7183dfe6473f..9f152d373df8 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -17,6 +18,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers.c b/rust/helpers.c index 78ec4162b03b..388ff1100ea5 100644 --- a/rust/helpers.c +++ b/rust/helpers.c @@ -19,6 +19,7 @@ */ #include +#include #include #include #include @@ -375,6 +376,18 @@ void rust_helper_init_completion(struct completion *c) } EXPORT_SYMBOL_GPL(rust_helper_init_completion); +dma_addr_t rust_helper_sg_dma_address(const struct scatterlist *sg) +{ + return sg_dma_address(sg); +} +EXPORT_SYMBOL_GPL(rust_helper_sg_dma_address); + +int rust_helper_sg_dma_len(const struct scatterlist *sg) +{ + return sg_dma_len(sg); +} +EXPORT_SYMBOL_GPL(rust_helper_sg_dma_len); + #ifdef CONFIG_DRM void rust_helper_drm_gem_object_get(struct drm_gem_object *obj) @@ -395,6 +408,60 @@ __u64 rust_helper_drm_vma_node_offset_addr(struct drm_vma_offset_node *node) } EXPORT_SYMBOL_GPL(rust_helper_drm_vma_node_offset_addr); +#ifdef CONFIG_DRM_GEM_SHMEM_HELPER + +void rust_helper_drm_gem_shmem_object_free(struct drm_gem_object *obj) +{ + return drm_gem_shmem_object_free(obj); +} +EXPORT_SYMBOL_GPL(rust_helper_drm_gem_shmem_object_free); + +void rust_helper_drm_gem_shmem_object_print_info(struct drm_printer *p, unsigned int indent, + const struct drm_gem_object *obj) +{ + drm_gem_shmem_object_print_info(p, indent, obj); +} +EXPORT_SYMBOL_GPL(rust_helper_drm_gem_shmem_object_print_info); + +int rust_helper_drm_gem_shmem_object_pin(struct drm_gem_object *obj) +{ + return drm_gem_shmem_object_pin(obj); +} +EXPORT_SYMBOL_GPL(rust_helper_drm_gem_shmem_object_pin); + +void rust_helper_drm_gem_shmem_object_unpin(struct drm_gem_object *obj) +{ + drm_gem_shmem_object_unpin(obj); +} +EXPORT_SYMBOL_GPL(rust_helper_drm_gem_shmem_object_unpin); + +struct sg_table *rust_helper_drm_gem_shmem_object_get_sg_table(struct drm_gem_object *obj) +{ + return drm_gem_shmem_object_get_sg_table(obj); +} +EXPORT_SYMBOL_GPL(rust_helper_drm_gem_shmem_object_get_sg_table); + +int rust_helper_drm_gem_shmem_object_vmap(struct drm_gem_object *obj, + struct iosys_map *map) +{ + return drm_gem_shmem_object_vmap(obj, map); +} +EXPORT_SYMBOL_GPL(rust_helper_drm_gem_shmem_object_vmap); + +void rust_helper_drm_gem_shmem_object_vunmap(struct drm_gem_object *obj, + struct iosys_map *map) +{ + drm_gem_shmem_object_vunmap(obj, map); +} +EXPORT_SYMBOL_GPL(rust_helper_drm_gem_shmem_object_vunmap); + +int rust_helper_drm_gem_shmem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma) +{ + return drm_gem_shmem_object_mmap(obj, vma); +} +EXPORT_SYMBOL_GPL(rust_helper_drm_gem_shmem_object_mmap); + +#endif #endif /* diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs index 8a7d99613718..e66bdef35c2e 100644 --- a/rust/kernel/drm/gem/mod.rs +++ b/rust/kernel/drm/gem/mod.rs @@ -4,6 +4,9 @@ //! //! C header: [`include/linux/drm/drm_gem.h`](../../../../include/linux/drm/drm_gem.h) +#[cfg(CONFIG_RUST_DRM_GEM_SHMEM_HELPER)] +pub mod shmem; + use alloc::boxed::Box; use crate::{ diff --git a/rust/kernel/drm/gem/shmem.rs b/rust/kernel/drm/gem/shmem.rs new file mode 100644 index 000000000000..15446ea1113e --- /dev/null +++ b/rust/kernel/drm/gem/shmem.rs @@ -0,0 +1,381 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! DRM GEM shmem helper objects +//! +//! C header: [`include/linux/drm/drm_gem_shmem_helper.h`](../../../../include/linux/drm/drm_gem_shmem_helper.h) + +use crate::drm::{device, drv, gem}; +use crate::{ + error::{from_kernel_err_ptr, to_result}, + prelude::*, +}; +use core::{ + marker::PhantomData, + mem, + mem::{ManuallyDrop, MaybeUninit}, + ops::{Deref, DerefMut}, + ptr::addr_of_mut, + slice, +}; + +use gem::BaseObject; + +/// Trait which must be implemented by drivers using shmem-backed GEM objects. +pub trait DriverObject: gem::BaseDriverObject> { + /// Parent `Driver` for this object. + type Driver: drv::Driver; +} + +// FIXME: This is terrible and I don't know how to avoid it +#[cfg(CONFIG_NUMA)] +macro_rules! vm_numa_fields { + ( $($field:ident: $val:expr),* $(,)? ) => { + bindings::vm_operations_struct { + $( $field: $val ),*, + set_policy: None, + get_policy: None, + } + } +} + +#[cfg(not(CONFIG_NUMA))] +macro_rules! vm_numa_fields { + ( $($field:ident: $val:expr),* $(,)? ) => { + bindings::vm_operations_struct { + $( $field: $val ),* + } + } +} + +const SHMEM_VM_OPS: bindings::vm_operations_struct = vm_numa_fields! { + open: Some(bindings::drm_gem_shmem_vm_open), + close: Some(bindings::drm_gem_shmem_vm_close), + may_split: None, + mremap: None, + mprotect: None, + fault: Some(bindings::drm_gem_shmem_fault), + huge_fault: None, + map_pages: None, + pagesize: None, + page_mkwrite: None, + pfn_mkwrite: None, + access: None, + name: None, + find_special_page: None, +}; + +/// A shmem-backed GEM object. +#[repr(C)] +pub struct Object { + obj: bindings::drm_gem_shmem_object, + // The DRM core ensures the Device exists as long as its objects exist, so we don't need to + // manage the reference count here. + dev: ManuallyDrop>, + inner: T, +} + +unsafe extern "C" fn gem_create_object( + raw_dev: *mut bindings::drm_device, + size: usize, +) -> *mut bindings::drm_gem_object { + // SAFETY: GEM ensures the device lives as long as its objects live, + // so we can conjure up a reference from thin air and never drop it. + let dev = ManuallyDrop::new(unsafe { device::Device::from_raw(raw_dev) }); + + let inner = match T::new(&*dev, size) { + Ok(v) => v, + Err(e) => return e.to_ptr(), + }; + + let p = unsafe { + bindings::krealloc( + core::ptr::null(), + Object::::SIZE, + bindings::GFP_KERNEL | bindings::__GFP_ZERO, + ) as *mut Object + }; + + if p.is_null() { + return ENOMEM.to_ptr(); + } + + // SAFETY: p is valid as long as the alloc succeeded + unsafe { + addr_of_mut!((*p).dev).write(dev); + addr_of_mut!((*p).inner).write(inner); + } + + // SAFETY: drm_gem_shmem_object is safe to zero-init, and + // the rest of Object has been initialized + let new: &mut Object = unsafe { &mut *(p as *mut _) }; + + new.obj.base.funcs = &Object::::VTABLE; + &mut new.obj.base +} + +unsafe extern "C" fn free_callback(obj: *mut bindings::drm_gem_object) { + // SAFETY: All of our objects are Object. + let p = crate::container_of!(obj, Object, obj) as *mut Object; + + // SAFETY: p is never used after this + unsafe { + core::ptr::drop_in_place(&mut (*p).inner); + } + + // SAFETY: This pointer has to be valid, since p is valid + unsafe { + bindings::drm_gem_shmem_free(&mut (*p).obj); + } +} + +impl Object { + /// The size of this object's structure. + const SIZE: usize = mem::size_of::(); + + /// `drm_gem_object_funcs` vtable suitable for GEM shmem objects. + const VTABLE: bindings::drm_gem_object_funcs = bindings::drm_gem_object_funcs { + free: Some(free_callback::), + open: Some(super::open_callback::>), + close: Some(super::close_callback::>), + print_info: Some(bindings::drm_gem_shmem_object_print_info), + export: None, + pin: Some(bindings::drm_gem_shmem_object_pin), + unpin: Some(bindings::drm_gem_shmem_object_unpin), + get_sg_table: Some(bindings::drm_gem_shmem_object_get_sg_table), + vmap: Some(bindings::drm_gem_shmem_object_vmap), + vunmap: Some(bindings::drm_gem_shmem_object_vunmap), + mmap: Some(bindings::drm_gem_shmem_object_mmap), + vm_ops: &SHMEM_VM_OPS, + }; + + // SAFETY: Must only be used with DRM functions that are thread-safe + unsafe fn mut_shmem(&self) -> *mut bindings::drm_gem_shmem_object { + &self.obj as *const _ as *mut _ + } + + /// Create a new shmem-backed DRM object of the given size. + pub fn new(dev: &device::Device, size: usize) -> Result> { + // SAFETY: This function can be called as long as the ALLOC_OPS are set properly + // for this driver, and the gem_create_object is called. + let p = unsafe { bindings::drm_gem_shmem_create(dev.raw() as *mut _, size) }; + let p = crate::container_of!(p, Object, obj) as *mut _; + + // SAFETY: The gem_create_object callback ensures this is a valid Object, + // so we can take a unique reference to it. + let obj_ref = gem::UniqueObjectRef { ptr: p }; + + Ok(obj_ref) + } + + /// Returns the `Device` that owns this GEM object. + pub fn dev(&self) -> &device::Device { + &self.dev + } + + /// Creates (if necessary) and returns a scatter-gather table of DMA pages for this object. + /// + /// This will pin the object in memory. + pub fn sg_table(&self) -> Result> { + // SAFETY: drm_gem_shmem_get_pages_sgt is thread-safe. + let sgt = from_kernel_err_ptr(unsafe { + bindings::drm_gem_shmem_get_pages_sgt(self.mut_shmem()) + })?; + + Ok(SGTable { + sgt, + _owner: self.reference(), + }) + } + + /// Creates and returns a virtual kernel memory mapping for this object. + pub fn vmap(&self) -> Result> { + let mut map: MaybeUninit = MaybeUninit::uninit(); + + // SAFETY: drm_gem_shmem_vmap is thread-safe + to_result(unsafe { bindings::drm_gem_shmem_vmap(self.mut_shmem(), map.as_mut_ptr()) })?; + + // SAFETY: if drm_gem_shmem_vmap did not fail, map is initialized now + let map = unsafe { map.assume_init() }; + + Ok(VMap { + map, + owner: self.reference(), + }) + } + + /// Set the write-combine flag for this object. + /// + /// Should be called before any mappings are made. + pub fn set_wc(&mut self, map_wc: bool) { + unsafe { (*self.mut_shmem()).map_wc = map_wc }; + } +} + +impl Deref for Object { + type Target = T; + + fn deref(&self) -> &Self::Target { + &self.inner + } +} + +impl DerefMut for Object { + fn deref_mut(&mut self) -> &mut Self::Target { + &mut self.inner + } +} + +impl crate::private::Sealed for Object {} + +impl gem::IntoGEMObject for Object { + type Driver = T::Driver; + + fn gem_obj(&self) -> *mut bindings::drm_gem_object { + &self.obj.base as *const _ as *mut _ + } + + fn from_gem_obj(obj: *mut bindings::drm_gem_object) -> *mut Object { + crate::container_of!(obj, Object, obj) as *mut Object + } +} + +impl drv::AllocImpl for Object { + const ALLOC_OPS: drv::AllocOps = drv::AllocOps { + gem_create_object: Some(gem_create_object::), + prime_handle_to_fd: Some(bindings::drm_gem_prime_handle_to_fd), + prime_fd_to_handle: Some(bindings::drm_gem_prime_fd_to_handle), + gem_prime_import: None, + gem_prime_import_sg_table: Some(bindings::drm_gem_shmem_prime_import_sg_table), + gem_prime_mmap: Some(bindings::drm_gem_prime_mmap), + dumb_create: Some(bindings::drm_gem_shmem_dumb_create), + dumb_map_offset: None, + dumb_destroy: None, + }; +} + +/// A virtual mapping for a shmem-backed GEM object in kernel address space. +pub struct VMap { + map: bindings::iosys_map, + owner: gem::ObjectRef>, +} + +impl VMap { + /// Returns a const raw pointer to the start of the mapping. + pub fn as_ptr(&self) -> *const core::ffi::c_void { + // SAFETY: The shmem helpers always return non-iomem maps + unsafe { self.map.__bindgen_anon_1.vaddr } + } + + /// Returns a mutable raw pointer to the start of the mapping. + pub fn as_mut_ptr(&mut self) -> *mut core::ffi::c_void { + // SAFETY: The shmem helpers always return non-iomem maps + unsafe { self.map.__bindgen_anon_1.vaddr } + } + + /// Returns a byte slice view of the mapping. + pub fn as_slice(&self) -> &[u8] { + // SAFETY: The vmap maps valid memory up to the owner size + unsafe { slice::from_raw_parts(self.as_ptr() as *const u8, self.owner.size()) } + } + + /// Returns mutable a byte slice view of the mapping. + pub fn as_mut_slice(&mut self) -> &mut [u8] { + // SAFETY: The vmap maps valid memory up to the owner size + unsafe { slice::from_raw_parts_mut(self.as_mut_ptr() as *mut u8, self.owner.size()) } + } + + /// Borrows a reference to the object that owns this virtual mapping. + pub fn owner(&self) -> &gem::ObjectRef> { + &self.owner + } +} + +impl Drop for VMap { + fn drop(&mut self) { + // SAFETY: This function is thread-safe + unsafe { + bindings::drm_gem_shmem_vunmap(self.owner.mut_shmem(), &mut self.map); + } + } +} + +/// SAFETY: `iosys_map` objects are safe to send across threads. +unsafe impl Send for VMap {} +unsafe impl Sync for VMap {} + +/// A single scatter-gather entry, representing a span of pages in the device's DMA address space. +/// +/// For devices not behind a standalone IOMMU, this corresponds to physical addresses. +#[repr(transparent)] +pub struct SGEntry(bindings::scatterlist); + +impl SGEntry { + /// Returns the starting DMA address of this span + pub fn dma_address(&self) -> usize { + (unsafe { bindings::sg_dma_address(&self.0) }) as usize + } + + /// Returns the length of this span in bytes + pub fn dma_len(&self) -> usize { + (unsafe { bindings::sg_dma_len(&self.0) }) as usize + } +} + +/// A scatter-gather table of DMA address spans for a GEM shmem object. +/// +/// # Invariants +/// `sgt` must be a valid pointer to the `sg_table`, which must correspond to the owned +/// object in `_owner` (which ensures it remains valid). +pub struct SGTable { + sgt: *const bindings::sg_table, + _owner: gem::ObjectRef>, +} + +impl SGTable { + /// Returns an iterator through the SGTable's entries + pub fn iter(&'_ self) -> SGTableIter<'_> { + SGTableIter { + left: unsafe { (*self.sgt).nents } as usize, + sg: unsafe { (*self.sgt).sgl }, + _p: PhantomData, + } + } +} + +impl<'a, T: DriverObject> IntoIterator for &'a SGTable { + type Item = &'a SGEntry; + type IntoIter = SGTableIter<'a>; + + fn into_iter(self) -> Self::IntoIter { + self.iter() + } +} + +/// SAFETY: `sg_table` objects are safe to send across threads. +unsafe impl Send for SGTable {} +unsafe impl Sync for SGTable {} + +/// An iterator through `SGTable` entries. +/// +/// # Invariants +/// `sg` must be a valid pointer to the scatterlist, which must outlive our lifetime. +pub struct SGTableIter<'a> { + sg: *mut bindings::scatterlist, + left: usize, + _p: PhantomData<&'a ()>, +} + +impl<'a> Iterator for SGTableIter<'a> { + type Item = &'a SGEntry; + + fn next(&mut self) -> Option { + if self.left == 0 { + None + } else { + let sg = self.sg; + self.sg = unsafe { bindings::sg_next(self.sg) }; + self.left -= 1; + Some(unsafe { &(*(sg as *const SGEntry)) }) + } + } +}