From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 66771C8E6; Fri, 13 Feb 2026 01:59:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770947969; cv=pass; b=Ih/WSugaobB2zMJQsis5lV15esLSEjoghVPalyM4qus7pCyEjoPLAwAjwQI3YINAIaTp43pxUpN3vJRh4X9lA5GmhqxtxwwxTZ+oRHOEFDjIqw7luxEjyxiF2NXij3w4bDwBxhOhBxQvMwQnEdrSTQSU6pXljysnyMqeyCImRMY= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770947969; c=relaxed/simple; bh=cKrtYn7xDJh+n7aL25/NSTQWfOFgzKBZMk+uN7eSjZY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Fmmk1oAXtOkB7jVoV02VlBtxmbHunHftrygOCzEI2ea3ipL1hC4tjj4YEzzTckc2+Za8B8s0DUSgc+y+/yvCaoYJtekoBh7cDcWuFgOeQ7eUmjBmkFwpJ6bkBgzMOvosQAExny8YL1fKMe5ea4davgMGy9lhbEgTRViravjfThs= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=deborah.brouwer@collabora.com header.b=aBpLo5RY; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=deborah.brouwer@collabora.com header.b="aBpLo5RY" ARC-Seal: i=1; a=rsa-sha256; t=1770947951; cv=none; d=zohomail.com; s=zohoarc; b=LDN+WNAUdz0SWY52JwzhhhDQRNguvsp/kUWE223sjb0r4BaXIrkMWeZ8SIsVqvgOOzfuCf6pH5npUkDBjZD6ZyaG01hHTRajKZI7Kl5LLyAfJYn15kA1IMCpbLwB+zO1Ds7yvJj9UwEhfpp7Ro3E26RkdO1AoC4qVpEz0G2TnQ0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1770947951; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=C8g2vpgn9loO8Qzjl4rLA0gGBK3eJ5QEP0ztitLu7uc=; b=OVtuGyrRC+YNC4o6x4DMekKoBbweRISRzTAUVR0LuF0p9BLVCJ18HuYB/Bgu+svpruAwe9XNswF30LfDFfCTid4ppHs3RC3dROWUz3gkCbjXP902VN5Mz4kqLe1dLp5aL0FnzNKXsRgCJjdLekEHbr4oyr6BdKzcVxBDXE4aEg8= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=deborah.brouwer@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1770947951; s=zohomail; d=collabora.com; i=deborah.brouwer@collabora.com; h=Date:Date:From:From:To:To:Cc:Cc:Subject:Subject:Message-ID:References:MIME-Version:Content-Type:Content-Transfer-Encoding:In-Reply-To:Message-Id:Reply-To; bh=C8g2vpgn9loO8Qzjl4rLA0gGBK3eJ5QEP0ztitLu7uc=; b=aBpLo5RYGAkKFZRMDKOHrGB+wC/x7OwFWnUd3JhZ1pAUH/Hv5LIxHkgxL6rS87HG WnhextBe14iyKxZbV901wKW6j4GUDgW11NaMHh2rLo6WjMmU47QTHaKvDou/LXRONKn P1pVT0ezVb90bKRi/vdhN2mD7iPYBTE+m3d+6qzU= Received: by mx.zohomail.com with SMTPS id 1770947950819885.6940747393908; Thu, 12 Feb 2026 17:59:10 -0800 (PST) Date: Thu, 12 Feb 2026 17:59:09 -0800 From: Deborah Brouwer To: Lyude Paul Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org, Danilo Krummrich , nouveau@lists.freedesktop.org, Daniel Almeida , Gary Guo , Benno Lossin , Alexandre Courbot , Janne Grunau Subject: Re: [PATCH v7 6/7] rust: Introduce iosys_map bindings Message-ID: References: <20260206223431.693765-1-lyude@redhat.com> <20260206223431.693765-7-lyude@redhat.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260206223431.693765-7-lyude@redhat.com> Hi Lyude, On Fri, Feb 06, 2026 at 05:34:30PM -0500, Lyude Paul wrote: > This introduces a set of bindings for working with iosys_map in rust code > using the new Io traits. > > Signed-off-by: Lyude Paul > > --- > V5: > - Fix incorrect field size being passed to iosys_map_memcpy_to() > - Add an additional unit test, basic_macro(), which can successfully catch > the above issue so it doesn't happen again in the future. > V6: > - Drop as_slice/as_mut_slice (Alice Rhyl) > V7: > - Start using Alexandre Courbot's wonderful Io, IoCapable and IoKnownSize > traits instead of trying to roll our own IO accessors. This also changes > the following: > - We don't have a custom AsBytes/FromBytes type that we carry around any > longer with maps > - We now have optional compile-time size checking > - We don't need our own unit tests anymore > - RawIoSysMap can be used for unsafe IO operations, because why not. > - IoSysMapRef::new() can fail now since it needs to ensure SIZE is valid. > - We don't implement Deref for IoSysMapRef any longer. The > main reason for this is that we want to avoid users having to manually > specify if they want the RawIoSysMap or IoSysMapRef variant functions > like io_read()/io_write(). > This is fine IMHO, but to make sure things remain easy for APIs that > wrap around iosys map we make IoSysMapRef.raw_map pub(crate). > > rust/helpers/helpers.c | 1 + > rust/helpers/iosys_map.c | 34 +++++++ > rust/kernel/iosys_map.rs | 211 +++++++++++++++++++++++++++++++++++++++ > rust/kernel/lib.rs | 1 + > 4 files changed, 247 insertions(+) > create mode 100644 rust/helpers/iosys_map.c > create mode 100644 rust/kernel/iosys_map.rs > > diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c > index 1d3333cc0d2a8..bd8ad237aa02e 100644 > --- a/rust/helpers/helpers.c > +++ b/rust/helpers/helpers.c > @@ -31,6 +31,7 @@ > #include "irq.c" > #include "fs.c" > #include "io.c" > +#include "iosys_map.c" > #include "jump_label.c" > #include "kunit.c" > #include "maple_tree.c" > diff --git a/rust/helpers/iosys_map.c b/rust/helpers/iosys_map.c > new file mode 100644 > index 0000000000000..6861d4ec48a4b > --- /dev/null > +++ b/rust/helpers/iosys_map.c > @@ -0,0 +1,34 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#include > +#include > + > +#define rust_iosys_map_rd(type__) \ > + __rust_helper type__ \ > + rust_helper_iosys_map_rd_ ## type__(const struct iosys_map *map, size_t offset) \ > + { \ > + return iosys_map_rd(map, offset, type__); \ > + } > +#define rust_iosys_map_wr(type__) \ > + __rust_helper void \ > + rust_helper_iosys_map_wr_ ## type__(const struct iosys_map *map, size_t offset, \ > + type__ value) \ > + { \ > + iosys_map_wr(map, offset, type__, value); \ > + } > + > +rust_iosys_map_rd(u8); > +rust_iosys_map_rd(u16); > +rust_iosys_map_rd(u32); > + > +rust_iosys_map_wr(u8); > +rust_iosys_map_wr(u16); > +rust_iosys_map_wr(u32); > + > +#ifdef CONFIG_64BIT > +rust_iosys_map_rd(u64); > +rust_iosys_map_wr(u64); > +#endif > + > +#undef rust_iosys_map_rd > +#undef rust_iosys_map_wr > diff --git a/rust/kernel/iosys_map.rs b/rust/kernel/iosys_map.rs > new file mode 100644 > index 0000000000000..2070f0fb42cb8 > --- /dev/null > +++ b/rust/kernel/iosys_map.rs > @@ -0,0 +1,211 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +//! IO-agnostic memory mapping interfaces. > +//! > +//! This crate provides bindings for the `struct iosys_map` type, which provides a common interface > +//! for memory mappings which can reside within coherent memory, or within IO memory. > +//! > +//! C header: [`include/linux/iosys-map.h`](srctree/include/linux/pci.h) > + > +use crate::{ > + error::code::*, > + io::{ > + Io, > + IoCapable, > + IoKnownSize, // > + }, > + prelude::*, // > +}; > +use bindings; > +use core::marker::PhantomData; > + > +/// Raw unsized representation of a `struct iosys_map`. > +/// > +/// This struct is a transparent wrapper around `struct iosys_map`. The C API does not provide the > +/// size of the mapping by default, and thus this type also does not include the size of the > +/// mapping. As such, it cannot be used for actually accessing the underlying data pointed to by the > +/// mapping. > +/// > +/// With the exception of kernel crates which may provide their own wrappers around `RawIoSysMap`, > +/// users will typically not interact with this type directly. > +#[repr(transparent)] > +pub struct RawIoSysMap(bindings::iosys_map); > + > +impl RawIoSysMap { > + /// Convert from a raw `bindings::iosys_map`. > + #[expect(unused)] > + #[inline] > + pub(crate) fn from_raw(val: bindings::iosys_map) -> Self { > + Self(val) > + } > + > + /// Returns whether the mapping is within IO memory space or not. > + #[inline] > + pub fn is_iomem(&self) -> bool { > + self.0.is_iomem > + } > + > + /// Convert from a `RawIoSysMap` to a raw `bindings::iosys_map` ref. > + #[expect(unused)] > + #[inline] > + pub(crate) fn as_raw(&self) -> &bindings::iosys_map { > + &self.0 > + } > + > + /// Convert from a `RawIoSysMap` to a raw mutable `bindings::iosys_map` ref. > + #[allow(unused)] > + #[inline] > + pub(crate) fn as_raw_mut(&mut self) -> &mut bindings::iosys_map { > + &mut self.0 > + } > + > + /// Returns the address pointed to by this iosys map. > + /// > + /// Note that this address is not guaranteed to be valid, and may or may not reside in I/O > + /// memory. > + #[inline] > + pub fn addr(&self) -> usize { > + (if self.is_iomem() { > + // SAFETY: We confirmed above that this iosys map is contained within iomem, so it's > + // safe to read vaddr_iomem > + unsafe { self.0.__bindgen_anon_1.vaddr_iomem } > + } else { > + // SAFETY: We confirmed above that this iosys map is not contaned within iomem, so it's > + // safe to read vaddr. > + unsafe { self.0.__bindgen_anon_1.vaddr } > + }) as usize > + } > +} > + > +// SAFETY: As we make no guarantees about the validity of the mapping, there's no issue with sending > +// this type between threads. > +unsafe impl Send for RawIoSysMap {} > + > +impl Clone for RawIoSysMap { > + fn clone(&self) -> Self { > + Self(self.0) > + } > +} > + > +macro_rules! impl_raw_iosys_map_io_capable { > + ($ty:ty, $read_fn:ident, $write_fn:ident) => { > + impl IoCapable<$ty> for RawIoSysMap { > + #[inline(always)] > + unsafe fn io_read(&self, address: usize) -> $ty { > + // SAFETY: By the trait invariant `address` is a valid address for iosys map > + // operations. > + unsafe { bindings::$read_fn(&self.0, address) } > + } > + > + #[inline(always)] > + unsafe fn io_write(&self, value: $ty, address: usize) { > + // SAFETY: By the trait invariant `address` is a valid address for iosys map > + // operations. > + unsafe { bindings::$write_fn(&self.0, address, value) }; > + } > + } > + }; > +} > + I think there might be a mismatch between the absolute address being passed to these read and write functions and the bindings helpers that expect an offset argument. This crashed Tyr when I tried to write the firmware in u8 chunks at incremental offsets. But if i just calculated the offset and passed that instead of the absolute address, this worked fine: let offset = address - self.addr(); unsafe { bindings::$write_fn(&self.0, offset, value) }; Here's some of the call trace: [ 31.553727] tyr fb000000.gpu: supply sram not found, using dummy regulator [ 31.555096] tyr fb000000.gpu: mali-unknown id 0xa867 major 0x67 minor 0x0 status 0x5 [ 31.555778] tyr fb000000.gpu: Features: L2:0x7120306 Tiler:0x809 Mem:0x301 MMU:0x2830 AS:0xff [ 31.556521] tyr fb000000.gpu: shader_present=0x0000000000050005 l2_present=0x0000000000000001 tiler_present=0x0000000000000001 [ 31.557868] stackdepot: allocating hash table of 524288 entries via kvcalloc [ OK ] Started systemd-tmpfiles-clean.tim…y Cleanup of Temporary Directories. [ 31.562424] stackdepot: allocating space for 8192 stack pools via kvcalloc [ OK ] Reached target timers.target - Timer Units. [ 31.563676] tyr: Firmware protected mode entry not supported, ignoring [ 31.571391] Unable to handle kernel paging request at virtual address 0000000000800069 [ 31.572762] Mem abort info: [ 31.573027] ESR = 0x0000000096000021 [ 31.573402] EC = 0x25: DABT (current EL), IL = 32 bits [ 31.573878] SET = 0, FnV = 0 [ 31.574157] EA = 0, S1PTW = 0 [ 31.574442] FSC = 0x21: alignment fault [ OK ] Listening on dbus.socket - D-Bus System Message Bus Socket. [ 31.593348] Data abort info: [ 31.593628] ISV = 0, ISS = 0x00000021, ISS2 = 0x00000000 [ 31.594117] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 31.594567] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 31.595042] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000105e50000 [ 31.595613] [0000000000800069] pgd=0000000000000000, p4d=0000000000000000 [ 31.596434] Internal error: Oops: 0000000096000021 [#1] SMP [ 31.596936] Modules linked in: snd tyr(+) soundcore sha256 cfg80211 rfkill pci_endpoint_test fuse dm_mod ipv6 [ 31.597830] CPU: 3 UID: 0 PID: 241 Comm: (udev-worker) Not tainted 6.19.0-rc5 #282 PREEMPT [ 31.598561] Hardware name: Radxa ROCK 5B (DT) [ 31.598944] pstate: 00400009 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 31.599554] pc : __d_lookup_rcu+0xbc/0x168 [ 31.599921] lr : __d_lookup_rcu+0x60/0x168 [ 31.600283] sp : ffff800081ebba00 [ 31.600574] x29: ffff800081ebba00 x28: 0000000000000049 x27: ffff00010d07002b [ 31.601205] x26: 0000000000000081 x25: 000000000006915e x24: ffff0002f6600000 [ 31.601848] x23: ffff00010396a040 x22: ffff000102098460 x21: 000000036915e207 [ 31.601859] x20: ffff000101e10af8 x19: ffff800081ebbcac x18: 2f64662f666c6573 [ 31.601867] x17: ffffff00666c6573 x16: 00000000fffffffc x15: 0000000000003431 [ 31.601875] x14: 000000000000000f x13: 0080205100800107 x12: 0000000000800069 [ 31.601882] x11: ffffffffffffffff x10: 0000000000000018 x9 : 0000000000000003 [ 31.601890] x8 : 00000000008000a1 x7 : ffffb9d13df173c8 x6 : 0000000000000000 [ 31.601897] x5 : 0000000000000000 x4 : 0000000000000010 x3 : ffffffffffff0a00 [ 31.601905] x2 : ffff800081ebbcac x1 : ffffb9d1406be718 x0 : 0000000000000001 [ 31.601913] Call trace: [ 31.601915] __d_lookup_rcu+0xbc/0x168 (P) [ 31.601922] lookup_fast+0x98/0x174 [ 31.601929] link_path_walk+0x280/0x528 [ 31.601935] path_lookupat+0x60/0x1f0 [ 31.601941] do_o_path+0x34/0xb4 [ 31.601947] path_openat+0xccc/0xe34 [ 31.601953] do_filp_open+0xc0/0x170 [ 31.601958] do_sys_openat2+0x88/0x10c [ 31.601963] __arm64_sys_openat+0x70/0x9c [ 31.601968] invoke_syscall+0x40/0xcc [ 31.601974] el0_svc_common+0x80/0xd8 [ 31.601979] do_el0_svc+0x1c/0x28 [ 31.601984] el0_svc+0x54/0x1d4 [ 31.601991] el0t_64_sync_handler+0x84/0x12c [ 31.601997] el0t_64_sync+0x198/0x19c [ 31.602005] Code: 14000003 f9400108 b4000428 d100e10c (88dffd8c) [ 31.602009] ---[ end trace 0000000000000000 ]--- [ OK ] Listening on sshd-unix-local.socke…temd-ssh-generator, AF_UNIX Local). [ 31.620067] mc: Linux media interface: v0.10 [ 31.623483] [drm] Initialized panthor 1.5.0 for fb000000.gpu on minor 0 [ 31.623765] Unable to handle kernel paging request at virtual address 00802a4d0080284d [ 31.624285] tyr fb000000.gpu: Tyr initialized correctly. [ 31.624752] Mem abort info: [ 31.624754] ESR = 0x0000000096000004 [ 31.625847] EC = 0x25: DABT (current EL), IL = 32 bits [ 31.626310] SET = 0, FnV = 0 [ 31.626578] EA = 0, S1PTW = 0 [ 31.626853] FSC = 0x04: level 0 translation fault [ 31.627277] Data abort info: [ 31.627529] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 31.628006] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 31.628447] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 31.628910] [00802a4d0080284d] address between user and kernel address ranges [ 31.629535] Internal error: Oops: 0000000096000004 [#2] SMP [ 31.630030] Modules linked in: mc drm_client_lib snd tyr soundcore sha256 cfg80211 rfkill pci_endpoint_test fuse dm_mod ipv6 [ 31.631017] CPU: 4 UID: 0 PID: 225 Comm: systemd-udevd Tainted: G D 6.19.0-rc5 #282 PREEMPT [ 31.631877] Tainted: [D]=DIE [ 31.632129] Hardware name: Radxa ROCK 5B (DT) [ 31.632506] pstate: a0400009 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 31.633111] pc : ___d_drop+0xd8/0x144 [ 31.633433] lr : d_invalidate+0x3c/0x110 [ 31.633776] sp : ffff800081d3ba70 [ 31.634064] x29: ffff800081d3ba90 x28: 0000000000000001 x27: ffffb9d140bfa000 [ 31.634685] x26: ffff0001039b5108 x25: ffff00010396a000 x24: ffffb9d140166275 [ 31.635305] x23: ffffb9d140bfa000 x22: ffffb9d140152f3a x21: ffff000104076000 [ 31.635925] x20: ffff00010e520098 x19: ffff00010396a000 x18: 0000000000000000 [ 31.636545] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 31.637165] x14: 0000000000000000 x13: ffff00010792b8f0 x12: 000000000000017a [ 31.637785] x11: 00000000008000a1 x10: 00802a4d0080284d x9 : ffff0002f6604010 [ 31.638405] x8 : ffff000105bfcd40 x7 : 0000000000000000 x6 : ffffb9d13e272c60 [ 31.639026] x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000 [ 31.639646] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff00010396a000 [ 31.640266] Call trace: [ 31.640479] ___d_drop+0xd8/0x144 (P) [ 31.640800] d_invalidate+0x3c/0x110 [ 31.641113] proc_invalidate_siblings_dcache+0x244/0x2b8 [ 31.641577] proc_flush_pid+0x1c/0x28 [ 31.641897] release_task+0x560/0x668 [ 31.642218] wait_consider_task+0x5a0/0xb44 [ 31.642582] __do_wait+0x154/0x1f0 [ 31.642879] do_wait+0x84/0x16c [ 31.643154] __arm64_sys_waitid+0xac/0x218 [ 31.643512] invoke_syscall+0x40/0xcc [ 31.643833] el0_svc_common+0x80/0xd8 [ 31.644152] do_el0_svc+0x1c/0x28 [ 31.644441] el0_svc+0x54/0x1d4 [ 31.644718] el0t_64_sync_handler+0x84/0x12c [ 31.645090] el0t_64_sync+0x198/0x19c [ 31.645412] Code: 5280002a f85f83a0 17fffff1 a944280b (f940014c) [ 31.645941] ---[ end trace 0000000000000000 ]--- thanks, Deborah