Hey! Sorry for the long delay in response Would you mind sending me the size/offset numbers you used here? My unit tests should have caught issues like this, so if they're happening I definitely should add it to the testcases I've got to make sure there's no problems
On Thu, 2026-02-12 at 17:59 -0800, Deborah Brouwer wrote: > 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 <[email protected]> > > > > --- > > 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<RawIoSysMap> 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 <linux/iosys-map.h> > > +#include <linux/types.h> > > + > > +#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<const SIZE: usize = > > 0>(bindings::iosys_map); > > + > > +impl<const SIZE: usize> RawIoSysMap<SIZE> { > > + /// 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<SIZE>` 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<SIZE>` 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<const SIZE: usize> Send for RawIoSysMap<SIZE> {} > > + > > +impl<const SIZE: usize> Clone for RawIoSysMap<SIZE> { > > + fn clone(&self) -> Self { > > + Self(self.0) > > + } > > +} > > + > > +macro_rules! impl_raw_iosys_map_io_capable { > > + ($ty:ty, $read_fn:ident, $write_fn:ident) => { > > + impl<const SIZE: usize> IoCapable<$ty> for > > RawIoSysMap<SIZE> { > > + #[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
