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linux/rust/helpers/helpers.c
FUJITA Tomonori 1b7bbd5975 rust: time: Avoid 64-bit integer division on 32-bit architectures
Avoid 64-bit integer division that 32-bit architectures don't
implement generally. This uses ktime_to_us() and ktime_to_ms()
instead.

The time abstraction needs i64 / u32 division so C's div_s64() can be
used but ktime_to_us() and ktime_to_ms() provide a simpler solution
for this time abstraction problem on 32-bit architectures.

32-bit ARM is the only 32-bit architecture currently supported by
Rust. Using the cfg attribute, only 32-bit architectures will call
ktime_to_us() and ktime_to_ms(), while the other 64-bit architectures
will continue to use the current code as-is to avoid the overhead.

One downside of calling the C's functions is that the as_micros/millis
methods can no longer be const fn. We stick with the simpler approach
unless there's a compelling need for a const fn.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20250502004524.230553-1-fujita.tomonori@gmail.com
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
2025-06-16 15:01:15 +02:00

49 lines
1.0 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions
* cannot be called either. This file explicitly creates functions ("helpers")
* that wrap those so that they can be called from Rust.
*
* Sorted alphabetically.
*/
#include "auxiliary.c"
#include "blk.c"
#include "bug.c"
#include "build_assert.c"
#include "build_bug.c"
#include "clk.c"
#include "cpu.c"
#include "cpufreq.c"
#include "cpumask.c"
#include "cred.c"
#include "device.c"
#include "dma.c"
#include "drm.c"
#include "err.c"
#include "fs.c"
#include "io.c"
#include "jump_label.c"
#include "kunit.c"
#include "mm.c"
#include "mutex.c"
#include "page.c"
#include "platform.c"
#include "pci.c"
#include "pid_namespace.c"
#include "rbtree.c"
#include "rcu.c"
#include "refcount.c"
#include "security.c"
#include "signal.c"
#include "slab.c"
#include "spinlock.c"
#include "sync.c"
#include "task.c"
#include "time.c"
#include "uaccess.c"
#include "vmalloc.c"
#include "wait.c"
#include "workqueue.c"
#include "xarray.c"