Revision 435faf5c218a47fd6258187f62d9bb1009717896 authored by Linus Torvalds on 05 June 2020, 03:14:18 UTC, committed by Linus Torvalds on 05 June 2020, 03:14:18 UTC
Pull RISC-V updates from Palmer Dabbelt: - The remainder of the code necessary to support the Kendryte K210: * Support for building device trees into the kernel, as the K210 doesn't have a bootloader that provides one * A K210 device tree and the associated defconfig update * Support for skipping PMP initialization on systems that trap on PMP accesses rather than treating them as WARL - Support for KGDB - Improvements to text patching - Some cleanups to the SiFive L2 cache driver * tag 'riscv-for-linus-5.8-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: soc: sifive: l2 cache: Mark l2_get_priv_group as static soc: sifive: l2 cache: Eliminate an unsigned zero compare warning riscv: Add support to determine no. of L2 cache way enabled riscv: cacheinfo: Implement cache_get_priv_group with a generic ops structure riscv: Use text_mutex instead of patch_lock riscv: Use NOKPROBE_SYMBOL() instead of __krpobes annotation riscv: Remove the 'riscv_' prefix of function name riscv: Add SW single-step support for KDB riscv: Use the XML target descriptions to report 3 system registers riscv: Add KGDB support kgdb: Add kgdb_has_hit_break function RISC-V: Skip setting up PMPs on traps riscv: K210: Update defconfig riscv: K210: Add a built-in device tree riscv: Allow device trees to be built into the kernel
once.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/once.h>
#include <linux/random.h>
struct once_work {
struct work_struct work;
struct static_key_true *key;
};
static void once_deferred(struct work_struct *w)
{
struct once_work *work;
work = container_of(w, struct once_work, work);
BUG_ON(!static_key_enabled(work->key));
static_branch_disable(work->key);
kfree(work);
}
static void once_disable_jump(struct static_key_true *key)
{
struct once_work *w;
w = kmalloc(sizeof(*w), GFP_ATOMIC);
if (!w)
return;
INIT_WORK(&w->work, once_deferred);
w->key = key;
schedule_work(&w->work);
}
static DEFINE_SPINLOCK(once_lock);
bool __do_once_start(bool *done, unsigned long *flags)
__acquires(once_lock)
{
spin_lock_irqsave(&once_lock, *flags);
if (*done) {
spin_unlock_irqrestore(&once_lock, *flags);
/* Keep sparse happy by restoring an even lock count on
* this lock. In case we return here, we don't call into
* __do_once_done but return early in the DO_ONCE() macro.
*/
__acquire(once_lock);
return false;
}
return true;
}
EXPORT_SYMBOL(__do_once_start);
void __do_once_done(bool *done, struct static_key_true *once_key,
unsigned long *flags)
__releases(once_lock)
{
*done = true;
spin_unlock_irqrestore(&once_lock, *flags);
once_disable_jump(once_key);
}
EXPORT_SYMBOL(__do_once_done);
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