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authorKees Cook <kees+treewide@kernel.org>2026-09-02 15:31:14 -0700
committerKees Cook <kees@kernel.org>2026-09-04 21:37:00 -0700
commit3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch)
treec65086f9bdcd48c6360fb7cb4598bca084da1f32 /lib/atomic64.c
downloadlinux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.tar.gz
linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.zip
treewide: refresh kmalloc_obj() conversionsgrafted
This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook <kees+treewide@kernel.org>
Diffstat (limited to 'lib/atomic64.c')
-rw-r--r--lib/atomic64.c207
1 files changed, 207 insertions, 0 deletions
diff --git a/lib/atomic64.c b/lib/atomic64.c
new file mode 100644
index 000000000..1a72bba36
--- /dev/null
+++ b/lib/atomic64.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Generic implementation of 64-bit atomics using spinlocks,
+ * useful on processors that don't have 64-bit atomic instructions.
+ *
+ * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ */
+#include <linux/types.h>
+#include <linux/cache.h>
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/atomic.h>
+
+/*
+ * We use a hashed array of spinlocks to provide exclusive access
+ * to each atomic64_t variable. Since this is expected to used on
+ * systems with small numbers of CPUs (<= 4 or so), we use a
+ * relatively small array of 16 spinlocks to avoid wasting too much
+ * memory on the spinlock array.
+ */
+#define NR_LOCKS 16
+
+/*
+ * Ensure each lock is in a separate cacheline.
+ */
+static union {
+ arch_spinlock_t lock;
+ char pad[L1_CACHE_BYTES];
+} atomic64_lock[NR_LOCKS] __cacheline_aligned_in_smp = {
+ [0 ... (NR_LOCKS - 1)] = {
+ .lock = __ARCH_SPIN_LOCK_UNLOCKED,
+ },
+};
+
+static inline arch_spinlock_t *lock_addr(const atomic64_t *v)
+{
+ unsigned long addr = (unsigned long) v;
+
+ addr >>= L1_CACHE_SHIFT;
+ addr ^= (addr >> 8) ^ (addr >> 16);
+ return &atomic64_lock[addr & (NR_LOCKS - 1)].lock;
+}
+
+s64 generic_atomic64_read(const atomic64_t *v)
+{
+ unsigned long flags;
+ arch_spinlock_t *lock = lock_addr(v);
+ s64 val;
+
+ local_irq_save(flags);
+ arch_spin_lock(lock);
+ val = v->counter;
+ arch_spin_unlock(lock);
+ local_irq_restore(flags);
+ return val;
+}
+EXPORT_SYMBOL(generic_atomic64_read);
+
+void generic_atomic64_set(atomic64_t *v, s64 i)
+{
+ unsigned long flags;
+ arch_spinlock_t *lock = lock_addr(v);
+
+ local_irq_save(flags);
+ arch_spin_lock(lock);
+ v->counter = i;
+ arch_spin_unlock(lock);
+ local_irq_restore(flags);
+}
+EXPORT_SYMBOL(generic_atomic64_set);
+
+#define ATOMIC64_OP(op, c_op) \
+void generic_atomic64_##op(s64 a, atomic64_t *v) \
+{ \
+ unsigned long flags; \
+ arch_spinlock_t *lock = lock_addr(v); \
+ \
+ local_irq_save(flags); \
+ arch_spin_lock(lock); \
+ v->counter c_op a; \
+ arch_spin_unlock(lock); \
+ local_irq_restore(flags); \
+} \
+EXPORT_SYMBOL(generic_atomic64_##op);
+
+#define ATOMIC64_OP_RETURN(op, c_op) \
+s64 generic_atomic64_##op##_return(s64 a, atomic64_t *v) \
+{ \
+ unsigned long flags; \
+ arch_spinlock_t *lock = lock_addr(v); \
+ s64 val; \
+ \
+ local_irq_save(flags); \
+ arch_spin_lock(lock); \
+ val = (v->counter c_op a); \
+ arch_spin_unlock(lock); \
+ local_irq_restore(flags); \
+ return val; \
+} \
+EXPORT_SYMBOL(generic_atomic64_##op##_return);
+
+#define ATOMIC64_FETCH_OP(op, c_op) \
+s64 generic_atomic64_fetch_##op(s64 a, atomic64_t *v) \
+{ \
+ unsigned long flags; \
+ arch_spinlock_t *lock = lock_addr(v); \
+ s64 val; \
+ \
+ local_irq_save(flags); \
+ arch_spin_lock(lock); \
+ val = v->counter; \
+ v->counter c_op a; \
+ arch_spin_unlock(lock); \
+ local_irq_restore(flags); \
+ return val; \
+} \
+EXPORT_SYMBOL(generic_atomic64_fetch_##op);
+
+#define ATOMIC64_OPS(op, c_op) \
+ ATOMIC64_OP(op, c_op) \
+ ATOMIC64_OP_RETURN(op, c_op) \
+ ATOMIC64_FETCH_OP(op, c_op)
+
+ATOMIC64_OPS(add, +=)
+ATOMIC64_OPS(sub, -=)
+
+#undef ATOMIC64_OPS
+#define ATOMIC64_OPS(op, c_op) \
+ ATOMIC64_OP(op, c_op) \
+ ATOMIC64_FETCH_OP(op, c_op)
+
+ATOMIC64_OPS(and, &=)
+ATOMIC64_OPS(or, |=)
+ATOMIC64_OPS(xor, ^=)
+
+#undef ATOMIC64_OPS
+#undef ATOMIC64_FETCH_OP
+#undef ATOMIC64_OP
+
+s64 generic_atomic64_dec_if_positive(atomic64_t *v)
+{
+ unsigned long flags;
+ arch_spinlock_t *lock = lock_addr(v);
+ s64 val;
+
+ local_irq_save(flags);
+ arch_spin_lock(lock);
+ val = v->counter - 1;
+ if (val >= 0)
+ v->counter = val;
+ arch_spin_unlock(lock);
+ local_irq_restore(flags);
+ return val;
+}
+EXPORT_SYMBOL(generic_atomic64_dec_if_positive);
+
+s64 generic_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n)
+{
+ unsigned long flags;
+ arch_spinlock_t *lock = lock_addr(v);
+ s64 val;
+
+ local_irq_save(flags);
+ arch_spin_lock(lock);
+ val = v->counter;
+ if (val == o)
+ v->counter = n;
+ arch_spin_unlock(lock);
+ local_irq_restore(flags);
+ return val;
+}
+EXPORT_SYMBOL(generic_atomic64_cmpxchg);
+
+s64 generic_atomic64_xchg(atomic64_t *v, s64 new)
+{
+ unsigned long flags;
+ arch_spinlock_t *lock = lock_addr(v);
+ s64 val;
+
+ local_irq_save(flags);
+ arch_spin_lock(lock);
+ val = v->counter;
+ v->counter = new;
+ arch_spin_unlock(lock);
+ local_irq_restore(flags);
+ return val;
+}
+EXPORT_SYMBOL(generic_atomic64_xchg);
+
+s64 generic_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
+{
+ unsigned long flags;
+ arch_spinlock_t *lock = lock_addr(v);
+ s64 val;
+
+ local_irq_save(flags);
+ arch_spin_lock(lock);
+ val = v->counter;
+ if (val != u)
+ v->counter += a;
+ arch_spin_unlock(lock);
+ local_irq_restore(flags);
+
+ return val;
+}
+EXPORT_SYMBOL(generic_atomic64_fetch_add_unless);