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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 /include/vdso/helpers.h
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 'include/vdso/helpers.h')
-rw-r--r--include/vdso/helpers.h116
1 files changed, 116 insertions, 0 deletions
diff --git a/include/vdso/helpers.h b/include/vdso/helpers.h
new file mode 100644
index 000000000..65151b681
--- /dev/null
+++ b/include/vdso/helpers.h
@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_HELPERS_H
+#define __VDSO_HELPERS_H
+
+#ifndef __ASSEMBLER__
+
+#include <asm/barrier.h>
+#include <vdso/datapage.h>
+#include <vdso/processor.h>
+#include <vdso/clocksource.h>
+
+static __always_inline bool vdso_is_timens_clock(const struct vdso_clock *vc)
+{
+ return IS_ENABLED(CONFIG_TIME_NS) && vc->clock_mode == VDSO_CLOCKMODE_TIMENS;
+}
+
+static __always_inline u32 vdso_read_begin(const struct vdso_clock *vc)
+{
+ u32 seq;
+
+ while (unlikely((seq = READ_ONCE(vc->seq)) & 1))
+ cpu_relax();
+
+ smp_rmb();
+ return seq;
+}
+
+/*
+ * Variant of vdso_read_begin() to handle VDSO_CLOCKMODE_TIMENS.
+ *
+ * Time namespace enabled tasks have a special VVAR page installed which has
+ * vc->seq set to 1 and vc->clock_mode set to VDSO_CLOCKMODE_TIMENS. For non
+ * time namespace affected tasks this does not affect performance because if
+ * vc->seq is odd, i.e. a concurrent update is in progress the extra check for
+ * vc->clock_mode is just a few extra instructions while spin waiting for
+ * vc->seq to become even again.
+ */
+static __always_inline bool vdso_read_begin_timens(const struct vdso_clock *vc, u32 *seq)
+{
+ while (unlikely((*seq = READ_ONCE(vc->seq)) & 1)) {
+ if (vdso_is_timens_clock(vc))
+ return true;
+ cpu_relax();
+ }
+ smp_rmb();
+
+ return false;
+}
+
+static __always_inline u32 vdso_read_retry(const struct vdso_clock *vc,
+ u32 start)
+{
+ u32 seq;
+
+ smp_rmb();
+ seq = READ_ONCE(vc->seq);
+ return unlikely(seq != start);
+}
+
+static __always_inline void vdso_write_seq_begin(struct vdso_clock *vc)
+{
+ /*
+ * WRITE_ONCE() is required otherwise the compiler can validly tear
+ * updates to vc->seq and it is possible that the value seen by the
+ * reader is inconsistent.
+ */
+ WRITE_ONCE(vc->seq, vc->seq + 1);
+}
+
+static __always_inline void vdso_write_seq_end(struct vdso_clock *vc)
+{
+ /*
+ * WRITE_ONCE() is required otherwise the compiler can validly tear
+ * updates to vc->seq and it is possible that the value seen by the
+ * reader is inconsistent.
+ */
+ WRITE_ONCE(vc->seq, vc->seq + 1);
+}
+
+static __always_inline void vdso_write_begin_clock(struct vdso_clock *vc)
+{
+ vdso_write_seq_begin(vc);
+ /* Ensure the sequence invalidation is visible before data is modified */
+ smp_wmb();
+}
+
+static __always_inline void vdso_write_end_clock(struct vdso_clock *vc)
+{
+ /* Ensure the data update is visible before the sequence is set valid again */
+ smp_wmb();
+ vdso_write_seq_end(vc);
+}
+
+static __always_inline void vdso_write_begin(struct vdso_time_data *vd)
+{
+ struct vdso_clock *vc = vd->clock_data;
+
+ vdso_write_seq_begin(&vc[CS_HRES_COARSE]);
+ vdso_write_seq_begin(&vc[CS_RAW]);
+ /* Ensure the sequence invalidation is visible before data is modified */
+ smp_wmb();
+}
+
+static __always_inline void vdso_write_end(struct vdso_time_data *vd)
+{
+ struct vdso_clock *vc = vd->clock_data;
+
+ /* Ensure the data update is visible before the sequence is set valid again */
+ smp_wmb();
+ vdso_write_seq_end(&vc[CS_HRES_COARSE]);
+ vdso_write_seq_end(&vc[CS_RAW]);
+}
+
+#endif /* !__ASSEMBLER__ */
+
+#endif /* __VDSO_HELPERS_H */