Resguardo inicial

linux-7.2.3/lib/vdso/Kconfig

@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+
+config HAVE_GENERIC_VDSO
+	bool
+
+if HAVE_GENERIC_VDSO
+
+config GENERIC_GETTIMEOFDAY
+	bool
+	help
+	  This is a generic implementation of gettimeofday vdso.
+	  Each architecture that enables this feature has to
+	  provide the fallback implementation.
+
+config GENERIC_VDSO_OVERFLOW_PROTECT
+	bool
+	help
+	  Select to add multiplication overflow protection to the VDSO
+	  time getter functions for the price of an extra conditional
+	  in the hotpath.
+
+config VDSO_GETRANDOM
+	bool
+	help
+	  Selected by architectures that support vDSO getrandom().
+
+endif

linux-7.2.3/lib/vdso/Makefile

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_HAVE_GENERIC_VDSO) += datastore.o

linux-7.2.3/lib/vdso/Makefile.include

@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0
+
+GENERIC_VDSO_MK_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
+GENERIC_VDSO_DIR := $(dir $(GENERIC_VDSO_MK_PATH))
+
+c-gettimeofday-$(CONFIG_GENERIC_GETTIMEOFDAY) := $(addprefix $(GENERIC_VDSO_DIR), gettimeofday.c)
+c-getrandom-$(CONFIG_VDSO_GETRANDOM) := $(addprefix $(GENERIC_VDSO_DIR), getrandom.c)
+
+# This cmd checks that the vdso library does not contain dynamic relocations.
+# It has to be called after the linking of the vdso library and requires it
+# as a parameter.
+#
+# As a workaround for some GNU ld ports which produce unneeded R_*_NONE
+# dynamic relocations, ignore R_*_NONE.
+quiet_cmd_vdso_check = VDSOCHK $@
+      cmd_vdso_check = if $(READELF) -rW $@ | grep -v _NONE | grep -q " R_\w*_"; \
+		       then (echo >&2 "$@: dynamic relocations are not supported"; \
+			     rm -f $@; /bin/false); fi

linux-7.2.3/lib/vdso/datastore.c

@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/time_namespace.h>
+#include <linux/types.h>
+#include <linux/vdso_datastore.h>
+#include <vdso/datapage.h>
+
+static u8 vdso_initdata[VDSO_NR_PAGES * PAGE_SIZE] __aligned(PAGE_SIZE) __initdata = {};
+
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+struct vdso_time_data *vdso_k_time_data __ro_after_init =
+	(void *)&vdso_initdata[VDSO_TIME_PAGE_OFFSET * PAGE_SIZE];
+
+static_assert(sizeof(struct vdso_time_data) <= PAGE_SIZE);
+#endif /* CONFIG_GENERIC_GETTIMEOFDAY */
+
+#ifdef CONFIG_VDSO_GETRANDOM
+struct vdso_rng_data *vdso_k_rng_data __ro_after_init =
+	(void *)&vdso_initdata[VDSO_RNG_PAGE_OFFSET * PAGE_SIZE];
+
+static_assert(sizeof(struct vdso_rng_data) <= PAGE_SIZE);
+#endif /* CONFIG_VDSO_GETRANDOM */
+
+#ifdef CONFIG_ARCH_HAS_VDSO_ARCH_DATA
+struct vdso_arch_data *vdso_k_arch_data __ro_after_init =
+	(void *)&vdso_initdata[VDSO_ARCH_PAGES_START * PAGE_SIZE];
+#endif /* CONFIG_ARCH_HAS_VDSO_ARCH_DATA */
+
+void __init vdso_setup_data_pages(void)
+{
+	unsigned int order = get_order(VDSO_NR_PAGES * PAGE_SIZE);
+	struct page *pages;
+
+	/*
+	 * Allocate the data pages dynamically. SPARC does not support mapping
+	 * static pages to be mapped into userspace.
+	 * It is also a requirement for mlockall() support.
+	 *
+	 * Do not use folios. In time namespaces the pages are mapped in a different order
+	 * to userspace, which is not handled by the folio optimizations in finish_fault().
+	 */
+	pages = alloc_pages(GFP_KERNEL, order);
+	if (!pages)
+		panic("Unable to allocate VDSO storage pages");
+
+	/* The pages are mapped one-by-one into userspace and each one needs to be refcounted. */
+	split_page(pages, order);
+
+	/* Move the data already written by other subsystems to the new pages */
+	memcpy(page_address(pages), vdso_initdata, VDSO_NR_PAGES * PAGE_SIZE);
+
+	if (IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY))
+		vdso_k_time_data = page_address(pages + VDSO_TIME_PAGE_OFFSET);
+
+	if (IS_ENABLED(CONFIG_VDSO_GETRANDOM))
+		vdso_k_rng_data = page_address(pages + VDSO_RNG_PAGE_OFFSET);
+
+	if (IS_ENABLED(CONFIG_ARCH_HAS_VDSO_ARCH_DATA))
+		vdso_k_arch_data = page_address(pages + VDSO_ARCH_PAGES_START);
+}
+
+static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
+			     struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct page *page, *timens_page;
+
+	timens_page = find_timens_vvar_page(vma);
+
+	switch (vmf->pgoff) {
+	case VDSO_TIME_PAGE_OFFSET:
+		if (!IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY))
+			return VM_FAULT_SIGBUS;
+		page = virt_to_page(vdso_k_time_data);
+		if (timens_page) {
+			/*
+			 * Fault in VVAR page too, since it will be accessed
+			 * to get clock data anyway.
+			 */
+			unsigned long addr;
+			vm_fault_t err;
+
+			addr = vmf->address + VDSO_TIMENS_PAGE_OFFSET * PAGE_SIZE;
+			err = vmf_insert_page(vma, addr, page);
+			if (unlikely(err & VM_FAULT_ERROR))
+				return err;
+			page = timens_page;
+		}
+		break;
+	case VDSO_TIMENS_PAGE_OFFSET:
+		/*
+		 * If a task belongs to a time namespace then a namespace
+		 * specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and
+		 * the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET
+		 * offset.
+		 * See also the comment near timens_setup_vdso_data().
+		 */
+		if (!IS_ENABLED(CONFIG_TIME_NS) || !timens_page)
+			return VM_FAULT_SIGBUS;
+		page = virt_to_page(vdso_k_time_data);
+		break;
+	case VDSO_RNG_PAGE_OFFSET:
+		if (!IS_ENABLED(CONFIG_VDSO_GETRANDOM))
+			return VM_FAULT_SIGBUS;
+		page = virt_to_page(vdso_k_rng_data);
+		break;
+	case VDSO_ARCH_PAGES_START ... VDSO_ARCH_PAGES_END:
+		if (!IS_ENABLED(CONFIG_ARCH_HAS_VDSO_ARCH_DATA))
+			return VM_FAULT_SIGBUS;
+		page = virt_to_page(vdso_k_arch_data) + vmf->pgoff - VDSO_ARCH_PAGES_START;
+		break;
+	default:
+		return VM_FAULT_SIGBUS;
+	}
+
+	get_page(page);
+	vmf->page = page;
+	return 0;
+}
+
+const struct vm_special_mapping vdso_vvar_mapping = {
+	.name	= "[vvar]",
+	.fault	= vvar_fault,
+};
+
+struct vm_area_struct *vdso_install_vvar_mapping(struct mm_struct *mm, unsigned long addr)
+{
+	return _install_special_mapping(mm, addr, VDSO_NR_PAGES * PAGE_SIZE,
+					VM_READ | VM_MAYREAD | VM_IO | VM_DONTDUMP |
+					VM_MIXEDMAP | VM_SEALED_SYSMAP,
+					&vdso_vvar_mapping);
+}

linux-7.2.3/lib/vdso/getrandom.c

@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include <linux/array_size.h>
+#include <linux/minmax.h>
+#include <vdso/datapage.h>
+#include <vdso/getrandom.h>
+#include <vdso/limits.h>
+#include <vdso/unaligned.h>
+#include <asm/barrier.h>
+#include <asm/vdso/getrandom.h>
+#include <uapi/linux/errno.h>
+#include <uapi/linux/mman.h>
+#include <uapi/linux/random.h>
+
+/* Bring in default accessors */
+#include <vdso/vsyscall.h>
+
+#undef PAGE_SIZE
+#undef PAGE_MASK
+#define PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
+#define PAGE_MASK (~(PAGE_SIZE - 1))
+
+#define MEMCPY_AND_ZERO_SRC(type, dst, src, len) do {				\
+	while (len >= sizeof(type)) {						\
+		__put_unaligned_t(type, __get_unaligned_t(type, src), dst);	\
+		__put_unaligned_t(type, 0, src);				\
+		dst += sizeof(type);						\
+		src += sizeof(type);						\
+		len -= sizeof(type);						\
+	}									\
+} while (0)
+
+static void memcpy_and_zero_src(void *dst, void *src, size_t len)
+{
+	if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) {
+		if (IS_ENABLED(CONFIG_64BIT))
+			MEMCPY_AND_ZERO_SRC(u64, dst, src, len);
+		MEMCPY_AND_ZERO_SRC(u32, dst, src, len);
+		MEMCPY_AND_ZERO_SRC(u16, dst, src, len);
+	}
+	MEMCPY_AND_ZERO_SRC(u8, dst, src, len);
+}
+
+/**
+ * __cvdso_getrandom_data - Generic vDSO implementation of getrandom() syscall.
+ * @rng_info:		Describes state of kernel RNG, memory shared with kernel.
+ * @buffer:		Destination buffer to fill with random bytes.
+ * @len:		Size of @buffer in bytes.
+ * @flags:		Zero or more GRND_* flags.
+ * @opaque_state:	Pointer to an opaque state area.
+ * @opaque_len:		Length of opaque state area.
+ *
+ * This implements a "fast key erasure" RNG using ChaCha20, in the same way that the kernel's
+ * getrandom() syscall does. It periodically reseeds its key from the kernel's RNG, at the same
+ * schedule that the kernel's RNG is reseeded. If the kernel's RNG is not ready, then this always
+ * calls into the syscall.
+ *
+ * If @buffer, @len, and @flags are 0, and @opaque_len is ~0UL, then @opaque_state is populated
+ * with a struct vgetrandom_opaque_params and the function returns 0; if it does not return 0,
+ * this function should not be used.
+ *
+ * @opaque_state *must* be allocated by calling mmap(2) using the mmap_prot and mmap_flags fields
+ * from the struct vgetrandom_opaque_params, and states must not straddle pages. Unless external
+ * locking is used, one state must be allocated per thread, as it is not safe to call this function
+ * concurrently with the same @opaque_state. However, it is safe to call this using the same
+ * @opaque_state that is shared between main code and signal handling code, within the same thread.
+ *
+ * Returns:	The number of random bytes written to @buffer, or a negative value indicating an error.
+ */
+static __always_inline ssize_t
+__cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_t len,
+		       unsigned int flags, void *opaque_state, size_t opaque_len)
+{
+	ssize_t ret = min_t(size_t, INT_MAX & PAGE_MASK /* = MAX_RW_COUNT */, len);
+	struct vgetrandom_state *state = opaque_state;
+	size_t batch_len, nblocks, orig_len = len;
+	bool in_use, have_retried = false;
+	void *orig_buffer = buffer;
+	u64 current_generation;
+	u32 counter[2] = { 0 };
+
+	if (unlikely(opaque_len == ~0UL && !buffer && !len && !flags)) {
+		struct vgetrandom_opaque_params *params = opaque_state;
+		params->size_of_opaque_state = sizeof(*state);
+		params->mmap_prot = PROT_READ | PROT_WRITE;
+		params->mmap_flags = MAP_DROPPABLE | MAP_ANONYMOUS;
+		for (size_t i = 0; i < ARRAY_SIZE(params->reserved); ++i)
+			params->reserved[i] = 0;
+		return 0;
+	}
+
+	/* The state must not straddle a page, since pages can be zeroed at any time. */
+	if (unlikely(((unsigned long)opaque_state & ~PAGE_MASK) + sizeof(*state) > PAGE_SIZE))
+		return -EFAULT;
+
+	/* Handle unexpected flags by falling back to the kernel. */
+	if (unlikely(flags & ~(GRND_NONBLOCK | GRND_RANDOM | GRND_INSECURE)))
+		goto fallback_syscall;
+
+	/* If the caller passes the wrong size, which might happen due to CRIU, fallback. */
+	if (unlikely(opaque_len != sizeof(*state)))
+		goto fallback_syscall;
+
+	/*
+	 * If the kernel's RNG is not yet ready, then it's not possible to provide random bytes from
+	 * userspace, because A) the various @flags require this to block, or not, depending on
+	 * various factors unavailable to userspace, and B) the kernel's behavior before the RNG is
+	 * ready is to reseed from the entropy pool at every invocation.
+	 */
+	if (unlikely(!READ_ONCE(rng_info->is_ready)))
+		goto fallback_syscall;
+
+	/*
+	 * This condition is checked after @rng_info->is_ready, because before the kernel's RNG is
+	 * initialized, the @flags parameter may require this to block or return an error, even when
+	 * len is zero.
+	 */
+	if (unlikely(!len))
+		return 0;
+
+	/*
+	 * @state->in_use is basic reentrancy protection against this running in a signal handler
+	 * with the same @opaque_state, but obviously not atomic wrt multiple CPUs or more than one
+	 * level of reentrancy. If a signal interrupts this after reading @state->in_use, but before
+	 * writing @state->in_use, there is still no race, because the signal handler will run to
+	 * its completion before returning execution.
+	 */
+	in_use = READ_ONCE(state->in_use);
+	if (unlikely(in_use))
+		/* The syscall simply fills the buffer and does not touch @state, so fallback. */
+		goto fallback_syscall;
+	WRITE_ONCE(state->in_use, true);
+
+retry_generation:
+	/*
+	 * @rng_info->generation must always be read here, as it serializes @state->key with the
+	 * kernel's RNG reseeding schedule.
+	 */
+	current_generation = READ_ONCE(rng_info->generation);
+
+	/*
+	 * If @state->generation doesn't match the kernel RNG's generation, then it means the
+	 * kernel's RNG has reseeded, and so @state->key is reseeded as well.
+	 */
+	if (unlikely(state->generation != current_generation)) {
+		/*
+		 * Write the generation before filling the key, in case of fork. If there is a fork
+		 * just after this line, the parent and child will get different random bytes from
+		 * the syscall, which is good. However, were this line to occur after the getrandom
+		 * syscall, then both child and parent could have the same bytes and the same
+		 * generation counter, so the fork would not be detected. Therefore, write
+		 * @state->generation before the call to the getrandom syscall.
+		 */
+		WRITE_ONCE(state->generation, current_generation);
+
+		/*
+		 * Prevent the syscall from being reordered wrt current_generation. Pairs with the
+		 * smp_store_release(&vdso_k_rng_data->generation) in random.c.
+		 */
+		smp_rmb();
+
+		/* Reseed @state->key using fresh bytes from the kernel. */
+		if (getrandom_syscall(state->key, sizeof(state->key), 0) != sizeof(state->key)) {
+			/*
+			 * If the syscall failed to refresh the key, then @state->key is now
+			 * invalid, so invalidate the generation so that it is not used again, and
+			 * fallback to using the syscall entirely.
+			 */
+			WRITE_ONCE(state->generation, 0);
+
+			/*
+			 * Set @state->in_use to false only after the last write to @state in the
+			 * line above.
+			 */
+			WRITE_ONCE(state->in_use, false);
+
+			goto fallback_syscall;
+		}
+
+		/*
+		 * Set @state->pos to beyond the end of the batch, so that the batch is refilled
+		 * using the new key.
+		 */
+		state->pos = sizeof(state->batch);
+	}
+
+	/* Set len to the total amount of bytes that this function is allowed to read, ret. */
+	len = ret;
+more_batch:
+	/*
+	 * First use bytes out of @state->batch, which may have been filled by the last call to this
+	 * function.
+	 */
+	batch_len = min_t(size_t, sizeof(state->batch) - state->pos, len);
+	if (batch_len) {
+		/* Zeroing at the same time as memcpying helps preserve forward secrecy. */
+		memcpy_and_zero_src(buffer, state->batch + state->pos, batch_len);
+		state->pos += batch_len;
+		buffer += batch_len;
+		len -= batch_len;
+	}
+
+	if (!len) {
+		/* Prevent the loop from being reordered wrt ->generation. */
+		barrier();
+
+		/*
+		 * Since @rng_info->generation will never be 0, re-read @state->generation, rather
+		 * than using the local current_generation variable, to learn whether a fork
+		 * occurred or if @state was zeroed due to memory pressure. Primarily, though, this
+		 * indicates whether the kernel's RNG has reseeded, in which case generate a new key
+		 * and start over.
+		 */
+		if (unlikely(READ_ONCE(state->generation) != READ_ONCE(rng_info->generation))) {
+			/*
+			 * Prevent this from looping forever in case of low memory or racing with a
+			 * user force-reseeding the kernel's RNG using the ioctl.
+			 */
+			if (have_retried) {
+				WRITE_ONCE(state->in_use, false);
+				goto fallback_syscall;
+			}
+
+			have_retried = true;
+			buffer = orig_buffer;
+			goto retry_generation;
+		}
+
+		/*
+		 * Set @state->in_use to false only when there will be no more reads or writes of
+		 * @state.
+		 */
+		WRITE_ONCE(state->in_use, false);
+		return ret;
+	}
+
+	/* Generate blocks of RNG output directly into @buffer while there's enough room left. */
+	nblocks = len / CHACHA_BLOCK_SIZE;
+	if (nblocks) {
+		__arch_chacha20_blocks_nostack(buffer, state->key, counter, nblocks);
+		buffer += nblocks * CHACHA_BLOCK_SIZE;
+		len -= nblocks * CHACHA_BLOCK_SIZE;
+	}
+
+	BUILD_BUG_ON(sizeof(state->batch_key) % CHACHA_BLOCK_SIZE != 0);
+
+	/* Refill the batch and overwrite the key, in order to preserve forward secrecy. */
+	__arch_chacha20_blocks_nostack(state->batch_key, state->key, counter,
+				       sizeof(state->batch_key) / CHACHA_BLOCK_SIZE);
+
+	/* Since the batch was just refilled, set the position back to 0 to indicate a full batch. */
+	state->pos = 0;
+	goto more_batch;
+
+fallback_syscall:
+	return getrandom_syscall(orig_buffer, orig_len, flags);
+}
+
+static __always_inline ssize_t
+__cvdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len)
+{
+	return __cvdso_getrandom_data(__arch_get_vdso_u_rng_data(), buffer, len, flags,
+				      opaque_state, opaque_len);
+}

linux-7.2.3/lib/vdso/gettimeofday.c

@@ -0,0 +1,493 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic userspace implementations of gettimeofday() and similar.
+ */
+#include <vdso/auxclock.h>
+#include <vdso/clocksource.h>
+#include <vdso/datapage.h>
+#include <vdso/helpers.h>
+#include <vdso/ktime.h>
+#include <vdso/limits.h>
+#include <vdso/math64.h>
+#include <vdso/time32.h>
+#include <vdso/time64.h>
+
+/*
+ * The generic vDSO implementation requires that gettimeofday.h
+ * provides:
+ * - __arch_get_hw_counter(): to get the hw counter based on the
+ *   clock_mode.
+ * - gettimeofday_fallback(): fallback for gettimeofday.
+ * - clock_gettime_fallback(): fallback for clock_gettime.
+ * - clock_getres_fallback(): fallback for clock_getres.
+ */
+#include <asm/vdso/gettimeofday.h>
+
+/* Bring in default accessors */
+#include <vdso/vsyscall.h>
+
+#ifndef vdso_calc_ns
+
+#ifdef VDSO_DELTA_NOMASK
+# define VDSO_DELTA_MASK(vd)	ULLONG_MAX
+#else
+# define VDSO_DELTA_MASK(vd)	(vd->mask)
+#endif
+
+#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT
+static __always_inline bool vdso_delta_ok(const struct vdso_clock *vc, u64 delta)
+{
+	return delta < vc->max_cycles;
+}
+#else
+static __always_inline bool vdso_delta_ok(const struct vdso_clock *vc, u64 delta)
+{
+	return true;
+}
+#endif
+
+#ifndef vdso_shift_ns
+static __always_inline u64 vdso_shift_ns(u64 ns, u32 shift)
+{
+	return ns >> shift;
+}
+#endif
+
+/*
+ * Default implementation which works for all sane clocksources. That
+ * obviously excludes x86/TSC.
+ */
+static __always_inline u64 vdso_calc_ns(const struct vdso_clock *vc, u64 cycles, u64 base)
+{
+	u64 delta = (cycles - vc->cycle_last) & VDSO_DELTA_MASK(vc);
+
+	if (likely(vdso_delta_ok(vc, delta)))
+		return vdso_shift_ns((delta * vc->mult) + base, vc->shift);
+
+	return mul_u64_u32_add_u64_shr(delta, vc->mult, base, vc->shift);
+}
+#endif /* vdso_calc_ns */
+
+#ifndef __arch_vdso_hres_capable
+static inline bool __arch_vdso_hres_capable(void)
+{
+	return true;
+}
+#endif
+
+#ifndef vdso_clocksource_ok
+static inline bool vdso_clocksource_ok(const struct vdso_clock *vc)
+{
+	return vc->clock_mode != VDSO_CLOCKMODE_NONE;
+}
+#endif
+
+#ifndef vdso_cycles_ok
+static inline bool vdso_cycles_ok(u64 cycles)
+{
+	return true;
+}
+#endif
+
+static __always_inline bool vdso_clockid_valid(clockid_t clock)
+{
+	/* Check for negative values or invalid clocks */
+	return likely((u32) clock <= CLOCK_AUX_LAST);
+}
+
+/*
+ * Must not be invoked within the sequence read section as a race inside
+ * that loop could result in __iter_div_u64_rem() being extremely slow.
+ */
+static __always_inline void vdso_set_timespec(struct __kernel_timespec *ts, u64 sec, u64 ns)
+{
+	ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+	ts->tv_nsec = ns;
+}
+
+static __always_inline
+bool vdso_get_timestamp(const struct vdso_time_data *vd, const struct vdso_clock *vc,
+			unsigned int clkidx, u64 *sec, u64 *ns)
+{
+	const struct vdso_timestamp *vdso_ts = &vc->basetime[clkidx];
+	u64 cycles;
+
+	if (unlikely(!vdso_clocksource_ok(vc)))
+		return false;
+
+	cycles = __arch_get_hw_counter(vc->clock_mode, vd);
+	if (unlikely(!vdso_cycles_ok(cycles)))
+		return false;
+
+	*ns = vdso_calc_ns(vc, cycles, vdso_ts->nsec);
+	*sec = vdso_ts->sec;
+
+	return true;
+}
+
+static __always_inline
+const struct vdso_time_data *vdso_timens_data(const struct vdso_time_data *vd)
+{
+	return (void *)vd + PAGE_SIZE;
+}
+
+static __always_inline
+bool do_hres_timens(const struct vdso_time_data *vdns, const struct vdso_clock *vcns,
+		    clockid_t clk, struct __kernel_timespec *ts)
+{
+	const struct vdso_time_data *vd = vdso_timens_data(vdns);
+	const struct timens_offset *offs = &vcns->offset[clk];
+	const struct vdso_clock *vc = vd->clock_data;
+	u32 seq;
+	s64 sec;
+	u64 ns;
+
+	if (clk != CLOCK_MONOTONIC_RAW)
+		vc = &vc[CS_HRES_COARSE];
+	else
+		vc = &vc[CS_RAW];
+
+	do {
+		seq = vdso_read_begin(vc);
+
+		if (!vdso_get_timestamp(vd, vc, clk, &sec, &ns))
+			return false;
+	} while (vdso_read_retry(vc, seq));
+
+	/* Add the namespace offset */
+	sec += offs->sec;
+	ns += offs->nsec;
+
+	vdso_set_timespec(ts, sec, ns);
+
+	return true;
+}
+
+static __always_inline
+bool do_hres(const struct vdso_time_data *vd, const struct vdso_clock *vc,
+	     clockid_t clk, struct __kernel_timespec *ts)
+{
+	u64 sec, ns;
+	u32 seq;
+
+	/* Allows to compile the high resolution parts out */
+	if (!__arch_vdso_hres_capable())
+		return false;
+
+	do {
+		if (vdso_read_begin_timens(vc, &seq))
+			return do_hres_timens(vd, vc, clk, ts);
+
+		if (!vdso_get_timestamp(vd, vc, clk, &sec, &ns))
+			return false;
+	} while (vdso_read_retry(vc, seq));
+
+	vdso_set_timespec(ts, sec, ns);
+
+	return true;
+}
+
+static __always_inline
+bool do_coarse_timens(const struct vdso_time_data *vdns, const struct vdso_clock *vcns,
+		      clockid_t clk, struct __kernel_timespec *ts)
+{
+	const struct vdso_time_data *vd = vdso_timens_data(vdns);
+	const struct timens_offset *offs = &vcns->offset[clk];
+	const struct vdso_clock *vc = vd->clock_data;
+	const struct vdso_timestamp *vdso_ts;
+	u64 nsec;
+	s64 sec;
+	s32 seq;
+
+	vdso_ts = &vc->basetime[clk];
+
+	do {
+		seq = vdso_read_begin(vc);
+		sec = vdso_ts->sec;
+		nsec = vdso_ts->nsec;
+	} while (vdso_read_retry(vc, seq));
+
+	/* Add the namespace offset */
+	sec += offs->sec;
+	nsec += offs->nsec;
+
+	vdso_set_timespec(ts, sec, nsec);
+
+	return true;
+}
+
+static __always_inline
+bool do_coarse(const struct vdso_time_data *vd, const struct vdso_clock *vc,
+	       clockid_t clk, struct __kernel_timespec *ts)
+{
+	const struct vdso_timestamp *vdso_ts = &vc->basetime[clk];
+	u32 seq;
+
+	do {
+		if (vdso_read_begin_timens(vc, &seq))
+			return do_coarse_timens(vd, vc, clk, ts);
+
+		ts->tv_sec = vdso_ts->sec;
+		ts->tv_nsec = vdso_ts->nsec;
+	} while (vdso_read_retry(vc, seq));
+
+	return true;
+}
+
+static __always_inline
+bool do_aux(const struct vdso_time_data *vd, clockid_t clock, struct __kernel_timespec *ts)
+{
+	const struct vdso_clock *vc;
+	u32 seq, idx;
+	u64 sec, ns;
+
+	if (!IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS))
+		return false;
+
+	idx = clock - CLOCK_AUX;
+	vc = &vd->aux_clock_data[idx];
+
+	do {
+		while (vdso_read_begin_timens(vc, &seq)) {
+			/* Re-read from the real time data page, reload seq by looping */
+			vd = vdso_timens_data(vd);
+			vc = &vd->aux_clock_data[idx];
+		}
+
+		/* Auxclock disabled? */
+		if (vc->clock_mode == VDSO_CLOCKMODE_NONE)
+			return false;
+
+		if (!vdso_get_timestamp(vd, vc, VDSO_BASE_AUX, &sec, &ns))
+			return false;
+	} while (vdso_read_retry(vc, seq));
+
+	vdso_set_timespec(ts, sec, ns);
+
+	return true;
+}
+
+static __always_inline bool
+__cvdso_clock_gettime_common(const struct vdso_time_data *vd, clockid_t clock,
+			     struct __kernel_timespec *ts)
+{
+	const struct vdso_clock *vc = vd->clock_data;
+	u32 msk;
+
+	if (!vdso_clockid_valid(clock))
+		return false;
+
+	/*
+	 * Convert the clockid to a bitmask and use it to check which
+	 * clocks are handled in the VDSO directly.
+	 */
+	msk = 1U << clock;
+	if (likely(msk & VDSO_HRES))
+		vc = &vc[CS_HRES_COARSE];
+	else if (msk & VDSO_COARSE)
+		return do_coarse(vd, &vc[CS_HRES_COARSE], clock, ts);
+	else if (msk & VDSO_RAW)
+		vc = &vc[CS_RAW];
+	else if (msk & VDSO_AUX)
+		return do_aux(vd, clock, ts);
+	else
+		return false;
+
+	return do_hres(vd, vc, clock, ts);
+}
+
+static int
+__cvdso_clock_gettime_data(const struct vdso_time_data *vd, clockid_t clock,
+			   struct __kernel_timespec *ts)
+{
+	bool ok;
+
+	ok = __cvdso_clock_gettime_common(vd, clock, ts);
+
+	if (unlikely(!ok))
+		return clock_gettime_fallback(clock, ts);
+	return 0;
+}
+
+static __maybe_unused int
+__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
+{
+	return __cvdso_clock_gettime_data(__arch_get_vdso_u_time_data(), clock, ts);
+}
+
+#ifdef BUILD_VDSO32
+static int
+__cvdso_clock_gettime32_data(const struct vdso_time_data *vd, clockid_t clock,
+			     struct old_timespec32 *res)
+{
+	struct __kernel_timespec ts;
+	bool ok;
+
+	ok = __cvdso_clock_gettime_common(vd, clock, &ts);
+
+	if (unlikely(!ok))
+		return clock_gettime32_fallback(clock, res);
+
+	/* For ok == true */
+	res->tv_sec = ts.tv_sec;
+	res->tv_nsec = ts.tv_nsec;
+
+	return 0;
+}
+
+static __maybe_unused int
+__cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
+{
+	return __cvdso_clock_gettime32_data(__arch_get_vdso_u_time_data(), clock, res);
+}
+#endif /* BUILD_VDSO32 */
+
+static int
+__cvdso_gettimeofday_data(const struct vdso_time_data *vd,
+			  struct __kernel_old_timeval *tv, struct timezone *tz)
+{
+	const struct vdso_clock *vc = vd->clock_data;
+
+	if (likely(tv != NULL)) {
+		struct __kernel_timespec ts;
+
+		if (!do_hres(vd, &vc[CS_HRES_COARSE], CLOCK_REALTIME, &ts))
+			return gettimeofday_fallback(tv, tz);
+
+		tv->tv_sec = ts.tv_sec;
+		tv->tv_usec = (u32)ts.tv_nsec / NSEC_PER_USEC;
+	}
+
+	if (unlikely(tz != NULL)) {
+		if (vdso_is_timens_clock(vc))
+			vd = vdso_timens_data(vd);
+
+		tz->tz_minuteswest = vd[CS_HRES_COARSE].tz_minuteswest;
+		tz->tz_dsttime = vd[CS_HRES_COARSE].tz_dsttime;
+	}
+
+	return 0;
+}
+
+static __maybe_unused int
+__cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
+{
+	return __cvdso_gettimeofday_data(__arch_get_vdso_u_time_data(), tv, tz);
+}
+
+#ifdef VDSO_HAS_TIME
+static __kernel_old_time_t
+__cvdso_time_data(const struct vdso_time_data *vd, __kernel_old_time_t *time)
+{
+	const struct vdso_clock *vc = vd->clock_data;
+	__kernel_old_time_t t;
+
+	if (vdso_is_timens_clock(vc)) {
+		vd = vdso_timens_data(vd);
+		vc = vd->clock_data;
+	}
+
+	t = READ_ONCE(vc[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec);
+
+	if (time)
+		*time = t;
+
+	return t;
+}
+
+static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time)
+{
+	return __cvdso_time_data(__arch_get_vdso_u_time_data(), time);
+}
+#endif /* VDSO_HAS_TIME */
+
+#ifdef VDSO_HAS_CLOCK_GETRES
+static __always_inline
+bool __cvdso_clock_getres_common(const struct vdso_time_data *vd, clockid_t clock,
+				 struct __kernel_timespec *res)
+{
+	const struct vdso_clock *vc = vd->clock_data;
+	u32 msk;
+	u64 ns;
+
+	if (!vdso_clockid_valid(clock))
+		return false;
+
+	if (vdso_is_timens_clock(vc))
+		vd = vdso_timens_data(vd);
+
+	/*
+	 * Convert the clockid to a bitmask and use it to check which
+	 * clocks are handled in the VDSO directly.
+	 */
+	msk = 1U << clock;
+	if (msk & (VDSO_HRES | VDSO_RAW)) {
+		/*
+		 * Preserves the behaviour of posix_get_hrtimer_res().
+		 */
+		ns = READ_ONCE(vd->hrtimer_res);
+	} else if (msk & VDSO_COARSE) {
+		/*
+		 * Preserves the behaviour of posix_get_coarse_res().
+		 */
+		ns = LOW_RES_NSEC;
+	} else if (msk & VDSO_AUX) {
+		ns = aux_clock_resolution_ns();
+	} else {
+		return false;
+	}
+
+	if (likely(res)) {
+		res->tv_sec = 0;
+		res->tv_nsec = ns;
+	}
+	return true;
+}
+
+static
+int __cvdso_clock_getres_data(const struct vdso_time_data *vd, clockid_t clock,
+			      struct __kernel_timespec *res)
+{
+	bool ok;
+
+	ok =  __cvdso_clock_getres_common(vd, clock, res);
+
+	if (unlikely(!ok))
+		return clock_getres_fallback(clock, res);
+	return 0;
+}
+
+static __maybe_unused
+int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
+{
+	return __cvdso_clock_getres_data(__arch_get_vdso_u_time_data(), clock, res);
+}
+
+#ifdef BUILD_VDSO32
+static int
+__cvdso_clock_getres_time32_data(const struct vdso_time_data *vd, clockid_t clock,
+				 struct old_timespec32 *res)
+{
+	struct __kernel_timespec ts;
+	bool ok;
+
+	ok = __cvdso_clock_getres_common(vd, clock, &ts);
+
+	if (unlikely(!ok))
+		return clock_getres32_fallback(clock, res);
+
+	if (likely(res)) {
+		res->tv_sec = ts.tv_sec;
+		res->tv_nsec = ts.tv_nsec;
+	}
+	return 0;
+}
+
+static __maybe_unused int
+__cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
+{
+	return __cvdso_clock_getres_time32_data(__arch_get_vdso_u_time_data(),
+						clock, res);
+}
+#endif /* BUILD_VDSO32 */
+#endif /* VDSO_HAS_CLOCK_GETRES */