@@ -4,12 +4,28 @@
#ifndef __ASSEMBLY__
+#ifdef CONFIG_GENERIC_VDSO_DATA_STORE
+
+#ifndef __arch_get_vdso_u_time_data
+static __always_inline const struct vdso_time_data *__arch_get_vdso_u_time_data(void)
+{
+ return vdso_u_time_data;
+}
+#endif
+
+#else /* !CONFIG_GENERIC_VDSO_DATA_STORE */
+
#ifndef __arch_get_k_vdso_data
static __always_inline struct vdso_data *__arch_get_k_vdso_data(void)
{
return NULL;
}
#endif /* __arch_get_k_vdso_data */
+#define vdso_k_time_data __arch_get_k_vdso_data()
+
+#define __arch_get_vdso_u_time_data __arch_get_vdso_data
+
+#endif /* CONFIG_GENERIC_VDSO_DATA_STORE */
#ifndef __arch_update_vsyscall
static __always_inline void __arch_update_vsyscall(struct vdso_data *vdata)
@@ -8,6 +8,7 @@
#include <linux/ns_common.h>
#include <linux/err.h>
#include <linux/time64.h>
+#include <vdso/datapage.h>
struct user_namespace;
extern struct user_namespace init_user_ns;
new file mode 100644
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_VDSO_DATASTORE_H
+#define _LINUX_VDSO_DATASTORE_H
+
+#include <linux/mm_types.h>
+
+extern const struct vm_special_mapping vdso_vvar_mapping;
+struct vm_area_struct *vdso_install_vvar_mapping(struct mm_struct *mm, unsigned long addr);
+
+#endif /* _LINUX_VDSO_DATASTORE_H */
@@ -45,11 +45,11 @@ struct arch_vdso_time_data {};
*
* There is one vdso_timestamp object in vvar for each vDSO-accelerated
* clock_id. For high-resolution clocks, this encodes the time
- * corresponding to vdso_data.cycle_last. For coarse clocks this encodes
+ * corresponding to vdso_time_data.cycle_last. For coarse clocks this encodes
* the actual time.
*
* To be noticed that for highres clocks nsec is left-shifted by
- * vdso_data.cs[x].shift.
+ * vdso_time_data[x].shift.
*/
struct vdso_timestamp {
u64 sec;
@@ -57,7 +57,7 @@ struct vdso_timestamp {
};
/**
- * struct vdso_data - vdso datapage representation
+ * struct vdso_time_data - vdso datapage representation
* @seq: timebase sequence counter
* @clock_mode: clock mode
* @cycle_last: timebase at clocksource init
@@ -74,7 +74,7 @@ struct vdso_timestamp {
* @arch_data: architecture specific data (optional, defaults
* to an empty struct)
*
- * vdso_data will be accessed by 64 bit and compat code at the same time
+ * vdso_time_data will be accessed by 64 bit and compat code at the same time
* so we should be careful before modifying this structure.
*
* The ordering of the struct members is optimized to have fast access to the
@@ -92,7 +92,7 @@ struct vdso_timestamp {
* For clocks which are not affected by time namespace adjustment the
* offset must be zero.
*/
-struct vdso_data {
+struct vdso_time_data {
u32 seq;
s32 clock_mode;
@@ -117,6 +117,8 @@ struct vdso_data {
struct arch_vdso_time_data arch_data;
};
+#define vdso_data vdso_time_data
+
/**
* struct vdso_rng_data - vdso RNG state information
* @generation: counter representing the number of RNG reseeds
@@ -136,18 +138,34 @@ struct vdso_rng_data {
* With the hidden visibility, the compiler simply generates a PC-relative
* relocation, and this is what we need.
*/
-extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));
-extern struct vdso_data _timens_data[CS_BASES] __attribute__((visibility("hidden")));
+#ifndef CONFIG_GENERIC_VDSO_DATA_STORE
+extern struct vdso_time_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));
+extern struct vdso_time_data _timens_data[CS_BASES] __attribute__((visibility("hidden")));
extern struct vdso_rng_data _vdso_rng_data __attribute__((visibility("hidden")));
+#else
+extern struct vdso_time_data vdso_u_time_data[CS_BASES] __attribute__((visibility("hidden")));
+
+extern struct vdso_time_data *vdso_k_time_data;
+#endif
/**
* union vdso_data_store - Generic vDSO data page
*/
union vdso_data_store {
- struct vdso_data data[CS_BASES];
+ struct vdso_time_data data[CS_BASES];
u8 page[1U << CONFIG_PAGE_SHIFT];
};
+#ifdef CONFIG_GENERIC_VDSO_DATA_STORE
+
+enum vdso_pages {
+ VDSO_TIME_PAGE_OFFSET,
+ VDSO_TIMENS_PAGE_OFFSET,
+ VDSO_NR_PAGES
+};
+
+#endif /* CONFIG_GENERIC_VDSO_DATA_STORE */
+
/*
* The generic vDSO implementation requires that gettimeofday.h
* provides:
@@ -164,6 +182,13 @@ union vdso_data_store {
#include <asm/vdso/gettimeofday.h>
#endif /* ENABLE_COMPAT_VDSO */
+#else /* !__ASSEMBLY__ */
+
+#define VDSO_VVAR_SYMS \
+ PROVIDE(vdso_u_data = . - __VDSO_PAGES * PAGE_SIZE); \
+ PROVIDE(vdso_u_time_data = vdso_u_data); \
+
+
#endif /* !__ASSEMBLY__ */
#endif /* __VDSO_DATAPAGE_H */
@@ -77,7 +77,7 @@ static inline void update_vdso_data(struct vdso_data *vdata,
void update_vsyscall(struct timekeeper *tk)
{
- struct vdso_data *vdata = __arch_get_k_vdso_data();
+ struct vdso_data *vdata = vdso_k_time_data;
struct vdso_timestamp *vdso_ts;
s32 clock_mode;
u64 nsec;
@@ -128,7 +128,7 @@ void update_vsyscall(struct timekeeper *tk)
void update_vsyscall_tz(void)
{
- struct vdso_data *vdata = __arch_get_k_vdso_data();
+ struct vdso_data *vdata = vdso_k_time_data;
vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest;
vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
@@ -150,7 +150,7 @@ void update_vsyscall_tz(void)
*/
unsigned long vdso_update_begin(void)
{
- struct vdso_data *vdata = __arch_get_k_vdso_data();
+ struct vdso_data *vdata = vdso_k_time_data;
unsigned long flags = timekeeper_lock_irqsave();
vdso_write_begin(vdata);
@@ -167,7 +167,7 @@ unsigned long vdso_update_begin(void)
*/
void vdso_update_end(unsigned long flags)
{
- struct vdso_data *vdata = __arch_get_k_vdso_data();
+ struct vdso_data *vdata = vdso_k_time_data;
vdso_write_end(vdata);
__arch_sync_vdso_data(vdata);
@@ -132,7 +132,7 @@ endif
obj-$(CONFIG_DEBUG_INFO_REDUCED) += debug_info.o
CFLAGS_debug_info.o += $(call cc-option, -femit-struct-debug-detailed=any)
-obj-y += math/ crypto/
+obj-y += math/ crypto/ vdso/
obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
@@ -43,3 +43,8 @@ config VDSO_GETRANDOM
bool
help
Selected by architectures that support vDSO getrandom().
+
+config GENERIC_VDSO_DATA_STORE
+ bool
+ help
+ Selected by architectures that use the generic vDSO data store.
new file mode 100644
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_GENERIC_VDSO_DATA_STORE) += datastore.o
new file mode 100644
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/linkage.h>
+#include <linux/mmap_lock.h>
+#include <linux/mm.h>
+#include <linux/time_namespace.h>
+#include <linux/types.h>
+#include <linux/vdso_datastore.h>
+#include <vdso/datapage.h>
+
+/*
+ * The vDSO data page.
+ */
+#ifdef CONFIG_HAVE_GENERIC_VDSO
+static union vdso_data_store vdso_time_data_store __page_aligned_data;
+struct vdso_time_data *vdso_k_time_data = vdso_time_data_store.data;
+static_assert(sizeof(vdso_time_data_store) == PAGE_SIZE);
+#endif /* CONFIG_HAVE_GENERIC_VDSO */
+
+static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
+ struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct page *timens_page = find_timens_vvar_page(vma);
+ unsigned long addr, pfn;
+ vm_fault_t err;
+
+ switch (vmf->pgoff) {
+ case VDSO_TIME_PAGE_OFFSET:
+ if (!IS_ENABLED(CONFIG_HAVE_GENERIC_VDSO))
+ return VM_FAULT_SIGBUS;
+ pfn = __phys_to_pfn(__pa_symbol(vdso_k_time_data));
+ if (timens_page) {
+ /*
+ * Fault in VVAR page too, since it will be accessed
+ * to get clock data anyway.
+ */
+ addr = vmf->address + VDSO_TIMENS_PAGE_OFFSET * PAGE_SIZE;
+ err = vmf_insert_pfn(vma, addr, pfn);
+ if (unlikely(err & VM_FAULT_ERROR))
+ return err;
+ pfn = page_to_pfn(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;
+ pfn = __phys_to_pfn(__pa_symbol(vdso_k_time_data));
+ break;
+ default:
+ return VM_FAULT_SIGBUS;
+ }
+
+ return vmf_insert_pfn(vma, vmf->address, pfn);
+}
+
+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_PFNMAP,
+ &vdso_vvar_mapping);
+}
+
+#ifdef CONFIG_TIME_NS
+/*
+ * The vvar page layout depends on whether a task belongs to the root or
+ * non-root time namespace. Whenever a task changes its namespace, the VVAR
+ * page tables are cleared and then they will be re-faulted with a
+ * corresponding layout.
+ * See also the comment near timens_setup_vdso_data() for details.
+ */
+int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
+{
+ struct mm_struct *mm = task->mm;
+ struct vm_area_struct *vma;
+ VMA_ITERATOR(vmi, mm, 0);
+
+ mmap_read_lock(mm);
+ for_each_vma(vmi, vma) {
+ if (vma_is_special_mapping(vma, &vdso_vvar_mapping))
+ zap_vma_pages(vma);
+ }
+ mmap_read_unlock(mm);
+
+ return 0;
+}
+
+struct vdso_time_data *arch_get_vdso_data(void *vvar_page)
+{
+ return (struct vdso_time_data *)vvar_page;
+}
+#endif
@@ -5,6 +5,9 @@
#include <vdso/datapage.h>
#include <vdso/helpers.h>
+/* Bring in default accessors */
+#include <vdso/vsyscall.h>
+
#ifndef vdso_calc_ns
#ifdef VDSO_DELTA_NOMASK
@@ -69,6 +72,16 @@ static inline bool vdso_cycles_ok(u64 cycles)
#endif
#ifdef CONFIG_TIME_NS
+
+#ifdef CONFIG_GENERIC_VDSO_DATA_STORE
+static __always_inline
+const struct vdso_time_data *__arch_get_vdso_u_timens_data(const struct vdso_time_data *vd)
+{
+ return (void *)vd + PAGE_SIZE;
+}
+#define __arch_get_timens_vdso_data(vd) __arch_get_vdso_u_timens_data(vd)
+#endif /* CONFIG_GENERIC_VDSO_DATA_STORE */
+
static __always_inline int do_hres_timens(const struct vdso_data *vdns, clockid_t clk,
struct __kernel_timespec *ts)
{
@@ -282,7 +295,7 @@ __cvdso_clock_gettime_data(const struct vdso_data *vd, clockid_t clock,
static __maybe_unused int
__cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
{
- return __cvdso_clock_gettime_data(__arch_get_vdso_data(), clock, ts);
+ return __cvdso_clock_gettime_data(__arch_get_vdso_u_time_data(), clock, ts);
}
#ifdef BUILD_VDSO32
@@ -308,7 +321,7 @@ __cvdso_clock_gettime32_data(const struct vdso_data *vd, clockid_t clock,
static __maybe_unused int
__cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res)
{
- return __cvdso_clock_gettime32_data(__arch_get_vdso_data(), clock, res);
+ return __cvdso_clock_gettime32_data(__arch_get_vdso_u_time_data(), clock, res);
}
#endif /* BUILD_VDSO32 */
@@ -342,7 +355,7 @@ __cvdso_gettimeofday_data(const struct vdso_data *vd,
static __maybe_unused int
__cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
{
- return __cvdso_gettimeofday_data(__arch_get_vdso_data(), tv, tz);
+ return __cvdso_gettimeofday_data(__arch_get_vdso_u_time_data(), tv, tz);
}
#ifdef VDSO_HAS_TIME
@@ -365,7 +378,7 @@ __cvdso_time_data(const struct vdso_data *vd, __kernel_old_time_t *time)
static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time)
{
- return __cvdso_time_data(__arch_get_vdso_data(), time);
+ return __cvdso_time_data(__arch_get_vdso_u_time_data(), time);
}
#endif /* VDSO_HAS_TIME */
@@ -425,7 +438,7 @@ int __cvdso_clock_getres_data(const struct vdso_data *vd, clockid_t clock,
static __maybe_unused
int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
{
- return __cvdso_clock_getres_data(__arch_get_vdso_data(), clock, res);
+ return __cvdso_clock_getres_data(__arch_get_vdso_u_time_data(), clock, res);
}
#ifdef BUILD_VDSO32
@@ -451,7 +464,7 @@ __cvdso_clock_getres_time32_data(const struct vdso_data *vd, clockid_t clock,
static __maybe_unused int
__cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res)
{
- return __cvdso_clock_getres_time32_data(__arch_get_vdso_data(),
+ return __cvdso_clock_getres_time32_data(__arch_get_vdso_u_time_data(),
clock, res);
}
#endif /* BUILD_VDSO32 */