diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Makefile | 2 | ||||
| -rw-r--r-- | lib/vdso/Kconfig | 5 | ||||
| -rw-r--r-- | lib/vdso/Makefile | 3 | ||||
| -rw-r--r-- | lib/vdso/datastore.c | 103 | ||||
| -rw-r--r-- | lib/vdso/gettimeofday.c | 25 |
5 files changed, 131 insertions, 7 deletions
diff --git a/lib/Makefile b/lib/Makefile index d5cfc7afbbb8..fcdee83deb5c 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -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-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o diff --git a/lib/vdso/Kconfig b/lib/vdso/Kconfig index 82fe827af542..45df764b49ad 100644 --- a/lib/vdso/Kconfig +++ b/lib/vdso/Kconfig @@ -43,3 +43,8 @@ config VDSO_GETRANDOM bool help Selected by architectures that support vDSO getrandom(). + +config GENERIC_VDSO_DATA_STORE + bool + help + Selected by architectures that use the generic vDSO data store. diff --git a/lib/vdso/Makefile b/lib/vdso/Makefile new file mode 100644 index 000000000000..aedd40aaa950 --- /dev/null +++ b/lib/vdso/Makefile @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only + +obj-$(CONFIG_GENERIC_VDSO_DATA_STORE) += datastore.o diff --git a/lib/vdso/datastore.c b/lib/vdso/datastore.c new file mode 100644 index 000000000000..d3181768424c --- /dev/null +++ b/lib/vdso/datastore.c @@ -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 diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index c01eaafd8041..20c5b8752fcc 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -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 */ |