| Message ID | 20200225073731.465270-3-avagin@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: add the time namespace support | expand |
On 2/25/20 7:37 AM, Andrei Vagin wrote: > 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. > > Signed-off-by: Andrei Vagin <avagin@gmail.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> > --- > arch/arm64/kernel/vdso.c | 32 ++++++++++++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > > diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c > index 290c36d74e03..6ac9cdeac5be 100644 > --- a/arch/arm64/kernel/vdso.c > +++ b/arch/arm64/kernel/vdso.c > @@ -131,6 +131,38 @@ static int __vdso_init(enum arch_vdso_type arch_index) > return 0; > } > > +#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 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; > + > + if (down_write_killable(&mm->mmap_sem)) > + return -EINTR; > + > + for (vma = mm->mmap; vma; vma = vma->vm_next) { > + unsigned long size = vma->vm_end - vma->vm_start; > + > + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO].dm)) > + zap_page_range(vma, vma->vm_start, size); > +#ifdef CONFIG_COMPAT_VDSO > + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO32].dm)) > + zap_page_range(vma, vma->vm_start, size); > +#endif > + } > + > + up_write(&mm->mmap_sem); > + return 0; > +} > +#endif > + > static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, > struct vm_area_struct *vma, struct vm_fault *vmf) > { >
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 290c36d74e03..6ac9cdeac5be 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -131,6 +131,38 @@ static int __vdso_init(enum arch_vdso_type arch_index) return 0; } +#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 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; + + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + + for (vma = mm->mmap; vma; vma = vma->vm_next) { + unsigned long size = vma->vm_end - vma->vm_start; + + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO].dm)) + zap_page_range(vma, vma->vm_start, size); +#ifdef CONFIG_COMPAT_VDSO + if (vma_is_special_mapping(vma, vdso_lookup[ARM64_VDSO32].dm)) + zap_page_range(vma, vma->vm_start, size); +#endif + } + + up_write(&mm->mmap_sem); + return 0; +} +#endif + static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, struct vm_area_struct *vma, struct vm_fault *vmf) {
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. Signed-off-by: Andrei Vagin <avagin@gmail.com> --- arch/arm64/kernel/vdso.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)