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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
vdso/timens: Refactor copy-pasted find_timens_vvar_page() helper into one copy
find_timens_vvar_page() is not architecture-specific, as can be seen from
how all five per-architecture versions of it are the same.
(arm64, powerpc and riscv are exactly the same; x86 and s390 have two
characters difference inside a comment, less blank lines, and mark the
!CONFIG_TIME_NS version as inline.)
Refactor the five copies into a central copy in kernel/time/namespace.c.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221130115320.2918447-1-jannh@google.com
authored by
Jann Horn
and committed by
Thomas Gleixner
d6c494e8
e0d3da98
+24
-109
-22
arch/arm64/kernel/vdso.c
-22
arch/arm64/kernel/vdso.c
···
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mmap_read_unlock(mm);
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return 0;
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}
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-
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static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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if (likely(vma->vm_mm == current->mm))
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return current->nsproxy->time_ns->vvar_page;
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/*
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* VM_PFNMAP | VM_IO protect .fault() handler from being called
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* through interfaces like /proc/$pid/mem or
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* process_vm_{readv,writev}() as long as there's no .access()
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* in special_mapping_vmops.
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* For more details check_vma_flags() and __access_remote_vm()
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*/
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WARN(1, "vvar_page accessed remotely");
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return NULL;
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}
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#else
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static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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return NULL;
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}
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#endif
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static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
-22
arch/powerpc/kernel/vdso.c
-22
arch/powerpc/kernel/vdso.c
···
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return 0;
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}
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-
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static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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if (likely(vma->vm_mm == current->mm))
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return current->nsproxy->time_ns->vvar_page;
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-
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/*
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* VM_PFNMAP | VM_IO protect .fault() handler from being called
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* through interfaces like /proc/$pid/mem or
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* process_vm_{readv,writev}() as long as there's no .access()
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* in special_mapping_vmops.
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* For more details check_vma_flags() and __access_remote_vm()
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*/
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WARN(1, "vvar_page accessed remotely");
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return NULL;
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}
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#else
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static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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return NULL;
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}
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#endif
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static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
-22
arch/riscv/kernel/vdso.c
-22
arch/riscv/kernel/vdso.c
···
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mmap_read_unlock(mm);
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return 0;
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}
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-
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static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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if (likely(vma->vm_mm == current->mm))
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return current->nsproxy->time_ns->vvar_page;
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-
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/*
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* VM_PFNMAP | VM_IO protect .fault() handler from being called
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* through interfaces like /proc/$pid/mem or
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* process_vm_{readv,writev}() as long as there's no .access()
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* in special_mapping_vmops.
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* For more details check_vma_flags() and __access_remote_vm()
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*/
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WARN(1, "vvar_page accessed remotely");
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return NULL;
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}
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#else
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static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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return NULL;
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}
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#endif
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static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
-20
arch/s390/kernel/vdso.c
-20
arch/s390/kernel/vdso.c
···
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return (struct vdso_data *)(vvar_page);
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}
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-
static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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if (likely(vma->vm_mm == current->mm))
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return current->nsproxy->time_ns->vvar_page;
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/*
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* VM_PFNMAP | VM_IO protect .fault() handler from being called
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* through interfaces like /proc/$pid/mem or
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* process_vm_{readv,writev}() as long as there's no .access()
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* in special_mapping_vmops().
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* For more details check_vma_flags() and __access_remote_vm()
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*/
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WARN(1, "vvar_page accessed remotely");
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return NULL;
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}
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-
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/*
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* The VVAR page layout depends on whether a task belongs to the root or
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* non-root time namespace. Whenever a task changes its namespace, the VVAR
···
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}
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mmap_read_unlock(mm);
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return 0;
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}
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#else
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static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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return NULL;
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}
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#endif
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-23
arch/x86/entry/vdso/vma.c
-23
arch/x86/entry/vdso/vma.c
···
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}
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#ifdef CONFIG_TIME_NS
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static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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if (likely(vma->vm_mm == current->mm))
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return current->nsproxy->time_ns->vvar_page;
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-
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/*
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* VM_PFNMAP | VM_IO protect .fault() handler from being called
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* through interfaces like /proc/$pid/mem or
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* process_vm_{readv,writev}() as long as there's no .access()
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* in special_mapping_vmops().
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* For more details check_vma_flags() and __access_remote_vm()
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*/
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WARN(1, "vvar_page accessed remotely");
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return NULL;
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}
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/*
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* The vvar page layout depends on whether a task belongs to the root or
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* non-root time namespace. Whenever a task changes its namespace, the VVAR
···
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mmap_read_unlock(mm);
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return 0;
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}
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#else
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static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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return NULL;
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}
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#endif
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+6
include/linux/time_namespace.h
+6
include/linux/time_namespace.h
···
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void free_time_ns(struct time_namespace *ns);
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void timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk);
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struct vdso_data *arch_get_vdso_data(void *vvar_page);
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struct page *find_timens_vvar_page(struct vm_area_struct *vma);
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static inline void put_time_ns(struct time_namespace *ns)
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{
···
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struct task_struct *tsk)
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{
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return;
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}
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+
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static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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return NULL;
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}
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static inline void timens_add_monotonic(struct timespec64 *ts) { }
+18
kernel/time/namespace.c
+18
kernel/time/namespace.c
···
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offset[CLOCK_BOOTTIME_ALARM] = boottime;
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}
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struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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if (likely(vma->vm_mm == current->mm))
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return current->nsproxy->time_ns->vvar_page;
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+
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/*
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* VM_PFNMAP | VM_IO protect .fault() handler from being called
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* through interfaces like /proc/$pid/mem or
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* process_vm_{readv,writev}() as long as there's no .access()
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* in special_mapping_vmops().
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* For more details check_vma_flags() and __access_remote_vm()
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*/
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WARN(1, "vvar_page accessed remotely");
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return NULL;
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}
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+
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/*
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* Protects possibly multiple offsets writers racing each other
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* and tasks entering the namespace.