Commit eb3710efffce1dcff83761db4615f91d93aabfcb ("LoongArch: Add support
to clone a time namespace") backports the TIMENS support for LoongArch
(corresponding upstream commit aa5e65dc0818bbf676bf06927368ec46867778fd)
but causes build errors:
CC arch/loongarch/kernel/vdso.o
arch/loongarch/kernel/vdso.c: In function ‘vvar_fault’:
arch/loongarch/kernel/vdso.c:54:36: error: implicit declaration of
function ‘find_timens_vvar_page’ [-Werror=implicit-function-declaration]
54 | struct page *timens_page = find_timens_vvar_page(vma);
| ^~~~~~~~~~~~~~~~~~~~~
arch/loongarch/kernel/vdso.c:54:36: warning: initialization of ‘struct
page *’ from ‘int’ makes pointer from integer without a cast
[-Wint-conversion]
arch/loongarch/kernel/vdso.c: In function ‘vdso_join_timens’:
arch/loongarch/kernel/vdso.c:143:25: error: implicit declaration of
function ‘zap_vma_pages’; did you mean ‘zap_vma_ptes’?
[-Werror=implicit-function-declaration]
143 | zap_vma_pages(vma);
| ^~~~~~~~~~~~~
| zap_vma_ptes
cc1: some warnings being treated as errors
Because in 6.1.y we should define find_timens_vvar_page() by ourselves
and use zap_page_range() instead of zap_vma_pages(), so fix it.
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
---
arch/loongarch/kernel/vdso.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c
index 59aa9dd466e8..64eb5386e7b2 100644
--- a/arch/loongarch/kernel/vdso.c
+++ b/arch/loongarch/kernel/vdso.c
@@ -40,6 +40,8 @@ static struct page *vdso_pages[] = { NULL };
struct vdso_data *vdso_data = generic_vdso_data.data;
struct vdso_pcpu_data *vdso_pdata = loongarch_vdso_data.vdata.pdata;
+static struct page *find_timens_vvar_page(struct vm_area_struct *vma);
+
static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
{
current->mm->context.vdso = (void *)(new_vma->vm_start);
@@ -139,13 +141,37 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
mmap_read_lock(mm);
for_each_vma(vmi, vma) {
+ unsigned long size = vma->vm_end - vma->vm_start;
+
if (vma_is_special_mapping(vma, &vdso_info.data_mapping))
- zap_vma_pages(vma);
+ zap_page_range(vma, vma->vm_start, size);
}
mmap_read_unlock(mm);
return 0;
}
+
+static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
+{
+ if (likely(vma->vm_mm == current->mm))
+ return current->nsproxy->time_ns->vvar_page;
+
+ /*
+ * VM_PFNMAP | VM_IO protect .fault() handler from being called
+ * through interfaces like /proc/$pid/mem or
+ * process_vm_{readv,writev}() as long as there's no .access()
+ * in special_mapping_vmops.
+ * For more details check_vma_flags() and __access_remote_vm()
+ */
+ WARN(1, "vvar_page accessed remotely");
+
+ return NULL;
+}
+#else
+static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
+{
+ return NULL;
+}
#endif
static unsigned long vdso_base(void)
--
2.43.5
