This is a note to let you know that I've just added the patch titled
LoongArch: Add support to clone a time namespace
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
loongarch-add-support-to-clone-a-time-namespace.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1ca1890bfd2afb8ee256b1afcf9f1f106c2b54d5
Author: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
Date: Thu Jun 29 20:58:43 2023 +0800
LoongArch: Add support to clone a time namespace
[ Upstream commit aa5e65dc0818bbf676bf06927368ec46867778fd ]
We can see that "Time namespaces are not supported" on LoongArch:
(1) clone3 test
# cd tools/testing/selftests/clone3 && make && ./clone3
...
# Time namespaces are not supported
ok 18 # SKIP Skipping clone3() with CLONE_NEWTIME
# Totals: pass:17 fail:0 xfail:0 xpass:0 skip:1 error:0
(2) timens test
# cd tools/testing/selftests/timens && make && ./timens
...
1..0 # SKIP Time namespaces are not supported
On LoongArch the current kernel does not support CONFIG_TIME_NS which
depends on GENERIC_VDSO_TIME_NS, select GENERIC_VDSO_TIME_NS to enable
CONFIG_TIME_NS to build kernel/time/namespace.c.
Additionally, it needs to define some arch-dependent functions for the
timens, such as __arch_get_timens_vdso_data(), arch_get_vdso_data() and
vdso_join_timens().
At the same time, modify the layout of vvar to use one page size for
generic vdso data, expand another page size for timens vdso data and
assign LOONGARCH_VDSO_DATA_SIZE (maybe exceeds a page size if expand in
the future) for loongarch vdso data, at last add the callback function
vvar_fault() and modify stack_top().
With this patch under CONFIG_TIME_NS:
(1) clone3 test
# cd tools/testing/selftests/clone3 && make && ./clone3
...
ok 18 [739] Result (0) matches expectation (0)
# Totals: pass:18 fail:0 xfail:0 xpass:0 skip:0 error:0
(2) timens test
# cd tools/testing/selftests/timens && make && ./timens
...
# Totals: pass:10 fail:0 xfail:0 xpass:0 skip:0 error:0
Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Stable-dep-of: 134475a9ab84 ("LoongArch: Don't crash in stack_top() for tasks without vDSO")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index fa3171f563274..f4ba3638b76a8 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -78,6 +78,7 @@ config LOONGARCH
select GENERIC_SCHED_CLOCK
select GENERIC_SMP_IDLE_THREAD
select GENERIC_TIME_VSYSCALL
+ select GENERIC_VDSO_TIME_NS
select GPIOLIB
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_MMAP_RND_BITS if MMU
diff --git a/arch/loongarch/include/asm/page.h b/arch/loongarch/include/asm/page.h
index 53f284a961823..bbac81dd73788 100644
--- a/arch/loongarch/include/asm/page.h
+++ b/arch/loongarch/include/asm/page.h
@@ -81,6 +81,7 @@ typedef struct { unsigned long pgprot; } pgprot_t;
#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET - PHYS_OFFSET))
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
+#define sym_to_pfn(x) __phys_to_pfn(__pa_symbol(x))
#ifdef CONFIG_FLATMEM
diff --git a/arch/loongarch/include/asm/vdso/gettimeofday.h b/arch/loongarch/include/asm/vdso/gettimeofday.h
index 7b2cd37641e2a..89e6b222c2f2d 100644
--- a/arch/loongarch/include/asm/vdso/gettimeofday.h
+++ b/arch/loongarch/include/asm/vdso/gettimeofday.h
@@ -91,9 +91,16 @@ static inline bool loongarch_vdso_hres_capable(void)
static __always_inline const struct vdso_data *__arch_get_vdso_data(void)
{
- return get_vdso_data();
+ return (const struct vdso_data *)get_vdso_data();
}
+#ifdef CONFIG_TIME_NS
+static __always_inline
+const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data *vd)
+{
+ return (const struct vdso_data *)(get_vdso_data() + VVAR_TIMENS_PAGE_OFFSET * PAGE_SIZE);
+}
+#endif
#endif /* !__ASSEMBLY__ */
#endif /* __ASM_VDSO_GETTIMEOFDAY_H */
diff --git a/arch/loongarch/include/asm/vdso/vdso.h b/arch/loongarch/include/asm/vdso/vdso.h
index 3b55d32a0619c..5a12309d9fb55 100644
--- a/arch/loongarch/include/asm/vdso/vdso.h
+++ b/arch/loongarch/include/asm/vdso/vdso.h
@@ -16,10 +16,33 @@ struct vdso_pcpu_data {
struct loongarch_vdso_data {
struct vdso_pcpu_data pdata[NR_CPUS];
- struct vdso_data data[CS_BASES]; /* Arch-independent data */
};
-#define VDSO_DATA_SIZE PAGE_ALIGN(sizeof(struct loongarch_vdso_data))
+/*
+ * The layout of vvar:
+ *
+ * high
+ * +---------------------+--------------------------+
+ * | loongarch vdso data | LOONGARCH_VDSO_DATA_SIZE |
+ * +---------------------+--------------------------+
+ * | time-ns vdso data | PAGE_SIZE |
+ * +---------------------+--------------------------+
+ * | generic vdso data | PAGE_SIZE |
+ * +---------------------+--------------------------+
+ * low
+ */
+#define LOONGARCH_VDSO_DATA_SIZE PAGE_ALIGN(sizeof(struct loongarch_vdso_data))
+#define LOONGARCH_VDSO_DATA_PAGES (LOONGARCH_VDSO_DATA_SIZE >> PAGE_SHIFT)
+
+enum vvar_pages {
+ VVAR_GENERIC_PAGE_OFFSET,
+ VVAR_TIMENS_PAGE_OFFSET,
+ VVAR_LOONGARCH_PAGES_START,
+ VVAR_LOONGARCH_PAGES_END = VVAR_LOONGARCH_PAGES_START + LOONGARCH_VDSO_DATA_PAGES - 1,
+ VVAR_NR_PAGES,
+};
+
+#define VVAR_SIZE (VVAR_NR_PAGES << PAGE_SHIFT)
static inline unsigned long get_vdso_base(void)
{
@@ -34,10 +57,9 @@ static inline unsigned long get_vdso_base(void)
return addr;
}
-static inline const struct vdso_data *get_vdso_data(void)
+static inline unsigned long get_vdso_data(void)
{
- return (const struct vdso_data *)(get_vdso_base()
- - VDSO_DATA_SIZE + SMP_CACHE_BYTES * NR_CPUS);
+ return get_vdso_base() - VVAR_SIZE;
}
#endif /* __ASSEMBLY__ */
diff --git a/arch/loongarch/kernel/process.c b/arch/loongarch/kernel/process.c
index 1259bc3129790..51176e5ecee59 100644
--- a/arch/loongarch/kernel/process.c
+++ b/arch/loongarch/kernel/process.c
@@ -273,7 +273,7 @@ unsigned long stack_top(void)
/* Space for the VDSO & data page */
top -= PAGE_ALIGN(current->thread.vdso->size);
- top -= PAGE_SIZE;
+ top -= VVAR_SIZE;
/* Space to randomize the VDSO base */
if (current->flags & PF_RANDOMIZE)
diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c
index 8c9826062652e..59aa9dd466e84 100644
--- a/arch/loongarch/kernel/vdso.c
+++ b/arch/loongarch/kernel/vdso.c
@@ -14,6 +14,7 @@
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/time_namespace.h>
#include <linux/timekeeper_internal.h>
#include <asm/page.h>
@@ -26,12 +27,17 @@ extern char vdso_start[], vdso_end[];
/* Kernel-provided data used by the VDSO. */
static union {
- u8 page[VDSO_DATA_SIZE];
+ u8 page[PAGE_SIZE];
+ struct vdso_data data[CS_BASES];
+} generic_vdso_data __page_aligned_data;
+
+static union {
+ u8 page[LOONGARCH_VDSO_DATA_SIZE];
struct loongarch_vdso_data vdata;
} loongarch_vdso_data __page_aligned_data;
static struct page *vdso_pages[] = { NULL };
-struct vdso_data *vdso_data = loongarch_vdso_data.vdata.data;
+struct vdso_data *vdso_data = generic_vdso_data.data;
struct vdso_pcpu_data *vdso_pdata = loongarch_vdso_data.vdata.pdata;
static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
@@ -41,6 +47,43 @@ static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struc
return 0;
}
+static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
+ struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ unsigned long pfn;
+ struct page *timens_page = find_timens_vvar_page(vma);
+
+ switch (vmf->pgoff) {
+ case VVAR_GENERIC_PAGE_OFFSET:
+ if (!timens_page)
+ pfn = sym_to_pfn(vdso_data);
+ else
+ pfn = page_to_pfn(timens_page);
+ break;
+#ifdef CONFIG_TIME_NS
+ case VVAR_TIMENS_PAGE_OFFSET:
+ /*
+ * If a task belongs to a time namespace then a namespace specific
+ * VVAR is mapped with the VVAR_GENERIC_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 (!timens_page)
+ return VM_FAULT_SIGBUS;
+ else
+ pfn = sym_to_pfn(vdso_data);
+ break;
+#endif /* CONFIG_TIME_NS */
+ case VVAR_LOONGARCH_PAGES_START ... VVAR_LOONGARCH_PAGES_END:
+ pfn = sym_to_pfn(&loongarch_vdso_data) + vmf->pgoff - VVAR_LOONGARCH_PAGES_START;
+ break;
+ default:
+ return VM_FAULT_SIGBUS;
+ }
+
+ return vmf_insert_pfn(vma, vmf->address, pfn);
+}
+
struct loongarch_vdso_info vdso_info = {
.vdso = vdso_start,
.size = PAGE_SIZE,
@@ -51,6 +94,7 @@ struct loongarch_vdso_info vdso_info = {
},
.data_mapping = {
.name = "[vvar]",
+ .fault = vvar_fault,
},
.offset_sigreturn = vdso_offset_sigreturn,
};
@@ -73,6 +117,37 @@ static int __init init_vdso(void)
}
subsys_initcall(init_vdso);
+#ifdef CONFIG_TIME_NS
+struct vdso_data *arch_get_vdso_data(void *vvar_page)
+{
+ return (struct vdso_data *)(vvar_page);
+}
+
+/*
+ * The vvar mapping contains data for a specific time namespace, so when a
+ * task changes namespace we must unmap its vvar data for the old namespace.
+ * Subsequent faults will map in data for the new namespace.
+ *
+ * For more details see timens_setup_vdso_data().
+ */
+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_info.data_mapping))
+ zap_vma_pages(vma);
+ }
+ mmap_read_unlock(mm);
+
+ return 0;
+}
+#endif
+
static unsigned long vdso_base(void)
{
unsigned long base = STACK_TOP;
@@ -88,7 +163,7 @@ static unsigned long vdso_base(void)
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
int ret;
- unsigned long vvar_size, size, data_addr, vdso_addr;
+ unsigned long size, data_addr, vdso_addr;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
struct loongarch_vdso_info *info = current->thread.vdso;
@@ -100,32 +175,23 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
* Determine total area size. This includes the VDSO data itself
* and the data pages.
*/
- vvar_size = VDSO_DATA_SIZE;
- size = vvar_size + info->size;
+ size = VVAR_SIZE + info->size;
data_addr = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
if (IS_ERR_VALUE(data_addr)) {
ret = data_addr;
goto out;
}
- vdso_addr = data_addr + VDSO_DATA_SIZE;
- vma = _install_special_mapping(mm, data_addr, vvar_size,
- VM_READ | VM_MAYREAD,
+ vma = _install_special_mapping(mm, data_addr, VVAR_SIZE,
+ VM_READ | VM_MAYREAD | VM_PFNMAP,
&info->data_mapping);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
goto out;
}
- /* Map VDSO data page. */
- ret = remap_pfn_range(vma, data_addr,
- virt_to_phys(&loongarch_vdso_data) >> PAGE_SHIFT,
- vvar_size, PAGE_READONLY);
- if (ret)
- goto out;
-
- /* Map VDSO code page. */
+ vdso_addr = data_addr + VVAR_SIZE;
vma = _install_special_mapping(mm, vdso_addr, info->size,
VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
&info->code_mapping);
diff --git a/arch/loongarch/vdso/vgetcpu.c b/arch/loongarch/vdso/vgetcpu.c
index e02e775f53608..9e445be39763a 100644
--- a/arch/loongarch/vdso/vgetcpu.c
+++ b/arch/loongarch/vdso/vgetcpu.c
@@ -21,7 +21,7 @@ static __always_inline int read_cpu_id(void)
static __always_inline const struct vdso_pcpu_data *get_pcpu_data(void)
{
- return (struct vdso_pcpu_data *)(get_vdso_base() - VDSO_DATA_SIZE);
+ return (struct vdso_pcpu_data *)(get_vdso_data() + VVAR_LOONGARCH_PAGES_START * PAGE_SIZE);
}
extern
