[PATCH RESEND v1 4/4] powerpc/vdso: Add support for time namespaces
This patch adds the necessary glue to provide time namespaces.
Things are mainly copied from ARM64.
__arch_get_timens_vdso_data() calculates timens vdso data position
based on the vdso data position, knowing it is the next page in vvar.
This avoids having to redo the mflr/bcl/mflr/mtlr dance to locate
the page relative to running code position.
Signed-off-by: Christophe Leroy
---
arch/powerpc/Kconfig | 3 +-
arch/powerpc/include/asm/vdso/gettimeofday.h | 10 ++
arch/powerpc/include/asm/vdso_datapage.h | 2 -
arch/powerpc/kernel/vdso.c | 116 ---
arch/powerpc/kernel/vdso32/vdso32.lds.S | 2 +-
arch/powerpc/kernel/vdso64/vdso64.lds.S | 2 +-
6 files changed, 114 insertions(+), 21 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c1344c05226c..71daff5f15d5 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -172,6 +172,7 @@ config PPC
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_VULNERABILITIES if PPC_BARRIER_NOSPEC
select GENERIC_EARLY_IOREMAP
+ select GENERIC_GETTIMEOFDAY
select GENERIC_IRQ_SHOW
select GENERIC_IRQ_SHOW_LEVEL
select GENERIC_PCI_IOMAPif PCI
@@ -179,7 +180,7 @@ config PPC
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select GENERIC_TIME_VSYSCALL
- select GENERIC_GETTIMEOFDAY
+ select GENERIC_VDSO_TIME_NS
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_HUGE_VMAP if PPC_BOOK3S_64 &&
PPC_RADIX_MMU
select HAVE_ARCH_JUMP_LABEL
diff --git a/arch/powerpc/include/asm/vdso/gettimeofday.h
b/arch/powerpc/include/asm/vdso/gettimeofday.h
index d453e725c79f..e448df1dd071 100644
--- a/arch/powerpc/include/asm/vdso/gettimeofday.h
+++ b/arch/powerpc/include/asm/vdso/gettimeofday.h
@@ -2,6 +2,8 @@
#ifndef _ASM_POWERPC_VDSO_GETTIMEOFDAY_H
#define _ASM_POWERPC_VDSO_GETTIMEOFDAY_H
+#include
+
#ifdef __ASSEMBLY__
#include
@@ -153,6 +155,14 @@ static __always_inline u64 __arch_get_hw_counter(s32
clock_mode,
const struct vdso_data *__arch_get_vdso_data(void);
+#ifdef CONFIG_TIME_NS
+static __always_inline
+const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data *vd)
+{
+ return (void *)vd + PAGE_SIZE;
+}
+#endif
+
static inline bool vdso_clocksource_ok(const struct vdso_data *vd)
{
return true;
diff --git a/arch/powerpc/include/asm/vdso_datapage.h
b/arch/powerpc/include/asm/vdso_datapage.h
index 3f958ecf2beb..a585c8e538ff 100644
--- a/arch/powerpc/include/asm/vdso_datapage.h
+++ b/arch/powerpc/include/asm/vdso_datapage.h
@@ -107,9 +107,7 @@ extern struct vdso_arch_data *vdso_data;
bcl 20, 31, .+4
999:
mflr\ptr
-#if CONFIG_PPC_PAGE_SHIFT > 14
addis \ptr, \ptr, (_vdso_datapage - 999b)@ha
-#endif
addi\ptr, \ptr, (_vdso_datapage - 999b)@l
.endm
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index b14907209822..717f2c9a7573 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -18,6 +18,7 @@
#include
#include
#include
+#include
#include
#include
@@ -50,6 +51,12 @@ static union {
} vdso_data_store __page_aligned_data;
struct vdso_arch_data *vdso_data = &vdso_data_store.data;
+enum vvar_pages {
+ VVAR_DATA_PAGE_OFFSET,
+ VVAR_TIMENS_PAGE_OFFSET,
+ VVAR_NR_PAGES,
+};
+
static int vdso_mremap(const struct vm_special_mapping *sm, struct
vm_area_struct *new_vma,
unsigned long text_size)
{
@@ -73,8 +80,12 @@ static int vdso64_mremap(const struct vm_special_mapping
*sm, struct vm_area_str
return vdso_mremap(sm, new_vma, &vdso64_end - &vdso64_start);
}
+static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
+struct vm_area_struct *vma, struct vm_fault *vmf);
+
static struct vm_special_mapping vvar_spec __ro_after_init = {
.name = "[vvar]",
+ .fault = vvar_fault,
};
static struct vm_special_mapping vdso32_spec __ro_after_init = {
@@ -87,6 +98,94 @@ static struct vm_special_mapping vdso64_spec __ro_after_init
= {
.mremap = vdso64_mremap,
};
+#ifdef CONFIG_TIME_NS
+struct vdso_data *arch_get_vdso_data(void *vvar_page)
+{
+ return ((struct vdso_arch_data *)vvar_page)->data;
+}
+
+/*
+ * 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;
+
+ mmap_read_lock(mm);
+
+ for (vma = mm->mmap; vma; vma = vma->vm_next) {
+ unsigned long size = vma->vm_end - vma->vm_start;
+
Re: [PATCH RESEND v1 4/4] powerpc/vdso: Add support for time namespaces
On Wed, Mar 31, 2021 at 04:48:47PM +, Christophe Leroy wrote: > This patch adds the necessary glue to provide time namespaces. > > Things are mainly copied from ARM64. > > __arch_get_timens_vdso_data() calculates timens vdso data position > based on the vdso data position, knowing it is the next page in vvar. > This avoids having to redo the mflr/bcl/mflr/mtlr dance to locate > the page relative to running code position. > Acked-by: Andrei Vagin > Signed-off-by: Christophe Leroy
Re: [PATCH RESEND v1 4/4] powerpc/vdso: Add support for time namespaces
On 3/31/21 5:48 PM, Christophe Leroy wrote:
> This patch adds the necessary glue to provide time namespaces.
>
> Things are mainly copied from ARM64.
>
> __arch_get_timens_vdso_data() calculates timens vdso data position
> based on the vdso data position, knowing it is the next page in vvar.
> This avoids having to redo the mflr/bcl/mflr/mtlr dance to locate
> the page relative to running code position.
>
> Signed-off-by: Christophe Leroy
Reviewed-by: Vincenzo Frascino # vDSO parts
> ---
> arch/powerpc/Kconfig | 3 +-
> arch/powerpc/include/asm/vdso/gettimeofday.h | 10 ++
> arch/powerpc/include/asm/vdso_datapage.h | 2 -
> arch/powerpc/kernel/vdso.c | 116 ---
> arch/powerpc/kernel/vdso32/vdso32.lds.S | 2 +-
> arch/powerpc/kernel/vdso64/vdso64.lds.S | 2 +-
> 6 files changed, 114 insertions(+), 21 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index c1344c05226c..71daff5f15d5 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -172,6 +172,7 @@ config PPC
> select GENERIC_CPU_AUTOPROBE
> select GENERIC_CPU_VULNERABILITIES if PPC_BARRIER_NOSPEC
> select GENERIC_EARLY_IOREMAP
> + select GENERIC_GETTIMEOFDAY
> select GENERIC_IRQ_SHOW
> select GENERIC_IRQ_SHOW_LEVEL
> select GENERIC_PCI_IOMAPif PCI
> @@ -179,7 +180,7 @@ config PPC
> select GENERIC_STRNCPY_FROM_USER
> select GENERIC_STRNLEN_USER
> select GENERIC_TIME_VSYSCALL
> - select GENERIC_GETTIMEOFDAY
> + select GENERIC_VDSO_TIME_NS
> select HAVE_ARCH_AUDITSYSCALL
> select HAVE_ARCH_HUGE_VMAP if PPC_BOOK3S_64 &&
> PPC_RADIX_MMU
> select HAVE_ARCH_JUMP_LABEL
> diff --git a/arch/powerpc/include/asm/vdso/gettimeofday.h
> b/arch/powerpc/include/asm/vdso/gettimeofday.h
> index d453e725c79f..e448df1dd071 100644
> --- a/arch/powerpc/include/asm/vdso/gettimeofday.h
> +++ b/arch/powerpc/include/asm/vdso/gettimeofday.h
> @@ -2,6 +2,8 @@
> #ifndef _ASM_POWERPC_VDSO_GETTIMEOFDAY_H
> #define _ASM_POWERPC_VDSO_GETTIMEOFDAY_H
>
> +#include
> +
> #ifdef __ASSEMBLY__
>
> #include
> @@ -153,6 +155,14 @@ static __always_inline u64 __arch_get_hw_counter(s32
> clock_mode,
>
> const struct vdso_data *__arch_get_vdso_data(void);
>
> +#ifdef CONFIG_TIME_NS
> +static __always_inline
> +const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data
> *vd)
> +{
> + return (void *)vd + PAGE_SIZE;
> +}
> +#endif
> +
> static inline bool vdso_clocksource_ok(const struct vdso_data *vd)
> {
> return true;
> diff --git a/arch/powerpc/include/asm/vdso_datapage.h
> b/arch/powerpc/include/asm/vdso_datapage.h
> index 3f958ecf2beb..a585c8e538ff 100644
> --- a/arch/powerpc/include/asm/vdso_datapage.h
> +++ b/arch/powerpc/include/asm/vdso_datapage.h
> @@ -107,9 +107,7 @@ extern struct vdso_arch_data *vdso_data;
> bcl 20, 31, .+4
> 999:
> mflr\ptr
> -#if CONFIG_PPC_PAGE_SHIFT > 14
> addis \ptr, \ptr, (_vdso_datapage - 999b)@ha
> -#endif
> addi\ptr, \ptr, (_vdso_datapage - 999b)@l
> .endm
>
> diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
> index b14907209822..717f2c9a7573 100644
> --- a/arch/powerpc/kernel/vdso.c
> +++ b/arch/powerpc/kernel/vdso.c
> @@ -18,6 +18,7 @@
> #include
> #include
> #include
> +#include
> #include
>
> #include
> @@ -50,6 +51,12 @@ static union {
> } vdso_data_store __page_aligned_data;
> struct vdso_arch_data *vdso_data = &vdso_data_store.data;
>
> +enum vvar_pages {
> + VVAR_DATA_PAGE_OFFSET,
> + VVAR_TIMENS_PAGE_OFFSET,
> + VVAR_NR_PAGES,
> +};
> +
> static int vdso_mremap(const struct vm_special_mapping *sm, struct
> vm_area_struct *new_vma,
> unsigned long text_size)
> {
> @@ -73,8 +80,12 @@ static int vdso64_mremap(const struct vm_special_mapping
> *sm, struct vm_area_str
> return vdso_mremap(sm, new_vma, &vdso64_end - &vdso64_start);
> }
>
> +static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
> + struct vm_area_struct *vma, struct vm_fault *vmf);
> +
> static struct vm_special_mapping vvar_spec __ro_after_init = {
> .name = "[vvar]",
> + .fault = vvar_fault,
> };
>
> static struct vm_special_mapping vdso32_spec __ro_after_init = {
> @@ -87,6 +98,94 @@ static struct vm_special_mapping vdso64_spec
> __ro_after_init = {
> .mremap = vdso64_mremap,
> };
>
> +#ifdef CONFIG_TIME_NS
> +struct vdso_data *arch_get_vdso_data(void *vvar_page)
> +{
> + return ((struct vdso_arch_data *)vvar_page)->data;
> +}
> +
> +/*
> + * 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_
