Commit aa5e65dc authored by Tiezhu Yang's avatar Tiezhu Yang Committed by Huacai Chen
Browse files

LoongArch: Add support to clone a time namespace 



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: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 65eea6b4

arch/loongarch/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -82,6 +82,7 @@ config LOONGARCH 
	select GENERIC_SCHED_CLOCK

	select GENERIC_SMP_IDLE_THREAD

	select GENERIC_TIME_VSYSCALL

	select GENERIC_VDSO_TIME_NS

	select GPIOLIB

	select HAS_IOPORT

	select HAVE_ARCH_AUDITSYSCALL

arch/loongarch/include/asm/page.h

+1 −0
Original line number Diff line number Diff line
@@ -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))



#define virt_to_pfn(kaddr)	PFN_DOWN(PHYSADDR(kaddr))

#define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))

arch/loongarch/include/asm/vdso/gettimeofday.h

+8 −1
Original line number Diff line number Diff line
@@ -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 */

arch/loongarch/include/asm/vdso/vdso.h

+27 −5
Original line number Diff line number Diff line
@@ -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__ */

arch/loongarch/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -285,7 +285,7 @@ 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)