6.1-stable review patch. If anyone has any objections, please let me know.
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From: Tiezhu Yang yangtiezhu@loongson.cn
[ 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@loongson.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn Stable-dep-of: 134475a9ab84 ("LoongArch: Don't crash in stack_top() for tasks without vDSO") Signed-off-by: Sasha Levin sashal@kernel.org --- arch/loongarch/Kconfig | 1 + arch/loongarch/include/asm/page.h | 1 + .../loongarch/include/asm/vdso/gettimeofday.h | 9 +- arch/loongarch/include/asm/vdso/vdso.h | 32 +++++- arch/loongarch/kernel/process.c | 2 +- arch/loongarch/kernel/vdso.c | 98 ++++++++++++++++--- arch/loongarch/vdso/vgetcpu.c | 2 +- 7 files changed, 121 insertions(+), 24 deletions(-)
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