--- /dev/null
+From 1ca1890bfd2afb8ee256b1afcf9f1f106c2b54d5 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Thu, 29 Jun 2023 20:58:43 +0800
+Subject: LoongArch: Add support to clone a time namespace
+
+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
+--
+2.43.0
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
