diff options
| -rw-r--r-- | arch/powerpc/Kconfig | 3 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/vdso/gettimeofday.h | 10 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/vdso_datapage.h | 2 | ||||
| -rw-r--r-- | arch/powerpc/kernel/vdso.c | 116 | ||||
| -rw-r--r-- | arch/powerpc/kernel/vdso32/vdso32.lds.S | 2 | ||||
| -rw-r--r-- | 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 7c5c72cbf19f..475d77a6ebbe 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -173,6 +173,7 @@ 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_IOMAP if PCI @@ -180,7 +181,7 @@ 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 77c635c2c90d..1faff0be1111 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 <asm/page.h> + #ifdef __ASSEMBLY__ #include <asm/ppc_asm.h> @@ -154,6 +156,14 @@ 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 <linux/security.h> #include <linux/memblock.h> #include <linux/syscalls.h> +#include <linux/time_namespace.h> #include <vdso/datapage.h> #include <asm/syscall.h> @@ -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; + + if (vma_is_special_mapping(vma, &vvar_spec)) + zap_page_range(vma, vma->vm_start, size); + } + + mmap_read_unlock(mm); + return 0; +} + +static struct page *find_timens_vvar_page(struct vm_area_struct *vma) +{ + if (likely(vma->vm_mm == current->mm)) + return current->nsproxy->time_ns->vvar_page; + + /* + * VM_PFNMAP | VM_IO protect .fault() handler from being called + * through interfaces like /proc/$pid/mem or + * process_vm_{readv,writev}() as long as there's no .access() + * in special_mapping_vmops. + * For more details check_vma_flags() and __access_remote_vm() + */ + WARN(1, "vvar_page accessed remotely"); + + return NULL; +} +#else +static struct page *find_timens_vvar_page(struct vm_area_struct *vma) +{ + return NULL; +} +#endif + +static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, + struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct page *timens_page = find_timens_vvar_page(vma); + unsigned long pfn; + + switch (vmf->pgoff) { + case VVAR_DATA_PAGE_OFFSET: + if (timens_page) + pfn = page_to_pfn(timens_page); + else + pfn = virt_to_pfn(vdso_data); + 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_DATA_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; + pfn = virt_to_pfn(vdso_data); + break; +#endif /* CONFIG_TIME_NS */ + default: + return VM_FAULT_SIGBUS; + } + + return vmf_insert_pfn(vma, vmf->address, pfn); +} + /* * This is called from binfmt_elf, we create the special vma for the * vDSO and insert it into the mm struct tree @@ -95,7 +194,7 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int { unsigned long vdso_size, vdso_base, mappings_size; struct vm_special_mapping *vdso_spec; - unsigned long vvar_size = PAGE_SIZE; + unsigned long vvar_size = VVAR_NR_PAGES * PAGE_SIZE; struct mm_struct *mm = current->mm; struct vm_area_struct *vma; @@ -266,19 +365,6 @@ static struct page ** __init vdso_setup_pages(void *start, void *end) return pagelist; } -static struct page ** __init vvar_setup_pages(void) -{ - struct page **pagelist; - - /* .pages is NULL-terminated */ - pagelist = kcalloc(2, sizeof(struct page *), GFP_KERNEL); - if (!pagelist) - panic("%s: Cannot allocate page list for VVAR", __func__); - - pagelist[0] = virt_to_page(vdso_data); - return pagelist; -} - static int __init vdso_init(void) { #ifdef CONFIG_PPC64 @@ -317,8 +403,6 @@ static int __init vdso_init(void) if (IS_ENABLED(CONFIG_PPC64)) vdso64_spec.pages = vdso_setup_pages(&vdso64_start, &vdso64_end); - vvar_spec.pages = vvar_setup_pages(); - smp_wmb(); return 0; diff --git a/arch/powerpc/kernel/vdso32/vdso32.lds.S b/arch/powerpc/kernel/vdso32/vdso32.lds.S index a4b806b0d618..58e0099f70f4 100644 --- a/arch/powerpc/kernel/vdso32/vdso32.lds.S +++ b/arch/powerpc/kernel/vdso32/vdso32.lds.S @@ -17,7 +17,7 @@ ENTRY(_start) SECTIONS { - PROVIDE(_vdso_datapage = . - PAGE_SIZE); + PROVIDE(_vdso_datapage = . - 2 * PAGE_SIZE); . = SIZEOF_HEADERS; .hash : { *(.hash) } :text diff --git a/arch/powerpc/kernel/vdso64/vdso64.lds.S b/arch/powerpc/kernel/vdso64/vdso64.lds.S index 2f3c359cacd3..0288cad428b0 100644 --- a/arch/powerpc/kernel/vdso64/vdso64.lds.S +++ b/arch/powerpc/kernel/vdso64/vdso64.lds.S @@ -17,7 +17,7 @@ ENTRY(_start) SECTIONS { - PROVIDE(_vdso_datapage = . - PAGE_SIZE); + PROVIDE(_vdso_datapage = . - 2 * PAGE_SIZE); . = SIZEOF_HEADERS; .hash : { *(.hash) } :text |