diff options
Diffstat (limited to 'mm/gup.c')
| -rw-r--r-- | mm/gup.c | 127 |
1 files changed, 107 insertions, 20 deletions
@@ -1,3 +1,4 @@ +#define __DISABLE_GUP_DEPRECATED 1 #include <linux/kernel.h> #include <linux/errno.h> #include <linux/err.h> @@ -14,6 +15,7 @@ #include <linux/rwsem.h> #include <linux/hugetlb.h> +#include <asm/mmu_context.h> #include <asm/pgtable.h> #include <asm/tlbflush.h> @@ -363,6 +365,8 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, return -ENOENT; if (*flags & FOLL_WRITE) fault_flags |= FAULT_FLAG_WRITE; + if (*flags & FOLL_REMOTE) + fault_flags |= FAULT_FLAG_REMOTE; if (nonblocking) fault_flags |= FAULT_FLAG_ALLOW_RETRY; if (*flags & FOLL_NOWAIT) @@ -413,11 +417,13 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma, static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) { vm_flags_t vm_flags = vma->vm_flags; + int write = (gup_flags & FOLL_WRITE); + int foreign = (gup_flags & FOLL_REMOTE); if (vm_flags & (VM_IO | VM_PFNMAP)) return -EFAULT; - if (gup_flags & FOLL_WRITE) { + if (write) { if (!(vm_flags & VM_WRITE)) { if (!(gup_flags & FOLL_FORCE)) return -EFAULT; @@ -443,6 +449,12 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) if (!(vm_flags & VM_MAYREAD)) return -EFAULT; } + /* + * gups are always data accesses, not instruction + * fetches, so execute=false here + */ + if (!arch_vma_access_permitted(vma, write, false, foreign)) + return -EFAULT; return 0; } @@ -609,6 +621,28 @@ next_page: } EXPORT_SYMBOL(__get_user_pages); +bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags) +{ + bool write = !!(fault_flags & FAULT_FLAG_WRITE); + bool foreign = !!(fault_flags & FAULT_FLAG_REMOTE); + vm_flags_t vm_flags = write ? VM_WRITE : VM_READ; + + if (!(vm_flags & vma->vm_flags)) + return false; + + /* + * The architecture might have a hardware protection + * mechanism other than read/write that can deny access. + * + * gup always represents data access, not instruction + * fetches, so execute=false here: + */ + if (!arch_vma_access_permitted(vma, write, false, foreign)) + return false; + + return true; +} + /* * fixup_user_fault() - manually resolve a user page fault * @tsk: the task_struct to use for page fault accounting, or @@ -644,7 +678,6 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, bool *unlocked) { struct vm_area_struct *vma; - vm_flags_t vm_flags; int ret, major = 0; if (unlocked) @@ -655,8 +688,7 @@ retry: if (!vma || address < vma->vm_start) return -EFAULT; - vm_flags = (fault_flags & FAULT_FLAG_WRITE) ? VM_WRITE : VM_READ; - if (!(vm_flags & vma->vm_flags)) + if (!vma_permits_fault(vma, fault_flags)) return -EFAULT; ret = handle_mm_fault(mm, vma, address, fault_flags); @@ -807,15 +839,15 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, * if (locked) * up_read(&mm->mmap_sem); */ -long get_user_pages_locked(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, unsigned long nr_pages, +long get_user_pages_locked6(unsigned long start, unsigned long nr_pages, int write, int force, struct page **pages, int *locked) { - return __get_user_pages_locked(tsk, mm, start, nr_pages, write, force, - pages, NULL, locked, true, FOLL_TOUCH); + return __get_user_pages_locked(current, current->mm, start, nr_pages, + write, force, pages, NULL, locked, true, + FOLL_TOUCH); } -EXPORT_SYMBOL(get_user_pages_locked); +EXPORT_SYMBOL(get_user_pages_locked6); /* * Same as get_user_pages_unlocked(...., FOLL_TOUCH) but it allows to @@ -860,17 +892,16 @@ EXPORT_SYMBOL(__get_user_pages_unlocked); * or if "force" shall be set to 1 (get_user_pages_fast misses the * "force" parameter). */ -long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, unsigned long nr_pages, +long get_user_pages_unlocked5(unsigned long start, unsigned long nr_pages, int write, int force, struct page **pages) { - return __get_user_pages_unlocked(tsk, mm, start, nr_pages, write, - force, pages, FOLL_TOUCH); + return __get_user_pages_unlocked(current, current->mm, start, nr_pages, + write, force, pages, FOLL_TOUCH); } -EXPORT_SYMBOL(get_user_pages_unlocked); +EXPORT_SYMBOL(get_user_pages_unlocked5); /* - * get_user_pages() - pin user pages in memory + * get_user_pages_remote() - pin user pages in memory * @tsk: the task_struct to use for page fault accounting, or * NULL if faults are not to be recorded. * @mm: mm_struct of target mm @@ -924,14 +955,32 @@ EXPORT_SYMBOL(get_user_pages_unlocked); * should use get_user_pages because it cannot pass * FAULT_FLAG_ALLOW_RETRY to handle_mm_fault. */ -long get_user_pages(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, unsigned long nr_pages, int write, - int force, struct page **pages, struct vm_area_struct **vmas) +long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, unsigned long nr_pages, + int write, int force, struct page **pages, + struct vm_area_struct **vmas) { return __get_user_pages_locked(tsk, mm, start, nr_pages, write, force, - pages, vmas, NULL, false, FOLL_TOUCH); + pages, vmas, NULL, false, + FOLL_TOUCH | FOLL_REMOTE); +} +EXPORT_SYMBOL(get_user_pages_remote); + +/* + * This is the same as get_user_pages_remote(), just with a + * less-flexible calling convention where we assume that the task + * and mm being operated on are the current task's. We also + * obviously don't pass FOLL_REMOTE in here. + */ +long get_user_pages6(unsigned long start, unsigned long nr_pages, + int write, int force, struct page **pages, + struct vm_area_struct **vmas) +{ + return __get_user_pages_locked(current, current->mm, start, nr_pages, + write, force, pages, vmas, NULL, false, + FOLL_TOUCH); } -EXPORT_SYMBOL(get_user_pages); +EXPORT_SYMBOL(get_user_pages6); /** * populate_vma_page_range() - populate a range of pages in the vma. @@ -1144,6 +1193,9 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, pte_protnone(pte) || (write && !pte_write(pte))) goto pte_unmap; + if (!arch_pte_access_permitted(pte, write)) + goto pte_unmap; + VM_BUG_ON(!pfn_valid(pte_pfn(pte))); page = pte_page(pte); head = compound_head(page); @@ -1467,3 +1519,38 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write, } #endif /* CONFIG_HAVE_GENERIC_RCU_GUP */ + +long get_user_pages8(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, unsigned long nr_pages, + int write, int force, struct page **pages, + struct vm_area_struct **vmas) +{ + WARN_ONCE(tsk != current, "get_user_pages() called on remote task"); + WARN_ONCE(mm != current->mm, "get_user_pages() called on remote mm"); + + return get_user_pages6(start, nr_pages, write, force, pages, vmas); +} +EXPORT_SYMBOL(get_user_pages8); + +long get_user_pages_locked8(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, unsigned long nr_pages, + int write, int force, struct page **pages, int *locked) +{ + WARN_ONCE(tsk != current, "get_user_pages_locked() called on remote task"); + WARN_ONCE(mm != current->mm, "get_user_pages_locked() called on remote mm"); + + return get_user_pages_locked6(start, nr_pages, write, force, pages, locked); +} +EXPORT_SYMBOL(get_user_pages_locked8); + +long get_user_pages_unlocked7(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, unsigned long nr_pages, + int write, int force, struct page **pages) +{ + WARN_ONCE(tsk != current, "get_user_pages_unlocked() called on remote task"); + WARN_ONCE(mm != current->mm, "get_user_pages_unlocked() called on remote mm"); + + return get_user_pages_unlocked5(start, nr_pages, write, force, pages); +} +EXPORT_SYMBOL(get_user_pages_unlocked7); + |