diff options
Diffstat (limited to 'mm/nommu.c')
| -rw-r--r-- | mm/nommu.c | 150 |
1 files changed, 123 insertions, 27 deletions
diff --git a/mm/nommu.c b/mm/nommu.c index 9cb6e99215e2..b624acec6d2e 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -42,18 +42,11 @@ #include <asm/mmu_context.h> #include "internal.h" -void *high_memory; -EXPORT_SYMBOL(high_memory); -struct page *mem_map; -unsigned long max_mapnr; -EXPORT_SYMBOL(max_mapnr); unsigned long highest_memmap_pfn; -int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS; int heap_stack_gap = 0; atomic_long_t mmap_pages_allocated; -EXPORT_SYMBOL(mem_map); /* list of mapped, potentially shareable regions */ static struct kmem_cache *vm_region_jar; @@ -207,7 +200,23 @@ void *vmalloc_noprof(unsigned long size) } EXPORT_SYMBOL(vmalloc_noprof); -void *vmalloc_huge_noprof(unsigned long size, gfp_t gfp_mask) __weak __alias(__vmalloc_noprof); +/* + * vmalloc_huge_node - allocate virtually contiguous memory, on a node + * + * @size: allocation size + * @gfp_mask: flags for the page level allocator + * @node: node to use for allocation or NUMA_NO_NODE + * + * Allocate enough pages to cover @size from the page level + * allocator and map them into contiguous kernel virtual space. + * + * Due to NOMMU implications the node argument and HUGE page attribute is + * ignored. + */ +void *vmalloc_huge_node_noprof(unsigned long size, gfp_t gfp_mask, int node) +{ + return __vmalloc_noprof(size, gfp_mask); +} /* * vzalloc - allocate virtually contiguous memory with zero fill @@ -392,8 +401,22 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) return mm->brk = brk; } +static int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS; + +static const struct ctl_table nommu_table[] = { + { + .procname = "nr_trim_pages", + .data = &sysctl_nr_trim_pages, + .maxlen = sizeof(sysctl_nr_trim_pages), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + }, +}; + /* - * initialise the percpu counter for VM and region record slabs + * initialise the percpu counter for VM and region record slabs, initialise VMA + * state. */ void __init mmap_init(void) { @@ -402,6 +425,8 @@ void __init mmap_init(void) ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); VM_BUG_ON(ret); vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT); + register_sysctl_init("vm", nommu_table); + vma_state_init(); } /* @@ -620,22 +645,6 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) EXPORT_SYMBOL(find_vma); /* - * At least xtensa ends up having protection faults even with no - * MMU.. No stack expansion, at least. - */ -struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm, - unsigned long addr, struct pt_regs *regs) -{ - struct vm_area_struct *vma; - - mmap_read_lock(mm); - vma = vma_lookup(mm, addr); - if (!vma) - mmap_read_unlock(mm); - return vma; -} - -/* * expand a stack to a given address * - not supported under NOMMU conditions */ @@ -1191,7 +1200,7 @@ share: setup_vma_to_mm(vma, current->mm); current->mm->map_count++; /* add the VMA to the tree */ - vma_iter_store(&vmi, vma); + vma_iter_store_new(&vmi, vma); /* we flush the region from the icache only when the first executable * mapping of it is made */ @@ -1356,7 +1365,7 @@ static int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, setup_vma_to_mm(vma, mm); setup_vma_to_mm(new, mm); - vma_iter_store(vmi, new); + vma_iter_store_new(vmi, new); mm->map_count++; return 0; @@ -1701,6 +1710,85 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in } EXPORT_SYMBOL_GPL(access_process_vm); +#ifdef CONFIG_BPF_SYSCALL +/* + * Copy a string from another process's address space as given in mm. + * If there is any error return -EFAULT. + */ +static int __copy_remote_vm_str(struct mm_struct *mm, unsigned long addr, + void *buf, int len) +{ + unsigned long addr_end; + struct vm_area_struct *vma; + int ret = -EFAULT; + + *(char *)buf = '\0'; + + if (mmap_read_lock_killable(mm)) + return ret; + + /* the access must start within one of the target process's mappings */ + vma = find_vma(mm, addr); + if (!vma) + goto out; + + if (check_add_overflow(addr, len, &addr_end)) + goto out; + + /* don't overrun this mapping */ + if (addr_end > vma->vm_end) + len = vma->vm_end - addr; + + /* only read mappings where it is permitted */ + if (vma->vm_flags & VM_MAYREAD) { + ret = strscpy(buf, (char *)addr, len); + if (ret < 0) + ret = len - 1; + } + +out: + mmap_read_unlock(mm); + return ret; +} + +/** + * copy_remote_vm_str - copy a string from another process's address space. + * @tsk: the task of the target address space + * @addr: start address to read from + * @buf: destination buffer + * @len: number of bytes to copy + * @gup_flags: flags modifying lookup behaviour (unused) + * + * The caller must hold a reference on @mm. + * + * Return: number of bytes copied from @addr (source) to @buf (destination); + * not including the trailing NUL. Always guaranteed to leave NUL-terminated + * buffer. On any error, return -EFAULT. + */ +int copy_remote_vm_str(struct task_struct *tsk, unsigned long addr, + void *buf, int len, unsigned int gup_flags) +{ + struct mm_struct *mm; + int ret; + + if (unlikely(len == 0)) + return 0; + + mm = get_task_mm(tsk); + if (!mm) { + *(char *)buf = '\0'; + return -EFAULT; + } + + ret = __copy_remote_vm_str(mm, addr, buf, len); + + mmput(mm); + + return ret; +} +EXPORT_SYMBOL_GPL(copy_remote_vm_str); +#endif /* CONFIG_BPF_SYSCALL */ + /** * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode * @inode: The inode to check @@ -1804,3 +1892,11 @@ static int __meminit init_admin_reserve(void) return 0; } subsys_initcall(init_admin_reserve); + +int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) +{ + mmap_write_lock(oldmm); + dup_mm_exe_file(mm, oldmm); + mmap_write_unlock(oldmm); + return 0; +} |