X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=mm%2Futil.c;h=d5259b62f8d770eca8a9b1921fdd603f5f8be998;hb=ec1daf23e45a1de48e382494cf7d972ec6ff7837;hp=ab1424dbe2e6c9396ee66ab4446f1bc1cd557382;hpb=91e14b294f3fe4d8b28516b21ceef187ea9b1bdf;p=firefly-linux-kernel-4.4.55.git diff --git a/mm/util.c b/mm/util.c index ab1424dbe2e6..d5259b62f8d7 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1,18 +1,40 @@ #include #include #include +#include #include #include #include #include #include #include +#include +#include +#include + +#include #include #include "internal.h" -#define CREATE_TRACE_POINTS -#include +static inline int is_kernel_rodata(unsigned long addr) +{ + return addr >= (unsigned long)__start_rodata && + addr < (unsigned long)__end_rodata; +} + +/** + * kfree_const - conditionally free memory + * @x: pointer to the memory + * + * Function calls kfree only if @x is not in .rodata section. + */ +void kfree_const(const void *x) +{ + if (!is_kernel_rodata((unsigned long)x)) + kfree(x); +} +EXPORT_SYMBOL(kfree_const); /** * kstrdup - allocate space for and copy an existing string @@ -35,6 +57,24 @@ char *kstrdup(const char *s, gfp_t gfp) } EXPORT_SYMBOL(kstrdup); +/** + * kstrdup_const - conditionally duplicate an existing const string + * @s: the string to duplicate + * @gfp: the GFP mask used in the kmalloc() call when allocating memory + * + * Function returns source string if it is in .rodata section otherwise it + * fallbacks to kstrdup. + * Strings allocated by kstrdup_const should be freed by kfree_const. + */ +const char *kstrdup_const(const char *s, gfp_t gfp) +{ + if (is_kernel_rodata((unsigned long)s)) + return s; + + return kstrdup(s, gfp); +} +EXPORT_SYMBOL(kstrdup_const); + /** * kstrndup - allocate space for and copy an existing string * @s: the string to duplicate @@ -107,97 +147,6 @@ void *memdup_user(const void __user *src, size_t len) } EXPORT_SYMBOL(memdup_user); -static __always_inline void *__do_krealloc(const void *p, size_t new_size, - gfp_t flags) -{ - void *ret; - size_t ks = 0; - - if (p) - ks = ksize(p); - - if (ks >= new_size) - return (void *)p; - - ret = kmalloc_track_caller(new_size, flags); - if (ret && p) - memcpy(ret, p, ks); - - return ret; -} - -/** - * __krealloc - like krealloc() but don't free @p. - * @p: object to reallocate memory for. - * @new_size: how many bytes of memory are required. - * @flags: the type of memory to allocate. - * - * This function is like krealloc() except it never frees the originally - * allocated buffer. Use this if you don't want to free the buffer immediately - * like, for example, with RCU. - */ -void *__krealloc(const void *p, size_t new_size, gfp_t flags) -{ - if (unlikely(!new_size)) - return ZERO_SIZE_PTR; - - return __do_krealloc(p, new_size, flags); - -} -EXPORT_SYMBOL(__krealloc); - -/** - * krealloc - reallocate memory. The contents will remain unchanged. - * @p: object to reallocate memory for. - * @new_size: how many bytes of memory are required. - * @flags: the type of memory to allocate. - * - * The contents of the object pointed to are preserved up to the - * lesser of the new and old sizes. If @p is %NULL, krealloc() - * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a - * %NULL pointer, the object pointed to is freed. - */ -void *krealloc(const void *p, size_t new_size, gfp_t flags) -{ - void *ret; - - if (unlikely(!new_size)) { - kfree(p); - return ZERO_SIZE_PTR; - } - - ret = __do_krealloc(p, new_size, flags); - if (ret && p != ret) - kfree(p); - - return ret; -} -EXPORT_SYMBOL(krealloc); - -/** - * kzfree - like kfree but zero memory - * @p: object to free memory of - * - * The memory of the object @p points to is zeroed before freed. - * If @p is %NULL, kzfree() does nothing. - * - * Note: this function zeroes the whole allocated buffer which can be a good - * deal bigger than the requested buffer size passed to kmalloc(). So be - * careful when using this function in performance sensitive code. - */ -void kzfree(const void *p) -{ - size_t ks; - void *mem = (void *)p; - - if (unlikely(ZERO_OR_NULL_PTR(mem))) - return; - ks = ksize(mem); - memset(mem, 0, ks); - kfree(mem); -} -EXPORT_SYMBOL(kzfree); - /* * strndup_user - duplicate an existing string from user space * @s: The string to duplicate @@ -250,52 +199,16 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, } /* Check if the vma is being used as a stack by this task */ -static int vm_is_stack_for_task(struct task_struct *t, - struct vm_area_struct *vma) +int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t) { return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t)); } -/* - * Check if the vma is being used as a stack. - * If is_group is non-zero, check in the entire thread group or else - * just check in the current task. Returns the pid of the task that - * the vma is stack for. - */ -pid_t vm_is_stack(struct task_struct *task, - struct vm_area_struct *vma, int in_group) -{ - pid_t ret = 0; - - if (vm_is_stack_for_task(task, vma)) - return task->pid; - - if (in_group) { - struct task_struct *t; - rcu_read_lock(); - if (!pid_alive(task)) - goto done; - - t = task; - do { - if (vm_is_stack_for_task(t, vma)) { - ret = t->pid; - goto done; - } - } while_each_thread(task, t); -done: - rcu_read_unlock(); - } - - return ret; -} - #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) void arch_pick_mmap_layout(struct mm_struct *mm) { mm->mmap_base = TASK_UNMAPPED_BASE; mm->get_unmapped_area = arch_get_unmapped_area; - mm->unmap_area = arch_unmap_area; } #endif @@ -305,7 +218,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm) * If the architecture not support this function, simply return with no * page pinned */ -int __attribute__((weak)) __get_user_pages_fast(unsigned long start, +int __weak __get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) { return 0; @@ -336,18 +249,12 @@ EXPORT_SYMBOL_GPL(__get_user_pages_fast); * callers need to carefully consider what to use. On many architectures, * get_user_pages_fast simply falls back to get_user_pages. */ -int __attribute__((weak)) get_user_pages_fast(unsigned long start, +int __weak get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) { struct mm_struct *mm = current->mm; - int ret; - - down_read(&mm->mmap_sem); - ret = get_user_pages(current, mm, start, nr_pages, - write, 0, pages, NULL); - up_read(&mm->mmap_sem); - - return ret; + return get_user_pages_unlocked(current, mm, start, nr_pages, + write, 0, pages); } EXPORT_SYMBOL_GPL(get_user_pages_fast); @@ -377,35 +284,157 @@ unsigned long vm_mmap(struct file *file, unsigned long addr, { if (unlikely(offset + PAGE_ALIGN(len) < offset)) return -EINVAL; - if (unlikely(offset & ~PAGE_MASK)) + if (unlikely(offset_in_page(offset))) return -EINVAL; return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT); } EXPORT_SYMBOL(vm_mmap); +void kvfree(const void *addr) +{ + if (is_vmalloc_addr(addr)) + vfree(addr); + else + kfree(addr); +} +EXPORT_SYMBOL(kvfree); + +static inline void *__page_rmapping(struct page *page) +{ + unsigned long mapping; + + mapping = (unsigned long)page->mapping; + mapping &= ~PAGE_MAPPING_FLAGS; + + return (void *)mapping; +} + +/* Neutral page->mapping pointer to address_space or anon_vma or other */ +void *page_rmapping(struct page *page) +{ + page = compound_head(page); + return __page_rmapping(page); +} + +struct anon_vma *page_anon_vma(struct page *page) +{ + unsigned long mapping; + + page = compound_head(page); + mapping = (unsigned long)page->mapping; + if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON) + return NULL; + return __page_rmapping(page); +} + struct address_space *page_mapping(struct page *page) { - struct address_space *mapping = page->mapping; + unsigned long mapping; + + /* This happens if someone calls flush_dcache_page on slab page */ + if (unlikely(PageSlab(page))) + return NULL; - VM_BUG_ON(PageSlab(page)); -#ifdef CONFIG_SWAP if (unlikely(PageSwapCache(page))) { swp_entry_t entry; entry.val = page_private(page); - mapping = swap_address_space(entry); - } else -#endif - if ((unsigned long)mapping & PAGE_MAPPING_ANON) - mapping = NULL; - return mapping; + return swap_address_space(entry); + } + + mapping = (unsigned long)page->mapping; + if (mapping & PAGE_MAPPING_FLAGS) + return NULL; + return page->mapping; } -/* Tracepoints definitions. */ -EXPORT_TRACEPOINT_SYMBOL(kmalloc); -EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); -EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); -EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); -EXPORT_TRACEPOINT_SYMBOL(kfree); -EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); +int overcommit_ratio_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret; + + ret = proc_dointvec(table, write, buffer, lenp, ppos); + if (ret == 0 && write) + sysctl_overcommit_kbytes = 0; + return ret; +} + +int overcommit_kbytes_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret; + + ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos); + if (ret == 0 && write) + sysctl_overcommit_ratio = 0; + return ret; +} + +/* + * Committed memory limit enforced when OVERCOMMIT_NEVER policy is used + */ +unsigned long vm_commit_limit(void) +{ + unsigned long allowed; + + if (sysctl_overcommit_kbytes) + allowed = sysctl_overcommit_kbytes >> (PAGE_SHIFT - 10); + else + allowed = ((totalram_pages - hugetlb_total_pages()) + * sysctl_overcommit_ratio / 100); + allowed += total_swap_pages; + + return allowed; +} + +/** + * get_cmdline() - copy the cmdline value to a buffer. + * @task: the task whose cmdline value to copy. + * @buffer: the buffer to copy to. + * @buflen: the length of the buffer. Larger cmdline values are truncated + * to this length. + * Returns the size of the cmdline field copied. Note that the copy does + * not guarantee an ending NULL byte. + */ +int get_cmdline(struct task_struct *task, char *buffer, int buflen) +{ + int res = 0; + unsigned int len; + struct mm_struct *mm = get_task_mm(task); + if (!mm) + goto out; + if (!mm->arg_end) + goto out_mm; /* Shh! No looking before we're done */ + + len = mm->arg_end - mm->arg_start; + + if (len > buflen) + len = buflen; + + res = access_process_vm(task, mm->arg_start, buffer, len, 0); + + /* + * If the nul at the end of args has been overwritten, then + * assume application is using setproctitle(3). + */ + if (res > 0 && buffer[res-1] != '\0' && len < buflen) { + len = strnlen(buffer, res); + if (len < res) { + res = len; + } else { + len = mm->env_end - mm->env_start; + if (len > buflen - res) + len = buflen - res; + res += access_process_vm(task, mm->env_start, + buffer+res, len, 0); + res = strnlen(buffer, res); + } + } +out_mm: + mmput(mm); +out: + return res; +}