mirror of
https://github.com/torvalds/linux
synced 2024-07-21 18:51:47 +00:00
uaccess: add generic __{get,put}_kernel_nofault
Nine architectures are still missing __{get,put}_kernel_nofault:
alpha, ia64, microblaze, nds32, nios2, openrisc, sh, sparc32, xtensa.
Add a generic version that lets everything use the normal
copy_{from,to}_kernel_nofault() code based on these, removing the last
use of get_fs()/set_fs() from architecture-independent code.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann
parent
90997c1280
commit
34737e2698
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@ -476,8 +476,6 @@ do { \
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: "r" (x), "i" (-EFAULT) \
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: "cc")
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#define HAVE_GET_KERNEL_NOFAULT
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#define __get_kernel_nofault(dst, src, type, err_label) \
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do { \
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const type *__pk_ptr = (src); \
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@ -26,8 +26,6 @@
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#include <asm/memory.h>
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#include <asm/extable.h>
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#define HAVE_GET_KERNEL_NOFAULT
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/*
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* Test whether a block of memory is a valid user space address.
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* Returns 1 if the range is valid, 0 otherwise.
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@ -390,8 +390,6 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
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#define INLINE_COPY_FROM_USER
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#define INLINE_COPY_TO_USER
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#define HAVE_GET_KERNEL_NOFAULT
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#define __get_kernel_nofault(dst, src, type, err_label) \
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do { \
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type *__gk_dst = (type *)(dst); \
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@ -296,8 +296,6 @@ struct __large_struct { unsigned long buf[100]; };
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(val) = __gu_tmp.t; \
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}
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#define HAVE_GET_KERNEL_NOFAULT
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#define __get_kernel_nofault(dst, src, type, err_label) \
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do { \
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int __gu_err; \
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@ -95,7 +95,6 @@ struct exception_table_entry {
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(val) = (__force __typeof__(*(ptr))) __gu_val; \
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}
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#define HAVE_GET_KERNEL_NOFAULT
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#define __get_kernel_nofault(dst, src, type, err_label) \
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{ \
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type __z; \
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@ -467,8 +467,6 @@ do { \
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unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \
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} while (0)
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#define HAVE_GET_KERNEL_NOFAULT
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#define __get_kernel_nofault(dst, src, type, err_label) \
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__get_user_size_goto(*((type *)(dst)), \
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(__force type __user *)(src), sizeof(type), err_label)
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@ -346,8 +346,6 @@ unsigned long __must_check clear_user(void __user *to, unsigned long n)
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__clear_user(to, n) : n;
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}
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#define HAVE_GET_KERNEL_NOFAULT
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#define __get_kernel_nofault(dst, src, type, err_label) \
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do { \
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long __kr_err; \
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@ -282,8 +282,6 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo
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int copy_to_user_real(void __user *dest, void *src, unsigned long count);
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void *s390_kernel_write(void *dst, const void *src, size_t size);
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#define HAVE_GET_KERNEL_NOFAULT
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int __noreturn __put_kernel_bad(void);
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#define __put_kernel_asm(val, to, insn) \
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@ -210,8 +210,6 @@ __asm__ __volatile__( \
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: "=r" (ret), "=r" (x) : "r" (__m(addr)), \
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"i" (-EFAULT))
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#define HAVE_GET_KERNEL_NOFAULT
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#define __get_user_nocheck(data, addr, size, type) ({ \
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register int __gu_ret; \
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register unsigned long __gu_val; \
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@ -44,8 +44,6 @@ static inline int __access_ok(unsigned long addr, unsigned long size)
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}
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/* no pagefaults for kernel addresses in um */
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#define HAVE_GET_KERNEL_NOFAULT 1
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#define __get_kernel_nofault(dst, src, type, err_label) \
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do { \
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*((type *)dst) = get_unaligned((type *)(src)); \
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@ -507,8 +507,6 @@ do { \
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unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \
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} while (0)
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#define HAVE_GET_KERNEL_NOFAULT
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#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
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#define __get_kernel_nofault(dst, src, type, err_label) \
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__get_user_size(*((type *)(dst)), (__force type __user *)(src), \
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@ -77,8 +77,6 @@ do { \
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goto err_label; \
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} while (0)
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#define HAVE_GET_KERNEL_NOFAULT 1
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static inline __must_check unsigned long
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raw_copy_from_user(void *to, const void __user * from, unsigned long n)
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{
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@ -368,6 +368,25 @@ long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
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long count);
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long strnlen_user_nofault(const void __user *unsafe_addr, long count);
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#ifndef __get_kernel_nofault
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#define __get_kernel_nofault(dst, src, type, label) \
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do { \
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type __user *p = (type __force __user *)(src); \
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type data; \
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if (__get_user(data, p)) \
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goto label; \
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*(type *)dst = data; \
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} while (0)
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#define __put_kernel_nofault(dst, src, type, label) \
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do { \
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type __user *p = (type __force __user *)(dst); \
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type data = *(type *)src; \
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if (__put_user(data, p)) \
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goto label; \
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} while (0)
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#endif
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/**
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* get_kernel_nofault(): safely attempt to read from a location
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* @val: read into this variable
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108
mm/maccess.c
108
mm/maccess.c
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@ -12,8 +12,6 @@ bool __weak copy_from_kernel_nofault_allowed(const void *unsafe_src,
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return true;
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}
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#ifdef HAVE_GET_KERNEL_NOFAULT
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#define copy_from_kernel_nofault_loop(dst, src, len, type, err_label) \
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while (len >= sizeof(type)) { \
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__get_kernel_nofault(dst, src, type, err_label); \
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@ -102,112 +100,6 @@ long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
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dst[-1] = '\0';
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return -EFAULT;
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}
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#else /* HAVE_GET_KERNEL_NOFAULT */
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/**
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* copy_from_kernel_nofault(): safely attempt to read from kernel-space
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* @dst: pointer to the buffer that shall take the data
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* @src: address to read from
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* @size: size of the data chunk
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*
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* Safely read from kernel address @src to the buffer at @dst. If a kernel
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* fault happens, handle that and return -EFAULT. If @src is not a valid kernel
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* address, return -ERANGE.
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*
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* We ensure that the copy_from_user is executed in atomic context so that
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* do_page_fault() doesn't attempt to take mmap_lock. This makes
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* copy_from_kernel_nofault() suitable for use within regions where the caller
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* already holds mmap_lock, or other locks which nest inside mmap_lock.
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*/
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long copy_from_kernel_nofault(void *dst, const void *src, size_t size)
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{
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long ret;
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mm_segment_t old_fs = get_fs();
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if (!copy_from_kernel_nofault_allowed(src, size))
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return -ERANGE;
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set_fs(KERNEL_DS);
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pagefault_disable();
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ret = __copy_from_user_inatomic(dst, (__force const void __user *)src,
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size);
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pagefault_enable();
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set_fs(old_fs);
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if (ret)
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return -EFAULT;
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return 0;
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}
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EXPORT_SYMBOL_GPL(copy_from_kernel_nofault);
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/**
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* copy_to_kernel_nofault(): safely attempt to write to a location
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* @dst: address to write to
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* @src: pointer to the data that shall be written
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* @size: size of the data chunk
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*
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* Safely write to address @dst from the buffer at @src. If a kernel fault
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* happens, handle that and return -EFAULT.
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*/
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long copy_to_kernel_nofault(void *dst, const void *src, size_t size)
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{
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long ret;
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mm_segment_t old_fs = get_fs();
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set_fs(KERNEL_DS);
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pagefault_disable();
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ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
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pagefault_enable();
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set_fs(old_fs);
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if (ret)
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return -EFAULT;
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return 0;
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}
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/**
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* strncpy_from_kernel_nofault: - Copy a NUL terminated string from unsafe
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* address.
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* @dst: Destination address, in kernel space. This buffer must be at
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* least @count bytes long.
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* @unsafe_addr: Unsafe address.
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* @count: Maximum number of bytes to copy, including the trailing NUL.
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*
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* Copies a NUL-terminated string from unsafe address to kernel buffer.
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*
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* On success, returns the length of the string INCLUDING the trailing NUL.
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*
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* If access fails, returns -EFAULT (some data may have been copied and the
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* trailing NUL added). If @unsafe_addr is not a valid kernel address, return
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* -ERANGE.
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*
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* If @count is smaller than the length of the string, copies @count-1 bytes,
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* sets the last byte of @dst buffer to NUL and returns @count.
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*/
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long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
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{
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mm_segment_t old_fs = get_fs();
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const void *src = unsafe_addr;
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long ret;
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if (unlikely(count <= 0))
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return 0;
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if (!copy_from_kernel_nofault_allowed(unsafe_addr, count))
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return -ERANGE;
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set_fs(KERNEL_DS);
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pagefault_disable();
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do {
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ret = __get_user(*dst++, (const char __user __force *)src++);
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} while (dst[-1] && ret == 0 && src - unsafe_addr < count);
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dst[-1] = '\0';
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pagefault_enable();
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set_fs(old_fs);
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return ret ? -EFAULT : src - unsafe_addr;
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}
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#endif /* HAVE_GET_KERNEL_NOFAULT */
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/**
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* copy_from_user_nofault(): safely attempt to read from a user-space location
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