new helper: uaccess_kernel()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/alpha/include/asm/uaccess.h

@@ -425,7 +425,7 @@ clear_user(void __user *to, long len)
 #undef __module_call
 
 #define user_addr_max() \
-        (segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL)
+        (uaccess_kernel() ? ~0UL : TASK_SIZE)
 
 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 extern __must_check long strlen_user(const char __user *str);

arch/arc/include/asm/uaccess.h

@@ -27,7 +27,7 @@
 #include <linux/string.h>	/* for generic string functions */
 
 
-#define __kernel_ok		(segment_eq(get_fs(), KERNEL_DS))
+#define __kernel_ok		(uaccess_kernel())
 
 /*
  * Algorithmically, for __user_ok() we want do:

arch/arm/include/asm/uaccess.h

@@ -266,7 +266,7 @@ static inline void set_fs(mm_segment_t fs)
 #define access_ok(type, addr, size)	(__range_ok(addr, size) == 0)
 
 #define user_addr_max() \
-	(segment_eq(get_fs(), KERNEL_DS) ? ~0UL : get_fs())
+	(uaccess_kernel() ? ~0UL : get_fs())
 
 /*
  * The "__xxx" versions of the user access functions do not verify the

arch/arm/lib/uaccess_with_memcpy.c

@@ -90,7 +90,7 @@ __copy_to_user_memcpy(void __user *to, const void *from, unsigned long n)
 	unsigned long ua_flags;
 	int atomic;
 
-	if (unlikely(segment_eq(get_fs(), KERNEL_DS))) {
+	if (uaccess_kernel()) {
 		memcpy((void *)to, from, n);
 		return 0;
 	}
@@ -162,7 +162,7 @@ __clear_user_memset(void __user *addr, unsigned long n)
 {
 	unsigned long ua_flags;
 
-	if (unlikely(segment_eq(get_fs(), KERNEL_DS))) {
+	if (uaccess_kernel()) {
 		memset((void *)addr, 0, n);
 		return 0;
 	}

arch/blackfin/kernel/process.c

@@ -370,7 +370,7 @@ int _access_ok(unsigned long addr, unsigned long size)
 	/* Check that things do not wrap around */
 	if (addr > ULONG_MAX - size)
 		return 0;
-	if (segment_eq(get_fs(), KERNEL_DS))
+	if (uaccess_kernel())
 		return 1;
 #ifdef CONFIG_MTD_UCLINUX
 	if (1)

arch/c6x/kernel/sys_c6x.c

@@ -23,7 +23,7 @@ int _access_ok(unsigned long addr, unsigned long size)
 	if (!addr || addr > (0xffffffffUL - (size - 1)))
 		goto _bad_access;
 
-	if (segment_eq(get_fs(), KERNEL_DS))
+	if (uaccess_kernel())
 		return 1;
 
 	if (memory_start <= addr && (addr + size - 1) < memory_end)

arch/cris/include/asm/uaccess.h

@@ -43,7 +43,7 @@
 
 #define segment_eq(a, b)	((a).seg == (b).seg)
 
-#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
+#define __kernel_ok (uaccess_kernel())
 #define __user_ok(addr, size) \
 	(((size) <= TASK_SIZE) && ((addr) <= TASK_SIZE-(size)))
 #define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))

arch/m68k/include/asm/uaccess_mm.h

@@ -375,7 +375,7 @@ __constant_copy_to_user(void __user *to, const void *from, unsigned long n)
 #define copy_to_user(to, from, n)	__copy_to_user(to, from, n)
 
 #define user_addr_max() \
-	(segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL)
+	(uaccess_kernel() ? ~0UL : TASK_SIZE)
 
 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 extern __must_check long strlen_user(const char __user *str);

arch/metag/include/asm/uaccess.h

@@ -24,7 +24,7 @@
 
 #define segment_eq(a, b)	((a).seg == (b).seg)
 
-#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
+#define __kernel_ok (uaccess_kernel())
 /*
  * Explicitly allow NULL pointers here. Parts of the kernel such
  * as readv/writev use access_ok to validate pointers, but want

arch/mips/include/asm/checksum.h

@@ -50,7 +50,7 @@ __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,
 				   __wsum sum, int *err_ptr)
 {
 	might_fault();
-	if (segment_eq(get_fs(), get_ds()))
+	if (uaccess_kernel())
 		return __csum_partial_copy_kernel((__force void *)src, dst,
 						  len, sum, err_ptr);
 	else
@@ -82,7 +82,7 @@ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
 {
 	might_fault();
 	if (access_ok(VERIFY_WRITE, dst, len)) {
-		if (segment_eq(get_fs(), get_ds()))
+		if (uaccess_kernel())
 			return __csum_partial_copy_kernel(src,
 							  (__force void *)dst,
 							  len, sum, err_ptr);

arch/mips/include/asm/r4kcache.h

@@ -20,7 +20,7 @@
 #include <asm/cpu-features.h>
 #include <asm/cpu-type.h>
 #include <asm/mipsmtregs.h>
-#include <linux/uaccess.h> /* for segment_eq() */
+#include <linux/uaccess.h> /* for uaccess_kernel() */
 
 extern void (*r4k_blast_dcache)(void);
 extern void (*r4k_blast_icache)(void);
@@ -714,7 +714,7 @@ static inline void protected_blast_##pfx##cache##_range(unsigned long start,\
 									\
 	__##pfx##flush_prologue						\
 									\
-	if (segment_eq(get_fs(), USER_DS)) {				\
+	if (!uaccess_kernel()) {					\
 		while (1) {						\
 			protected_cachee_op(hitop, addr);		\
 			if (addr == aend)				\

arch/mips/include/asm/uaccess.h

@@ -88,7 +88,7 @@ static inline bool eva_kernel_access(void)
 	if (!IS_ENABLED(CONFIG_EVA))
 		return false;
 
-	return segment_eq(get_fs(), get_ds());
+	return uaccess_kernel();
 }
 
 /*

arch/mips/kernel/unaligned.c

@@ -1026,7 +1026,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
 			goto sigbus;
 
 		if (IS_ENABLED(CONFIG_EVA)) {
-			if (segment_eq(get_fs(), get_ds()))
+			if (uaccess_kernel())
 				LoadHW(addr, value, res);
 			else
 				LoadHWE(addr, value, res);
@@ -1045,7 +1045,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
 			goto sigbus;
 
 		if (IS_ENABLED(CONFIG_EVA)) {
-			if (segment_eq(get_fs(), get_ds()))
+			if (uaccess_kernel())
 				LoadW(addr, value, res);
 			else
 				LoadWE(addr, value, res);
@@ -1064,7 +1064,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
 			goto sigbus;
 
 		if (IS_ENABLED(CONFIG_EVA)) {
-			if (segment_eq(get_fs(), get_ds()))
+			if (uaccess_kernel())
 				LoadHWU(addr, value, res);
 			else
 				LoadHWUE(addr, value, res);
@@ -1132,7 +1132,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
 		value = regs->regs[insn.i_format.rt];
 
 		if (IS_ENABLED(CONFIG_EVA)) {
-			if (segment_eq(get_fs(), get_ds()))
+			if (uaccess_kernel())
 				StoreHW(addr, value, res);
 			else
 				StoreHWE(addr, value, res);
@@ -1152,7 +1152,7 @@ static void emulate_load_store_insn(struct pt_regs *regs,
 		value = regs->regs[insn.i_format.rt];
 
 		if (IS_ENABLED(CONFIG_EVA)) {
-			if (segment_eq(get_fs(), get_ds()))
+			if (uaccess_kernel())
 				StoreW(addr, value, res);
 			else
 				StoreWE(addr, value, res);

arch/openrisc/include/asm/uaccess.h

@@ -292,7 +292,7 @@ clear_user(void *addr, unsigned long size)
 }
 
 #define user_addr_max() \
-	(segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL)
+	(uaccess_kernel() ? ~0UL : TASK_SIZE)
 
 extern long strncpy_from_user(char *dest, const char __user *src, long count);
 

arch/parisc/include/asm/futex.h

@@ -109,7 +109,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 	/* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
 	 * our gateway page, and causes no end of trouble...
 	 */
-	if (segment_eq(KERNEL_DS, get_fs()) && !uaddr)
+	if (uaccess_kernel() && !uaddr)
 		return -EFAULT;
 
 	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))

arch/parisc/lib/memcpy.c

@@ -76,7 +76,7 @@ DECLARE_PER_CPU(struct exception_data, exception_data);
 		goto label;						\
 } while (0)
 
-#define get_user_space() (segment_eq(get_fs(), KERNEL_DS) ? 0 : mfsp(3))
+#define get_user_space() (uaccess_kernel() ? 0 : mfsp(3))
 #define get_kernel_space() (0)
 
 #define MERGE(w0, sh_1, w1, sh_2)  ({					\

arch/s390/include/asm/uaccess.h

@@ -37,7 +37,7 @@
 static inline void set_fs(mm_segment_t fs)
 {
 	current->thread.mm_segment = fs;
-	if (segment_eq(fs, KERNEL_DS)) {
+	if (uaccess_kernel()) {
 		set_cpu_flag(CIF_ASCE_SECONDARY);
 		__ctl_load(S390_lowcore.kernel_asce, 7, 7);
 	} else {

arch/sparc/include/asm/uaccess.h

@@ -7,7 +7,7 @@
 #endif
 
 #define user_addr_max() \
-	(segment_eq(get_fs(), USER_DS) ? TASK_SIZE : ~0UL)
+	(uaccess_kernel() ? ~0UL : TASK_SIZE)
 
 long strncpy_from_user(char *dest, const char __user *src, long count);
 

arch/sparc/include/asm/uaccess_32.h

@@ -36,7 +36,7 @@
  * large size and address near to PAGE_OFFSET - a fault will break his intentions.
  */
 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; })
-#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
+#define __kernel_ok (uaccess_kernel())
 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size)))
 #define access_ok(type, addr, size) \
 	({ (void)(type); __access_ok((unsigned long)(addr), size); })

arch/um/include/asm/uaccess.h

@@ -45,7 +45,7 @@ static inline int __access_ok(unsigned long addr, unsigned long size)
 	return __addr_range_nowrap(addr, size) &&
 		(__under_task_size(addr, size) ||
 		__access_ok_vsyscall(addr, size) ||
-		segment_eq(get_fs(), KERNEL_DS));
+		uaccess_kernel());
 }
 
 #endif

arch/um/kernel/skas/uaccess.c

@@ -141,7 +141,7 @@ static int copy_chunk_from_user(unsigned long from, int len, void *arg)
 
 long __copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	if (segment_eq(get_fs(), KERNEL_DS)) {
+	if (uaccess_kernel()) {
 		memcpy(to, (__force void*)from, n);
 		return 0;
 	}
@@ -161,7 +161,7 @@ static int copy_chunk_to_user(unsigned long to, int len, void *arg)
 
 long __copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-	if (segment_eq(get_fs(), KERNEL_DS)) {
+	if (uaccess_kernel()) {
 		memcpy((__force void *) to, from, n);
 		return 0;
 	}
@@ -189,7 +189,7 @@ long __strncpy_from_user(char *dst, const char __user *src, long count)
 	long n;
 	char *ptr = dst;
 
-	if (segment_eq(get_fs(), KERNEL_DS)) {
+	if (uaccess_kernel()) {
 		strncpy(dst, (__force void *) src, count);
 		return strnlen(dst, count);
 	}
@@ -210,7 +210,7 @@ static int clear_chunk(unsigned long addr, int len, void *unused)
 
 unsigned long __clear_user(void __user *mem, unsigned long len)
 {
-	if (segment_eq(get_fs(), KERNEL_DS)) {
+	if (uaccess_kernel()) {
 		memset((__force void*)mem, 0, len);
 		return 0;
 	}
@@ -235,7 +235,7 @@ long __strnlen_user(const void __user *str, long len)
 {
 	int count = 0, n;
 
-	if (segment_eq(get_fs(), KERNEL_DS))
+	if (uaccess_kernel())
 		return strnlen((__force char*)str, len) + 1;
 
 	n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);

arch/unicore32/include/asm/uaccess.h

@@ -20,7 +20,7 @@
 #define __strnlen_user		__strnlen_user
 #define __clear_user		__clear_user
 
-#define __kernel_ok		(segment_eq(get_fs(), KERNEL_DS))
+#define __kernel_ok		(uaccess_kernel())
 #define __user_ok(addr, size)	(((size) <= TASK_SIZE)			\
 				&& ((addr) <= TASK_SIZE - (size)))
 #define __access_ok(addr, size)	(__kernel_ok || __user_ok((addr), (size)))

arch/unicore32/kernel/process.c

@@ -178,7 +178,7 @@ void __show_regs(struct pt_regs *regs)
 		buf, interrupts_enabled(regs) ? "n" : "ff",
 		fast_interrupts_enabled(regs) ? "n" : "ff",
 		processor_modes[processor_mode(regs)],
-		segment_eq(get_fs(), get_ds()) ? "kernel" : "user");
+		uaccess_kernel() ? "kernel" : "user");
 	{
 		unsigned int ctrl;
 

arch/xtensa/include/asm/uaccess.h

@@ -37,7 +37,7 @@
 
 #define segment_eq(a, b)	((a).seg == (b).seg)
 
-#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
+#define __kernel_ok (uaccess_kernel())
 #define __user_ok(addr, size) \
 		(((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size)))
 #define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))

block/bsg.c

@@ -650,7 +650,7 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 
 	dprintk("%s: write %zd bytes\n", bd->name, count);
 
-	if (unlikely(segment_eq(get_fs(), KERNEL_DS)))
+	if (unlikely(uaccess_kernel()))
 		return -EINVAL;
 
 	bsg_set_block(bd, file);

drivers/scsi/sg.c

@@ -581,7 +581,7 @@ sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
 	sg_io_hdr_t *hp;
 	unsigned char cmnd[SG_MAX_CDB_SIZE];
 
-	if (unlikely(segment_eq(get_fs(), KERNEL_DS)))
+	if (unlikely(uaccess_kernel()))
 		return -EINVAL;
 
 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))

include/linux/uaccess.h

@@ -7,6 +7,8 @@
 #define VERIFY_READ 0
 #define VERIFY_WRITE 1
 
+#define uaccess_kernel() segment_eq(get_fs(), KERNEL_DS)
+
 #include <asm/uaccess.h>
 
 static __always_inline void pagefault_disabled_inc(void)

include/rdma/ib.h

@@ -100,7 +100,7 @@ struct sockaddr_ib {
  */
 static inline bool ib_safe_file_access(struct file *filp)
 {
-	return filp->f_cred == current_cred() && segment_eq(get_fs(), USER_DS);
+	return filp->f_cred == current_cred() && !uaccess_kernel();
 }
 
 #endif /* _RDMA_IB_H */

kernel/trace/bpf_trace.c

@@ -96,7 +96,7 @@ BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
 	if (unlikely(in_interrupt() ||
 		     current->flags & (PF_KTHREAD | PF_EXITING)))
 		return -EPERM;
-	if (unlikely(segment_eq(get_fs(), KERNEL_DS)))
+	if (unlikely(uaccess_kernel()))
 		return -EPERM;
 	if (!access_ok(VERIFY_WRITE, unsafe_ptr, size))
 		return -EPERM;

lib/iov_iter.c

@@ -413,7 +413,7 @@ void iov_iter_init(struct iov_iter *i, int direction,
 			size_t count)
 {
 	/* It will get better.  Eventually... */
-	if (segment_eq(get_fs(), KERNEL_DS)) {
+	if (uaccess_kernel()) {
 		direction |= ITER_KVEC;
 		i->type = direction;
 		i->kvec = (struct kvec *)iov;

mm/memory.c

@@ -4136,7 +4136,7 @@ void __might_fault(const char *file, int line)
 	 * get paged out, therefore we'll never actually fault, and the
 	 * below annotations will generate false positives.
 	 */
-	if (segment_eq(get_fs(), KERNEL_DS))
+	if (uaccess_kernel())
 		return;
 	if (pagefault_disabled())
 		return;

security/tomoyo/network.c

@@ -608,7 +608,7 @@ static int tomoyo_check_unix_address(struct sockaddr *addr,
 static bool tomoyo_kernel_service(void)
 {
 	/* Nothing to do if I am a kernel service. */
-	return segment_eq(get_fs(), KERNEL_DS);
+	return uaccess_kernel();
 }
 
 /**