diff mbox series

[1/2] riscv: consolidate __ex_table construction

Message ID 20211017000443.4275747d@xhacker (mailing list archive)
State New, archived
Headers show
Series riscv: switch to relative extable | expand

Commit Message

Jisheng Zhang Oct. 16, 2021, 4:04 p.m. UTC 
From: Jisheng Zhang <jszhang@kernel.org>

Consolidate all the __ex_table constuction code with a _ASM_EXTABLE
helper.

There should be no functional change as a result of this patch.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 arch/riscv/include/asm/futex.h   | 12 +++-------
 arch/riscv/include/asm/uaccess.h | 40 +++++++++++---------------------
 2 files changed, 17 insertions(+), 35 deletions(-)

Comments

kernel test robot Oct. 18, 2021, 12:14 a.m. UTC | #1 
Hi Jisheng,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v5.15-rc5 next-20211015]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Jisheng-Zhang/riscv-switch-to-relative-extable/20211017-001318
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 8fe31e0995f048d16b378b90926793a0aa4af1e5
config: riscv-randconfig-r032-20211017 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 746dd6a700931988dd9021d3d04718f1929885a5)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://github.com/0day-ci/linux/commit/23c273bf6ec4ca672a21dba701725087208dc784
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Jisheng-Zhang/riscv-switch-to-relative-extable/20211017-001318
        git checkout 23c273bf6ec4ca672a21dba701725087208dc784
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from kernel/futex.c:36:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:10:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __raw_readb(PCI_IOBASE + addr);
                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu'
   #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
                                                     ^
   In file included from kernel/futex.c:36:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:10:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
                                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu'
   #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
                                                     ^
   In file included from kernel/futex.c:36:
   In file included from include/linux/pagemap.h:11:
   In file included from include/linux/highmem.h:10:
   In file included from include/linux/hardirq.h:11:
   In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
   In file included from include/asm-generic/hardirq.h:17:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:13:
   In file included from arch/riscv/include/asm/io.h:136:
   include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
                                                         ~~~~~~~~~~ ^
   include/asm-generic/io.h:1024:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
                                                     ~~~~~~~~~~ ^
   In file included from kernel/futex.c:43:
>> arch/riscv/include/asm/futex.h:51:3: error: expected ')'
                   __futex_atomic_op("amoswap.w.aqrl %[ov],%z[op],%[u]",
                   ^
   arch/riscv/include/asm/futex.h:33:3: note: expanded from macro '__futex_atomic_op'
                   _ASM_EXTABLE(1b, 3b)                            \
                   ^
   arch/riscv/include/asm/futex.h:55:3: error: expected ')'
                   __futex_atomic_op("amoadd.w.aqrl %[ov],%z[op],%[u]",
                   ^
   arch/riscv/include/asm/futex.h:33:3: note: expanded from macro '__futex_atomic_op'
                   _ASM_EXTABLE(1b, 3b)                            \
                   ^
   arch/riscv/include/asm/futex.h:59:3: error: expected ')'
                   __futex_atomic_op("amoor.w.aqrl %[ov],%z[op],%[u]",
                   ^
   arch/riscv/include/asm/futex.h:33:3: note: expanded from macro '__futex_atomic_op'
                   _ASM_EXTABLE(1b, 3b)                            \
                   ^
   arch/riscv/include/asm/futex.h:63:3: error: expected ')'
                   __futex_atomic_op("amoand.w.aqrl %[ov],%z[op],%[u]",
                   ^
   arch/riscv/include/asm/futex.h:33:3: note: expanded from macro '__futex_atomic_op'
                   _ASM_EXTABLE(1b, 3b)                            \
                   ^
   arch/riscv/include/asm/futex.h:67:3: error: expected ')'
                   __futex_atomic_op("amoxor.w.aqrl %[ov],%z[op],%[u]",
                   ^
   arch/riscv/include/asm/futex.h:33:3: note: expanded from macro '__futex_atomic_op'
                   _ASM_EXTABLE(1b, 3b)                            \
                   ^
   arch/riscv/include/asm/futex.h:103:3: error: expected ')'
                   _ASM_EXTABLE(1b, 4b)                    \
                   ^
   7 warnings and 6 errors generated.


vim +51 arch/riscv/include/asm/futex.h

b90edb33010bcf Jim Wilson 2018-10-16  40  
b90edb33010bcf Jim Wilson 2018-10-16  41  static inline int
b90edb33010bcf Jim Wilson 2018-10-16  42  arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
b90edb33010bcf Jim Wilson 2018-10-16  43  {
b90edb33010bcf Jim Wilson 2018-10-16  44  	int oldval = 0, ret = 0;
b90edb33010bcf Jim Wilson 2018-10-16  45  
a08971e9488d12 Al Viro    2020-02-16  46  	if (!access_ok(uaddr, sizeof(u32)))
a08971e9488d12 Al Viro    2020-02-16  47  		return -EFAULT;
b90edb33010bcf Jim Wilson 2018-10-16  48  
b90edb33010bcf Jim Wilson 2018-10-16  49  	switch (op) {
b90edb33010bcf Jim Wilson 2018-10-16  50  	case FUTEX_OP_SET:
b90edb33010bcf Jim Wilson 2018-10-16 @51  		__futex_atomic_op("amoswap.w.aqrl %[ov],%z[op],%[u]",
b90edb33010bcf Jim Wilson 2018-10-16  52  				  ret, oldval, uaddr, oparg);
b90edb33010bcf Jim Wilson 2018-10-16  53  		break;
b90edb33010bcf Jim Wilson 2018-10-16  54  	case FUTEX_OP_ADD:
b90edb33010bcf Jim Wilson 2018-10-16  55  		__futex_atomic_op("amoadd.w.aqrl %[ov],%z[op],%[u]",
b90edb33010bcf Jim Wilson 2018-10-16  56  				  ret, oldval, uaddr, oparg);
b90edb33010bcf Jim Wilson 2018-10-16  57  		break;
b90edb33010bcf Jim Wilson 2018-10-16  58  	case FUTEX_OP_OR:
b90edb33010bcf Jim Wilson 2018-10-16  59  		__futex_atomic_op("amoor.w.aqrl %[ov],%z[op],%[u]",
b90edb33010bcf Jim Wilson 2018-10-16  60  				  ret, oldval, uaddr, oparg);
b90edb33010bcf Jim Wilson 2018-10-16  61  		break;
b90edb33010bcf Jim Wilson 2018-10-16  62  	case FUTEX_OP_ANDN:
b90edb33010bcf Jim Wilson 2018-10-16  63  		__futex_atomic_op("amoand.w.aqrl %[ov],%z[op],%[u]",
b90edb33010bcf Jim Wilson 2018-10-16  64  				  ret, oldval, uaddr, ~oparg);
b90edb33010bcf Jim Wilson 2018-10-16  65  		break;
b90edb33010bcf Jim Wilson 2018-10-16  66  	case FUTEX_OP_XOR:
b90edb33010bcf Jim Wilson 2018-10-16  67  		__futex_atomic_op("amoxor.w.aqrl %[ov],%z[op],%[u]",
b90edb33010bcf Jim Wilson 2018-10-16  68  				  ret, oldval, uaddr, oparg);
b90edb33010bcf Jim Wilson 2018-10-16  69  		break;
b90edb33010bcf Jim Wilson 2018-10-16  70  	default:
b90edb33010bcf Jim Wilson 2018-10-16  71  		ret = -ENOSYS;
b90edb33010bcf Jim Wilson 2018-10-16  72  	}
b90edb33010bcf Jim Wilson 2018-10-16  73  
b90edb33010bcf Jim Wilson 2018-10-16  74  	if (!ret)
b90edb33010bcf Jim Wilson 2018-10-16  75  		*oval = oldval;
b90edb33010bcf Jim Wilson 2018-10-16  76  
b90edb33010bcf Jim Wilson 2018-10-16  77  	return ret;
b90edb33010bcf Jim Wilson 2018-10-16  78  }
b90edb33010bcf Jim Wilson 2018-10-16  79  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Jisheng Zhang Oct. 20, 2021, 2:03 p.m. UTC | #2 
On Mon, 18 Oct 2021 08:14:28 +0800
kernel test robot <lkp@intel.com> wrote:

> Hi Jisheng,
> 
> I love your patch! Yet something to improve:
> 
> [auto build test ERROR on linus/master]
> [also build test ERROR on v5.15-rc5 next-20211015]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
> 
> url:    https://github.com/0day-ci/linux/commits/Jisheng-Zhang/riscv-switch-to-relative-extable/20211017-001318
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 8fe31e0995f048d16b378b90926793a0aa4af1e5
> config: riscv-randconfig-r032-20211017 (attached as .config)
> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 746dd6a700931988dd9021d3d04718f1929885a5)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install riscv cross compiling tool for clang build
>         # apt-get install binutils-riscv64-linux-gnu
>         # https://github.com/0day-ci/linux/commit/23c273bf6ec4ca672a21dba701725087208dc784
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Jisheng-Zhang/riscv-switch-to-relative-extable/20211017-001318
>         git checkout 23c273bf6ec4ca672a21dba701725087208dc784
>         # save the attached .config to linux build tree
>         mkdir build_dir
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from kernel/futex.c:36:
>    In file included from include/linux/pagemap.h:11:
>    In file included from include/linux/highmem.h:10:
>    In file included from include/linux/hardirq.h:11:
>    In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:136:
>    include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __raw_readb(PCI_IOBASE + addr);
>                              ~~~~~~~~~~ ^
>    include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
>                                                            ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu'
>    #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
>                                                      ^
>    In file included from kernel/futex.c:36:
>    In file included from include/linux/pagemap.h:11:
>    In file included from include/linux/highmem.h:10:
>    In file included from include/linux/hardirq.h:11:
>    In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:136:
>    include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
>                                                            ~~~~~~~~~~ ^
>    include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu'
>    #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
>                                                      ^
>    In file included from kernel/futex.c:36:
>    In file included from include/linux/pagemap.h:11:
>    In file included from include/linux/highmem.h:10:
>    In file included from include/linux/hardirq.h:11:
>    In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
>    In file included from include/asm-generic/hardirq.h:17:
>    In file included from include/linux/irq.h:20:
>    In file included from include/linux/io.h:13:
>    In file included from arch/riscv/include/asm/io.h:136:
>    include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writeb(value, PCI_IOBASE + addr);
>                                ~~~~~~~~~~ ^

The warnings like this are not caused by this patch, they existed for a long
time since NOMMU is supported. But no good solution so far.

>    include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
>                                                          ~~~~~~~~~~ ^
>    include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
>                                                          ~~~~~~~~~~ ^
>    include/asm-generic/io.h:1024:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>            return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
>                                                      ~~~~~~~~~~ ^
>    In file included from kernel/futex.c:43:
> >> arch/riscv/include/asm/futex.h:51:3: error: expected ')'  
>                    __futex_atomic_op("amoswap.w.aqrl %[ov],%z[op],%[u]",
>                    ^
>    arch/riscv/include/asm/futex.h:33:3: note: expanded from macro '__futex_atomic_op'
>                    _ASM_EXTABLE(1b, 3b)                            \
>                    ^

Errors like this are caused by my patch, I missed NOMMU. Fixed in V2.


Thanks
diff mbox series

Patch

diff --git a/arch/riscv/include/asm/futex.h b/arch/riscv/include/asm/futex.h
index 1b00badb9f87..3191574e135c 100644
--- a/arch/riscv/include/asm/futex.h
+++ b/arch/riscv/include/asm/futex.h
@@ -30,10 +30,7 @@ 
 	"3:	li %[r],%[e]				\n"	\
 	"	jump 2b,%[t]				\n"	\
 	"	.previous				\n"	\
-	"	.section __ex_table,\"a\"		\n"	\
-	"	.balign " RISCV_SZPTR "			\n"	\
-	"	" RISCV_PTR " 1b, 3b			\n"	\
-	"	.previous				\n"	\
+		_ASM_EXTABLE(1b, 3b)				\
 	: [r] "+r" (ret), [ov] "=&r" (oldval),			\
 	  [u] "+m" (*uaddr), [t] "=&r" (tmp)			\
 	: [op] "Jr" (oparg), [e] "i" (-EFAULT)			\
@@ -103,11 +100,8 @@  futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 	"4:	li %[r],%[e]				\n"
 	"	jump 3b,%[t]				\n"
 	"	.previous				\n"
-	"	.section __ex_table,\"a\"		\n"
-	"	.balign " RISCV_SZPTR "			\n"
-	"	" RISCV_PTR " 1b, 4b			\n"
-	"	" RISCV_PTR " 2b, 4b			\n"
-	"	.previous				\n"
+		_ASM_EXTABLE(1b, 4b)			\
+		_ASM_EXTABLE(2b, 4b)			\
 	: [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr), [t] "=&r" (tmp)
 	: [ov] "Jr" (oldval), [nv] "Jr" (newval), [e] "i" (-EFAULT)
 	: "memory");
diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
index f314ff44c48d..5e4c9a5a17c5 100644
--- a/arch/riscv/include/asm/uaccess.h
+++ b/arch/riscv/include/asm/uaccess.h
@@ -47,6 +47,12 @@ 
 	likely(__access_ok((unsigned long __force)(addr), (size)));	\
 })
 
+#define _ASM_EXTABLE(from, to)						\
+	"	.pushsection	__ex_table, \"a\"\n"			\
+	"	.balign "	RISCV_SZPTR "	 \n"			\
+	"	" RISCV_PTR	"(" #from "), (" #to ")\n"		\
+	"	.popsection\n"
+
 /*
  * Ensure that the range [addr, addr+size) is within the process's
  * address space
@@ -93,10 +99,7 @@  do {								\
 		"	li %1, 0\n"				\
 		"	jump 2b, %2\n"				\
 		"	.previous\n"				\
-		"	.section __ex_table,\"a\"\n"		\
-		"	.balign " RISCV_SZPTR "\n"			\
-		"	" RISCV_PTR " 1b, 3b\n"			\
-		"	.previous"				\
+			_ASM_EXTABLE(1b, 3b)			\
 		: "+r" (err), "=&r" (__x), "=r" (__tmp)		\
 		: "m" (*(ptr)), "i" (-EFAULT));			\
 	(x) = __x;						\
@@ -125,11 +128,8 @@  do {								\
 		"	li %2, 0\n"				\
 		"	jump 3b, %3\n"				\
 		"	.previous\n"				\
-		"	.section __ex_table,\"a\"\n"		\
-		"	.balign " RISCV_SZPTR "\n"			\
-		"	" RISCV_PTR " 1b, 4b\n"			\
-		"	" RISCV_PTR " 2b, 4b\n"			\
-		"	.previous"				\
+			_ASM_EXTABLE(1b, 4b)			\
+			_ASM_EXTABLE(2b, 4b)			\
 		: "+r" (err), "=&r" (__lo), "=r" (__hi),	\
 			"=r" (__tmp)				\
 		: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]),	\
@@ -233,10 +233,7 @@  do {								\
 		"	li %0, %4\n"				\
 		"	jump 2b, %1\n"				\
 		"	.previous\n"				\
-		"	.section __ex_table,\"a\"\n"		\
-		"	.balign " RISCV_SZPTR "\n"			\
-		"	" RISCV_PTR " 1b, 3b\n"			\
-		"	.previous"				\
+			_ASM_EXTABLE(1b, 3b)			\
 		: "+r" (err), "=r" (__tmp), "=m" (*(ptr))	\
 		: "rJ" (__x), "i" (-EFAULT));			\
 } while (0)
@@ -262,11 +259,8 @@  do {								\
 		"	li %0, %6\n"				\
 		"	jump 3b, %1\n"				\
 		"	.previous\n"				\
-		"	.section __ex_table,\"a\"\n"		\
-		"	.balign " RISCV_SZPTR "\n"			\
-		"	" RISCV_PTR " 1b, 4b\n"			\
-		"	" RISCV_PTR " 2b, 4b\n"			\
-		"	.previous"				\
+			_ASM_EXTABLE(1b, 4b)			\
+			_ASM_EXTABLE(2b, 4b)			\
 		: "+r" (err), "=r" (__tmp),			\
 			"=m" (__ptr[__LSW]),			\
 			"=m" (__ptr[__MSW])			\
@@ -417,10 +411,7 @@  unsigned long __must_check clear_user(void __user *to, unsigned long n)
 		"	li %[err], %[efault]\n"			\
 		"	jump 1b, %[rc]\n"			\
 		".previous\n"					\
-		".section __ex_table,\"a\"\n"			\
-		".balign " RISCV_SZPTR "\n"			\
-		"	" RISCV_PTR " 1b, 2b\n"			\
-		".previous\n"					\
+		_ASM_EXTABLE(1b, 2b)				\
 			: [ret] "=&r" (__ret),			\
 			  [rc]  "=&r" (__rc),			\
 			  [ptr] "+A" (*__ptr),			\
@@ -443,10 +434,7 @@  unsigned long __must_check clear_user(void __user *to, unsigned long n)
 		"	li %[err], %[efault]\n"			\
 		"	jump 1b, %[rc]\n"			\
 		".previous\n"					\
-		".section __ex_table,\"a\"\n"			\
-		".balign " RISCV_SZPTR "\n"			\
-		"	" RISCV_PTR " 1b, 2b\n"			\
-		".previous\n"					\
+		_ASM_EXTABLE(1b, 2b)				\
 			: [ret] "=&r" (__ret),			\
 			  [rc]  "=&r" (__rc),			\
 			  [ptr] "+A" (*__ptr),			\