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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 10/15] powerpc/uaccess: Remove calls to __get_user_bad() and __put_user_bad()
Date: Wed, 10 Mar 2021 17:46:49 +0000 (UTC)	[thread overview]
Message-ID: <d7d839e994f49fae4ff7b70fac72bd951272436b.1615398265.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1615398265.git.christophe.leroy@csgroup.eu>

__get_user_bad() and __put_user_bad() are functions that are
declared but not defined, in order to make the link fail in
case they are called.

Nowadays, we have BUILD_BUG() and BUILD_BUG_ON() for that, and
they have the advantage to break the build earlier as it breaks
it at compile time instead of link time.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/include/asm/uaccess.h | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index a9f2639ca3a8..a8c683695ec7 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -53,8 +53,6 @@ static inline bool __access_ok(unsigned long addr, unsigned long size)
 #define __put_user(x, ptr) \
 	__put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 
-extern long __put_user_bad(void);
-
 #define __put_user_size(x, ptr, size, retval)			\
 do {								\
 	__label__ __pu_failed;					\
@@ -136,12 +134,10 @@ do {								\
 	case 2: __put_user_asm_goto(x, __pus_addr, label, "sth"); break;	\
 	case 4: __put_user_asm_goto(x, __pus_addr, label, "stw"); break;	\
 	case 8: __put_user_asm2_goto(x, __pus_addr, label); break;		\
-	default: __put_user_bad();				\
+	default: BUILD_BUG();					\
 	}							\
 } while (0)
 
-extern long __get_user_bad(void);
-
 /*
  * This does an atomic 128 byte aligned load from userspace.
  * Upto caller to do enable_kernel_vmx() before calling!
@@ -196,14 +192,13 @@ extern long __get_user_bad(void);
 #define __get_user_size_allowed(x, ptr, size, retval)		\
 do {								\
 	retval = 0;						\
-	if (size > sizeof(x))					\
-		(x) = __get_user_bad();				\
+	BUILD_BUG_ON(size > sizeof(x));				\
 	switch (size) {						\
 	case 1: __get_user_asm(x, (u8 __user *)ptr, retval, "lbz"); break;	\
 	case 2: __get_user_asm(x, (u16 __user *)ptr, retval, "lhz"); break;	\
 	case 4: __get_user_asm(x, (u32 __user *)ptr, retval, "lwz"); break;	\
 	case 8: __get_user_asm2(x, (u64 __user *)ptr, retval);  break;	\
-	default: (x) = __get_user_bad();			\
+	default: BUILD_BUG();					\
 	}							\
 } while (0)
 
-- 
2.25.0


  parent reply	other threads:[~2021-03-10 17:50 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-10 17:46 [PATCH v2 00/15] powerpc: Cleanup of uaccess.h and adding asm goto for get_user() Christophe Leroy
2021-03-10 17:46 ` [PATCH v2 01/15] powerpc/uaccess: Remove __get_user_allowed() and unsafe_op_wrap() Christophe Leroy
2021-03-10 21:47   ` Daniel Axtens
2021-03-10 17:46 ` [PATCH v2 02/15] powerpc/uaccess: Define ___get_user_instr() for ppc32 Christophe Leroy
2021-03-10 17:46 ` [PATCH v2 03/15] powerpc/align: Convert emulate_spe() to user_access_begin Christophe Leroy
2021-03-10 22:31   ` Daniel Axtens
2021-03-11  5:45     ` Christophe Leroy
2021-03-12 13:25   ` [PATCH v3 " Christophe Leroy
2021-04-10 14:28     ` Michael Ellerman
2021-03-10 17:46 ` [PATCH v2 04/15] powerpc/uaccess: Remove __get/put_user_inatomic() Christophe Leroy
2021-03-10 22:37   ` Daniel Axtens
2021-03-10 17:46 ` [PATCH v2 05/15] powerpc/uaccess: Move get_user_instr helpers in asm/inst.h Christophe Leroy
2021-03-25 21:59   ` Daniel Axtens
2021-03-10 17:46 ` [PATCH v2 06/15] powerpc/align: Don't use __get_user_instr() on kernel addresses Christophe Leroy
2021-03-25 22:12   ` Daniel Axtens
2021-03-10 17:46 ` [PATCH v2 07/15] powerpc/uaccess: Call might_fault() inconditionaly Christophe Leroy
2021-03-25 22:38   ` Daniel Axtens
2021-03-25 22:44     ` Daniel Axtens
2021-03-10 17:46 ` [PATCH v2 08/15] powerpc/uaccess: Remove __unsafe_put_user_goto() Christophe Leroy
2021-03-10 17:46 ` [PATCH v2 09/15] powerpc/uaccess: Remove __chk_user_ptr() in __get/put_user Christophe Leroy
2021-03-10 17:46 ` Christophe Leroy [this message]
2021-03-10 17:46 ` [PATCH v2 11/15] powerpc/uaccess: Split out __get_user_nocheck() Christophe Leroy
2021-03-10 17:46 ` [PATCH v2 12/15] powerpc/uaccess: Rename __get/put_user_check/nocheck Christophe Leroy
2021-03-10 17:46 ` [PATCH v2 13/15] powerpc/uaccess: Refactor get/put_user() and __get/put_user() Christophe Leroy
2021-03-10 17:46 ` [PATCH v2 14/15] powerpc/uaccess: Introduce __get_user_size_goto() Christophe Leroy
2021-03-10 17:46 ` [PATCH v2 15/15] powerpc/uaccess: Use asm goto for get_user when compiler supports it Christophe Leroy
2021-04-10 14:28 ` [PATCH v2 00/15] powerpc: Cleanup of uaccess.h and adding asm goto for get_user() Michael Ellerman

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