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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Bernd Edlinger <bernd.edlinger@hotmail.de>,
	Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH 4.4 23/23] ARM: fix put_user() for gcc-8
Date: Fri, 27 Jul 2018 12:09:24 +0200	[thread overview]
Message-ID: <20180727100846.050436889@linuxfoundation.org> (raw)
In-Reply-To: <20180727100845.054377089@linuxfoundation.org>

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@arndb.de>

Building kernels before linux-4.7 with gcc-8 results in many build failures
when gcc triggers a check that was meant to catch broken compilers:

/tmp/ccCGMQmS.s:648: Error: .err encountered

According to the discussion in the gcc bugzilla, a local "register
asm()" variable is still supposed to be the correct way to force an
inline assembly to use a particular register, but marking it 'const'
lets the compiler do optimizations that break that, i.e the compiler is
free to treat the variable as either 'const' or 'register' in that case.

Upstream commit 9f73bd8bb445 ("ARM: uaccess: remove put_user() code
duplication") fixed this problem in linux-4.8 as part of a larger change,
but seems a little too big to be backported to 4.4.

Let's take the simplest fix and change only the one broken line in the
same way as newer kernels.

Suggested-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85745
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86673
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm/include/asm/uaccess.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -251,7 +251,7 @@ extern int __put_user_8(void *, unsigned
 	({								\
 		unsigned long __limit = current_thread_info()->addr_limit - 1; \
 		const typeof(*(p)) __user *__tmp_p = (p);		\
-		register const typeof(*(p)) __r2 asm("r2") = (x);	\
+		register typeof(*(p)) __r2 asm("r2") = (x);	\
 		register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \
 		register unsigned long __l asm("r1") = __limit;		\
 		register int __e asm("r0");				\



  parent reply	other threads:[~2018-07-27 10:12 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-27 10:09 [PATCH 4.4 00/23] 4.4.145-stable review Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 01/23] MIPS: ath79: fix register address in ath79_ddr_wb_flush() Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 02/23] ip: hash fragments consistently Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 03/23] net/mlx4_core: Save the qpn from the input modifier in RST2INIT wrapper Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 04/23] rtnetlink: add rtnl_link_state check in rtnl_configure_link Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 05/23] tcp: fix dctcp delayed ACK schedule Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 06/23] tcp: helpers to send special DCTCP ack Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 07/23] tcp: do not cancel delay-AcK on DCTCP special ACK Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 08/23] tcp: do not delay ACK in DCTCP upon CE status change Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 09/23] tcp: avoid collapses in tcp_prune_queue() if possible Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 10/23] tcp: detect malicious patterns in tcp_collapse_ofo_queue() Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 11/23] ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 12/23] usb: cdc_acm: Add quirk for Castles VEGA3000 Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 13/23] usb: core: handle hub C_PORT_OVER_CURRENT condition Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 14/23] usb: gadget: f_fs: Only return delayed status when len is 0 Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 15/23] driver core: Partially revert "driver core: correct devices shutdown order" Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 16/23] can: xilinx_can: fix RX loop if RXNEMP is asserted without RXOK Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 17/23] can: xilinx_can: fix recovery from error states not being propagated Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 18/23] can: xilinx_can: fix device dropping off bus on RX overrun Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 19/23] can: xilinx_can: keep only 1-2 frames in TX FIFO to fix TX accounting Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 20/23] can: xilinx_can: fix incorrect clear of non-processed interrupts Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 21/23] can: xilinx_can: fix RX overflow interrupt not being enabled Greg Kroah-Hartman
2018-07-27 10:09 ` [PATCH 4.4 22/23] turn off -Wattribute-alias Greg Kroah-Hartman
2018-07-27 10:09 ` Greg Kroah-Hartman [this message]
2018-07-27 12:22 ` [PATCH 4.4 00/23] 4.4.145-stable review Nathan Chancellor
2018-07-27 17:28 ` Guenter Roeck
2018-07-27 20:06 ` Shuah Khan
2018-07-28  6:55 ` Naresh Kamboju

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