| Message ID | 15326847436103@kroah.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Patch "ARM: fix put_user() for gcc-8" has been added to the 4.4-stable tree | expand |
--- 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"); \
This is a note to let you know that I've just added the patch titled ARM: fix put_user() for gcc-8 to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm-fix-put_user-for-gcc-8.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@vger.kernel.org> know about it. From arnd@arndb.de Fri Jul 27 11:21:29 2018 From: Arnd Bergmann <arnd@arndb.de> Date: Thu, 26 Jul 2018 10:13:23 +0200 Subject: ARM: fix put_user() for gcc-8 To: stable@vger.kernel.org Cc: gregkh@linuxfoundation.org, Arnd Bergmann <arnd@arndb.de>, Russell King <linux@arm.linux.org.uk>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Message-ID: <20180726081358.3829157-2-arnd@arndb.de> 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(-) Patches currently in stable-queue which might be from arnd@arndb.de are queue-4.4/arm-fix-put_user-for-gcc-8.patch queue-4.4/turn-off-wattribute-alias.patch