commit 55e15b2f44d7f7d9350b70890b0e39a8ee713504
author James Morse <james.morse@arm.com> Tue Feb 02 15:53:59 2016 +0000
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Thu Dec 15 08:49:23 2016 -0800
tree 74232e98afcd9f41a420bc8f87dd2c9d024914ff
parent e29949ed3903930e38dead204b01e7912c98fe33

arm64: futex.h: Add missing PAN toggling

commit 811d61e384e24759372bb3f01772f3744b0a8327 upstream.

futex.h's futex_atomic_cmpxchg_inatomic() does not use the
__futex_atomic_op() macro and needs its own PAN toggling. This was missed
when the feature was implemented.

Fixes: 338d4f49d6f ("arm64: kernel: Add support for Privileged Access Never")
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm64/include/asm/futex.h

diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h
index 007a69f..5f3ab8c 100644
--- a/arch/arm64/include/asm/futex.h
+++ b/arch/arm64/include/asm/futex.h
@@ -121,6 +121,7 @@
 		return -EFAULT;
 
 	asm volatile("// futex_atomic_cmpxchg_inatomic\n"
+ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
 "	prfm	pstl1strm, %2\n"
 "1:	ldxr	%w1, %2\n"
 "	sub	%w3, %w1, %w4\n"
@@ -137,6 +138,7 @@
 "	.align	3\n"
 "	.quad	1b, 4b, 2b, 4b\n"
 "	.popsection\n"
+ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
 	: "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp)
 	: "r" (oldval), "r" (newval), "Ir" (-EFAULT)
 	: "memory");