arm64: armv8_deprecated: ensure extension of addr
authorMark Rutland <mark.rutland@arm.com>
Wed, 3 May 2017 15:09:36 +0000 (16:09 +0100)
committerCatalin Marinas <catalin.marinas@arm.com>
Tue, 9 May 2017 16:47:05 +0000 (17:47 +0100)
commit55de49f9aa17b0b2b144dd2af587177b9aadf429
treeb2642413678ada5a4e3fceca50dd84b5ddf793d1
parenta06040d7a791a9177581dcf7293941bd92400856
arm64: armv8_deprecated: ensure extension of addr

Our compat swp emulation holds the compat user address in an unsigned
int, which it passes to __user_swpX_asm(). When a 32-bit value is passed
in a register, the upper 32 bits of the register are unknown, and we
must extend the value to 64 bits before we can use it as a base address.

This patch casts the address to unsigned long to ensure it has been
suitably extended, avoiding the potential issue, and silencing a related
warning from clang.

Fixes: bd35a4adc413 ("arm64: Port SWP/SWPB emulation support from arm")
Cc: <stable@vger.kernel.org> # 3.19.x-
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arch/arm64/kernel/armv8_deprecated.c