4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mark Rutland <mark.rutland@xxxxxxx>
commit 55de49f9aa17b0b2b144dd2af587177b9aadf429 upstream.
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@xxxxxxxxxxxxxxx> # 3.19.x-
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/armv8_deprecated.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/arm64/kernel/armv8_deprecated.c
+++ b/arch/arm64/kernel/armv8_deprecated.c
@@ -305,7 +305,8 @@ static void register_insn_emulation_sysc
ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \
CONFIG_ARM64_PAN) \
: "=&r" (res), "+r" (data), "=&r" (temp) \
- : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT) \
+ : "r" ((unsigned long)addr), "i" (-EAGAIN), \
+ "i" (-EFAULT) \
: "memory")
#define __user_swp_asm(data, addr, res, temp) \