4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Mark Rutland <[email protected]> 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") Acked-by: Will Deacon <[email protected]> Signed-off-by: Mark Rutland <[email protected]> Signed-off-by: Catalin Marinas <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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 @@ -309,7 +309,8 @@ static void __init register_insn_emulati ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \ CONFIG_ARM64_PAN) \ : "=&r" (res), "+r" (data), "=&r" (temp), "=&r" (temp2) \ - : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT), \ + : "r" ((unsigned long)addr), "i" (-EAGAIN), \ + "i" (-EFAULT), \ "i" (__SWP_LL_SC_LOOPS) \ : "memory")
