The xfeature mask is 64bit so a shift from a number to its mask should have LL prefix or else nr > 31 will be lost. This is not a problem now but should XFEATURE_MASK_SUPERVISOR gain a bit >31 then this check won't catch it.
Use BIT_ULL() to compute a mask from a number. Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- arch/x86/kernel/fpu/xstate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 87a57b7642d36..69d5740ed2546 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -444,7 +444,7 @@ static int xfeature_uncompacted_offset(int xfeature_nr) * format. Checking a supervisor state's uncompacted offset is * an error. */ - if (XFEATURE_MASK_SUPERVISOR & (1 << xfeature_nr)) { + if (XFEATURE_MASK_SUPERVISOR & BIT_ULL(xfeature_nr)) { WARN_ONCE(1, "No fixed offset for xstate %d\n", xfeature_nr); return -1; } -- 2.20.0.rc1
