linux-kernel - [PATCH 01/29] x86/fpu: Use ULL for shift in xfeature_uncompacted

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Message-Id: <20181128222035.2996-2-bigeasy@linutronix.de>
Date:   Wed, 28 Nov 2018 23:20:07 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     linux-kernel@...r.kernel.org
Cc:     x86@...nel.org, Andy Lutomirski <luto@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        kvm@...r.kernel.org, "Jason A. Donenfeld" <Jason@...c4.com>,
        Rik van Riel <riel@...riel.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH 01/29] x86/fpu: Use ULL for shift in xfeature_uncompacted_offset()

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 <bigeasy@...utronix.de>
---
 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