linux-kernel - [patch] x86/apic/uv: silence a shift wrapping warning

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Message-ID: <20161123221908.GA23997@mwanda>
Date:   Thu, 24 Nov 2016 01:19:08 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Thomas Gleixner <tglx@...utronix.de>, Mike Travis <travis@....com>
Cc:     Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>,
        x86@...nel.org, Dimitri Sivanich <sivanich@....com>,
        Nathan Zimmer <nzimmer@....com>,
        Alex Thorlton <athorlton@....com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [patch] x86/apic/uv: silence a shift wrapping warning

m_io is stored in 6 bits so it's a number in the 0-63 range.  Static
analysis tools complain that 1 << 63 will wrap so I have changed it to
1ULL << m_io.

This code is over three years old so presumably the bug doesn't happen
very frequently in real life or someone would have complained by now.

Fixes: b15cc4a12bed ("x86, uv, uv3: Update x2apic Support for SGI UV3")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
Please review this one, carefully because I'm not positive about it.

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index aeef53c..35690a1 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -815,9 +815,9 @@ static __init void map_mmioh_high_uv3(int index, int min_pnode, int max_pnode)
 				l = li;
 			}
 			addr1 = (base << shift) +
-				f * (unsigned long)(1 << m_io);
+				f * (1ULL << m_io);
 			addr2 = (base << shift) +
-				(l + 1) * (unsigned long)(1 << m_io);
+				(l + 1) * (1ULL << m_io);
 			pr_info("UV: %s[%03d..%03d] NASID 0x%04x ADDR 0x%016lx - 0x%016lx\n",
 				id, fi, li, lnasid, addr1, addr2);
 			if (max_io < l)