linux-kernel - [tip:x86/cpu] x86/CPU: Use correct macros for Cyrix calls

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Date:   Sat, 22 Sep 2018 02:57:52 -0700
From:   tip-bot for Matthew Whitehead <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     qianyue.zj@...baba-inc.com, mingo@...nel.org, tglx@...utronix.de,
        luto@...capital.net, hpa@...or.com, linux-kernel@...r.kernel.org,
        gregkh@...uxfoundation.org, bp@...e.de, pombredanne@...b.com,
        peterz@...radead.org, tedheadster@...il.com
Subject: [tip:x86/cpu] x86/CPU: Use correct macros for Cyrix calls

Commit-ID:  03b099bdcdf7125d4a63dc9ddeefdd454e05123d
Gitweb:     https://git.kernel.org/tip/03b099bdcdf7125d4a63dc9ddeefdd454e05123d
Author:     Matthew Whitehead <tedheadster@...il.com>
AuthorDate: Fri, 21 Sep 2018 17:20:40 -0400
Committer:  Borislav Petkov <bp@...e.de>
CommitDate: Sat, 22 Sep 2018 11:46:56 +0200

x86/CPU: Use correct macros for Cyrix calls

There are comments in processor-cyrix.h advising you to _not_ make calls
using the deprecated macros in this style:

  setCx86_old(CX86_CCR4, getCx86_old(CX86_CCR4) | 0x80);

This is because it expands the macro into a non-functioning calling
sequence. The calling order must be:

  outb(CX86_CCR2, 0x22);
  inb(0x23);

>From the comments:

 * When using the old macros a line like
 *   setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x88);
 * gets expanded to:
 *  do {
 *    outb((CX86_CCR2), 0x22);
 *    outb((({
 *        outb((CX86_CCR2), 0x22);
 *        inb(0x23);
 *    }) | 0x88), 0x23);
 *  } while (0);

The new macros fix this problem, so use them instead.

Signed-off-by: Matthew Whitehead <tedheadster@...il.com>
Signed-off-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Andy Lutomirski <luto@...capital.net>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Jia Zhang <qianyue.zj@...baba-inc.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Philippe Ombredanne <pombredanne@...b.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/20180921212041.13096-2-tedheadster@gmail.com
---
 arch/x86/kernel/cpu/cyrix.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/cyrix.c b/arch/x86/kernel/cpu/cyrix.c
index 8949b7ae6d92..d12226f60168 100644
--- a/arch/x86/kernel/cpu/cyrix.c
+++ b/arch/x86/kernel/cpu/cyrix.c
@@ -437,7 +437,7 @@ static void cyrix_identify(struct cpuinfo_x86 *c)
 			/* enable MAPEN  */
 			setCx86(CX86_CCR3, (ccr3 & 0x0f) | 0x10);
 			/* enable cpuid  */
-			setCx86_old(CX86_CCR4, getCx86_old(CX86_CCR4) | 0x80);
+			setCx86(CX86_CCR4, getCx86(CX86_CCR4) | 0x80);
 			/* disable MAPEN */
 			setCx86(CX86_CCR3, ccr3);
 			local_irq_restore(flags);