linux-kernel - Re: [GIT PULL] x86/platform updates for v5.10

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Date:   Mon, 12 Oct 2020 23:56:42 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Mike Travis <mike.travis@....com>, x86-ml <x86@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [GIT PULL] x86/platform updates for v5.10

On Mon, Oct 12, 2020 at 02:46:10PM -0700, Linus Torvalds wrote:
> At least "git grep" only shows two assignments to it.
> 
> Of course, that would miss any cases that play games with preprocessor
> token pasting etc, so it's not entirely meaningful, but it's certainly
> a hint..

>From a quick staring at gcc asm, it looks write only. And gcc didn't
warn because it optimized that assignment away completely AFAICT.

> And yes, I expect that the fix is to just make it "unsigned long", but
> if it truly isn't actually used, maybe removal is better.

Yeah, below is a proper patch which builds fine with gcc and clang-10.
You guys have fun - I'm going to bed. :-)

---
From: Mike Travis <mike.travis@....com>
Date: Mon, 12 Oct 2020 23:46:34 +0200
Subject: [PATCH] x86/platform/uv: Correct uvh_nmi_mmrx_mask's type

Clang rightfully warns:

  arch/x86/platform/uv/uv_nmi.c:250:23: warning: implicit conversion
  from 'unsigned long' to 'int' changes value from 1152921504606846976
  to 0 [-Wconstant-conversion]
                  uvh_nmi_mmrx_mask = UVH_EVENT_OCCURRED0_EXTIO_INT0_MASK;
                                  ~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Make the variable unsigned long.

 [ bp: Productize it. ]

Signed-off-by: Mike Travis <mike.travis@....com>
Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/platform/uv/uv_nmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c
index 0f5cbcf0da63..8566730f154d 100644
--- a/arch/x86/platform/uv/uv_nmi.c
+++ b/arch/x86/platform/uv/uv_nmi.c
@@ -59,7 +59,7 @@ DEFINE_PER_CPU(struct uv_cpu_nmi_s, uv_cpu_nmi);
 static unsigned long uvh_nmi_mmrx;		/* UVH_EVENT_OCCURRED0/1 */
 static unsigned long uvh_nmi_mmrx_clear;	/* UVH_EVENT_OCCURRED0/1_ALIAS */
 static int uvh_nmi_mmrx_shift;			/* UVH_EVENT_OCCURRED0/1_EXTIO_INT0_SHFT */
-static int uvh_nmi_mmrx_mask;			/* UVH_EVENT_OCCURRED0/1_EXTIO_INT0_MASK */
+static unsigned long uvh_nmi_mmrx_mask;			/* UVH_EVENT_OCCURRED0/1_EXTIO_INT0_MASK */
 static char *uvh_nmi_mmrx_type;			/* "EXTIO_INT0" */
 
 /* Non-zero indicates newer SMM NMI handler present */
-- 
2.21.0

-- 
Regards/Gruss,
    Boris.

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